Pontobulbar palsy and sensorineural deafness (Brown-Vialetto-van Laere syndrome): A case from Northwest Iran.

Brown–-Vialetto–-van Laere (BVVL) syndrome is a rare neurological disorder, which usually presents in late childhood and adolescence with various neurological symptoms and is characterized by progressive ponto-bulbar palsy and bilateral sensorineural deafness that usually precedes neurological symptoms.[123] It was first described in 1894 and since then almost 65 cases have been reported. Nearly 50% of patients are sporadic cases[13] and it usually involves females more than males.[1]

In this report, we describe a patient with BVVL syndrome with clinical and neurophysiological evidence of progressive nerve damage from Northwest of Iran. In the literature, there are only four reported BVVL syndrome cases from Iran.[4]

This paper reports a 10-year-old female patient from Tabriz, Northwest Iran with complete vaccination as scheduled with no family history of any progressive neuromuscular disease and no history of cognitive disorders. The symptoms first begun at the age of two years with decreased attention to acoustic stimulus; this disorder deteriorated during the time and presented with difficulty in speaking and swallowing and dysphagia for solids. Two to three years later, the patient had progressive weakness and atrophy in upper limbs causing difficulty in combing the hair, picking up small objects and doing elegant works by hand. She had difficult gait with multiple fallings. She lost weight during this period. She had no sphincter weakness.

She was weak and slender with body weight of 22 kg, height of 133 cm and body mass index of 12.43 kg/m2. On physical examination, she was a little anxious and had reduced cooperation due to hearing loss. Her speech was dysphonic and dysarthric. In the evaluation of cranial nerves, we observed atrophic tongue with ample fasciculations, poor gag reflex and palate weakness. Rinne and Weber tests were abnormal. There was no ptosis, no ocular movement impairment. She had horizontal nystagmus and had ataxic and wide-base gait with decreased upper limb movement with no truncal ataxia. Romberg's test was positive only with eyes closed. Finger to nose test was not reliable due to upper limb weakness.

Facial muscle examinations were normal. She had no sphincter disturbances. There was slight weakness in extensor and flexor muscles of the neck. Upper limbs were completely atrophic with decreased muscle tone and power especially in distal muscles, lower limbs had a normal muscle tone with slightly decreased muscle power in both proximal and distal muscles. Deep tendon reflexes were absent in upper limb and were pathologic in lower limbs. Plantar responses were extensor. Pain sense was normal, but other sensations in both limbs were not tested due to patient's poor cooperation.

Auditory brainstem response test showed severe sensorineural hearing loss. Blood tests, brain magnetic resonance imaging and electroencephalography were normal. In electromyography (EMG) nerve conduction study, the sensory nerve action potential was normal in upper and lower limbs. Compound muscle action potential was normal in lower limbs, but had severe amplitude reduction with normal latency and nerve conduction velocity in upper limb. In EMG, there were neurogenic changes including recruitment decrease, increase in amplitude and duration and polyphasic potentials with fibrillation in tongue muscles, proximal and distal muscles of upper limbs and proximal muscles of lower limbs [Tables 1 and 2].

Table 1

Nerve conduction studies of the patient

Table 2

Needle EMG

Unfortunately, the patient died a month after our primary evaluation due to respiratory failure.

The BVVL syndrome is a rare neurological disorder of unknown etiology, characterized by progressive pontobulbar palsy associated with sensorineural deafness.[1] The sensorineural hearing loss with progressive weakness and atrophy in upper limbs and tongue with ample fasciculations of the tongue in our female patient are consistent with the diagnosis of the BVVL syndrome.

Sensorineural hearing loss is almost always the first presenting symptom of the disease. The other four cases reported in our country were female, all sporadic with negative family history and presented with bilateral hearing loss.[4] However, in few studies other findings were preceding the hearing impairment, as Sathasivam et al. reported a patient with speech problem and facial weakness[5] and Summers et al. described limb weakness before sensorineural hearing loss.[6] Except for sensorineural hearing loss, other features of the disease could be variable.[1]

The diagnosis of BVVL syndrome includes progressive pontobulbar palsy with sensorineural deafness, exclusion of other causes of these symptoms and positive findings from EMG and/or pathological examination.[1] Fazio-Londe disease is the most similar disease to BVVL with progressive bulbar involvement in young children and ptosis, but without hearing loss.[7]

Nathalie syndrome is another differential diagnosis of BVVL, which is characterized by deafness, spinal muscular atrophy, cataract, cardiac conduction defects and hypogonadism.[8] The other similar syndrome to BVVL is the Boltshauser syndrome, which is characterized by distal muscular atrophy with vocal cord paralysis and sensorineural hearing loss.[9] However, this syndrome is usually hereditary. The Madras motor neuron disease is another condition very close to BVVL;[10] however, this is mostly reported in India and not in other places.

The clinical and electrophysiological findings in our patient are indicative of BVVL syndrome. Unlike the above mentioned diseases, it was sporadic with no family history or ocular involvement.