Methylenetetrahydrofolate Reductase Deficiency: A Case Report.

Methylenetetrahydrofolate reductase (MTHFR) deficiency is an autosomal recessive disorder that results in hyperhomocysteinemia. Elevated homocysteine levels in the blood can cause arterial and venous thrombosis, atherosclerosis, recurrent pregnancy loss, and neurologic symptoms. Emerging research suggests links to other chronic illnesses as well. Anesthetic management of patients with MTHFR deficiency should focus on decreasing the risk of arterial or venous thrombosis and minimizing elevations in homocysteine levels. Thrombosis prevention includes the use of antiembolism compression stockings, intermittent pneumatic compression sleeves, subcutaneous heparin or low-molecular-weight heparin, early ambulation, and adequate hydration. Nitrous oxide is known to inhibit methionine synthase, a vitamin B12-dependent enzyme responsible for the breakdown of homocysteine, resulting in homocysteine elevation, and should be avoided in these patients. Intravenous vitamin B12 infusion before surgery may help decrease homocysteine levels; however, it is not readily available in most operating rooms. Propofol and sevoflurane do not increase homocysteine levels and are considered safe for patients with MTHFR deficiency. This case study describes a 58-year-old man with known MTHFR deficiency and his subsequent uneventful anesthetic care during a total knee replacement.