Early anion gap metabolic acidosis in acetaminophen overdose
Received 27 January 2009; received in revised form 25 March 2009; accepted 1 April 2009. published online 26 February 2010. Corrected Proof
Abstract
Purpose
The study aimed to determine the incidence and clinical significance of early high (>15 mEq/L) anion gap metabolic acidosis in acetaminophen (APAP) overdose.
Methods
A retrospective review of a cohort of 74 patients presenting within 24 hours of APAP overdose was conducted.
Results
Early high anion gap metabolic acidosis was present in 41% of patients on admission and persisted for 1.5 ± 0.1 days. The anion gap was associated with an elevated lactate level (4.5 ± 1 mmol/L) (r2 = 0.66, P < .05), which persisted for 1 day. The lactate level increased in proportion to the APAP concentration (r2 = 0.75, P < .05). Patients with increased anion gap had a higher incidence of confusion (48% vs 3%; P < .001) and lethargy (39% vs 6%; P = .003). Early high anion gap metabolic acidosis was found in the absence of shock or liver failure. All patients were treated with N-acetylcysteine and, despite the early high anion gap metabolic acidosis, none developed hepatic failure or hypoglycemia.
Conclusion
Early high anion gap metabolic acidosis in patients with APAP overdose is self-limited and does not predict clinical or laboratory outcomes. Persistent or late metabolic acidosis in the absence of liver failure is not likely due to APAP and should prompt a search for other causes of metabolic acidosis. Finally, APAP overdose should be considered in patients presenting to the emergency department with altered mental status, as this is a treatable condition when detected early.
aDivision of Pulmonary and Critical Care, Department of Internal Medicine, Kings County Hospital Center, Brooklyn, NY 11203, USA
bDepartments of Internal Medicine and Emergency Medicine, Kings County Hospital Center, Brooklyn, NY 11203, USA
cDivision of Pulmonary and Critical Care Medicine, Physiology, and Biophysics, University of Oklahoma Health Science Center, Box 26901, Oklahoma City, OK 73190, USA
dInternal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
eYaffe Ruden and Associates, NY 10065, New York, USA
Corresponding author. Division of Pulmonary and Critical Care, Department of Internal Medicine, Kings County Hospital Center, Brooklyn, NY 11203, USA.
Presented as a poster at the General Assembly of American College of Chest Physicians; Zein J, Kakoulas C, Toubia N, Kinasewitz G. Early high anion gap metabolic acidosis in patients with acetaminophen overdose: clinical significance. Chest 2004;126:872S.
ABSTRACT