1. Is there evidence of peripheral nerve involvement in this case, and, if so, what is the level(s) of the involvement? If peripheral nervous system involvement is present, how would you characterize that further?
Probably not. While numbness and paresthesias are common in the early stages of acute inflammatory demyelinating polyneuropathy or Guillain-Barré syndrome (GBS), these symptoms are soon overshadowed by progressive weakness and areflexia. Pure sensory variants of GBS and acute sensory neuronopathies (ganglionopathy) exist, but one would expect objective sensory loss in these entities.
2. Is there evidence of dorsal or ventral root involvement or spinal nerve involvement in this case, and, if so, what is the level(s) of the involvement?
No (same reasoning as in #1 above)
3. Is there evidence of spinal cord involvement in this case and, if so, at what level? If spinal cord involvement is present, what specific structures are involved by the pathologic process?
Yes. The patient’s symptoms could be caused by a pathologic process beginning near the midline in the posterior funiculi (posterior white columns) of the spinal cord at the L1 level or above and spreading outward into both fasciculi gracilis. This process could produce subjective numbness and paresthesias beginning in both feet and ascending to involve both lower limbs from the groin downward.
4. Could the patient’s signs and symptoms be caused by a lesion anywhere else in the central nervous system? If so, where would the lesion be located? What facts would support or refute this site of lesion localization?
Bilateral lower limb numbness and tingling could be caused by a midline lesion
involving the posterior (sensory) part of the paracentral lobule. However, these lesions (e.g., a parasagittal meningioma) usually produce symptoms mainly in the contralateral lower limb, since the falx cerebri tends to confine the lesion to one hemisphere. One would also expect motor impairment as well with such a lesion.
5. In general, what type of pathologic process do you think is involved in this case?
Demyelinating disease. This patient had multiple sclerosis, but this was his first symptomatic exacerbation.
6. What diagnostic procedures would you undertake at this point?
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