Amino acid intolerance during prolonged total parenteral nutrition reversed by molybdate therapy

Abstract

This report describes a patient suffering from intolerance to amino acids, mainly l-methionine, while on prolonged total parenteral nutrition. The patient displayed tachycardia, tachypnea, central scotomas, night blindness, and irritability, leading to coma while on total parenteral nutrition. The symptoms disappeared with discontinuation of the administered l-amino acid solutions. Biochemical abnormalities included high plasma methionine (110 to 130 µmol/L, normal 10 to 55 µmol/L) and low serum uric acid levels (0.5 to 1.4 mg/dl) associated with increased urinary excretion of sulfite (strong positive colorimetric reaction on Machery Nagel strips versus absent reaction in controls), thiosulfate (4.4 to 9.5 mM/d day or 30 to 50% of total sulfur excretion versus normal = 0.4 ± 0.1 mM/day or µg/day) improved the clinical condition, reversed the sulfur handling defect, and normalized uric acid production. This may represent the first case of diet-induced molybdenum deficiency in man.