[Combined sclerosis of the spinal cord "revisited"]

RENEWED INTEREST: There are at least three reasons for revisiting subacute combined degeneration.

There is evidence that diagnosis is too often differed until a time when irreversible lesions of the spinal cord are present. A high degree of suspicion is mandatory.

Magnetic resonance imaging of the spine supplies interesting information about the distribution of lesions and their course under treatment. NO: Nitous oxide is an emerging cause of cobalamin deficiency. Patients sometimes develop myeloneuropathy after repeated or single exposure to nitrous oxide. This is explained by inactivation of methylcobalamin as a result of irreversible oxidation.