Recurrent paraparesis and death of a patient with 'whippet' abuse.

Nitrous oxide is increasingly used as a recreational drug that is easily and legally available worldwide. Occasional nitrous oxide use has been considered relatively safe without the development of addiction or major adverse effects. However, heavy long-term nitrous oxide abuse can be associated with severe neurological complications, and even deaths have been described. The characteristic presentation is myeloneuropathy with dorsal column degeneration and demyelinating sensory polyneuropathy related to vitamin B12 deficiency. Described is a 23-year-old male who developed recurrent paraparesis related to nitrous oxide abuse. A second, more severe, episode of paraparesis was associated with predominantly lower motor neuron damage. A partial recovery was achieved by discontinuation of nitrous oxide use and initiation of vitamin B12 supplementation. However, the patient relapsed and ultimately died while being intoxicated with several abusive substances. The case adds to the cumulative literature about the clinical phenomenology and dangers of nitrous oxide abuse.