Severe hyperhomocysteinemia and peripheral neuropathy as side effects of nitrous oxide in two patients with sickle cell disease.

Nitrous oxide (N2O) is a widely used anesthetic agent. We report two patients with sickle cell disease (SCD) who presented with complications following the use of N2O. Patient 1, a 15-year-old girl, presented severe hyperhomocysteinemia, pancytopenia, vitamin B12 deficiency, and peripheral polyneuropathy after massive use of N2O for pain management. At the 1-year follow-up, hyperhomocysteinemia and B12 deficiency had resolved, but she had persisting mild symptoms of polyneuropathy. Patient 2, a 17-year-old boy, presented only severe hyperhomocysteinemia, only partially corrected by initial B12 supplementation. Careful monitoring of N2O use, especially in patients with SCD, is mandatory to prevent complications.