Hepatitis, Viral

Viral hepatitis accounts for more than 50% of cases of acute hepatitis in USA.

Caused by infection with any of at least five distinct viruses: HAV, HBV, HCV, HDV, and HEV.

Most commonly caused by HAV, HBV, or HCV.

With more widespread use of the HAV and HBV vaccine, the rate of infection has decreased.

Hepatitis is a very common infection in economically developing countries of Africa, Asia, and Latin America; children are frequently sources of outbreaks in crowded households, day care centers, and institutions; increased risk of disease is associated with travel to developing countries, men who have sex with men, users of injected and noninjected drugs, and persons with clotting-factor disorders.

Healthcare workers do not appear to be at increased risk for occupationally acquired infection.

Elective surgery should not be performed on pts with acute HAV infection.

Surgery in HBV infection depends on activity and stage of infection.

Worsening liver function, hepatic encephalopathy, and coagulopathy are risks in all cases of acute infection.

Risk of transmission of HCV from carrier to anesthesia personnel is ∼2% after percutaneous exposure.

With acute hepatic failure or end-stage liver disease: Coagulation abnormalities, decreased hepatic metabolism of drugs, decreased levels of plasma cholinesterase, hypoxemia from pulm shunting and edema, ascites and Na ⁺ overload, hypokalemia, hepatic encephalopathy and cerebral edema, impaired glucose metabolism and hypoglycemia, portal Htn and GI bleeding, acute renal failure and hepatorenal syndrome, infection and sepsis, malnutrition.

Maintenance of liver blood flow and O ₂ delivery; metabolism of drugs with hepatic clearance; hypoglycemia; prolonged effect of sedatives.

In addition to the use of universal precautions by anesthesia personnel, use of sharp devices for invasive procedures should be minimized and/or safety devices should replace standard sharps.

HAV replicates in the liver and is shed in the stool; the concentration in the stool is highest during the 2-wk period before to 1 wk after the onset of clinical symptoms; the risk of transmission of infection via the fecal-oral route is greatest during this time.

• Symptoms do not occur until the viral load in the stool begins to decrease; most pts with hepatitis A do not require hospitalization for treatment.

• In children <6 y of age, most HAV infections are asymptomatic; among older children and adults, most infections are symptomatic, with jaundice occurring in over 80%.

• The two most common physical findings are jaundice and hepatomegaly. In symptomatic pts, the most common lab findings are elevated levels of serum ALT and bilirubin.

• Chronic HAV infection does not occur; most acute infections resolve within 2 mo; 10–15% of symptomatic pts may have a relapse of illness for up to 6 mo.

• Fulminant hepatitis with acute liver failure occurs in about 0.5% of all pts with HAV infection; the rate is 1.8% among adults >50 y of age; pts with chronic liver disease are at increased risk for fulminant hepatitis when infected with HAV.

Hepatotropic viral infection: 90% of pts have self-limiting acute hepatitis; 10% become chronic HBV carriers, with about half of those progressing to chronic active hepatitis, cirrhosis, or hepatocellular carcinoma; 0.5% of pts with acute infection develop fulminant hepatitic failure.

• 70% with acute infection have subclinical hepatitis; symptomatic infection may produce jaundice, malaise, nausea, and abdominal pain.

Hepatotropic insidious viral infection; fulminant acute hepatitis C is rare.

• 60–70% of individuals with acute HCV infection are asymptomatic or have only a mild clinical illness.

• 70–85% of pts infected with HCV develop chronic infection; cirrhosis develops in up to 50% of individuals with chronic hepatitis C and hepatocellular carcinoma in 1–5%.

• Pts >50 y may have a more rapid progression of liver injury; alcohol use increases the risk of liver injury.

HAV is a 27-nm RNA nonenveloped virus transmitted by the fecal-oral route by either person-to-person contact or ingestion of contaminated food or water; rarely, HAV has been transmitted by transfusion of blood or blood products collected from donors in the viremic phase of infection.

HBV is a 42-nm DNA virus with eight genotypes that is carried in and spread by blood and body fluid contact. It is transmitted to nonimmune individuals via parenteral or mucocutaneous exposure to HBV-infected blood or body fluids.

HCV is a 30- to 60-nm RNA virus with at least six genotypes that is carried in and transmitted by exposure to blood and body fluids.