During the prodromal phase, the early nonspecific phase before jaundice, of hepatitis B virus (HBV) infection, a serum sickness-like syndrome occurs in 5-10% of patients. It is characterized by joint pain and arthritis, rash, angioedema (swelling of deeper layers of the skin), and hematuria and/or proteinuria (blood or protein in the urine). These symptoms appear before the icteric phase, the phase of jaundice, which is why the illness can be misdiagnosed as a rheumatological disorder.
Chronic infection
Chronic hepatitis B can be considered a complication of acute infection. Detecting no HBsAg (the hepatitis B surface antigen) after apparent resolution of the infection is a good sign of complete resolution. About 5% of adults who develop acute hepatitis B fail to clear HBsAg and remain seropositive beyond 6 months, becoming chronically infected; in infants infected around birth the proportion is far higher, with the large majority becoming chronic. The likelihood of remaining chronically infected with HBV, and seropositive for more than 6 months, is high in neonates, immunosuppressed patients, people with Down’s syndrome and chronically hemodialyzed patients.
Patients who stay seropositive for HBsAg for more than 6 months are in one of the conditions below:
- inactive carriers
- mild low-grade chronic hepatitis
- severe chronic hepatitis without cirrhosis
The risk of developing cirrhosis (scarring of the liver) and hepatocellular carcinoma (HCC, primary liver cancer) in chronic hepatitis B is directly correlated with the level of viral load. One important difference between chronic hepatitis C and chronic hepatitis B is that hepatitis C leads to HCC only when the patient is cirrhotic, whereas patients infected with HBV can progress to HCC even without entering the cirrhotic phase.
Signs that acute infection is becoming chronic
Because chronic infection can follow an acute illness, the course of the acute illness is watched for signs that it is not resolving. The following clinical and laboratory findings suggest that acute hepatitis B is entering its complication of chronic hepatitis B:
- seropositivity for HBsAg for more than 3 months, or 6 months after the onset of symptoms of acute hepatitis
- failure of bilirubin, serum aminotransferase and immunoglobulin to return to normal 6-12 months after the onset of symptoms
- lack of complete resolution of clinical symptoms such as weight loss, anorexia, fatigue and hepatomegaly
- presence of multi-lobular necrosis during severe protracted acute viral hepatitis B