Influenza A-associated Liver injury

Thanks Joel Horton for presenting a great case! And thanks to Emery Lin for coming and dropping some awesome pearls. This is a young woman presenting with URI symptoms, nausea/ vomiting found to have influenza A and associated liver injury complicated by oliguric renal failure necessitating hemodialysis.

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Main points:

  1. ) LFT abnormalities can be classified as hepatocellular (transaminitis predominant), cholestatic (hyperbilirubinemia, elevated alk phos), isolated hyperbilirubinemia, isolated synthetic dysfunction (abnormal albumin, INR) and cirrhosis (generally combination of hyperbilirubinemia and synthetic dysfunction). Each has its own differential diagnosis. Here is an excellent video that summarizes the approach to abnormal LFTs.
  2. ) Effectiveness of the influenza vaccine is generally estimated based on this season’s Southern Hemisphere responsiveness, and this year’s report from the Australian Government Department of Health estimates only a 10% effectiveness against influenza A (H3N2), the predominant strain.
  3. ) Evaluation of LFTs in the 1000s include thinking about and testing the following etiologies: viral, drug-induced, autoimmune, vascular, and shock. See the following ACG guidelines for more on evaluation and management of LFT abnormalities.

Want to learn more?

Influenza

  • the US sees approximately 140-710k hospitalizations and 12-56k influenza deaths per year
  • strain-specific vaccination occurs due to continued antigenic drift, which is made based on models to guess which strains will predominate the coming season
  • vaccines are generally trivalent or quadrivalent
  • at best, vaccine effectiveness has been 40-60%, but vaccine mismatches often occur (eg 2014-2015 influenza season)
  • the US Advisory Committee on Immunization Practices and the CDC recommend influenza vaccination for all individuals 6 months or older; generally the inactivated vaccine is used; the vaccine is safe in people with an egg allergy

LFT abnormalities in pregnancy Although this patient was not pregnant, there is a differential to consider for LFT abnormalities in pregnant patients, largely stratified by trimester and presentation. Here is a MKSAP chart that compares the different diagnoses and how they present.

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Here is a great review article about liver disease in pregnancy from the journal Hepatology.