Severe Isolated Peripheral Polyneuropathy without Myelopathy after Nitrous Oxide Abuse: A Case Report

Nitrous oxide (N2O) abuse induces vitamin B12 deficiency, resulting in complications the central and peripheral nervous systems. Some cases related to subacute combined degeneration or myeloneuropathy after N2O have been reported. However, isolated polyneuropathy without spinal cord involvement has rarely reported South Korea. We describe a 29-year-old woman who had inhaled “happy balloons” daily (1,000 balloons/day) for recreational purposes over 3-month period, presented with acute symmetrical hypoesthesia, paresthesia, motor weakness on bilateral lower limbs. Serologic tests showed megaloblastic anemia deficiency. Magnetic resonance imaging of brain spine no abnormalities. An electrodiagnostic study confirmed limb-dominant axonal sensorimotor due deficiency from abuse. The patient was treated intramuscular replacement. A follow-up 4 months initial only partial improvement. Despite legal efforts Korean government ban use other than medical purposes, its are rise, especially among young adults. Physicians should recognize strong possibility as an underlying cause responsive involvement.