A UNIQUE CASE OF AUTOIMMUNE HEPATITIS PRESENTING AFTER A 5-DAY COURSE OF NITROFURANTOIN FOR UNCOMPLICATED URINARY TRACT INFECTION

Document Type

Conference Proceeding

Publication Date

6-23-2023

Publication Title

J Gen Intern Med

Abstract

CASE: An 84-year-old African American woman with a history of type 2 diabetes mellitus presented with postprandial right upper quadrant sharp shooting abdominal pain with associated nausea and vomiting. She reported taking nitrofurantoin 100 mg tablets twice daily for five days for a recent UTI. Denied taking herbal remedies or unprescribed supplements. Never smoked or drank excessive alcohol. Initial blood tests revealed elevated liver biochemistry with bilirubin 7.6 mg/dL, alanine transaminase 343 IU/L, aspartate aminotransferase 261 IU/L, and alkaline phosphatase 135 U/L. Her coagulation screen, full blood count, electrolytes, and renal function were normal. Viral hepatitis profile was negative. Toxicology labs were negative for acetylsalicylic acid (ASA), acetaminophen, and alcohol. Abdominal imaging was unremarkable. Immunological tests revealed positive smooth muscle antibodies with a titer of 95 units: normal IgA and IgG levels and low IgM. Double-stranded DNA antibodies, anti-mitochondrial antibodies, and anti-microsomal antibodies were not detected. A liver biopsy was performed which showed acute hepatitis with moderate necroinflammatory activity consistent with AIH and drug-induced liver injury (DILI). IMPACT/DISCUSSION: Several viruses and drugs have been reported to have caused autoimmune liver disease. One of the drugs is nitrofurantoin which is commonly prescribed due to its low cost, high efficacy, and minimal antimicrobial resistance. Acute liver injury from nitrofurantoin has a prevalence of ∼0.3/100,000 prescriptions, while chronic nitrofurantoin liver injury is estimated to be one in 1500. AIH is more common in females than males, with a ratio of 3.6:1. Acute hepatotoxicity is drug-induced liver injury immediately after exposure; chronic nitrofurantoin use is associated with chronic AIH. Our case is unique as the patient developed AIH three weeks after a 5-day course of nitrofurantoin for an uncomplicated UTI. The patient never had elevated liver function tests, a negative viral hepatitis profile, and any history of autoimmune disease or alcohol abuse. Our case was not a DILI, as these usually occur immediately after exposure or when the patient is actively taking the medication. We hypothesize that nitrofurantoin is associated with the development of AIH and the formation of antibodies (in our case, anti-smooth muscle antibodies). It may not only be a dose-related immune response that needs months of constant exposure to be evident; it might be related to nitrofurantoin acting as an antigen, possibly an idiosyncratic reaction. Treatment with steroids improved the LFT and symptoms within days which is also evidence in favor of AIH. CONCLUSION: In patients with recently treated UTI with nitrofurantoin who presents with acute elevation of LFTs within a few weeks, always take into consideration nitrofurantoin-induced AIH. Moreover, treatment with steroids should begin if the antibodies come out positive.

Volume

38

Issue

Suppl 3

First Page

S430

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