Abstract
Objective
We report a case of a parotid-facial caseating granulomatous infection caused by atypical mycobacteria ( Mycobacterium avium ) in an immuno-competent child. The size and depth of the lesion and its proximity to the facial nerve present a challenge for a purely surgical treatment strategy. An alternative treatment strategy is developed to avoid severe disfigurement.
Study design/subject
Atypical mycobacterial infection of the parotid region in a 5 year old girl: timeline and definition of a planned combined treatment strategy with antibiotics and surgical excision.
Results/conclusion
Cervicofacial infections caused by non-tuberculous mycobacteria (NTM) may present surgical challenges due to the size and depth of the lesion and its proximity to the facial nerve and major vascular structures. Even minor scars are highly visible and poorly tolerated. Close clinical monitoring combined with judicious treatment strategies is necessary for successful treatment and good cosmesis. Recent literature provides insufficient guidance in formulating the best treatment strategy for the individual patient. Comparisons of antibiotic therapy with variations of surgical excision are abundant but poorly formulated. Our case presented with a lesion involving skin, superficial and deep lobe of the parotid gland. Lesion was in immediate proximity to the distribution of the facial nerve through the parotid gland. The risk of surgical damage to the facial nerve in the acute phase of the inflammation and the required extent of skin excision were significant. We decided to start treatment with combination antimycobacterial antibiotics in close cooperation with the pediatric infectious disease specialists. We observed and documented the regress and executed a delayed surgical excision when the lesion was reduced to skin only. In our opinion this was the best treatment strategy that helped us avoid extensive dissection in the vicinity of the facial nerve as well as a parotidectomy. Excision of the involved skin with the deep portion was performed 6.5 months after initial diagnosis.
1
Introduction
Non tuberculous mycobacterial (NTM) infections should always be included in the differential diagnosis of painless head and neck lymphadenitis of pediatric populations. These acid-fast, non-motile bacilli of slender shape are divided into two groups based on their growth characteristics in media: rapidly growing mycobacteria ( Mycobacterium marinum , M. kansasii , and M. avium-intracellulare ) and slowly growing mycobacteria ( M. fortuitum , M. chelonei , and M. abscessus ) .
NTMs are less virulent than Mycobacterium tuberculosis (MTB). They are ubiquitous in soil and water, are pathogens in birds and mammals and can be found in pharyngeal flora of asymptomatic humans . The usual route to infect a human host is from soil to oral cavity and then to respiratory tract. Incubation period can be long as 5 years. Infected pediatric patients are usually otherwise healthy and recover fully .
Cutaneous NTM infections develop spontaneously in immunocompromised patients or in immunocompetent patients following trauma, surgery or cosmetic procedures. Primary lesions may appear after weeks to months in the form of nodules, granulomas, ulcers or localized abscesses . Skin overlying NTM lesions often exhibits a characteristic purplish color described as ‘violaceous discoloration’. Diagnosis is clinical and usually confirmed with culture/nucleic acid assay of an aspirate (or swab) of the lesion. Selective mycobacterial medium is used for growth of material obtained for culture (Lowenstein–Jensen medium or Middlebrook 7K10 or 7K11 agar). Nucleic acid hybridization probes using target sequences of ribosomal RNA are used for rapid identification of clinical samples.
Pediatric NTM infection is most commonly located in the head and neck. Anterior cervical and submental lymph nodes are usually involved. The typical pediatric patient presents with isolated unilateral lymphadenopathy that is characterized as a subacute inflammation slowly increasing in size over weeks to months. The mass is usually painless and somewhat firm with overlying violaceous skin. Systemic symptoms are rare. NTM infections are predominant in winter and are not contagious through human-to-human contact .
The majority of cases of NTM disease are reported in children 1–5 years of age who happen to place soiled items and hands in their mouth frequently. Decreased immunity to Mycobacterium has also been reported in this age group . Exposure to poultry and farming have been identified as specific environmental risk factors for pediatric NTM infections . Widely used alcohol based gel disinfectants are ineffective against NTM and MTB. Our ID specialist observed that over-reliance on these gels for hand sanitation may have contributed to the increase in reported cases. Long term reflux treatment with H1 blockers and regulations reducing the upper temperature limit of home water heaters may also be implicated (non-published observations).
The natural course of NTM disease is variable. Infected lymph nodes may soften and erupt through the skin, leading to tract formation and persistent drainage. Lymph nodes may stay indurated, stable in size and acuity for several months. Late complications of NTM disease include reactivation especially after trauma or surgery adjacent to the affected area. If the affected nodes are located within the parotid gland, damage to the branches of the facial nerve can occur; usually this can be avoided with antimicrobial therapy .
A review of the incidence and outcomes of NTM infection was performed in Northern Ireland . Forty children ages 1 to 11 years, who had a unilateral neck infection, were included in a retrospective study covering a period of 14 years. Organisms isolated were M. avium / intracellulare (n = 27), M. malmoense (n = 12) and M. interjectum (n = 1). Twenty-eight of the 40 children (70%) were female. Patients were not randomized or stratified between the treatment methods (antibiotic treatment only, surgery alone or combination therapy). No patients had recurrence of infection. The annual incidence of NTM disease varied from 0 to 7 patients per year; with an overall increasing trend.
The incidence of cutaneous NTM infection in Olmsted County, MN was recently reviewed . Forty children and adults were identified over the span of 29 years. The overall sex and age adjusted incidence of cutaneous NTM infection was 1.3 per 100,000 person-years. Distal extremities were the most common sites of infection. No patient had HIV infection, but 23% were immunosuppressed for other reasons. Traumatic injury was the most common cause of NTM exposure. The most common species was M. marinum (n = 17, 45%), followed by M. chelonae / M. abscessus (n = 12, 32%). In the past decade (2000–2009) 15 of 24 species were rapidly growing mycobacteria compared with 4 of 14 species earlier (1980–1990) . Pediatric incidence was not evaluated separately.
Presentation of NTM disease and response to therapy were recently reviewed at Children’s Hospital in Boston, MA . Nineteen cases of NTM disease were identified over the course of 13 months. Initial surgical excision of affected lymph nodes was performed in 9 patients. Ten patients were treated with macrolide-containing antibiotic regimens. 5 patients who received Azithromycin, Isoniazid and Clofazimine required surgical excision of the affected lymph nodes. The treatments were administered for 1 to 7 months. The group without primary excision consisted of 10 patients. 6 of them had incision and drainage, 1 aspiration performed as initial procedure. The lesion resolved completely in 4 of the patients in this group. 4 of them required lymph node excision — one patient at 1 month, 2 patients at 5 and one at 6 months from initiation of treatment. One required cosmetic surgery and one incision and drainage for caseous necrotizing granulomas. Consistent with other literature, authors concluded that excision rather than incision with drainage should be performed. They reported a 50% cure rate with conservative treatment using Rifampin and Clarithromycin. The 4 patients requiring lymph node excision were treated with either rifampin and/or Clarithromycin with combination utilizing Azithromycin, Isoniazid and/or Clofazimine .
A retrospective study of management and clinical outcomes on 43 children younger than 12 years demonstrated the following: No surgery in 2% (n = 2), incision and drainage in 40% (n = 17) and fine needle aspiration (FNA) in 12% (n = 5). 91% of these patients needed subsequent excisions. Complete excision at initial presentation was performed in 47% (n = 20) of children: only 5% of these children needed revision surgery. The authors concluded that high index of suspicion and primary complete excision after diagnosis decrease morbidity. Effect of antimicrobial treatment was not evaluated in this study .
Retrospective studies reviewed show that surgical excision of the affected lymph nodes provides a cure rate of 92%–95%, especially if early excision is performed .
Cosmetic treatment outcomes of NTM cervicofacial lymphadenitis were studied in children aged 0–15 years. Fifty children were randomized into each of 2 groups: surgical excision of involved lymph nodes and antibiotic therapy. Observer Scar Assessment Scale (OSAS) was determined using Rasch analysis. The median OSAS score for the successful surgical group was 29.4 points, compared with 43.3 for the successful antibiotic group and 38.8 for the delayed surgery group. Overall, the cosmetic outcome was better in the successful surgery group
Lesions localized to the parotid and facial skin were not evaluated separately and facial cosmetic outcomes of surgical excisions were not reported, constituting an important deficiency of these reviews . Combined treatment modalities (surgery and antibiotic treatment) remain underexplored. No randomized trials are conducted.
A multidrug regimen combined with surgical excision is often used for treatment. Guidelines for prevention, diagnosis and treatment were published by the American Thoracic Society (ATS) and the Infectious Diseases Society of America (IDSA). NTM cervical lymphadenitis due to Mycobacterium avium complex (MAC) is treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy. Incisional biopsy alone or the use of anti-TB drugs alone (without a macrolide) has frequently been followed by persistent clinical disease, including sinus tract formation and chronic drainage, and should be avoided. An alternative for recurrent disease or for children in whom surgical risk is high (e.g., risk of facial nerve involvement with preauricular nodes) may be the use of a clarithromycin multidrug regimen such as that used for pulmonary disease. Experience with such an approach is limited but the proven activity of clarithromycin against MAC in other clinical settings and preliminary reports supports this combined approach. A multidrug treatment protocol consisting of a combination of the following drugs is recommended: Clarithromycin or Azithromycin, Rifampin or Rifabutin, Ethambutol, Amikacin, Streptomycin. Choice of drugs is based on causative organism, and clinical response as evaluated and monitored by an ID specialist. Patients should be treated until culture negative on therapy for 1 year .
The principal drawback of long-term antibiotic therapy is medication side effects, including but not limited to nausea, erythema, anorexia, weight loss, and peripheral eosinophilia . These can be managed successfully through close monitoring, dose adjustment and drug change. Overall, lower cure rates for conservative management compared to surgery are reported ] (see Table 1 ) and these reports shape referral patterns as well as treatment choices in general.
