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Definition and Epidemiology
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Tracheostomy stoma cellulitis is a bacterial infection of the epidermis lining of the tracheostomy opening. It is a dangerous infection that, if untreated, can spread contiguously through the tracheostomy site into the trachea or into the deep tissues of the neck and mediastinum. In the past, stoma infections occurred approximately in one-third of patients undergoing surgical tracheotomy placement.5 In more recent studies the rates of stoma infection have been significantly lower, ranging from 0% to 3%.6,7
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There is limited information on the pathogens responsible for tracheostomy stoma cellulitis. It appears that the bacteria colonizing the granulation tissue surrounding the tracheostomy cause most cases of stoma cellulitis. The epithelial granulation tissue lining the tracheostomy site is colonized with bacteria by direct contact with the bacterial flora of the surrounding skin. Polymicrobial colonization has been reported in the majority of tracheostomy granulation tissue specimens, with a mixture of gram-positive, gram-negative, and anaerobic bacteria. Approximately 6 bacteria are detected in each granulation tissue specimen sent for culture.8,9 The bacteria most frequently recovered from granulation tissue culture include alpha-hemolytic streptococci, Staphylococcus aureus, Peptostreptococcus species, Bacteroides species, Fusobacterium species, and Pseudomonas aeruginosa.9,10 Most isolates produced beta-lactamase, including all isolates of S. aureus and Bacteroides species.9
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The tracheostomy tube itself may also become colonized as it provides a portal of entry from the outside directly into the normally sterile trachea. Tracheostomy tubes are typically composed of plastic, with differing degrees of flexibility depending on the specific type of material (i.e., silicone or polyvinyl chloride). Bacteria with a polysaccharide shell can bond to the surface of a tracheostomy tube lumen, forming organized matrices of bacterial colonies. The colonies are often referred to as biofilm.11 The longer that a tracheostomy tube is used, the more likely that it will develop biofilm.
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The bacteria that most frequently colonize the tracheostomy tube include S. aureus and P. aeruginosa.12 Exposure to these pathogens likely occurs in the hospital. Most children undergo tracheotomy in an intensive care setting. Pretracheotomy intubation times may exceed more than 1 month4,13,14 while overall hospital lengths of stay associated with tracheotomy placement may exceed 50 days.1 This significant nosocomial exposure provides ample opportunity for colonization with flora endemic to the intensive care unit setting.
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Although many of the bacterial species that colonize granulation tissue and tracheostomy tubes are considered normal skin flora and are typically nonpathogenic, others can cause clinically significant infection. The most common bacterial pathogens believe to be responsible for tracheostomy stoma cellulitis include group A β-hemolytic streptococci, S. aureus, and P. aeruginosa in addition to various anaerobic bacteria. Additionally, candida species may also be responsible for tracheostomy stoma cellulitis.
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Clinical Presentation
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On history, parents of children with tracheotomy who have stoma cellulitis will commonly report a change in color of the granulation tissue of the tracheostomy stoma from pink to red. This redness may spread circumferentially throughout the skin surrounding the tracheostomy. Foul-smelling, yellow/green drainage and bleeding at the site have also been reported. The infection may be accompanied by a history of fever, malaise, overall discomfort, and localized pain.
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On physical examination, children may be febrile, tachycardic, and ill-appearing. Frank erythema, edema, and/or induration of the skin surrounding the tracheostomy site may be observed. Bleeding may be present. The skin may also feel warm to the touch. Purulent exudate may be visualized emerging from the stoma tissue. Supraclavicular and cervical lymphadenopathy may be palpable. Confluent papular erythema with erythematous satellite papules may be present with candidal tracheostomy cellulitis.
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Differential Diagnosis
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Noninfected, healthy granulation tissue or fibrous scar tissue is commonly mistaken for cellulitis. Most children with tracheotomy will likely develop pink granulation stoma epithelium to some degree (Figure 56–1). Characteristics that distinguish health stoma granulation tissue from stoma cellulitis are shown in Table 56–1. Stoma cellulitis is unlikely in the presence of exudate without other clinical features of infection.
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Superficial stoma cellulitis should also be differentiated from the extremely rare but life-threatening deep tissue infections such as cervical necrotizing fasciitis and mediastinitis.15 In these deep tissue infections, the erythema may progress rapidly; the patient is often ill-appearing with systemic signs of toxicity.16 In cases with cervical necrotizing fasciitis, the skin may appear gray, green, or purple. Subcutaneous emphysema may also be observed.16 Mediastinitis is difficult to recognize early; however, significant respiratory distress or even respiratory failure will likely be present.17 Patients who have undergone tracheotomy in relation to cardiac surgery are at increased risk for deep-tissue infection.18
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Tracheostomy stoma cellulitis is a clinical diagnosis. Laboratory and radiographic diagnostic tests are not helpful in making the diagnosis but may help guide empiric antibiotic therapy and facilitate early detection of complications such as deep-tissue infection. Gram stain and culture from the tracheotomy stoma tissue or exudates may help identify potential causative pathogens. However, since polymicrobial colonization of healthy granulation tissue is common, the presence of bacteria in a culture alone does not necessarily indicate cellulitis. We recommend that Gram stain and culture be obtained prior to treatment as a guide to antibiotic therapy, rather than as a diagnostic indicator of stoma cellulitis.
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The diagnostic role of blood inflammatory markers (white blood cell [WBC] count, differential, C-reactive protein, etc.) has not been evaluated in children with tracheostomy stoma bacterial infections. WBC counts less than 15,400 cells/mm3 have a negative predictive value of 99% excluding necrotizing fasciitis in adult patients with stoma cellulitis.19 Chest radiography or magnetic resonance imaging provide evidence of deep-tissue infection such as subcutaneous emphysema (on radiograph or magnetic resonance imaging) and fascia inflammation or abscess formation (on magnetic resonance imaging).
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Evidence-based guidelines for the treatment of tracheostomy stoma cellulitis do not currently exist. Clinical trials of antibiotic therapy for this infection have not been performed. However, since polymicrobial infections are common, initial antibiotic therapy should be broad-spectrum. Therapy should also be directed toward the most common pathogens (Table 56–2).
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Intravenous antibiotics are recommended for the ill-appearing patients and those with significant or rapidly progressing cellulitis. Close follow-up is recommended, especially given the possible direct route of bacterial spread into the trachea and into the deep tissues of the neck and chest if the infection progresses. For this reason, hospitalization is strongly encouraged for the initial portion of therapy for ill-appearing patients with stoma cellulitis. Intravenous options for single initial therapy may include ampicillin-sulbactam or, if Pseudomonas species are strongly suspected, piperacillin-tazobactam or imipenem. Children with severe penicillin allergy may receive imipenem alone or a combination of clindamycin and an aminoglycoside (i.e., tobramycin, amikacin, or gentamicin).20 Additional broad-spectrum coverage may be provided with the addition of either ciprofloxacin or cephalosporins with activity against P. aeruginosa, such as ceftazidime or cefepime. The stoma culture antibiotic susceptibilities may be used to adjust or narrow antibiotic therapy. Vancomycin may be required if methicillin-resistant S. aureus (MRSA) is suspected.21
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Transition from intravenously to enterally administered antibiotics is reasonable for patients who have initial treatment as indicated by decreased stoma site erythema, exudate, and induration. Reasons for failure in treatment response may include resistant organisms and extension of infection into the trachea or soft tissues. Surgical debridement may be warranted for deep-tissue infections.18
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Initial enteral antibiotic therapy may be appropriate for the nontoxic appearing patient with mild cellulitis, assuming that antibiotic absorption is not compromised by conditions such as diarrhea or short gut syndrome. In previous studies, bacteria present in granulation tissue at the tracheostomy site have been susceptible to amoxicillin-clavulanate or ciprofloxacin, suggesting that these antibiotics may be options for enteral therapy.8 The American Academy of Pediatrics does not endorse the use of fluoroquinolones for skin or soft-tissue infections in children younger than 18 years, unless there is no other available alternative therapy.22 Other enteral choices include clindamycin or trimethoprim-sulfamethoxazole.21 If candidal cellulitis is suspected, therapy with a topical antifungal medication (e.g., nystatin) may be appropriate.
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Most clinical trials of skin infections in children have used 10 days of antibiotic therapy.21 Current data suggests that 10–14 days of antibiotic therapy should be considered for children with tracheostomy stoma cellulitis. It is important to dispose or thoroughly clean home tracheostomy equipment at risk for bacterial contamination when a child experiences a stoma infection. This equipment may include trach ties, suction catheters, suction tubing, humidification nose, oxygenation and ventilation tubing.23 Consultation with an otolaryngologist and intensivist should be undertaken in situations where a tracheostomy tube must be replaced secondary to stoma cellulitis.