The hepatoprotective effects of N-acetylcysteine with repeated toxic acetaminophen ingestions: a case report
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Background: It has classically been taught that a patient with acetaminophen toxicity will not have any continued liver dysfunction after recovery from an initial acute insult. Despite this notion, there has not been a
case reported in the literature of recurrent acute acetaminophen (APAP)
overdose with known time of ingestion.
Methods: Retrospective chart review of one patient who presented 27
times after large acute acetaminophen ingestion, receiving Nacetylcysteine (NAC) 20 times, without residual signs of liver
Methods: The patient’s electronic medical record (EPIC®) was reviewed
at patient’s preferred hospital site as well as the Minnesota Poison Control
System (Toxicall®) to identify total number of ingestions, serum APAP
level, administration of NAC, and subsequent laboratory results. Serial
liver function tests and acetaminophen levels were analyzed to attempt to
determine induction of metabolism. Results: All presentations were very similar: witnessed by employees at
her group home, presented about 1 h after ingestion, and ingested 25 g of
APAP (50 tablets of 500 mg; not extended-release). The patient received
NAC 20 times over a 9-year period due to a toxic 4-h serum APAP level;
13 times in a 6-month period.
Despite the repeated toxic acetaminophen insults, there were no residual
signs of liver dysfunction. Her aspartate aminotransferase (AST) and
alanine aminotransferase (ALT) never reached 40 IU/L. One time, her
INR increased to 2.3 the day after a 4-h serum APAP level of 355 mcg/
mL, the highest APAP level recorded for this patient. Otherwise, INR was
never greater than 1.2.
Discussion: This patient was repeatedly witnessed ingesting a potentially hepatotoxic dose of acetaminophen with numerous serum
levels above the standard Rumack-Matthew nomogram line. This
case illustrates the long-taught concept that there is no residual
liver damage if an APAP overdose is adequately treated with Nacetylcysteine and patient reaches stage IV of APAP toxicity. It
also provides tangible evidence that repeat toxic ingestions do not
have a cumulative effect.
Conclusion: This case report demonstrates the intrinsic and repeated
hepatic reparative properties as long as the liver is allowed to heal between insults.
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