ACUTE LIVER FAILURE Acute liver failure is defined as the rapid development of hepatocellular dysfunction (WITHIN 8 WEEKS OF DISEASE ONSET), specifically coagulopathy and mental status changes (encephalopathy) in a patient without known prior liver disease. The commonest causes are viral hepatitis ( A , B,C,E) and drugs and toxins( commonest is acetaminophen)

Hepatic Failure Most severe clinical consequence of liver disease May be: result of sudden and massive hepatic destruction end-point of progressive chronic liver disease ( the name here is called decompensated liver ) 80% - 90% loss of hepatic functional capacity

Hepatic Failure Morphologic alterations causing liver failure: Massive hepatic necrosis Mechanisms: (i) direct damage to hepatocytes (ii) immune-mediated hepatocyte destruction a. drug or toxin-induced b. infection – viral hepatitis except hep. C Chronic liver disease – most common cause Hepatic dysfunction without over necrosis – e.g. Reye’s syndrome, tetracycline toxicity, acute fatty liver of pregnancy

Hepatic Failure Clinical Features: Jaundice Hypoalbuminemia  peripheral edema Hyperammonemia  cerebral dysfunction Fetor hepaticus  “musty” or “sweet & sour” body odor due to mercaptan formation by action of GI bacteria on methionine (sulfur-containing) Impaired estrogen metabolism  hyperestrogenemia (a) palmar erythema – 2o to local vasodilatation (b) spider angiomas – central, pulsing, dilated arteriole from which small vessels radiate (c) hypogonadism & gynecomastia in males

Hepatic Failure Clinical Features: Multi-organ system failure respiratory failure with pneumonia, sepsis + renal failure  cause of death Coagulopathy impaired synthesis of factors II, VII, IX and X  (+) bleeding tendency

Hepatic Failure Complications: Hepatic encephalopathy associated with increased blood ammonia levels reversible if underlying hepatic condition can be corrected features: (a) change in consciousness (b) fluctuating neurologic signs – rigidity, hyperreflexia, asterixis

Hepatic Failure Complications: Hepatorenal syndrome renal failure in patients with chronic liver disease main renal functional abnormalities: (a) sodium retention (b) impaired free water excretion (c) decreased renal perfusion (d) decreased GFR

Hepatic Failure Complications: Hepatorenal syndrome decreased urine output with rising BUN & creatinine ability to concentrate urine retained  hyperosmolar urine without proteins; abnormal sediments; dec. Na+