Encephalomyelitis with hearing loss: case report on neurobrucellosis

Abstract

Neurobrucellosis is a zoonotic infection transmitted by infected animals or by contact with animal products and is an important health problem in resource-limited settings. In this case report, we present the case of a middle-aged man presenting with encephalomyelitis with hearing loss and diagnosed with neurobrucellosis based on imaging and serological tests. Because brucellosis infection is indolent, a high index of suspicion should be maintained in individuals presenting with fever, neurological signs and symptoms so that early management can prevent long-term neurological sequelae such as focal neurological deficits, hydrocephalus and psychiatric sequelae.

Background

Brucellosis, caused by gram-negative bacteria, is a highly infectious, multi-systemic zoonotic disease. Neurological involvement in brucellosis is uncommon, though not rare, and can have devastating consequences if not managed efficiently. Predominant symptoms in neurobrucellosis include behavioural changes, headache, visual impairment and hearing loss. It can involve corticospinal and cerebellar tracts, can cause speech impairment, and may lead to peripheral neuropathy and sphincter disturbances as well.¹ Despite well-documented seroprevalence, human brucellosis is less commonly reported from this part of the world, which could be because of a lack of awareness, suspicion and diagnostic facilities. Moreover, wide neurological presentation due to neurobrucellosis in the present case prompted us to report this case.

Case presentation

Right-handed male in his early 40s living in sub-Himalayas, presented with bilateral lower limb weakness and bladder disturbances (urgency and urge incontinence) for 10 months. Along with these, he also had sensory disturbances over his lower limbs in the form of decreased touch, hot and cold sensations, with walking on cotton wool-like sensation. All these symptoms started after a bout of fever and joint pains lasting 10 days. Over the next 10 months, he became bed-bound due to severe weakness in both lower limbs. For the last 4 months, he also had symptoms of anger outbursts, apathy and undue irritability, along with bilateral hearing loss. On examination, his mental status examination revealed impaired frontal and temporal lobe function tests. Cranial nerve examination revealed bilateral sensorineural hearing loss with motor examination revealing the power of Medical Research Council grade 1/5 in lower limbs with impaired touch, pinprick and temperature sensations below the umbilicus and impaired joint position sensation at the big toe. Cerebellar and extrapyramidal examinations were normal.

Investigations

Keeping in view the above findings and history of fever, he was investigated on the lines of chronic infectious encephalomyelitis, the most common aetiologies thought of being central nervous system (CNS) tuberculosis, neurosyphilis and neurobrucellosis. His investigation revealed normal haemogram/liver and renal function tests. His cerebrospinal fluid (CSF) workup revealed a total of 108 cells (N5, L-95%), with proteins of 171 and reduced sugars of 18 mg%, Indian ink and tuberculosis gene expert, veneral disease research laboratory (VDRL), being negative (table 1). The vasculitic panel was negative. MRI revealed subtle leptomeningeal enhancement at peri-mesencephalic subarachnoid space and conus medullaris level along with T2 hyperintensity at b/l external capsule, anterior temporal lobe, subcortical white matter with mild cortical atrophy (figure 1). CT chest and abdomen were normal. On pure tone audiometry, he had severe sensorineural hearing loss.

Table 1.

All relevant investigations done in the patient

Serial No.	Investigations	Values/reports
1	HB/TLC/DLC/ESR	12.5/6450/70:28:2/16
2	Urea/Creatinine	38/1.10
3	Serum sodium/potassium/calcium/phosphorus	132/4.10/9.10/3.04
4	Total protein/albumin/SGOT/SGPT/ALP	7.0/4.5/38/65/118
5	CRP	1.73
6	ANA/ANCA/ACE levels	Negative/negative/21.9 (normal: 8–63)
7	HBsag/HIV elisa/HCV elisa	Negative
8	BAER	B/l prolonged I–III, III–V and I–V interpeak latency s/o peripheral and central hearing loss
9	VEP	VEP showing b/l normal Pl00 latencies
10	CT chest+abdomen	Normal study
11	CSF examination	108 cells (N5, L-95%), proteins of 171, reduced sugars of 18 mg%, Indian ink and tuberculosis gene expert, VDRL, being negative
12	Brucella Standard Agglutination Test	1:640 titre
13	CEMRI brain	Subtle leptomeningeal enhancement at perimesencephalic subarachnoid space and at conus medullaris level. T2 hyperintensity at b/l extreme capsule, anterior temporal lobe, subcortical white matter

ACE, Angiotensin-converting enzyme; ALP, Alkaline phosphatase; ANA, Anti-neutrophilic antibody; ANCA, Antineutrophilic cytoplasmic antibodies; BAER, Brainstem auditory evoked response; CEMRI, Contrast enhanced MRI; DLC, Differential leucocyte count; ESR, Erythrocyte sedimentation rate; HB, Haemoglobin; HCV, Hepatitis C virus; SGOT, Serum glutamic oxaloacetic transaminase; SGPT, Serum glutamic pyruvic transaminase; TLC, Sotal leukocyte count; VDRL, Veneral disease research laboratory; VEP, Visual evoked potential.

Figure 1.

MRI revealing subtle leptomeningeal enhancement at conus medullaris level (A) and peri-mesencephalic subarachnoid space (B) along with T2 hyperintensity at b/l external capsule, anterior temporal lobe, subcortical white matter with mild cortical atrophy (C).

The Brucella Standard Agglutination Test showed a titre of 1:640. His blood culture and CSF culture showed the growth of Brucella species.

Treatment

He received ceftriaxone for 2 weeks along with rifampicin, isoniazid and cotrimoxazole, which were continued. Steroids were not given as we could not find clear indication in patient for their use.

Outcome and follow-up

On a follow-up visit after 3 months, there was a significant improvement as he started walking with one-person support. Though there was no further deterioration in his hearing status his hearing deficit did not improve much on follow-up.

Discussion

Human brucellosis is a multisystem disease that commonly presents as a febrile illness along with a variable spectrum of clinical manifestations. Contact with animals and consumption of animal products are the principal source of infection to humans, and in our case too, probably consumption of animal products was the source of brucellosis. Neurological complications include meningoencephalitis, encephalitis, radiculitis, myelitis, peripheral and cranial neuropathies, subarachnoid haemorrhage and psychiatric manifestations.^{2 3} Damage in the inner ear caused by brucella toxin penetrating into the labyrinth and affecting the cochlear nerve could explain hearing loss in Brucella infection. The disease has a wide geographic distribution and is labelled as a regionally emerging zoonotic disease.⁴

Erdem et al defined chronic Brucella meningitis based on neurological symptoms lasting more than 4 weeks, the presence of typical CSF (protein concentrations >50 g/dL, pleocytosis over 10/mm³ and low CSF sugars), positive bacterial culture or serological test results for brucellosis in CSF or the blood (positive Rose Bengal Test and serum tube agglutination with a titre of 1/160).⁵ Based on these criteria alone, we established the diagnosis of neurobrucellosis in the present case. In neurobrucellosis, imaging findings may be normal or may show meningeal contrast enhancement, non-enhancing white matter changes, grey matter involvement and vascular changes.⁶ Dual or triple-combination therapy with doxycycline, rifampicin, trimethoprim-sulfamethoxazole, streptomycin or ceftriaxone for >2 months (3–6 months) has been recommended.⁷ A short course of steroids has been found to be effective in those with arachnoiditis, optic neuritis and multiple sclerosis like presentations.⁷ Sequelae among survivors despite appropriate antibiotic therapy are well known, however, mortality is uncommon.⁷ They are significant if the patient has diffuse CNS, encephalitis or spinal cord involvement compared with meningitis as a presentation.

We need to keep neurobrucellosis in mind in cases of fever of unknown origin, meningitis/meningoencephalitis with lymphocytic predominance in CSF, especially in endemic areas especially when these occur with hepatosplenomegaly or a recent history of weight loss.⁸

Learning points.

• Neurobrucellosis should be considered a treatable cause of chronic meningitis, particularly in the setting of bilateral hearing loss and a history of intake of raw milk products.

• Exclusion of other causes and positive cultures or serological tests remain the mainstay of diagnosis.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).