Tuberculous otitis media with mastoiditis and central nervous system involvement

Abstract

Tuberculosisof the middle ear and mastoid is currently a rare disease in developed countries, but this disease still occurs and may cause serious consequences. We report a case of disseminated tuberculosis involving the middle ear, mastoid, lung and central nervous system. Tuberculosis should be considered in the differential diagnosis of chronic ear drainage, especially in young children.

Although the annual number of tuberculosis cases has declined during the past decade and pediatric cases of tuberculosis now constitute only ∼6% of reported cases in the United States, ¹ new cases of tuberculosis continue to be reported in many areas in the United States. Tuberculosis is an uncommon cause of chronic infection of the middle ear and mastoid. The diagnosis of tuberculosis in the middle ear is difficult because most physicians are unfamiliar with its presenting features and special laboratory study is required. This report describes a young child with chronic ear drainage and the serious consequence of this infection.

CASE REPORTS

A 3-year-old African-American girl with no previous medical problems was admitted to our hospital in May 2001 for evaluation of bilateral chronic ear drainage unresponsive to medical treatment. Approximately 2 months earlier, she presented to her primary pediatrician because of bilateral ear drainage. She was diagnosed with acute otitis media and received a course of amoxicillin therapy. Subsequently a course of amoxicillin/clavulanate was prescribed for treatment of continuing ear drainage. No fever, weight loss or cough was reported. One month before admission her mother noticed that the child had developed an asymmetric smile, and 2 weeks before admission the child became unsteady when walking and shook when reaching for objects.

Physical examination at admission revealed a somewhat irritable child who was consolable by her mother. Profuse white granulation tissue in both external auditory canals obscured her tympanic membranes. No signs of inflammation over the mastoid area or displacement of the pinnae was noted. Several 2- by 2-cm cervical lymph nodes were palpable bilaterally. The neurologic examination was significant for a left-sided facial palsy and ataxic gait with no predominant side of falling. She had no paresis of her extremities or neck stiffness. Both hands trembled visibly during feeding or reaching for objects.

Initial laboratory data revealed a peripheral white blood cell count of 12 200 cell/mm³ (42% neutrophils, 20% band forms, 29% lymphocytes, 7% monocytes, 1% basophils and 1% reactive lymphocytes), hemoglobin of 7.1 g/dl and 495 000 platelets/mm³. Gram stain of ear drainage showed no cells and no microorganisms, and the culture subsequently grew coagulase-negative Staphylococcus sp. and 1 colony of Aspergillus niger. Initial treatment was intravenous ceftriaxone and gentamicin and an otic antibiotic suspension. On the third day of hospitalization, examination under anesthesia revealed diffuse polypoid granulation tissue in both external auditory canals extending to the middle ears suggestive of bilateral cholesteatoma. Pathologic examination of the tissue obtained revealed fibrinocellular inflammatory debris. Computed tomography of the temporal bones demonstrated a bilateral soft tissue density, a large destructive process within her right temporal bone with destruction of the tegmen tympani, partial destruction and distortion of the ossicles and scutum and milder destruction of her left temporal bone (Fig. 1). On Day 7 of hospitalization, she underwent right radical mastoidectomy and left modified radical mastoidectomy. During the operation, profuse white inflammatory debris was visualized over the entire external and middle ear canal, and erosion of the bone over the cerebellar dura, the carotid artery in the middle ear and the sigmoid sinus was documented. Gram stain and culture of the mastoid material were negative, but an acid-fast stained smear was positive. Culture of the mastoid grew Mycobacterium tuberculosis 4 weeks later, that was susceptible to routine antituberculous agents.

Fig. 1: A contrast-enhanced CT scan shows destruction of middle ear structures and erosion of bilateral temporal bones.

Four drugs (isoniazid, rifampin, pyrazinamide and streptomycin) were started when the smear result was reported, and an evaluation for the extent of tuberculosis infection was begun. The patient’s tuberculin skin test was positive at 15 mm 48 h after placement. Chest roentgenogram revealed an infiltrate in the right upper lobe without hilar lymphadenopathy. Three consecutive gastric aspirations were negative on stained smear but subsequently grew M. tuberculosis.

Computed tomography of the brain on Day 9 of hospitalization revealed numerous ring-enhancing lesions in the supra- and infratentorium area with a pressure effect on the fourth ventricle; a lumbar puncture was therefore not performed. She underwent external ventricular drainage surgery and subsequently a ventriculoperitoneal shunt was inserted to reduce cerebral edema. Initial examination of ventricular fluid revealed 9 white blood cells/mm³ (53% neutrophils, 47% lymphocytes), 14 841 red blood cells/mm³, glucose 77 mg/dl and protein 14 mg/dl. Stain and culture for acid-fast bacilli were negative.

Postoperatively she gradually improved and during her hospital stay was able to ambulate by herself with minimal support. She was discharged home receiving four antituberculous drugs (isoniazid, rifampin, ethambutol and pyrazinamide) under directly observed therapy. A follow-up imaging brain scan demonstrated substantial improvement as shown by decreasing size and number of lesions, which correlated well with her clinical course. Despite persistent bilateral profound hearing loss, more severe on the right than the left, she was able to speak in sentences and communicate during her clinic visits at 4 months follow-up with the assistance of bilateral hearing aids. During the past year she has continued to have good neurologic recovery, with documentation of normal gait, loss of tremors and catchup of developmental milestones.

Tuberculin skin tests placed on all family members were negative except for a 15-mm induration noted 48 h after placement in the child’s mother, who had tested negative ∼1 year earlier. The mother’s chest roentgenogram was normal and isoniazid prophylaxis was prescribed. No known tuberculosis contacts for either the mother or child were identified.

During the first week of hospitalization, only standard universal precautions were used in the care of this child. After identification of acid-fast bacilli on the operative specimen, documentation of a new positive purified protein derivative (PPD) skin test and abnormal chest radiograph, she was placed in airborne isolation to prevent potential aerosolization of tuberculosis from the external auditory canal. Review of her hospitalization noted multiple contacts with health care personnel who were closely involved with the debridement and irrigation of her external auditory canals in the emergency room, outpatient clinic and her hospital room. Therefore an investigation of the child’s contacts throughout her hospitalization was conducted. A total of 142 health care personnel who were likely to have been directly exposed to the child between the time of admission until the institution of proper isolation were identified, and 85 patients who were sharing a common room or corridor with the same air flow pattern were identified. Tuberculin skin tests were placed in all contacts in whom there was no known history of a reactive PPD during the first week after identification of the patient’s tuberculous otitis. Follow-up skin tests were offered 8 to 10 weeks later. An additional outpatient nurse-attended clinic was instituted to accomplish this goal at both times. No PPD conversions were documented among our hospital personnel, patients or families followed at our institution.

DISCUSSION

Tuberculous otitis media and mastoiditis are uncommon in developed countries. The incidence has declined substantially worldwide since the introduction of effective antituberculous drugs, although it is still seen in the developing world. Tuberculous otitis media is associated with significant sequelae including the development of profound and permanent hearing loss. ^2–4 A review of cases in Edinburgh followed between 1907 and 1914 reported 51 (2.8%) of 1797 cases of chronic otitis media in children <15 years of age caused by tuberculosis in comparison with 48 (9.5%) of 505 of those who were <5 years of age. ⁵ The incidence of this entity appeared to decrease even before the advent of effective therapy, because a follow-up study from the same institution during the years 1915 to 1924 showed that only 55 (1.3%) of 4285 cases of chronic otitis media were associated with tuberculosis. ⁶ This disease is rare in the US, with only 4 cases (0.06%) reported in 6310 patients with chronic otitis media between 1962 and 1984. ⁷ Isolated cases have been reported in the literature. ^8–13 Although the incidence has dropped, suspicion of this clinical disease may also have declined. Thus tuberculous otitis may be overlooked as a curable cause of chronic otitis media, especially in children who have no history and/or evidence of concurrent tuberculosis affecting another organ.

Our patient presented with classic symptoms of otitis media related to tuberculosis: painless draining ears; profuse granulation tissue on otoscopic examination; and significant hearing loss. ^{2–4, 7, 14} Her symptoms, even in retrospect, were only ∼2 months in duration in contrast to the majority of reported cases who had been affected substantially longer. However, the period of active symptom duration can vary from weeks to 40 years. ^{3, 4} Our patient’s chest radiograph showed an infiltrate in the right upper lobe without hilar lymphadenopathy, a relatively atypical finding in children who have primary pulmonary tuberculosis. It is possible that hilar lymphadenopathy might not be visible on the plain film when an extensive infiltrate or atelectasis is present, and further investigation with computed tomography or ultrasound could have been performed. Abnormal chest radiography consistent with pulmonary tuberculosis in association with tuberculous otitis media occurred in 58% of 74 chest radiographies available for analysis. ⁷ Concomitant pulmonary tuberculosis should suggest the etiology in a patient with chronic otitis media; however, tuberculous otitis media should not be excluded when otorrhea occurs in a patient without pulmonary disease.

The pathogenesis of tuberculous otitis media is likely related to three distinct mechanisms: spread to the middle ear via the Eustachian tube; hematogenous spread from another tuberculous focus; and, rarely, direct implantation through the external auditory canal and a tympanic membrane perforation. ^{9–11, 15} The most frequent complication is hearing loss, which may be profound. Generally tuberculosis of the middle ear is unilateral; the bilateral disease seen in our patient is uncommon. Another noteworthy complication is facial palsy. This complication was more common in children than in adults with rates of 45 and 39% reported in two studies. ^{5, 6} Our patient had a unilateral facial palsy which resolved after several months of antituberculosis medication with persistence of the severe bilateral hearing loss, features commonly reported in the medical literature.

A low incidence of secondary meningitis is associated with tuberculous otitis media. Rarely either intracranial tuberculoma or abscess has been reported, ^{5, 14, 15} and these appear to be a result of hematogenous spread rather than direct extension. Our patient had ring-enhancing lesions with surrounding vasogenic edema in multiple areas of the brain including the cerebellum. The differentiation of tuberculous brain abscess from tuberculoma by either clinical grounds or CT scan is difficult. The definitive diagnosis of a tuberculous brain abscess proposed by Whitener ¹⁶ is based on the following criteria: (1) macroscopic evidence of abscess characterized by cavity formation with central pus; (2) microscopic evidence of acute and chronic inflammatory changes in the abscess wall; and (3) bacteriologic proof of M. tuberculosis. Surgical excision or incision/drainage was not performed in our patient in part because of the location of masses in vital areas. Our patient was successfully treated without surgical intervention but with appropriate antituberculous therapy and an antiinflammatory agent.

Although transmission of tuberculosis most commonly occurs secondary to airborne spread from patients with pulmonary or laryngeal tuberculosis who are not treated with effective antituberculous therapy, a draining abscess or manipulation of infected tissue represents a potential source of transmission. ^17–20 Hutton et al. ¹⁷ reported 9 secondary cases of tuberculosis and 59 tuberculin skin test conversions in a hospital setting after exposure to a patient with a tuberculous abscess of the hip and thigh. Although aerosol transmission of tuberculosis from pediatric patients is uncommon, there is a potential for aerosolization of a heavy concentration of mycobacteria from any body site. Our experience with rescreening of hospital employees immediately after the exposure and 2 months later did not reveal any PPD conversions. This may reflect either the low concentration of tubercle bacilli in our patient’s ears, consistent with experience with pediatric disease, or limited exposure to patient’s draining ears resulting from cotton packing. Although extensive case contact investigation is not routinely necessary for exposure to pediatric tuberculosis, our postexposure investigation was deemed necessary because of the nature and extent of the draining otitis and the surgical procedures performed during the hospitalization. This entailed substantial cost, time and effort that could have been decreased or eliminated if a diagnosis of tuberculosis had been considered earlier and proper isolation procedures had been instituted. If the diagnosis had been considered earlier, the consequences of this disease (profound bilateral hearing loss, ventricular-peritoneal shunt placement, neurologic sequelae and 2 weeks of hospitalization in the intensive care unit) could possibly have been minimized or avoided.