Volume 3, Issue 2 , Pages 81-84, March 2008
Unusual protracted course of non-tuberculous mycobacterium otomastoiditis in a child
Article Outline
Summary
Mycobacterium chelonae, one of the rapidly growing non-tuberculous mycobacteria, is a rare but increasingly recognized cause of otomastoiditis. Recently, we have experienced an unusual protracted course in a 6-year-old girl with acute otomastoiditis on the left ear caused by M. chelonae, 8 months after ventilation tube insertion. During 142 consecutive admission days, she was treated with repeated surgical interventions coupled with long-term administration of antimicrobial agents. One year after discharge, she was rather well without recurrent otorrhea. In conclusion, when a child with intractable draining ear after ventilation tube insertion, unusual pathogen, e.g. M. chelonae should be taken into consideration, which deserves further confirmation. Subsequently, surgical intervention coupled with prolonged antibiotic treatment is essential to eradicate the infectious foci from middle ear and mastoid cleft.
Keywords: Non-tuberculous mycobacterium, Mycobacterium chelonae, Mastoiditis, Ventilation tube
Introduction
Acute otomastoiditis is an inflammatory process in the mastoid region frequently complicated by acute or subacute otitis media. Erythematous swelling of the post-auricular area and anterior displacement of the auricle are two major characteristics, followed by subperiosteal abscess formation with fluctuant post-auricular mass. With the aid of widespread use of antimicrobial agents, the incidence of acute otomastoiditis has decreased dramatically. Conversely, some suppurative complications of acute otitis media caused by unusual pathogen, e.g. non-tuberculous mycobacterium (NTM) occur, possibly due to increased prevalence of immunocompromised patients [1]. However, NTM can also affect children, manifested as lymphadenitis, skin ulcer, post-traumatic wound infection, but rarely otomastoiditis [2].
Mycobacterium chelonae is one of the rapid growing NTM. Its origin can be traced back to the early of the last century, when Friedmann firstly isolated M. chelonae from the lungs of two sea turtles, thus chelonae was termed after the Latin word “of a turtle”. Most outbreaks of nosocomial mycobacterial infection are contaminated with soil or various water sources, e.g. water-based solutions, tap water, ice water, etc., thus raises medical attention. In the otolaryngological field, NTM may affect many regions, with the most frequent site at the cervico-facial lymph nodes, while the middle ear space is rarely involved [3].
Recently, we have experienced an unusual protracted course in a 6-year-old girl having acute otomastoiditis caused by M. chelonae. Herein, we present this case.
Case report
A 6-year-old girl with repeated otitis media with effusion (OME) underwent ventilation tube insertion on both ears after failure of conservative treatment in December 2003. The post-operative 8 months were rather smooth, however, left draining ear recurred and ventilation tube in the left ear was removed on August 31, 2004. Unfortunately, erythematous swelling of the left post-auricular area developed, thus she was admitted to our ward on September 15, 2004.
During hospitalization, local check-up of the ears revealed a perforated eardrum with some granulation tissue and purulent discharge on the left ear, while the right eardrum displayed intact except a previously inserted ventilation tube well in position. In addition, a fluctuant post-auricular mass on the left side accompanied by lateralization of the auricle was noted. Subsequently, high resolution computed tomography (HRCT) revealed well pneumatization in the right mastoid area, while a soft tissue density fully occupied in the left middle ear and mastoid cleft with cortical bone destruction (Fig. 1).
Figure 1.
HRCT, axial view, demonstrates a soft tissue density fully occupied in the left middle ear and mastoid cleft, while well pneumatization in the mastoid area is noted on the right side.
She then underwent simple mastoidectomy for drainage of the mastoid abscess on September 23, and abundant whitish granulation tissue in the middle ear and mastoid cleft was disclosed. Post-operative microbiological study using polymerase chain reaction (PCR) test confirmed the infection of M. chelonae. Immunologic profile such as immunoglobulin G, M, A and mitogen were all within normal limits. Therefore, she was intravenously administered with Amikacin (7.5
mg/kg, q12h) and Imipenem (25mg/kg, q6h), accompanied by Clarithromycin (7.5mg/kg, q12h) orally.
Unfortunately, poor wound healing with discharge waxed and waned, post-operatively. Therefore, she received another three times of surgical interventions including modified radical mastoidectomy with removal of the malleus and incus in October; debridement of pre- and post-auricular wound, associated with removal of granulation tissue in the external ear canal in November. At the mean time, additional Cefoxitin (40mg/kg, q6h) was given due to some drug resistance during repeated cultures. Finally, revisited debridement of the mastoid cleft for eradicating the infectious foci was performed on January 12, 2005, that is, admission day 120.
After the last surgery, coupled with intravenous antibiotic treatment with Amikacin, Imipenem and Cefoxitin for 4 consecutive months, her condition became improved. She was discharged on February 2, 2006, with a total of 142 admission days.
She was then regularly followed at our clinic with oral medication such as Clarithromycin (250mg, q12h), Ciprofloxacin (250mg, q12h) for 1 year and Co-trimoxazole (400mg sulfamethoxazole and 80mg trimethoprim, q12h) for 45 days. One year after discharge, she was rather well without recurrent otorrhea.
Discussion
Acute otomastoiditis is a potentially serious infection in an otherwise healthy child during the antibiotic era, possibly due to increased antibiotics-resistance pathogens and identified uncommon microorganisms. Most cases with aggressive infectious process required surgical intervention coupled with prolonged antibiotic treatment [4]. Streptococcus pneumoniae, Streptococcus pyogen and Pseudomonas aeruginosa were proved as the most common pathogens for otomastoiditis [5], while drug-resistance strains included methicillin-resistance Staphylococcus aureus and penicillin-resistance S. pneumoniae [6], [7]. Rarely, otomastoiditis is caused by Mycobacterium tuberculosis [8] or NTM, which deserves our attention because how to eradicate the infectious foci is challenging.
M. chelonae is one of the rapid growing, nonpigmented NTM. It could cause lymphadenitis, cutaneous and soft tissue infection, catheter-related infection, pneumonia, and rarely otomastoiditis. Its transmission is mostly via contaminating with soil and natural water, tap water, ice water, distilled water or processed tap water used for dialysis.
While insertion of a ventilation tube has become the mainstay for the treatment of OME, complication such as persistent or delayed otorrhea ensued in some patients [9]. The most frequent isolated valid pathogens were S. pneumonia and Hemophilus influenzae [10], whereas atypical pathogen, e.g. NTM was rarely reported [11], [12], [13]. Although the role of a ventilation tube in NTM otomastoiditis remains unclear, there is high proportion of preceding history with ventilation tube in cases of NTM otomastoiditis. Likewise, our case also had insertion of ventilation tubes, 8 months prior to the occurrence of NTM otomastoiditis.
The protracted, relapsing course with granulation tissue serves as a characteristic finding in M. chelonae infection, which deserves repeated surgical intervention including mastoidectomy and debridement of the infectious foci, coupled with long-term antibiotic treatment [14].
Synergistic antibiotic therapy with Amikacin and Clarithromycin were given to this patient initially. However, intractable otomastoiditis persisted, thus Imipenem (the third generation of cephalosporin) and Cefoxitin were added according to the result of cultures with pharmaceutical sensitivity (Fig. 2). Multi-antibiotics therapy has been recommended to avoid drug-resistance strains and potential side effects. It is suggested that antimicrobial agents should be kept for 4–6 consecutive weeks for ordinary otomastoiditis until both clinical disease-free and laboratory pathogen-free are achieved [15]. However, in the current case, antibiotic treatment was given for more than 1 year including parental administration for 4 months and oral antibiotics for 15 months. This unusual protracted treatment course indicates that NTM otomastoiditis is really a tough case. Thereby, both the patient and the family should be informed first that repeated surgical interventions with prolonged antibiotic treatment are essential to eradicate the infectious foci.
Figure 2.
Clinical information of this patient.
In conclusion, when a child with intractable draining ear after ventilation tube insertion, unusual pathogen, e.g. M. chelonae should be taken into consideration, which deserves further confirmation. Subsequently, surgical intervention coupled with prolonged antibiotic treatment is essential to eradicate the infectious foci from middle ear and mastoid cleft.
Acknowledgement
Grant No. NSC 95-2314-B-002-071 from National Science Council, Taipei, Taiwan.
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PII: S1871-4048(07)00090-1
doi:10.1016/j.pedex.2007.11.002
© 2007 Elsevier Ireland Ltd. All rights reserved.
Volume 3, Issue 2 , Pages 81-84, March 2008
