Acute Liver Failure (Fulminant Hepatic Failure)



Acute Liver Failure (Fulminant Hepatic Failure)





(Hepatology 2005;41:1179-97)


DEFINITION:



  • Acute hepatic disease + coagulopathy (INR >1.5) + encephalopathy (without a history of prior liver disease, except Wilson’s & AIH)



    • Fulminant = develops within 8 weeks


    • Subfulminant (late-onset hepatic failure) = develops between 8 weeks and 6 months


  • Proposed other definitions: (Lancet 1993;342:273-275)



    • Hyperacute = encephalopathy develops within 7 days of the onset of jaundice


    • Acute = encephalopathy develops between 8-28 days of the onset of jaundice


    • Subacute = encephalopathy develops between 29 days and 12 weeks of the onset of jaundice


EPIDEMIOLOGY:



  • Rare: ˜2000 cases/year; Prior to transplant, survival was 15%


PATHOPHYSIOLOGY:



  • Outpouring of cytokines by a dying liver


  • See also Clinical Manifestations/Complications below


ETIOLOGIES: See also Liver- Drug Induced Liver Disease (Chapter 4.11)

ABC’s: Acetaminophen, HAV, AIH– HBV– HCV, CMV, Crypto- HDV, Drugs- E (esoteric): Wilson’s, Budd Chiari – Fatty: NASH, AFLP



  • Viral:



    • HAV, HBV, HCV (rare), HDV + HBV, HEV (especially if travel history or pregnant)


    • HSV (immunocompromised hosts), EBV, CMV, Adenovirus, Paramyxovirus, Parvovirus B19


  • Drugs/Toxins:

    General rule of thumb, new drugs started within 6 months of FHF



    • Acetaminophen (most common cause: ˜40-50% of all cases), accidental or suicidal


    • Other drugs (15-20%, 3rd most common cause): phenytoin, INH, rifampin, sulfonamides, tetracycline, valproate, amiodarone, PTU


    • Toxins: fluorinated hydrocarbons, CCL4, Amanita phalloides


    • Alternative remedies: black cohosh, kava, ma huang, gum thistle, he shon wu, comfrey, sunnhemp, bai-fang


  • Vascular:

    Should see global ischemia if this is the cause (i.e. ischemic pancreas); Liver has two blood supplies (Portal Vein, Hepatic Artery)



    • Ischemic hepatitis, Budd-Chiari syndrome, Hepatic veno-occlusive disease, Malignant infiltration


  • Malignancy:



    • Infiltrative types (i.e. HSM on exam): metastatic breast, melanoma (check LDH and get biopsy!), lymphoma/leukemia, small cell lung


  • Autoimmune Hepatitis (check ASMA, consider transjugular biopsy): Need to confirm because patients are likely to respond to steroids


  • Miscellaneous:



    • Wilson’s (always rule out in young person; ↑ unconjugated bili/hemolysis, urine copper; ↓ Aφ, ceruloplasmin) needs transplant urgently!


    • α1-AT deficiency, hemochromatosis, PBC, acute fatty liver of pregnancy, HELLP syndrome, Reye’s syndrome


  • Idiopathic (second most common cause ˜20-30%)



    • No markers of acute or chronic viral hepatitis, autoimmune hepatitis, or Wilson’s disease; No evidence of malignancy or pregnancy


    • No history of drug, toxin, alternative remedies or mushroom ingestion; No evidence of vascular etiology


    • Possible etiologies: viral hepatitis without markers, non A-E viral hepatitis, atypical non-hepatitis virus infection, unrecognized metabolic disorder or exposure to hepatotoxin



CLINICAL MANIFESTATIONS/COMPLICATIONS:

Most sequela are a combination of vasogenic edema, cytotoxicity via ammonia, systemic/intrarenal pressure changes, and immune derangements

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Aug 24, 2016 | Posted by in GASTROENTEROLOGY | Comments Off on Acute Liver Failure (Fulminant Hepatic Failure)

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