ESSENTIALS OF DIAGNOSIS
Defined by chronic infection (HBV, HCV, HDV) for longer than 3–6 months.
Diagnosis is usually made by antibody tests and viral nucleic acid in serum.
Chronic hepatitis is defined as chronic necroinflammation of the liver of more than 3–6 months’ duration, demonstrated by persistently elevated serum aminotransferase levels or characteristic histologic findings, often in the absence of symptoms. In many cases, the diagnosis of chronic hepatitis may be made on initial presentation. The causes of chronic hepatitis include HBV, HCV, and HDV as well as autoimmune hepatitis; alcoholic and nonalcoholic steatohepatitis; certain medications, such as isoniazid and nitrofurantoin; Wilson disease; alpha-1-antiprotease deficiency; and, rarely, celiac disease. Mortality from chronic HBV and HCV infection has been rising in the United States, and HCV has surpassed HIV as a cause of death. Chronic hepatitis is categorized on the basis of etiology (eFigure 16–11) (eFigure 16–12); the grade of portal, periportal, and lobular inflammation (minimal, mild, moderate, or severe); and the stage of fibrosis (none, mild, moderate, severe, cirrhosis). In the absence of advanced cirrhosis, patients are often asymptomatic or have mild nonspecific symptoms.
Mild chronic hepatitis (low power and high power).
Moderately severe chronic hepatitis (low power and high power).
1. CHRONIC HEPATITIS B & CHRONIC HEPATITIS D
Clinical Findings & Diagnosis
Chronic hepatitis B afflicts 248 million people worldwide (2 billion overall have been infected; endemic areas include Asia and sub-Saharan Africa) and up to 2.2 million (predominantly males) in the United States. It may be noted as a continuum of acute hepatitis B or diagnosed because of repeated detection of HBsAg in serum, often with elevated aminotransferase levels.
Five phases of chronic HBV infection are recognized: immune tolerant phase, immune active (or immune clearance) phase, inactive HBsAg carrier state, reactivated chronic hepatitis B phase, and the HBsAg-negative phase. In the immune tolerant phase (HBeAg-positive chronic HBV infection), HBeAg and HBV DNA are present in serum and are indicative of active viral replication, and serum aminotransferase levels are normal, with little necroinflammation in the liver. This phase is common in infants and young children whose immature immune system fails to mount an immune response to HBV.
Persons in the immune tolerant phase and those who acquire HBV infection later in life may enter an immune active phase (HBeAg-positive chronic hepatitis B), in which aminotransferase levels are elevated and necroinflammation is present in the liver, with a risk of progression to cirrhosis (at a rate of 2–5.5% per year) and of ...