Clinical toxicology : the official journal of the American Academy of Clinical Toxicology and European Association of Poisons Centres and Clinical Toxicologists
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Clin Toxicol (Phila) · Nov 2013
ReviewWhat is the clinical significance of 5-oxoproline (pyroglutamic acid) in high anion gap metabolic acidosis following paracetamol (acetaminophen) exposure?
Paracetamol (acetaminophen) ingestion is the most frequent pharmaceutical overdose in the developed world. Metabolic acidosis sometimes occurs, but the acidosis is infrequently persistent or severe. A growing number of case reports and case series describe high anion gap metabolic acidosis (HAGMA) following paracetamol exposure with subsequent detection or measurement of 5-oxoproline (also called pyroglutamic acid) in blood, urine, or both. Typically 5-oxoprolinuria or 5-oxoprolinemia occurs in the setting of inborn genetic errors in glutathione metabolism. It is unknown whether 5-oxoprolinemia in the setting of paracetamol exposure reflects an acquired or transient derangement of glutathione metabolism or previously unrecognized genetic defects. ⋯ In rare cases, HAGMA in the setting of paracetamol exposure is attributable to 5-oxoprolinemia. Clinicians should first exclude commoner and treatable causes of HAGMA, such as lactic acidosis, co-ingested drug administration, and ketoacidosis. It is likely that the propensity for HAGMA following paracetamol exposure may be genetically determined. The effects of acetylcysteine on 5-oxoproline concentrations or clinical outcome are unknown. When HAGMA is diagnosed, the 5-oxoproline concentration and the glutathione synthetase activity should be measured.