Case Studies

Correct answer: It is difficult in this gentleman to be certain of the site of the pathology as he clearly has evidence of peripheral nerve involvement with absent ankle jerks and sensory loss in a glove and stocking distribution in his hands and feet. However this cannot account for his spasticity as this would imply an upper motor neurone lesion and therefore involvement of the central nervous system. The ataxia could conceivably be due to his peripheral neuropathy although of course there could be a central component for it. Therefore the most likely pathological process in this gentleman involves both his central and peripheral nervous system.

Correct answer: In someone who is a vegan with peripheral and central nervous system involvement the most likely explanation is vitamin B12 deficiency. This can be easily proven by simply measuring serum B12 levels. B12 is necessary for the myelination of both peripheral and central nerves.

Correct answer: Clearly anything that involves the peripheral and central nervous system motor pathways could do this such as motorneurone disease. Rare causes are some forms of leucodystrophies but it is always important to remember that a lesion in the lower part of the spinal cord in the region of the conus can give this syndrome. Finally it is possible to have two different pathologies such as lumbar disc disease causing the loss of ankle jerks and an independent spinal cord lesion/compression causing the spastic legs such as a cervical myelopathy from cervical degenerative disease.

Correct answer: Yes as it could reflect demyelination in his dorsal columns as a result of his B12 deficiency. However it could not account for all of his symptoms given that he also has a glove and stocking sensory loss which would be most unusual for a lesion in this site. This latter symptoms is more likely to reflect peripheral nerve demyelination secondary to the B12 deficiency.