Clinical findings of hepatitis virus infections in humans
المؤلف:
Stefan Riedel, Jeffery A. Hobden, Steve Miller, Stephen A. Morse, Timothy A. Mietzner, Barbara Detrick, Thomas G. Mitchell, Judy A. Sakanari, Peter Hotez, Rojelio Mejia
المصدر:
Jawetz, Melnick, & Adelberg’s Medical Microbiology
الجزء والصفحة:
28e , p516-518
2025-11-30
75
The clinical features of infections by HAV, HBV, and HCV are summarized in Table 1. In individual cases, it is not possible to make a reliable clinical distinction among cases caused by the hepatitis viruses.
Table1. Epidemiologic and Clinical Features of Viral Hepatitis Types A, B, and C
Other viral diseases that may present as hepatitis are infectious mononucleosis, yellow fever, cytomegalovirus infection, herpes simplex, rubella, and some enterovirus infections. Hepatitis may occasionally occur as a complication of leptospirosis, syphilis, tuberculosis, toxoplasmosis, and amebiasis, all of which are susceptible to specific drug therapy. Noninfectious causes include biliary obstruction, primary biliary cirrhosis, Wilson disease, drug toxicity, and drug hypersensitivity reactions.
In viral hepatitis, onset of jaundice is often preceded by gastrointestinal symptoms, such as nausea, vomiting, anorexia, and mild fever. Jaundice may appear within a few days of the prodromal period, but anicteric hepatitis is more common.
Extrahepatic manifestations of viral hepatitis (primarily HBV) include a transient serum sickness-like prodrome consisting of fever, skin rash, and polyarthritis; necrotizing vasculitis (polyarteritis nodosa); and glomerulonephritis. Circulating immune complexes have been suggested as the cause of these syndromes. Diseases associated with chronic HCV infections include mixed cryoglobulinemia and glomerulonephritis. Extrahepatic manifestations are unusual with HAV infections.
Uncomplicated viral hepatitis rarely continues for more than 10 weeks without improvement. Relapses occur in 5–20% of cases and are manifested by abnormalities in liver function with or without the recurrence of clinical symptoms.
The median incubation period is different for each type of viral hepatitis (see Table1). However, there is considerable overlap in timing, and the patient may not know when exposure occurred, so the incubation period is not very useful in determining the specific viral cause.
The onset of disease tends to occur abruptly with HAV (within 24 hours) in contrast to a more insidious onset with HBV and HCV. Complete recovery occurs in most hepatitis A cases (Table 2). The disease is more severe in adults than in children, in whom it often goes unnoticed. Relapses of HAV infection can occur 1–4 months after initial symptoms have resolved.
Table2. Outcomes of Infection with Hepatitis A Virus a
The outcome after infection with HBV varies, ranging from complete recovery to progression to chronic hepatitis and, rarely, death from fulminant disease. In adults, 65–80% of infections are inapparent, with 90–95% of all patients recovering completely. In contrast, 80–95% of infants and young children infected with HBV become chronic carriers (Table 3), and their serum remains positive for HBsAg. The vast majority of individuals with chronic HBV remain asymptomatic for many years; there may or may not be bio chemical and histologic evidence of liver disease. Chronic carriers are at high risk of developing hepatocellular carcinoma.
Table3. Transmission of Hepatitis B Virus and Spectrum of Outcomes of Infection
Fulminant hepatitis occasionally develops during acute viral hepatitis, defined as hepatic encephalopathy within the first 8 weeks of disease in patients without preexisting liver disease. It is fatal in 70–90% of cases, with survival uncommon after the age of 40 years. Fulminant HBV disease is associated with superinfection by other agents, including HDV. Most patients who survive have complete restoration of the hepatic parenchyma with normal liver function after recovery. Fulminant disease rarely occurs with HAV or HCV infections.
Hepatitis C is usually clinically mild, with only minimal to moderate elevation of liver enzymes. Hospitalization is unusual, and jaundice occurs in fewer than 25% of patients. Despite the mild nature of the disease, 70–90% of cases progress to chronic liver disease. Most patients are asymptomatic, but histologic evaluation often reveals evidence of chronic active hepatitis, especially in those whose disease is acquired after transfusion. Many patients (20–50%) develop cirrhosis and are at high risk for hepatocellular carcinoma (5–25%) decades later. About 40% of chronic liver disease is HCV related, resulting in an estimated 8000–10,000 deaths annually in the United States. End-stage liver disease associated with HCV is the most frequent indication for adult liver transplants.
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