GENERAL CONSIDERATIONS

The term acute hepatitis is not well defined. It generally denotes conditions of self-limiting hepatic injury, although, in many instances, it also encompasses the early phase of chronic liver diseases such as hepatitis B and C. Implicit in the definition, liver histology at the time of presentation should have no evidence of chronicity, such as fibrosis.

Most cases of acute hepatitis are caused by viral hepatitis. Systemic infections such as pneumonia are also commonly associated with non-specific and reactive hepatitis. A smaller cohort is associated with drugs, vascular abnormalities, metabolic disturbance, autoimmunity, pregnancy and systemic illness, such as cardiogenic shock and metabolic disturbance (Table 34.1). However, in fulminant hepatic failure or subfulminant hepatic failure, drugs can become a dominant cause of acute hepatitis. The scope of this chapter will focus primarily on acute viral hepatitis.

TABLE 34.1 Differential diagnoses of acute hepatitis

CLINICAL PRESENTATION

The clinical spectrum of acute hepatitis may range from mild symptoms and signs (Table 34.2) associated with recent onset of liver enzyme abnormalities to fulminant hepatic failure. Most symptoms and signs are non-specific (Table 34.2) though there are some manifestations associated with specific conditions, and if present, are helpful in differential diagnosis (Table 34.3).

TABLE 34.2 Non-specific symptoms and signs of acute hepatitis

TABLE 34.3 Diagnostically helpful associations of acute hepatitis

DIFFERENTIAL DIAGNOSES

A diagnostic algorithm is suggested for assessing a patient presenting with acute hepatitis (Figure 34.1). There may be obvious clues at the outset such as pregnancy, history of paracetamol overdose or recent drug use. Serology for common causes of viral hepatitis and paracetamol level should be requested as initial investigations. Failing to identify an obvious cause, other less common causes would need to be considered and liver biopsy may be necessary.

FIGURE 34.1 An algorithm for diagnostic investigations for acute hepatitis.

ANA = antinuclear antibody; BSL = blood sugar level; CMV = cytomegalovirus; EBV = Epstein-Barr virus; HAV = hepatitis A virus; HBV = hepatitis B virus; HCV = hepatitis C virus; HIV = human immunodeficiency virus; SMA = anti-smooth muscle antibody; TFT = thyroid function tests; US = ultrasound.