04. Purulent-inflammatory diseases of bones, joints and soft tissue

TOPIC No.4 Purulent-inflammatory diseases bones joints AND soft tissue

 

Plan:

1.                Purulent-inflammatory disease of bones and joints:

             1.1 Acute and chronic osteomyelitis.

2.                Purulent-inflammatory disease of soft tissue:

2.1                      Neonatal phlegmon.

2.2                      Neonatal omphalitis.

2.3                      Mastitis.

     2.4 Perianal and Perirectal Abscess.

 

 

1. Purulent-inflammatory disease of bones and joints:

1.1. Acute chronic osteomyelitis.

 

Haematogenous Osteomyelitis

Haematogenous osteomyelitis (HO) is a common and devastating problem for children in less developed areas of the world1 due to its frequent association with sickle cell disease (23–44%), delayed presentation, misdiagnosis, and undertreatment.1–5 Sixty to eighty percent of children do not initially present until they have reached the stage of chronic osteomyelitis.1–4 In more medically advanced areas, the spectrum of HO has changed significantly in the past few decades with decreased prevalence, earlier presentation, better nourished children, increased awareness of HO, improved diagnostic modalities for confirmation, precise laboratory techniques for microbial identification, and advanced antimicrobial agents for successful eradication of the infection. In locations without advanced technology (LWATs), however, little has changed in the past half century in the presentation or management of children with HO. Most children in advanced areas undergo successful nonoperative eradication of HO, many with nothing more invasive than a blood  culture or bone aspiration.6–8 Most current Western literature concerning HO—which concentrates on whether diagnostic aspiration of the bone marrow is really necessary and whether one powerful antibiotic is better than another in the eradication of HO—therefore has little relevance to practitioners in LWATs who are fortunate if they have materials for a gram stain and enough antibiotics for a week of oral treatment before the family runs out of funds. The purpose of this chapter is to provide a functional and practical approach to the classification and treatment of HO in children, taking into consideration the economic and technologic restraints that are inherent in any medical practice in LWATs.

Demographics

The exact incidence of osteomyelitis in Africa is unknown, but in reported series, children with osteomyelitis represent 7–20% of hospitalised children.1–-3 Data from the United Kingdom have shown an annual incidence of 2.9 per 100,000,9 with boys affected more than girls, and half of osteomyelitis cases occurring in the first 5 years of life. In Africa, 56% of affected children are between 8 and 11 years of age.1 In Cote d’Ivoire, the median age is 7.2 years.2

Aetiology/Pathology

Haematogenous osteomyelitis begins with entry of bacteria through a break in the skin or mucosa from otitis, pharyngitis, respiratory tract infections, or urinary tract infections. Most often the bacteria are Staphylococcus, but in sickle-cell children, both Salmonella and Staphylococcus are implicated. The bacteria are haematogenously disseminated and deposited in the trabecular bone or marrow, usually in the metaphysis of the proximal tibia or distal femur (Figure 22.1(A)).

Sluggish blood flow in the metaphysis provides an ideal milieu for bacterial replication. Increasing pressure from the progressive, intramedullary purulent process results in destruction of the endosteal blood supply to the cortex. The pus under pressure escapes outward through Volkmann and Haversian canals (Figure 22.1(B)) and then spreads subperiosteally, stripping the cortex of its periosteal blood supply (Figure 22.1(C)). Without either endosteal or periosteal blood supply, the cortex becomes nonviable bone called sequestrum (Figure 22.1(D)). As the exudate increases in volume, it takes the path of least resistance. Sometimes, this involves circumferential stripping of the periosteum from one metaphysis to the other, resulting in a giant sequestrum consisting of the diaphysis and both metaphyses. At other times, the periosteum perforates under pressure, resulting in the spread of pus into muscles and along fascial planes. At this point, it is often confused with primary pyomyositis, and the bony origin is overlooked, resulting in inadequate decompression of the medullary canal. As the devascularised cortex is being absorbed, the inner surface of the periosteum produces new bone, called involucrum.

The multiple areas of subperiosteal involucrum formation coalesce to form new bone on the inner surface of the periosteum but on the outside of the sequestrum. If the sequestrum totally resorbs, the patient may recover without a problem, but this rarely occurs. The nonviable, unresorbed sequestrum usually serves as a nidus for recurrent abscesses or chronically draining sinuses.

Figure 22.1: Pathologic development of haematogenous osteomyelitis.

Osteomyelitis, or inflammation of the bone, usually is caused by bacterial infection. Bone infections in children are primarily of hematogenous origin, although cases secondary to penetrating trauma, surgery, or infection in a contiguous site also are seen.

Pathophysiology. In children through the age of puberty the long bones of the extremities are most often involved with the metaphysis as the initial infected site. In adults hematogenous osteomyelitis most often affects the spine. This age-dependent preference for bone relates to the vasculature and blood flow to the site. In children, the metaphysis is very active metabolic tissue with a large blood flow and with vasculature predisposed to infection. Phagocytes lining the capillaries in this region are deficient iumber and function. The nutrient arteries near the epiphyseal cartilage are nonanastomosing, thereby allowing any blockage to produce tissue necrosis and the sinusoids (venous side of capillary) have slow, turbulent flow predisposing to thrombosis. As aging occurs metaphysis metabolism slows down, blood flow decreases and phagocytic activity increases.

The host responds to the presence of bacteria in the metaphysis with a local increase in vascular permeability, resulting in edema, increased vascularity and the influx of polymorphonuclear leukocytes. Pressure increases as pus collects and is confined within rigid bone. Exudation through Volkmann’s canals and the haversian canal affords little relief, although the relatively inelastic periosteum may become elevated. The blood supply to the area of involvement is decreased secondary to the pressure; necrosis of the infected bone may result in the formation of a sequestrum. A protein-rich liquid containing inflammatory cells may collect in an adjacent joint but such effusions are sterile.

Bacterial causes of acute hematogenous osteomyelitis:

§           Newborns (younger than 4 mo): S aureus, Enterobacter species, and group A and B Streptococcus species;

§           Children (aged 4 mo to 4 y): S aureus, group A Streptococcus species, Haemophilus influenzae, and Enterobacter species;

§           Children, adolescents (aged 4 y to adult): S aureus (80%), group A Streptococcus species, H influenzae, and Enterobacter species;

§           Adult: S aureus and occasionally Enterobacter or Streptococcus species

Fig. Neonatal osteomyelitis due to Proteus mirabilis infection. Although Staphylococcus aureus is the most common etiologic agent of osteomyelitis in the neonate, many other organisms such as group B Streptococcus, E. coli, Klebsiella, Salmonella and Candida have been implicated.

Classification.

Traditionally, the stages of HO have been described as: (1) acute, (2) chronic, and (3) subacute. This traditional classification, however, is not very practical for use in LWATs. As a result, African practitioners have developed alternative classification systems.10–11 The classification system shown in Table 22.1 was developed in a Nigerian general medical practice hospital in 1993.12

This simplified and functional system classifies children at the time of initial diagnosis of HO into one of four stages based on symptoms, signs, and x-ray findings. In stage 1 HO (acute), there is pus in the medullary canal and perhaps subperiosteally. There are usually local and systemic signs, but no significant x-ray changes that would demonstrate bone destruction or the presence of sequestra. Bone destruction and sequestra formation do not usually result in significant x-ray changes for at least 2 weeks into the HO process. Therefore, stage 2 HO (acute with x-ray changes) begins around 2 weeks into the process and indicates that significant bone destruction has already taken place. Children with stage 3 HO (chronic localised) have usually suffered an acute bout of HO that has drained spontaneously or has been operatively drained at a health care facility. However the sequestrum, which has not resorbed nor been surgically removed, serves as a nidus for chronic draining sinuses or recurrent abscesses (Figure 22.2).

If a significant abscess occurs around the sequestrum and does not spontaneously drain, the child becomes systemically septic and reaches stage 4 HO (chronic systemic). This Nigerian staging system will be used throughout this chapter due to its practicality in areas with limited diagnostic and therapeutic resources.Because osteomyelitis is a complex disease state, various classification systems have emerged beyond the general categories of acute, subacute and chronic. The Waldvogel classification system divides osteomyelitis into the categories of hematogenous, contiguous and chronic. The more recent Cierny-Mader staging system is based on the status of the disease process, not etiology, chronicity or other factors. The terms “acute” and “chronic” are not used in the Cierny-Mader system. The stages in this system are dynamic and may be altered by changes in the medical condition of the patient (host), successful antibiotic therapy and other treatments.

Table 22.1: Classification and treatment system for haematogenous osteomyelitis in developing world children.

Classification of acute hematogenous osteomyelitis by clinical pictures:

Ø    Toxic (adynamic) type

Ø    Septico-pyemic type

Ø    Local

Classification of AHO by localization

Ø    Epiphyseal

Ø    Metaphyseal

Ø    Diaphyseal

Ø    Metadiaphyseal

Ø    Pelvic

Ø    Other localization

 

Fig. Osteomyelitis usually occurs in the long bones,but in the neonate frequently occurs in other bones such as the clavicle and ribs. This infant demonstrates inflammation and swelling over the right clavicle due to a staphylococcal osteomyelitis.

 

 

Fig. Severe scalp defect occurring as a result of an underlying staphylococcal osteomyelitis of the skull.

 

Figure 22.2: Neglected HO resulting in (A) chronic draining sinuses secondary to (B) a large sequestrum

 

Frequency. The overall prevalence is 1 per 5,000 children. Neonatal prevalence is approximately 1 per 1,000.

Age. Acute hematogenous osteomyelitis is primarily a disease in children. Approximately 50% of cases occur in preschool-aged children. Direct trauma and contiguous focus osteomyelitis are more common among adults and adolescents than in children.

Sex. Predominance in males is observed in all age groups.

Clinical manifestations. Acute hematogenous osteomyelitis is often preceded by the signs and symptoms of bacteremia: fever, inflammation, malaise, cephalgia, myalgia, anorexia. This phase of the illness may last for several days.

The second phase of the disease is the clinical onset of involvement of bone. This gives rise to: restricted motion, pseudoparalysis, soft tissue around the inflamed bone which is, hyperemic, warm, edematous, tender, bone tenderness .

Lab Studies. The WBC count may be elevated, but it frequently is normal. A leftward shift is common with increased polymorphonuclear leukocyte counts.

The C-reactive protein level usually is elevated and nonspecific; it may be more useful than the erythrocyte sedimentation rate.

The erythrocyte sedimentation rate usually is elevated (90%); this finding is clinically nonspecific.

Imaging Studies.

Radiograph. X-ray evidence of acute osteomyelitis first is suggested by overlying soft-tissue edema at 3-5 days after infection. Bony changes are not evident for 14-21 days and initially manifest as periosteal elevation followed by cortical or medullary lucencies. Approximately 40-50% focal bone loss is necessary to cause detectable lucency on plain films.

 

Magnetic resonance imaging (MRI) can be extremely helpful in unclear situations. This imaging modality is particularly useful when a patient is suspected of having osteomyelitis, discitis or septic arthritis involving the axial skeleton and pelvis.

Ultrasonography and computed tomographic (CT) scanning may be helpful in the evaluation of suspected osteomyelitis. An ultrasound examination can detect fluid collections (e.g., an abscess) and surface abnormalities of bone (e.g., periostitis), whereas the CT scan can reveal small areas of osteolysis in cortical bone, small foci of gas and minute foreign bodies.

Histopathologic and microbiologic examination of bone is the gold standard for diagnosing osteomyelitis. Cultures of sinus tract samples are not reliable for identifying causative organisms. Therefore, biopsy is advocated to determine the etiology of osteomyelitis. However, the accuracy of biopsy is often limited by lack of uniform specimen collection and previous antibiotic use.

Features of neonatal osteomyelitis

S aureus, enteric gram-negative bacilli (eg, Escherichia coli, Klebsiella species), and group B streptococci are common pathogens.

IV sites, scalp electrodes, and puncture wounds are often predisposing factors. Diagnosis may be delayed because swelling and erythema may not be evident at onset.

Decreased movement (pseudoparalysis) of the affected area may be the only symptom. As many as 50% of affected newborns may have multiple bone involvement. Associated arthritis also is common.

 

Unlike radiographic findings in older children, plain radiographs of newborns often have a lytic area at the time of diagnosis.

A significant number of patients develop permanent sequelae due to involvement of the adjacent joint and damage to the cartilaginous growth plate.

Treatment.

Medical care. Osteomyelitis rarely requires emergent stabilization or resuscitation. The primary treatment for osteomyelitis is parenteral antibiotics that penetrate bone and joint cavities.

Optimal antibiotic selection, adequate dose regimen, and a sufficiently prolonged antibiotic course are essential. Initiate antibiotic treatment promptly, preferably after obtaining blood and bone aspirates for culture. Initially, select one or more antimicrobial agents that provide adequate coverage for common pathogens.

Even though Haemophilus influenzae type b (Hib) disease has virtually disappeared from the Hib-immune population, third-generation cephalosporins (eg, cefotaxime, ceftriaxone) are used, in addition to nafcillin or clindamycin. This additional treatment is used commonly in children younger than 3 years. Do not use third-generation cephalosporins alone to treat osteomyelitis, as they are not optimal for treating serious S aureus infections.

Cefuroxime, a second-generation cephalosporin, can be used as a single agent against both S aureus and Hib.

Increasing incidence of penicillin-resistant S pneumoniae warrants the use of a clindamycin and cefotaxime/ceftriaxone combination in infants and children.

When treating neonatal osteomyelitis, consider nafcillin and tobramycin or nafcillin and cefotaxime combinations to provide coverage of bacteria from Enterobacteriaceae family, in addition to group B streptococci and S aureus.

Consider vancomycin as an alternative to clindamycin for empiric therapy in patients living in communities where there is a higher incidence of penicillin resistant S pneumoniae or community-acquired methicillin-resistant S aureus.

For successful treatment, ensure that high-dose antimicrobials are used for an optimal period and provide close follow-up care for the patient. When antibiotics are used for fewer than 3 weeks, recurrence rates are higher.

In a patient who is otherwise asymptomatic after at least 4 weeks of antibiotics, ensure that ESR is within the reference range before discontinuing antibiotics.

Sequential IV to oral antibiotic regimens have proven safe and effective for treatment of bone and joint infections. Once symptoms and signs of inflammation have subsided and the ESR has started to fall, consider switching to oral antibiotics.

In older children, it often is not possible to give higher oral dosages of antibiotics because they exceed the maximum allowable doses.

Provide close follow-up care for the patient throughout treatment with weekly sedimentation rates and CBCs to monitor response and diagnose antibiotic-related neutropenia.

Surgical Care. Bone aspiration may be necessary to identify the pathogen. Consider bone biopsy if other diagnoses are possible (eg, tumors). The patient may require repeat aspiration of the bone if fever, pain, and swelling fail to respond promptly, or if radiographs demonstrate significant periosteal elevation or periosteal abscess. Joint aspiration is recommended if signs and symptoms point toward pathology near shoulder or hip joints. This is critical, as arthrotomy is indicated if evidence of hip or shoulder arthritis is present. If signs and symptoms do not resolve within 48-72 hours of initiation of appropriate antimicrobial treatment, consider repeat bone aspiration to drain the pus.

Drainage: If there is an open wound or abscess, it may be drained through a procedure called needle aspiration. In this procedure, a needle is inserted into the infected area and the fluid is withdrawn. Deep aspirations or biopsy is much preferred in contrast to often-unreliable surface swabs.

 

Splinting or cast immobilization: This may be necessary to immobilize the affected bone and nearby joints in order to avoid further trauma and to help the area heal adequately and as quickly as possible. Splinting and cast immobilization are frequently done in children. However, eventually early motion of joints after initial control is important to prevent stiffness and atrophy.

 

 

Operative Techniques

This section considers in more detail the operative techniques used in the treatment of all stages of HO. An optimal basic instrument tray consists of the following instruments: soft tissue basic instruments (haemostat, scalpel, tissue forceps, needle holder, scissors); soft tissue retractors (self-retaining Gelpis are ideal); periosteal elevator; bone curette; bone rongeur; and bone drill. True orthopaedic bone drills are very expensive and justification of the cost is difficult for hospitals in LWATs. However, simple carpenter drills and bits can be used for orthopaedic purposes if proper sterilisation capabilities (ethylene oxide or formalin gas) are available. Cordless electric drills, commercially available in hardware stores, are relatively inexpensive and also can be effectively used for orthopaedic procedures if properly sterilised. They must, however, be used on a low speed because a high-speed mode will burn the bone. An orthopaedic exposure book13 is a valuable asset in determining the safest approach for draining and debriding bones affected by HO. The cost of such books is prohibitive in most LWATs, however, and a basic anatomy book can be substituted to determine appropriate approaches to bones and joints in the least potentially destructive manner. The low-cost Primary Surgery textbook14 presents good exposure techniques for the more commonly affected bones and joints. Ketamine anaesthesia is a very effective and safe technique in the operative management of children with HO in LWATs.15 Using an extremity tourniquet significantly decreases the operative blood loss, but tourniquets should not be used in children with SS or SC haemoglobinopathies because this may precipitate a sickling crisis.

Treatment of acute HO (stages 1 and 2) begins with the soft tissue approach to the bone. The recommended approach to the proximal tibia (the most commonly affected bone) is from the medial or lateral aspect of the tibia so that there will be soft tissue remaining to cover the affected bone. For the health care provider unaccustomed to approaching the tibia in this manner, however, it is acceptable to incise the soft tissue directly over the tibia with as small a soft tissue incision as necessary. Usually the periosteum has already been elevated from the bone and needs to be incised longitudinally to drain the pusunder pressure. If microbiological techniques (gram stain, culture) are available, a sample is taken. A periosteal elevator should not be used for this classic presentation because the increasing subperiosteal pressure has already stripped the periosteum from the cortex, and further periosteal elevation may impair blood flow to the remaining bone.

After the periosteum is incised, a drill is used to enter the metaphyseal medullary canal. Usually pus drains from the drill hole. If so, other drill holes are placed in the area and a curette and bone rongeur are used to remove a 2-cm cortical window. This window serves to decompress the medullary canal and allows for irrigation of the canal. The medullary canal in acute HO should not be curetted for fear of damaging the precarious endosteal blood supply. The wound is left open and the patient brought back daily for irrigation of the medullary canal using ketamine anaesthesia. When there is no more purulent drainage, an attempt can be made to close the incision (this is often unsuccessful), or it can simply be left open to heal by secondary intention. The treatment of chronic HO (stages 3 and 4) often requires a more extensive operative approach. There is rarely a total cure for chronic HO, but very long periods of remission can be achieved if all of the nonviable bone is removed. Sometimes the child with chronic HO has been neglected for so long that the sequestrum begins to spontaneously extrude. When this happens, the child can be appropriately treated by simply removing the sequestrum, curetting the inner surface of the involucrum, and irrigating the medullary canal to remove any remaining smaller pieces of the sequestrum. Sometimes the sequestra are incarcerated by the involucrum, and removal requires a cortical trough to adequately visualise and remove all of the sequestra. After the removal of the sequestra, advanced techniques for closure are available, including muscle and fascio-cutaneous flaps. Placement of antibiotic-impregnated beads can be used to decrease the number of relapses for chronic HO. Most of these advanced procedures are not commonly used in LWATs since in such locations the incidence of HO is so common as to be overwhelming for the resources of the hospital. In these instances, the large wounds can be left completely open, and they eventually will heal by secondary intention as long as all of the nonviable bone has been removed.

Parents can manage the wounds with daily water irrigation and coverage with a bandage made from scrap cloth. In hospitals with adequate health care personnel and facilities, the wounds can be managed in a wound care clinic, but hospitals without such facilities can provide alternatives. For example, the Baptist Medical Center in Ogbomoso, Nigeria, provides a water hose so each day children and parents can use the handheld shower apparatus to wash any debris out of the cortical trough. It is not painful for the children, and the wound can be managed solely by a parent without using the services of hospital personnel.

The proper procedure is controversial for management of chronic osteomyelitis when the total bone from metaphysis to metaphysis has sequestered and there is not yet enough new involucrum to provide stability to the bone. Some surgeons prefer to proceed with removal of the giant sequestrum and splinting of the extremity to allow the involucrum to grow in a clean environment without the infected sequestrum interfering. Other practitioners believe that the best splint for the affected extremity is the sequestrum itself and that it should be left in situ until the involucrum has coalesced. There are obviously no prospective randomised studies to support either course of action.

Complications:

·          Bone abscess

·          Bacteremia

·          Fracture

·          Overlying soft-tissue cellulitis

·          Draining soft-tissue sinus tracts

Prognosis. Despite adequate treatment and appropriate surgical intervention, 5-10% of patients may experience recurrence. Recurrences may lead to chronic osteomyelitis with discharging sinuses and other systemic sequelae.

 

2. Purulent-inflammatory disease of soft tissue:

2.1. Neonatal phlegmon.

 

Necrotizing fasciitis (NF) is a group of infections that present in any age group as an abrupt, rapidly advancing soft-tissue infection with systemic toxicity and high mortality (1). It is characterized by microbial spread along the fascial planes into deep tissue, which results iecrosis of the superficial tissue.

 

Introduction

The term necrotising fasciitis (NF) was first coined in 1952 by Wilson1 to describe a rapidly progressive inflammation and necrosis of subcutaneous tissues and the deep layer of superficial fascia with sparing of the deep fascia and muscle. It had previously been described variously as haemolytic gangrene, acute streptococcal gangrene, gangrenous erysipelas, necrotising erysipelas, suppurative fasciitis, and hospital gangrene, among other names.2,3 However, the term necrotising fasciitis is now used in a generic sense to include all diffuse necrotising soft tissue infections except gas gangrene (clostridial myonecrosis).4

Diffuse necrotising soft tissue infections include classic gas gangrene, Meleney’s haemolytic streptococcal gangrene, necrotising fasciitis as described by Wilson, and the gram-negative synergistic necrotising cellulitis of Stone. Generally, one condition cannot be distinguished from another at the time of diagnosis. Today, the orofacial form of NF is called cancrum oris (noma),5 and the perineal form is called Fournier’s gangrene. Idiopathic scrotal gangrene, however, is different in aetiology, extent, and clinical presentation from Fournier’s gangrene.4 NF poses a serious surgical challenge not only because of its rapid and progressive nature, but also because of its attending high morbidity

and mortality.6,7

Demographics

There is a general paucity of literature, particularly in Africa, on the exact incidence of NF, although one hospital-based report suggests two to three children are seen in most major tertiary health institutions every year; that report, however, excluded cancrum oris and Fournier’s gangrene.

8 There had been reports of cases in Europe and North America, especially during World War II, but more recent reports are from the developing countries of Africa, Asia, and South America.6,8–11 There is no gender or age preference, but studies would suggest that the trunk and the head and neck are more frequently involved in children.8,12

Pathology

Aetiology

Although NF may start spontaneously in apparently normal children, it is most often associated with pathological conditions related to impaired host response leading to lowered immunity.3–8,13 Some recognised predisposing factors include:

1. Debilitating state, such as anaemia and malnutrition, for which protein and vitamin B deficiencies appear predominant in importance.

Other conditions, such as obesity (Figure 21.1), diabetes mellitus, and cancer, play greater roles in adults than children. In recent years, human immunodeficiency virus/ acquired immune deficiency syndrome (HIV/ AIDS) is becoming increasingly significant.

Figure 21.1: NF involving the anterolateral trunk and thigh in a 14-yearold obese but otherwise previously normal girl (before and after the first debridement). Note the relatively unaffected abdominal wall muscles.

2. Trauma (or specific infection), such as needle pricks, skin abrasions, punctures, lacerations, or friction on cheek mucosa by an abnormally positioned tooth, could sometimes be trivial and go unnoticed. Occasionally, the trauma could be severe, such as those following road traffic accidents. NF can complicate such surgical procedures as colostomy (Figure 21.2), appendectomy, herniotomy,

Figure 21.2: Necrotising fasciitis following colostomy.

 

laparotomy, or dental extraction; or it can follow infections such as chicken pox, gingivitis, boil, or perineal abscess.9,13–15

3. General illness could be in the form of malaria or measles, especially in developing countries.

Microbiology

Necrotising fasciitis could result from a variety of microorganisms, particularly bacteria and occasionally fungi. Initially thought to be caused mainly by non-group-A beta-haemolytic streptococci, there is now enough evidence that NF results mostly from synergy between gram-positive cocci (such as non-group-A beta-haemolytic streptococci and staphylococci) and gram-negative organisms such as Bacteroides fragilis, peptostreptococci, Proteus sp., Pseudomonas sp., or Enterobacter sp.3,4,16,17 Much less common is a pure group-A streptococcal infection. Anaerobic bacteria may also be involved, although ofteot cultured. Vincent’s organisms and bacteroides are commonly isolated ioma. Recently described are new varieties of NF caused by Photobacterium damsela;18 halophilic marine vibrios, especially Vibrio fulnificus;19,20 and phycomycoses, especially Rhizopus arrhizus21 and Cryptococcus neophormans.22 Approximately 70–80% of NF is polymicrobial.

Pathophysiology

Aerobic pathogens are usually the primary tissue invaders. They destroy tissues and create an anaerobic environment conducive for anaerobic or microaerophilic organisms, which are secondary invaders.

2,3,7,13 The primary pathogens produce exotoxins, such as streptolysin, streptodornase, streptokinase, and many other proteases and cholagenases, which result in extensive tissue destruction and necrosis.

The infection is commonly polymicrobial and synergistic, and the resultant damage is usually more extensive than that attributable to any individual pathogen.2,3 Most bacteria, especially facultative gramnegative rods such as E. coli, produce insoluble gases whenever subjected to anerobic metabolism.4 Because human tissue cannot survive in an anaerobic environment, gas associated with infection implies the presence of dead tissues.

Streptococcal NF associated with toxic shock syndrome (StrepTSS) has been on the increase in the past two decades and is observed in previously normal children. Caused by a highly invasive strain of group-A streptococcus, the pathogenesis is related to streptococcal pyrogenic exotoxins (SPE) produced by specific strains of Streptococcus pyogenes.23

Natural History (Clinical Stages)

The different pathophysiological stages observed (Table 21.1) include inflammation (stage I), necrosis (stage II), repair (stage III), and sequelae (stage IV).2,3,7,13

Table 21.1: Clinical (pathophysiological) stages and features of NF.

Inflammation (stage I)

The prominent feature of NF is the stage of acute inflammation and results from the effects of the exotoxins, which lead to the release of cytokines, with local and systemic effects.4,23 The local features are mainly those of hyperaemia (or shiny skin), oedema (Figure 21.3) and pain. Systemic toxaemia commonly results in death if appropriate resuscitative measures are not put in place. The process can be arrested at this stage if appropriate antibiotics are given early.

Figure 21.3: Inflammatory phase of necrotising fasciitis.

Necrosis (stage II)

Tissue destruction results either from the direct effect of the enzymes or from vascular thrombosis involving the nutrient vessels serving the area. There is enough evidence to suggest that stages I and II may occur simultaneously in most cases.2,3 In addition, tissue oedema that results from inflammation could increase the pressure within the tight fascial compartment, further reducing blood supply to the tissues in the area. This destruction is rapidly progressive and could occur within 3–5 days.

Extensive subcutaneous/fascial necrosis may proceed with minimal skin involvement, giving rise to significant undermining. Although rare in NF, true muscle necrosis occurs in patients with StrepTSS.23 This condition, known as gangrenous streptococcal myositis, is similar to clostridial myonecrosis (gas gangrene) but differs from it in the absence of gas in the tissues.4

Repair (stage III)

Healing takes place by rejection of the slough, appearance of healthy granulation tissue, and, subsequently, scar tissue formation.

Sequelae (stage IV)

Disfigurement, contractures and trismus may result from tissue loss and scar formation after months to years if no appropriate preventive measures are taken.

Complications

Common complications that may be encountered include:

1. compartment syndrome, leading to Volkmann’s ischaemia, Volkmann’s ischaemic contracture, or gangrene;

2. septic arthritis or osteomyelitis;

3. septicaemia and multiple organ failure syndrome;

4. herniation of intraabdominal organs;

5. joint stiffness; and

6. contractures and trismus.

Clinical Presentation

A high index of suspicion is required to ensure prompt recognition and early treatment of NF. In the past, a significant number of affected children died at home at the stage of inflammation as a result of toxaemia, before getting to the hospital. With the advent of antibiotics, a significant number of these children are now seen in hospitals (Figure 21.4).

Most studies report a slight male preponderance, but any age group can be affected, including neonates and older children. In some studies, up to 40% of these children have malnutrition.8,13

The clinical presentation depends on the stage of NF at the time of presentation (see Table 21.1). The commonly encountered symptoms include pain, swelling, and fever. Although severe local pain that is out of proportion to the size and type of wound is a hallmark of NF in older children, this might be difficult to elucidate ieonates.

At the initial stages of cellulitis (inflammation), examination will reveal features of toxaemia, including elevated temperature (or hypothermia ieonates), oedema, hyperaemia, crepitus, tachycardia, and hypotension. Blebs and blisters may precede the appearance of dark skin patches (Figures 21.1, 21.4, and 21.5) that signify tissue necrosis, usually with severe undermining. Late presentation is common in Africa, and some patients are seen when the necrotic part of the skin, subcutaneous tissues, and fascia come out together as a complete cast from a limb (Figure 21.5). This exposes the underlying muscle(s), tendon(s), or teeth and oral cavity in the case of the cheek.

Figure 21.4: Necrotising fasciitis of the cheek, before (top) and after (bottom) removal of necrotic soft tissues.

Figure 21.5: Late presentation of NF in a 9-year-old boy. Here, the necrotic skin, subcutaneous fat, and fascia came off like a full cast, exposing the underlying muscles, which are relatively uninvolved.

 

Occasionally, some children are seen with structural deformities as a result of improper management of the earlier stages of the disease.

The clinical presentation of Vibrio NF is similar to classical NF and even more similar to streptococcal gangrene, which occurs in children with minor wounds exposed to seawater or sustained while cleaning seafood. In contrast, the clinical presentation of mycotic NF is insidious. On the other extreme are patients with StrepTSS, who present with rapid progression of the disease due to the high virulence of the offending organisms.23

Investigations

The diagnosis of NF is mainly clinical, but the following investigations are relevant.

Microbiologic Cultures

Any discharge or swab from the wound should be cultured (aerobic and anaerobic) to help in identifying the bacteria profile of the disease. Culture of tissue taken from the wound may provide a better yield, especially for anaerobes. In patients with systemic features, blood culture should also be done.

Imaging

It is important to emphasize that imaging studies should be undertaken only in children in whom the diagnosis of NF is not clear cut, as they may delay surgical intervention and frequently provide conflicting information.4

Plain radiographs may show gas within the tissues at the initial stages of the disease, but they are rarely necessary. Magnetic resonance imaging (MRI), where readily available, could assist in defining tissue planes and the presence of microabscesses.

Complete Blood Count

A haemogram should be ascertained; white cell count may indicate  leucocytosis.

Exclusion of Underlying Illness

Any underlying or predisposing illness should be excluded; often, this may involve HIV testing, blood film for malaria parasites, haemoglobin electrophoresis for sickle cell disease, and blood sugar to exclude diabetes mellitus. Doing any of these tests should be guided by clinical suspicion.

Treatment

Resuscitation

Correction of depletion

It is important to correct any existing physiological derangements, such as fluid and electrolyte imbalance. Blood transfusion may be necessary to correct anaemia.

Antibiotics and antimicrobials

The initial choice of parenteral antibiotics should take cognizance of the polymicrobial nature of the disease, previous knowledge of the microbiology of NF, and local sensitivity patterns.24 This should be broad-based and must take control of gram-negative, gram-positive, aerobic, and anaerobic microorganisms. Combinations of penicillins, aminoglycosides, and metronidazole (or cephalosporins with metronidazole) have been found useful in most studies.2–4,6–12 Some reports have found the use of quinolones equally effective in the treatment of NF;25 others, however, have avoided it because of the potential effect on the growth plate of bones in young children, although this risk is now considered quite minimal.8

In severe cases with systemic toxaemia, as in StrepTSS, intravenous human immunoglobulin has been found useful ieutralising the exotoxin already present in the system. Intravenous amphotericin B may be administered if the presence of hyphae on gram stain or on histologic section suggests phycomycotic NF.4

Analgesia

In the early stage and when pain is a prominent symptom, appropriate analgesics should be given. This will facilitate wound care and also help in preventing later joint stiffness.

Tetanus prophylaxis

Tetanus immunisation (both active and passive) will be necessary in most African settings.

Nutritional support

Appropriate nutritional support should be provided, especially for those patients who are malnourished.

Surgical Intervention

Fasciotomy

Even in the absence of obvious tissue necrosis, fasciotomy in the form of single or multiple linear incision(s) over the affected area may be necessary to achieve adequate compartmental decompression.

Thorough wound irrigation with antiseptics such as hydrogen peroxide or cetrimide and warm normal saline, then gentle packing with gauze in EUSOL (hypochlorite solution) or natural honey helps to control local infection and halts progression of the disease. At the time of fasciotomy, partial wound approximation could be effected without tension by using sutures, rubber bands, or special devices. About 5–7 days after fasciotomy, when oedema would have subsided and infection is reasonably controlled, skin closure could be achieved directly or by skin grafting.

Debridement

Prompt, adequate and sequential debridement of all necrotic tissues (see Figure 21.1) is of utmost importance in arresting progression of tissue necrosis in NF.2–4,6–12 Adequate arrangements for possible blood transfusion should be made during such necrosectomies, as this exercise may be attended by blood loss that could be significant to the child, especially the neonate. Debridement may be done by the bedside in very ill patients who are poor anaesthetic risks, especially neonates.

Wound resurfacing

Significant wound contraction could occur following adequate wound care, especially on the face, trunk, and perineum; the final mode of wound closure also depends on the initial size, however. Smaller wounds may contract adequately to heal by secondary intention or require direct suturing, whereas larger but granulating wounds will require skin grafting. In the event of three-dimensional tissue loss (such as check, lip, nose), or exposure of bare surfaces (tendon, bone, nerve, or blood vessels), local, regional, or distant flap reconstruction will be required.6,8,12,26

Rehabilitation

Rehabilitation efforts are directed at preserving the child’s physical function and supporting the child emotionally through the use of activity. The pain of the local infection may cause the patient to voluntarily immobilise affected areas of the body, so both passive and active movements should be encouraged as soon as pain and other preconditions allow.

As the wounds heal, prevention of deformity by minimising the effects of joint stiffness or scar contracture should take priority. Accordingly, appropriate splint(s) should be applied when and where indicated. The goal is to attain a position that opposes the forces of contracture, provide safe joint alignment, and maintain tendon balance without causing stretch or pressure injuries to the peripheral nerves or skin.

Role of Hyperbaric Oxygen

As in clostridial myonecrosis (gas gangrene), the use of hyperbaric oxygen in NF is still controversial. Although experimental results in animals appear promising, its usefulness is less specific in NF than gas gangrene following clinical trials in humans.4

Treatment of Underlying Condition

Any identified underlying or predisposing condition should be treated appropriately. This treatment must be simultaneous with treatment of the NF to avoid relentless progression of the latter.

Prognosis and Outcome

Factors that may affect outcome and prognosis are the following:

• age (neonates fare poorly);

• overall general condition of the patient at presentation;

• pre- or co-morbid conditions;

• virulence of the offending organisms versus host immunity; and

• promptness/aggressiveness of resuscitative, surgical, and supportive forms of therapy.

Despite the aggressive use of antibiotics and surgical intervention, morbidity and mortality following NF remain very high.2–4,6–12 Mortality rates range from 20% to 80%, but are frequently between 60% and 80%. Death results commonly from overwhelming infection and multiple organ failure. Those who survive are faced with a prolonged hospital stay and multiple surgical and reconstructive procedures, with their anaesthetic and socioeconomic implications.26

Prevention

Necrotising fasciitis is largely a preventable disease,26,27 but prevention will involve a multidisciplinary commitment and action by individuals, health personnel, and policy makers. Preventive measures involve:

• good oral and general body hygiene;

• prevention and control of malnutrition;

• prevention of all childhood immunisable diseases, such as measles,

through national mass immunisation programmes; and

• education on early recognition and treatment of NF.

The classification of NF is ambiguous because of its similarity to other syndromes and its numerous etiologies. Often, the diagnoses will overlap as infection spreads to adjacent tissue. For example, necrotizing cellulitis may involve the fascial planes secondarily or vice versa. Several studies have tried to classify NF based on anatomic location, bacterial flora, presence or absence of crepitance, and clinical progression.

NF falls under the general category of necrotizing soft tissue infection (NSTI). There are three types of NSTI: 1) NF, 2) necrotizing cellulitis, and 3) myonecrosis. However, NF is often used in clinical settings as a broadly inclusive term for overlapping types of NSTI. Clinically, there are three syndromes of NF that are often described and easy to conceptualize: Type I is polymicrobial and includes saltwater NF due mainly to marine Vibrio species. Type II is group A streptococcal NF. Type III is clostridial myonecrosis or gas gangrene (2). The most common form of NF is the polymicrobial Type I. In one pediatric study, 75% of children developed NF with polymicrobial etiology (Type I) (3). The most common species of bacteria cultured from a study of 182 subjects in Maryland were Streptococcal species, Staphylococcal species, Enterococcal species, and Bacteroides species. Anaerobes such as Clostridia were also common in type I NF and could be differentiated by gas production visible on imaging studies. The most common bacteria in type I NF is Bacteroides, which is a gram-negative anaerobic bacillus. Fournier’s gangrene is a variant of polymicrobial NF usually found in the scrotum or penis of older, often immunocompromised individuals. This variant is rare in children.

Type II infection with GABHS is probably the most extensively studied type of NF and is common in children (4,5). However, Type II NF has received extra attention in the lay press recently and is referred to as the “flesh-eating” bacterial infection (6). In cases where only one bacterium was present on culture, group A beta hemolytic streptococcus (GABHS) was the most common. In addition, GABHS (also known as Strep pyogenes) has been increasing in frequency since 1990 (7,8). The reason for this increase is unknown, but it may be related to the increasing incidence of other types of invasive streptococcal infections since 1985 (9).

The invasive nature of some GABHS infections and their increasing prevalence has been linked to several virulence factors. It should be noted that NF is rare compared to the total number of non-NF GABHS cellulitis infections which are much more common. The M protein has been found responsible for protecting the bacteria from phagocytosis by polymorphonuclear leukocytes (10). There are over 80 distinct M proteins, but the two most often isolated in NF are the M-1 and M-3 subtypes of S. pyogenes (8). Another important virulence factor is the exotoxin. There are five different exotoxin proteins: A, B, C, D, and E. Most commonly noted in NF are the streptococcal (scarlatina) pyrogenic exotoxins (SPE) types A, B, and C. Exotoxins recruit T cells and increase production of tumor necrosis factor alpha, interleukin 1-beta, and interleukin 6. The effects are characterized by fever, shock, edema, and multiple organ failure (11). The streptococcal superantigen (SSA) can also play a role in this process. Although these proteins are unique to the Streptococcal species, the clinical picture is often difficult to distinguish from other types of NF (4).

Type III NF is most often associated with crepitus due to growth of clostridium perfringens. This is often referred to as gas gangrene. The gas produced can often be seen on various imaging modalities such as x-ray, MRI, or CT.

The differential diagnosis of severe pain and inflammation of the skin includes cellulitis, erysipelas, acute febrile neutrophilic dermatosis, acute hemorrhagic edema of infancy, drug reactions, and vasculitis. NF is regularly confused with cellulitis because its early clinical presentation is also pain, erythema, and edema. However, cellulitis extends only to the subcutaneous tissue and is poorly demarcated. An experienced clinician is usually able to make an accurate diagnosis. Definitive differentiation from necrotizing cellulitis is generally established with surgical incision and probing. If any question remains after probing, a biopsy should be obtained (12). Erysipelas is red, raised, well-demarcated areas of induration and usually involves only the superficial cutaneous tissue. Ecthyma gangrenosum may also present as NF, but is due to Pseudomonas and appears ulcerated rather than bullous (13).

Although there are several distinct etiologies of NF, the clinical presentations are very similar. The clinical picture of NF is significant for pain, erythema, and swelling that progressively extends from the site of trauma, surgery or other provoking insult. The clinician’s history should include questions regarding any inciting event such as a small wound or traumatic occurrence at the site of infection. On the other hand, the absence of an initiating event does not rule out NF. Common initiating events depend on the age group as well as the patient’s immune status. In the newborn, NF can be a serious complication of omphalitis. It may begin as swelling and erythema around the umbilicus and progress to a purplish discoloration and periumbilical necrosis during the subsequent hours or days (13). In older children, NF may present after trauma, surgery, or with resolving varicella lesions. In a study, almost 50% of pediatric cases were superimposed upon varicella in its 3rd-4th day of progression (8). The history frequently reveals a persistent fever after the third day of rash, associated with severe, localized pain, over an area of swelling, erythema, and possibly necrosing skin (14). The mechanism of how varicella increases the risk for NF is unknown. An association has been shown between NF and NSAID use with varicella. Numerous studies examined this relationship, but the results have been mixed. Most believe these studies do not prove a causal relationship. However, physicians may consider recommending acetaminophen instead of ibuprofen for children with varicella (15).

Pain in an extremity is usually the presenting symptom. It is extreme and often out of proportion with the physical findings. NF has a propensity for the extremities, but can occur anywhere there is deep fascia (16). In the first 24-48 hours, it is associated with edema, erythema, and warmth of the skin overlying the necrotizing tissue. After that point, the skin will become dusky and discolored. It will develop blisters and bulla over the next seven to ten days. During that time, the discoloration will become sharply demarcated. Its tenderness will also disappear as the superficial nerves experience ischemia (17). This progression is both faster and more severe than that seen in cellulitis or erysipelas (18). If not addressed, NF can quickly progress to multi-organ failure, acute respiratory distress syndrome, renal impairment, coagulopathy, liver abnormalities, and generalized erythroderma (19).

Although the diagnosis of NF is primarily clinical, laboratory workup and imaging may be helpful. Surgical probing and frozen section biopsy are used for diagnosis of NF, but they are invasive and take time to complete. There must be a high index of suspicion for NF to move straight to surgery. Therefore, the most important first steps of medical management are probably the gram stain and cultures of both the blood and the wound, if one is present. This will help guide antibiotic therapy over the course of the disease. In addition, routine blood work such as a CBC and chemistry panels may be helpful.

Imaging can also be very useful in differentiating NF from cellulitis. Crepitus or soft tissue gas on plain x-rays are pathognomonic for NSTI. However, they are only found in 37%-57% of the cases (20). More recently, MRI and CT scans have been investigated to identify NF. Contrast enhanced images may show asymmetric thickening of the deep fascia and/or gas bubbles in the deep tissue. However, MRI may overestimate the extent of disease and intravenous contrast may be contraindicated in some patients in shock or with renal failure. In most cases, however, empiric treatment should be initiated as soon as possible, even prior to obtaining imaging results (21).

The mainstays of treatment for NF are intravenous antibiotics and surgical debridement. Generally, broad antibiotic coverage is necessary for empiric therapy. A study by Elliot suggested a combination of ampicillin, gentamicin, and clindamycin or ampicillin/sulbactam for broad coverage (4). Penicillin covers GABHS and most anaerobes. Clindamycin covers all anaerobes and it inhibits bacterial protein (toxin) synthesis in organisms that are not multiplying. However, anaerobic infections are frequently polymicrobial necessitating broad spectrum coverage. Specific antibiotic therapy can be employed after cultures return and bacterial sensitivities are known. Recent studies indicate clindamycin treatment produces better outcomes and decreases mortality in streptococcal disease. In fact, a combination of the two drugs is currently advocated in the literature (3,22). In the pediatric setting, there is no current recommendation for length of antimicrobial treatment, but it should be continued as long as there are signs of infection. Treatment for cellulitis is continued for at least three days after the acute inflammation has subsided (22). Therapy for NF should be continued for at least as long as for severe cellulitis.

Surgical debridement is recommended every day until the patient is stable and without signs of infection or sepsis. Debridement should cover the infected area as well as a margin of healthy tissue to prevent reoccurrence of infection. As a result, the patient may need extensive skin grafting to cover the debridement area. During recovery, frequent dressing changes are necessary. Unfortunately, scarring and disfigurement are very common after NF debridement and grafting. In addition, physical therapy and rehabilitation will be needed for those with extensive skin grafts (20).

Mortality is always worse if there is significant delay in therapy or inadequate surgical debridement. Unfortunately, NF is often diagnosed at a very late stage because the clinical presentation initially appears to be an ordinary cellulitis or wound infection. Therefore, management should begin as soon as possible with intravenous antibiotics and surgical debridement.

Hyperbaric oxygen (HBO) therapy has been evaluated as an adjunctive therapy. Treatment with HBO has not been examined adequately in randomized trials, but some studies have shown benefit in preventing the extension of NF. It may accomplish this by increasing the oxygen tension in the surrounding tissue (23). In fact, HBO has become standard treatment in clostridial myonecrosis (24). Unfortunately, HBO is difficult to obtain and is rarely utilized. Other management concerns are the systemic effects of NF. Organ system problems that need to be addressed may include respiratory insufficiency, transient renal failure, and blood pressure support.

Mortality in the literature ranges from 12% with early, aggressive treatment (1) to nearly 100% for those without surgical debridement (8). Prognosis depends most heavily on the patient’s age. In one study, NF patients younger than age 35 had no fatalities. In contrast, mortality was 61% in the age group above 65 years. This difference may be explained by the various predisposing factors in the older group, such as diabetes mellitus. In fact, 62% of all NF patients had predisposing factors, but none were present in the younger group. However, the younger group was also more likely to have undergone surgery, which may indicate more intense therapy for the younger group. Other important factors impacting disease outcomes are the development of bacteremia, shock or hypotension, use of antibiotics other than clindamycin, or lack of adequate surgical debridement (8). Complications with toxic shock syndrome occurred in 50% of cases in one study (25). However, there was no correlation between increased mortality and specific M-serotype or the presence of SPE (streptococcal pyrogenic exotoxins) A or C (8).

 

2.2. Neonatal omphalitis.

Omphalitis is an infection of the umbilical stump. Omphalitis typically presents as a superficial cellulitis that may progress to necrotizing fasciitis, myonecrosis, or systemic disease. The introduction of aseptic umbilical cord care has greatly reduced the occurrence of omphalitis iewborn infants. Omphalitis is predominantly a disease of the neonate, although several cases have been reported in adult patients.

Introduction

Omphalitis is defined as infection of the umbilicus—in particular, the umbilical stump in the newborn. It primarily affects neonates, in whom the combination of the umbilical stump and decreased immunity presents an opportunity for infection. It is rarely reported outside the neonatal period. Varieties of congenital conditions predispose to infection of the umbilical stump and are also among the differential diagnoses to consider for the presentation.

Omphalitis may extend into the portal vein and result in various acute complications requiring medical as well as surgical interventions. Although this condition is uncommon in developed countries, it remains a significant cause of morbidity and mortality in Africa and other parts of the world where health care is less readily available.

Umbilical cord infection contributes significantly to newborn infection and neonatal mortality in Africa, especially for infants delivered at home without skilled birth attendants and under unhygienic conditions.1

Demographics

Omphalitis is uncommon in developed countries, with an incidence of 0.2–0.7%.1 The incidence in developing countries has been quoted to be between 2 and 7 in every 100 live births.2,3 However, the incidence is even higher in communities that practise application of nonsterile home remedies to the cord. In one study of neonates admitted to an African general paediatric ward, omphalitis accounted for 28% of neonatal admissions.4 Hospital-based studies estimate that 2–54 babies per 1000 births will develop omphalitis.5 However, one report from Tanzania6 found a rate of 1.7% among babies of 3,262 women.

Although there is a male preponderance, there does not appear to be a racial or ethnic predilection to developing omphalitis. The mean age of onset is usually 3–5 days for preterm infants and 5–9 days for term infants. For those with complications, the age at presentation is 5–75 days (median, 33 days), according to one report.7

Unhygienic cord practices have been implicated as the main factor responsible for the high incidence of omphalitis in Africa. Risk factors include inappropriate cord handling (e.g., cultural application of substances such as engine oil, cow dung, talc powder, or palm oil to the cord); septic delivery secondary to prolonged rupture of membranes or maternal infection; nonsterile delivery; prematurity; and low birth weight. One report1 cited use of old instruments to cut the cord, mother not bathing (washing the perineum with water and soap) or shaving before delivery, and application of substances on the umbilical cord to be independently associated with the risk of developing omphalitis. Other risk factors include neonates with weakened or deficient immune systems or who are hospitalised and subjected to invasive procedures such as umbilical catheterisation. Genetic defects in contractile proteins have been implicated, and in some, immunological factors such as leukocyte adhesion deficiency (LAD) syndrome and neutrophil mobility may play a role.

Aetiology/Pathophysiology

The umbilical cord presents a unique substrate for bacterial colonisation. It is relatively rich in substrate, without the normal barrier of skin defences, and it undergoes ischaemia and degradation as the umbilical stump dries and falls off. Normally, the cord area becomes colonised with potential bacterial pathogens intrapartum or immediately postnatal.

Bacteria have the potential to invade the umbilical stump, leading to omphalitis. The pathophysiology of complications of omphalitis is closely related to the anatomy of the umbilicus. The infection can spread along the umbilical artery, umbilical veins, abdominal wall lymphatics and vessels, and by direct spread to contiguous areas (Figure 20.1).

Figure 20.1: Pathophysiology of surgical complications of omphalitis

The bacteriological spectrum of omphalitis is undergoing change, in light of the changes in cord care, antibiotic use, bacterial resistance profiles, and local practices. A single organism is causative in most cases. More often, aerobic organisms are causative. Common organisms include:

• Staphylococcus aureus (most common)

• Group A streptococcus

• Escherichia coli

• Klebsiella

• Proteus

Up to one-third of cases of omphalitis are associated with anaerobic

infection caused by:

• Bacteroides fragilis

• Peptostreptococcus

• Clostridium perfringens

Approximately 85% of cases are polymicrobial in origin. Aerobic bacteria are present in approximately 85% of infections, predominated by Staphylococcus aureus, group A Streptococcus, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. In the past, studies emphasized the importance of gram-positive organisms (eg, S aureus and group A Streptococcus) in the etiology of omphalitis; however, more recent studies have highlighted gram-negative organisms as the cause. These studies suggest that the change in etiology may be caused by the introduction of prophylactic umbilical cord care using antistaphylococcal agents, such as hexachlorophene and triple dye, and the subsequent increase in gram-negative colonization of the umbilical stump. In addition, anaerobic bacteria colonize the maternal genital tract.

 

Pathophysiology. The umbilical stump represents a unique but universally acquired wound, in which devitalized tissue provides a medium that supports bacterial growth. Normally, the cord area is colonized with potential bacterial pathogens during or soon after birth. These bacteria have the potential to invade the umbilical stump, leading to omphalitis. If this occurs, the infection may progress beyond the subcutaneous tissues to involve fascial planes (necrotizing fasciitis), abdominal wall musculature (myonecrosis), and the umbilical and portal veins (phlebitis). The factors that cause colonization to progress to infection are not well understood.

Frequency. Overall incidence varies from 0.2-0.7% in industrialized countries. Incidence is higher in hospitalized preterm infants than in full-term infants. Episodes of omphalitis are reported and usually are sporadic, but rarely, epidemics occur, eg, due to group A Streptococcus.

Age. In full-term infants, the mean age at onset is 5-9 days. In preterm infants, the mean age at onset is 3-5 days.

Clinical Presentation

Local signs of omphalitis include purulent or foul-smelling discharge from the umbilicus/umbilical stump, periumbilical erythema, oedaema, and tenderness. Systemic signs include fever (temperature >38°C) or hypothermia (temperature <36°C), unstable temperature, or jaundice.

Other systemic manifestations may include tachycardia (heart rate >180/min), hypotension and delayed capillary refill, tachypnoea (respiratory rate >60/min), signs of respiratory distress or apnoea, or abdominal distention with absent bowel sounds. Central nervous system involvement may manifest as irritability, lethargy, poor suckling, hypotonia, or hypertonia. A history of delayed cord separation may be present in LAD syndrome.

In advanced cases, the infant may present with septic shock or necrotising fasciitis (NF). NF is a severe complication of omphalitis that should be considered if the local signs have progressed to include a peau d’orange appearance, discolouration or bruising of the skin, skin necrosis, and crepitation.

Differential Diagnoses

The differential diagnoses of omphalitis (and specific features of each) include:

• umbilical granuloma (visible granuloma at the umbilicus);

• patent vitello-intestinal duct remnants (cystic swelling or fistulous opening with feculent matter discharging);

• patent urachus (fistulous opening with urine discharging) or urachal cyst;

• necrotising enterocolitis (abdominal distention, bilious vomiting, bloody stools);

• general sepsis; and rarely, appendiculo-omphalic anomalies.

Investigations

A microbiological swab of the umbilicus should be sent for aerobic and anaerobic cultures. A blood culture should be included when appropriate. A blood count with differential for white cell counts may show a neutrohilia (or occasionally a neutropaenia).

Other investigations are necessary either to rule out other differential diagnoses or to diagnose complications. Diagnostics may include the following:

• A plain abdominal radiograph is useful if necrotising enterocolitis is suspected. In addition, it may reveal intraperitoneal gas in those with peritonitis (caused by gas-producing bacteria). Multiple fluid levels may suggest adhesion obstruction but may also be present in simple ileus. Gas may be present within the subcutaneous tissue of the abdominal wall when clostridial infection is involved.

• Abdominal ultrasonography is useful in imaging the abdominal wall if a cyst is suspected It is helpful in the diagnosis of intraperitoneal, retroperitoneal, and hepatic abscesses.

• Dopplar ultrasonography is helpful if portal vein thrombosis is suspected.

• A fistulogram is indicated if a fistulous connection to the umbilicus is discovered. This will help define the anatomy of a vitello-intestinal or urachal remnant.

• Rarely, magnetic resonance imaging (MRI) or a computed tomography (CT) scan may be useful in assessing or ruling out congenital tracts or fistulas. Also rarely, a CT scan may be necessary to adequately localise intraabdominal abscesses in difficult diagnostic cases.

History. A detailed review of the pregnancy, labor, delivery, and the neonatal course is important

Anaerobic bacteria are part of the normal flora of the female genital tract and are commonly involved in ascending infections of the uterus and in septic complications of pregnancy; therefore, the higher incidence of omphalitis caused by anaerobes (especially B fragilis) in infants with adverse perinatal histories, such as premature or prolonged rupture of membranes and amnionitis, may relate to exposure to maternal infection.

History of urine or stool discharge from the umbilicus suggests an underlying anatomic abnormality.

Physical. Local disease: Physical signs vary with the extent of disease. Signs of localized infection include the following:

Ø    Purulent or malodorous discharge from the umbilical stump

Ø    Periumbilical erythema

Ø    Edema

Ø    Tenderness

Extensive local disease: The following signs indicate more extensive local disease, such as fasciitis or myonecrosis. These signs also may suggest infection by both aerobic and anaerobic organisms and include the following:

Ø    Periumbilical ecchymoses

Ø    Crepitus

Ø    Bullae

Ø    Progression of cellulitis despite antimicrobial therapy

Systemic disease: Signs of sepsis or other systemic disease are nonspecific and include disturbances of thermoregulation or evidence of dysfunction of multiple organ systems.

Causes. Omphalitis is a polymicrobial infection typically caused by a mixture of aerobic and anaerobic organisms. Associated risk factors include the following:

o        Low birthweight (<2500 g)

o        Prior umbilical catheterization

o        Septic delivery (as suggested by premature rupture of membranes, nonsterile delivery, or maternal infection)

o        Prolonged rupture of membranes

Omphalitis occasionally manifests from an underlying immunologic disorder. Several infants with chronic omphalitis were subsequently diagnosed with leukocyte adhesion deficiency, a rare immunologic disorder with an autosomal recessive pattern of inheritance.

Omphalitis also may be the initial manifestation of neutropenia in the neonate.

Rarely, an anatomic abnormality may be present, such as a patent urachus or patent omphalomesenteric duct.

Lab Studies

Obtain specimens from umbilical infection routinely, and submit specimens for Gram stain and culture for aerobic and anaerobic organisms. If myonecrosis is suspected, obtain specimens from the involved muscle rather than the wound surface.

Obtain a blood culture for aerobic and anaerobic organisms.

Obtain a complete blood count with manual differential. Neutrophilia or neutropenia may be present in acute infection. An immature-to-total neutrophil ratio greater than 0.2 may be a useful indicator of systemic bacterial infection in the first few days of life. Thrombocytopenia may be present.

Other nonspecific laboratory tests, either alone or in combination with a defined scoring system, have been evaluated for their usefulness in rapid detection of bacterial infection ieonates, although none has demonstrated sensitivity or specificity sufficiently high to dictate clinical care.

Imaging Studies:

Ø Abdominal radiographs may reveal intra-abdominal wall gas.

Ø Computed tomographic (CT) scan of the abdomen may determine the presence and extent of muscle involvement.

Treatment

Treatment of omphalitis (periumbilical edema, erythema, and tenderness) in the newborn includes antimicrobial therapy and supportive care.

Antimicrobial therapy

Include parenteral antimicrobial coverage for gram-positive and gram-negative organisms. A combination of an antistaphylococcal penicillin and an aminoglycoside antibiotic is recommended.

In addition to antimicrobial therapy, supportive care is essential to survival. These measures include the following:

Provide ventilatory assistance and supplementary oxygen for hypoxemia or apnea unresponsive to stimulation. Administer fluid, vasoactive agents, or both for hypotension. Administration of platelets, fresh frozen plasma, or cryoprecipitate for DIC and clinical bleeding is suggested.

Treat infants at centers capable of supporting cardiopulmonary function.

Treatment of uncomplicated cases requires prompt antibiotic therapy.

Antibiotics are the mainstay of medical treatment of omphalitis. Antibiotics specifically active against Staphylococcus aureus and an aminoglycoside to cover for both gram-positive and gram-negative organisms are used.

The local antibiotic susceptibility patterns need to be considered in the initial therapy. Examples include ampiclox, cloxacillin, flucloxacillin, and methicillin in combination with gentamycin. Metronidazole may be added when anaerobes are suspected. Duration of treatment is typically for 10–14 days with initial parenteral therapy for complicated cases. A short antibiotic therapy of 7 days is adequate for simple uncomplicated omphalitis. Complications such as respiratory failure, hypotension, and

disseminated intravascular coagulation (DIC) arising from infection may require supportive care in the form of intravenous fluids, fresh whole blood, fresh frozen plasma, platelets, or cryoprecipitate.

Other treatment considerations

Monitor patients for progression of disease. Early surgical intervention may be lifesaving. The role of hyperbaric oxygen in treatment of patients with anaerobic necrotizing fasciitis and myonecrosis is controversial because no prospective controlled data are available and pediatric data are scarce.

Surgical Care.

Management of necrotizing fasciitis and myonecrosis involves early and complete surgical debridement of the affected tissue and muscle. Although the extent of debridement depends on the viability of tissue and muscle, which is determined at the time of surgery, excision of preperitoneal tissue (including the umbilicus, umbilical vessels, and urachal remnant) is critically important in the eradication of the infection. These tissues can harbor invasive bacteria and provide a route for progressive spread of infection after less extensive debridement. Delay in diagnosis or surgery allows progression and spread of necrosis, leading to extensive tissue loss and worsening systemic toxicity. Several surgical procedures may be required before all nonviable tissue is removed.

Further Inpatient Care

Examine the patient frequently, and immediately debride any tissue showing signs of advancing infection or necrosis. Postoperatively, inspect the gross appearance of the tissue on the perimeter of the debrided area several times a day or more frequently if the infant has any unresolved signs of systemic infection.

Monitor aminoglycoside levels, and adjust dose accordingly.

Monitor and manage metabolic abnormalities, which are common in any ill neonate.

Treatment of Surgical Complications

The surgical complications of omphalitis could be acute/early or long term/ late and tend to be associated with significant morbidity and mortality. In addition to medical treatment for ongoing/active omphalitis, the surgical treatment is handled according to the surgical complication.

Necrotising Fasciitis

Necrotising fasciitis is one of the most commonly reported serious complications of omphalitis,1,8–12 occurring in 26% of patients with major complications, according to one report.6 It has been noted to occur in 13.5% of neonates with omphalitis.8 The condition starts initially as periumbilical cellulitis, which, without treatment, progresses rapidly to necrosis of the skin and subcutaneous tissue (Figures 20.2 and 20.3), and in some instances,

Figure 20.2: Periumbilical cellulitis with early necrosis of scrotal skin.

 

Figure 20.3: Early necrotising fasciitis beginning at the umbilicus.

 

myonecrosis. The scrotum is the most commonly affected by NF,7 but the abdominal wall may also be involved (Figure 20.4). If treated early, periumbilical cellulitis can be controlled by use of parenteral broad-spectrum antibiotics. The antibiotic regime should always include an antianaerobe (e.g., metronidazole).

Figure 20.4: Advanced necrotising fasciitis involving upper abdominal and lower chest wall.

 

NF should be treated by prompt debridement, removing all dead and dying tissues, followed by daily dressing of the wound. If the baby is too ill for a general anaesthetic, the debridement can be performed by the bedside (using parenteral paracetamol or rectal paracetamol for analgesia). The resulting wound will later require secondary closure (or skin grafting if the defect is large). However, scrotal wounds may heal well without secondary closure or skin grafting.13

Evisceration

Intestinal evisceration is another frequently reported serious complication (Figure 20.5).7 The eviscerated intestine is usually loops of small intestine, but large intestine may be involved. Rarely, presentation may be late, and the eviscerated intestine may be gangrenous.7

Figure 20.5: Intestinal evisceration from omphalitis.

 

The eviscerated intestine should be covered by clean moist gauze,  and placed in an intestinal bag (a transparent plastic bag will do if there is no intestinal bag available). Care should be taken to ensure that the intestine is not twisted.

Under general anaesthetic, the eviscerated intestine is cleaned and returned to the peritoneal cavity and the umbilicus repaired. If the umbilical defect is narrow, it may require extension in the transverse plane. In the presence of features of peritonitis or intestinal gangrene, a formal laparotomy needs to be done to drain any abscesses and clean the peritoneal cavity. Gangrenous intestine needs to be resected and intestinal continuity restored.

Peritonitis

Peritonitis may occur with or without intraperitoneal abscess collection. In the absence of an abscess, the infection could resolve with use of broadspectrum intravenous antibiotics alone, and surgery is usually not required. If an intraperitoneal abscess is confirmed by ultrasound, or there is no facility for ultrasonography, then laparotomy is required. Any abscess is drained and the peritoneal cavity thoroughly cleaned.

Abscesses

Abscesses may develop at various sites, but are frequently intraabdominal. Intraperitoneal abscess is drained at laparotomy. Retroperitoneal abscess14 is best drained by an extraperitoneal approach, but if located anteriorly in the retroperitoneal, an intraperitoneal approach may be required.

Hepatic abscess should be properly localised by ultrasonography or CT scan. The abscess is aspirated by a wide-bore needle under imaging guidance, and the abscess cavity is irrigated with normal saline. This can be repeated once more if it recollects. In difficult cases, or in recurrence after needle aspiration, open drainage may be required. If the abscess is multiple, parenteral antibiotics alone may suffice, and aspiration/drainage reserved for persistent cases. Abscesses may be located in the anterior abdominal wall or in other superficial locations. These would require drainage.

Late Complications

Late complications occur several weeks, months, or years after omphalitis in the neonatal period.

Portal Vein Thrombosis

Portal vein thrombosis (PVT) is a complication with serious consequences. Although an early complication, the major consequences produced are in the long term. In one report of 200 patients undergoing portosystemic shunt for portal hypertension due to PVT,15 15% of the PVT was suspected to be the result of neonatal omphalitis. The thrombosis may produce a carvernoma, which can cause biliary obstruction.16

A portosystemic shunt may be required if portal hypertension develops.15 Biliary obstruction is treated on its merit.

Umbilical Hernia

Umbilical hernia is a common problem in children in Africa, and several are the result of weakening of the umbilical cicatrix from neonatal omphalitis. The management of these hernias is discussed in Chapter 57.

Peritoneal Adhesions

Peritoneal adhesions are the result of previous subclinical or treated peritonitis from omphalitis. The adhesions may produce intestinal obstruction, which usually is not amenable to nonoperative measures. Laparotomy and lysis/excision of the adhesions are usually required. Any ischaemic intestinal segment needs to be resected.

Prognosis and Outcome

Promptly treated uncomplicated omphalitis usually resolves without serious morbidity. However, when presentation and treatment are delayed, mortality could be high, reaching 7–15%.1,7,13,17

Serious morbidity and mortality may occur from complications such as NF, peritonitis, and evisceration.6 Portal vein thrombosis may be fatal.18 Mortality may reach 38–87% following NF and myonecrosis.1,19,20 Also, certain risk factors such as prematurity, small size for gestational age, male sex, and septic delivery are associated with poor prognosis.

Prevention

The incidence of omphalitis is low in well-resourced countries and for those born in hospital. For these, there is probably little benefit of prophylactic measures to reduce the incidence. In developing countries, and especially after home birth, however, the incidence is high enough to consider prophylaxis to prevent the morbidity and mortality associated with late presentation of the disease. Access to proper maternity and delivery services helps reduce the incidence.

Teaching safe cord-care practice to mothers as well as using traditional birth attendants and primary-care workers are of utmost importance in the prevention of omphalitis in Africa. Vigilance is also important to identify major complications and refer patients early for prompt intervention. In most African hospital settings, methylated spirit and gentian violet are commonly used for cord care. In other parts of the world, betadine, bacitracin, silver sulfadiazine, or triple dye is recommended. Currently, not using any medicinal washes on the cord but just simply allowing the cord to dry and fall off is being advocated in developed parts of the world. There is little data to support any one cord care or lack thereof over the other.

In one report, a simple clean delivery kit produced by the United Nations Population Fund (UNFPA) was found to reduce cord infections.1 Babies of mothers who did not use the kit were 13 times more likely to develop cord infection than babies of mothers who used the kit. The same report also noted that babies of mothers who did not bathe before delivery were 3.9 times more likely to develop cord infection than babies of mothers who bathed.

 

2.3. Mastitis.

Inflammation or infection of breast tissue may occur in the neonatal period, this condition referred to as mastitis neonatorum. It typically presents as a subareolar abscess in the second or third week of life manifested by erythema, swelling, tenderness, and occasionally discharge at the location of the breast bud, accompanied by fever and agitation. The responsible microorganism is usually Staphylococcus aureus (6). Although the precise etiology is unclear, it is likely in part a consequence of breast stimulation by maternal hormones. The degree of physiologic breast enlargement does not. however, correlate with the incidence (7).

 

The preferred management of mastitis neonatorum includes antibiotics and needle aspiration of any abscesses. Aggressive surgical treatment such as incision and drainage or excision, should be avoided because this can result in undesirable disturbed growth of the breast bud, potentially causing significant hypoplasia, deformity, and/or asymmetry in subsequent years. If there is recurrence of the abscess, then repeat aspiration should be performed rather than aggressive surgical drainage. Close follow-up is essential to ensure response because insufficient therapy may result in further destruction of normal tissue.

Infection and abscess in the postpartum lactating breast is a well-described entity (8). Presentation typically includes local pain, tenderness, erythema, and occasionally purulent discharge. Ultrasound examination can sometimes be helpful to identify abscesses. Treatment employs adequate surgical drainage for abscess formation and antibiotics for cellulitis. The concerns relating to future breast development are less important. Illicit use of intravenous drugs may also lead to infections of the breast. A choice of injection site might include the superficial vessels of the breast, and the lack of aseptic technique or the use of nonsterile hypodermic needles can result in breast abscess at the site of injection. Incision and drainage in conjunction with antibiotics for cellulitis, and counseling to avoid recurring episodes are indicated.

 

2.4. Perianal and Perirectal Abscess.

Infants are commonly affected with infections and abscesses in the perianal area. Infected diaper rash is the most common cause of superficial abscesses. Staphylococ­cal or gram negative enteric organisms are the most common organisms involved. Deeper abscesses of the anal canal or perirectal tissues arise from crypt infections. These infections are usually caused by enteric and anaerobic organisms.

Clinical Presentation

Girls and boys are equally affected when less than 1 year of age. With children older than 1 year, males are more commonly affected. Parents frequently report the presence of a perianal mass and sitting intolerance. For perianal abscesses, examina­tion of the anus reveals a tender, erythematous mass lateral to the anus. Perirectal abscesses are frequently associated with fever and malaise in addition to sitting intol­erance.

On careful digital exam even deep perirectal abscesses may be palpable as a fluc­tuant mass. Crohn’s disease may present as a perirectal abscess and should always be considered. Rarely, infected rectal duplications or dermoid cysts can present clini­cally as perirectal abscesses. Type III saccrococcygeal teratomas have been mistak­enly identified and treated as perirectal abscesses. If the diagnosis is not obvious, CT scan of the abdomen and pelvis with oral, rectal and IV contrast will demonstrate most perirectal abscesses.

Treatment

Superficial perianal abscesses can be treated with Sitz baths. Typically antibiotics are not required. If the area becomes fluctuant, incision and drainage may be offered. Deeper infections require immediate drainage under general anesthesia along with intravenous antibiotics.

        Outcomes

One third of superficial perianal abscesses resolve without surgery but the major­ity require surgical drainage. One third of these abscesses recur. Nearly 30-50% of infants presenting with perianal abscesses actually have fistula-in-ano. Deeper infec­tions heal well after incision and drainage. As with the superficial lesions, recurrence is not uncommon.