Nitrous oxide misuse: a clue not to be missed in young patients with venous thromboembolism
C. Er, K. Breen, A. Cohen
Clinical medicine March 1, 2023 DOI: 10.7861/clinmed.2022-0516 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Case study Case report Peer reviewed |
|---|---|
| Sample size | 2 |
| Population | Young adults who misused nitrous oxide: a 27-year-old man and a 21-year-old woman |
| Measures | vitamin B12, methylmalonic acid, homocysteine |
| Key findings | Both patients who misused nitrous oxide developed venous thrombosis (deep vein thrombosis in the man, cerebral venous sinus thrombosis in the woman) alongside low-normal vitamin B12 and elevated methylmalonic acid; the woman also had elevated homocysteine from functional B12 deficiency. The authors argue that clinicians should ask young patients with apparently unprovoked venous thromboembolism about recreational drug use, citing 14 previously reported cases of nitrous oxide-associated arterial and venous thrombosis. |
Abstract
A 27-year-old man presented with altered mental status and unilateral right lower limb swelling. Brain imaging and cerebrospinal fluid analysis were unremarkable. He reported history of nitrous oxide misuse after he recovered from his delirium. The diagnosis of drug induced psychosis was made. The right lower limb swelling was found to be due to extensive deep vein thrombosis. In another case, a 21-year-old woman presented with headache, vomiting and dipoplia. Brain imaging showed extensive cerebral venous sinus thrombosis. She also misused nitrous oxide. Both cases had low-normal vitamin B12 and elevated methylmalonic acid, consistent with nitrous oxide misuse. The woman was found to have elevated homocysteine because of functional vitamin B12 deficiency. Homocysteine was not measured in the man. Raised homocysteine is associated with increased thrombosis risk. Fourteen cases of nitrous oxide misuse associated arterial and venous thrombosis have been reported. These two cases highlighted the importance of inquiring about recreational drug use in young patients who presented with apparently unprovoked venous thromboembolism.