A 66-year-old Indian man reported bilateral facial weakness that started when he was 15 to 20 years old and affected both upper and lower parts of the face. Two to three years later, he developed hoarseness and was found to have bilateral vocal cord paralysis, which required a tracheostomy several years later. Chronic slowly progressive course of findings shown in the video were associated with hearing impairment. Gradually, the patient developed slurring of speech, became deaf, and was found to have atrophy and fasciculations of the tongue. He denied swallowing or chewing difficulty, diplopia, or sensory symptoms. He also denied headache or weakness in the arms or legs or bowel or bladder disturbances, as well as muscle cramps, twitching, or weakness in the arms or legs. The following test results were all negative: MRI of the brain, cervical spines, thoracic spines, and a repeat cerebrospinal fluid exam. In addition, investigations for sarcoidosis were also negative. Electromyography and nerve conduction studies revealed no evidence of neuropathy. The patient’s tongue was denervated. Blink reflexes testing confirmed bilateral facial palsy. Brain stem responses suggested central interruption of the auditory pathway. He has two healthy brothers and one son. His parents did not have evidence of a neuromuscular problem.
The most likely diagnosis is:
1. Bulbar-onset ALS
2. Spinal muscular atrophy
3. Madras motor neuron disease
4. Brown-Vialetto-Van Laere syndrome
5. Facial-onset sensorimotor neuropathy
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The correct answer is: 3. Madras motor neuron disease.
Chronic slowly progressive cranial polyneuropathy (including facial nerves, vestibulo-cochlear nerves, hypoglossal nerves, and vagus nerves), the lack of sensory symptoms, and normal MRI of the brain stem suggested that the lesion was at the level of the motor neurons.
The patient had mild proximal weakness in the arms and legs and generalized areflexia with normal sural responses which also supported the notion of lower motor neuron disease.
There was no evidence of upper motor neuron involvement and the long duration strongly argued against ALS.
He had no family history to suggest spinal muscular atrophy. He also had no gynecomastia to suggest Kennedy disease.
Degenerative pathology was much more likely than autoimmune disease because of chronicity and normal cerebrospinal fluid exam and the lack of response to steroids.
Facial onset sensorimotor neuropathy can be considered, but the lack of sensory symptoms is atypical.
Madras variant of motor neuron disease is reported in South India (where the patient is from) and is most likely the case.1 Degeneration of cranial nerve nuclei 7, 9, and 10 and progressive hearing loss are typical.1 The cause is not clear.
Brown-Vialetto-Van Laere syndrome in the western literature seems to be the equivalent of it except that the former is not associated with riboflavin receptors mutation (it tested negative in this case).
1. Gourie-Devi M, Nalini A. Madras motor neuron disease variant, clinical features of seven patients. J Neurol Sci. 2003 209(1-2):13-7.