Multivitamin supplements and energy drinks in pyridoxine megavitaminosis

A 42-year-old woman with genetically confirmed but asymptomatic Huntington disease (HD) presented with a 2-year history of tingling along the lateral legs, intermittent band-like sensations in the legs that resolved with walking and worsened during rest, and searing pain from the knee down. She also noticed nocturnal leg jerking on days when she had energy drinks. She had no weakness, lower back pain, or bowel or bladder dysfunction. Family history was notable for HD in her brother and both parents. There was no significant alcohol use or other factors that may have contributed to her symptoms. Neurologic examination showed hyperreflexia in her legs but was otherwise normal (including intact perception of pinprick, light touch, and proprioception). She took duloxetine for anxiety and depression and zolpidem for insomnia. Diagnostic evaluation for multiple sclerosis, rheumatoid arthritis, and lupus was inconclusive. MRI showed mild C4–C7 posterior disk protrusions but no significant central or neural foraminal stenosis. Laboratory studies at presentation showed an elevated vitamin B6 (B6 or pyridoxine) level of 161.6 ng/mL (normal 2.1–21.7 ng/mL) and normal or negative complete blood count differential, metabolic profile (including fasting glucose), thyroid-stimulating hormone, vitamin B12, methylmalonic acid, antinuclear antibody, and Sjögren screen. Electrodiagnostic study showed no evidence of active lumbosacral radiculopathy or large fiber neuropathy. Addi...
Source: Nature Clinical Practice - Category: Neurology Authors: Tags: All Clinical Neurology, Peripheral neuropathy, All Pain, All Toxicology Cases Source Type: research