EPIDURAL ABSCESS DUE TO FOREIGN BODY INSERTION INTO THE EXTERNAL AUDITORY CANAL IN AUTISM
Introduction
Although the occurrence of intracranial complications due to otitis media has declined because of improved antibiotic therapy,1 they remain to be major challenges for physicians once they occur. We report a case of epidural abscess caused by the insertion of foreign bodies into the external auditory canal in an autistic patient.
Case
A 38-year-old male patient with autism and epilepsy presented with a two-day history of left ear discharge, fever, and vomiting. Purulent otorrhea and inflammatory granulation tissue were seen in his left ear, and several cotton-like foreign bodies were seen in his right ear. Audiometry was not possible due to mental retardation. He was febrile (39.2 degrees), with impaired consciousness (Glasgow coma scale: E3V3M5). Initial laboratory tests showed severe inflammation: white blood cell count, 14,100 /μL and C-reactive protein level, 33.4 mg/dL. Cerebrospinal fluid examination showed bacterial meningitis: increased leukocyte count (3,436 /mm3), increased protein level (292 mg/dL), and decreased glucose level (22 mg/dL).
CT and MRI findings
Head computed tomography (CT) scans of the axial view showed left tympanomastoiditis without aeration, and contained a hyperdense object lateral to ossicles (Fig. 1A), epidural abscess with gas formation in the posterior cranial fossa and sigmoid sinus occlusion (Fig. 1B). Head T1WI magnetic resonance (MR) with gadolinium contrast showed non-enhancing crescent in the lateral part of the posterior cranial fossa which was considered as abscess with sigmoid sinus occlusion (Fig. 2A). DWI MR illustrated hyperintense signal in the left posterior cranial fossa (Fig. 2B). Both CT scans and MR images revealed no midline shift of his brain. He was diagnosed as epidural abscess of the left posterior cranial fossa induced by tympanomastoiditis due to acute exacerbation of chronic otitis media.
Surgery
An emergent surgery was performed on the same day. We drained the posterior fossa abscess by drilling a burr hole in a retro-sigmoid region. Mastoidectomy was then performed and the foreign bodies of wood and cotton were removed. The bone covering the sigmoid sinus was removed to drain the posterior fossa abscess. The necrotic tissue around the sigmoid sinus was cleaned. A blind sac closure was performed to prevent the
Fig. 1. Head CT scans of the axial view showed left tympanomastoiditis without aeration, and contained a hyperdense object lateral to ossicles (arrows) (A), epidural abscess with gas formation (arrowheads) in the posterior cranial fossa and sigmoid sinus occlusion (B).
Fig. 2. Head T1WI MRI with gadolinium contrast showed non-enhancing crescent in the lateral part of the posterior cranial fossa which was considered as abscess with sigmoid sinus occlusion (arrowheads) (A). DWI MRI illustrated hyperintense signal in the left posterior cranial fossa (arrowheads) (B).
patient from touching his ear and inserting objects into it. Foreign bodies in his right auditory canal were then removed.
Post-operative course
The patient was treated with broad-spectrum antibiotics (MEPM 4 g/day, VCM 2 g/day). Prevotella sp. was isolated from the blood and the pus from the posterior cranial fossa. On post-operative day 7, his consciousness became clear and an enhanced head CT scan did not show the pus accumulation. On post-operative day 16, cerebrospinal fluid examination was normal. He was discharged on post-operative day 21. He had a habit of touching his ears and inserting things into them. After the surgery, we repeatedly showed him a picture saying ‘Don’t touch your ears’, since autistic patients tend to rely more on visual perception. He has never attempted to touch his ears and we have never detected foreign bodies in his right ear after the discharge. A head CT scan taken after three months the surgery revealed that the sigmoid sinus occlusion was cured. A follow-up CT scan one year after the surgery showed no iatrogenic cholesteatoma and showed an aeration cavity in the middle ear.
Recently, the occurrence of intracranial complications due to otitis media has declined. The incidence of otogenic intracranial complications is between 0.13 % and 1.97 %.1 In this case, however, epidural abscess occurred due to the following reasons. It was challenging to examine and treat the patient because of severe mental retardation. He habitually inserted foreign bodies to his external auditory canals. It was supposed that the abscess had been established secondary to inflammatory granulation of the external auditory canal and sustained infection derived from foreign bodies inside granulation.
Because epidural abscess caused meningitis and loss of consciousness, we performed emergent surgery to control the infection. Audiometry was not possible due to mental retardation, but his left hearing was presumed to be poor because of the erosion of ossicle chain and granulation of the tympanic cavity. Blind-sac closure was performed to avoid the secondary infection and to prevent him touching the ear canal.
In addition to blind-sac closure, psychotherapeutic approaches were effective. Autism is a neurodevelop-mental disorder characterized by impaired communication and social skills and repetitive or stereotypical behaviors.2 Because autistic patients tend to rely more on visual perception, it was reported effective to use pictures instead of words to help autistic patients to communicate.3
There was no trouble with his ears after the surgery. Both surgical and psychotherapeutic approaches were necessary to cope with such difficulties.
References
1.Dubey SP, Larawin V. Complications of chronic suppurative otitis media and their management. Laryngoscope 117:264–267, 2007
2.American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington D.C: American Psychiatric Association, 1994
3.Bondy A, Frost L. The Picture Exchange Communication System. Behav Modif 25:725–744, 2001
Address for correspondence: Risa Tona, 2–1-1 Minatojima-Minamimachi, chuou-ku, Kobe city, 650–0047, Japan. rkurihara@kcho.jp
Cholesteatoma and Ear Surgery – An Update, pp. 421–423
Edited by Haruo Takahashi
2013 © Kugler Publications, Amsterdam, The Netherlands