Clinical features

Hepatitis B virus infection has a wide-ranging incubation period - from 45-180 days, with an average of 60-90 days (1)

Acute infection is clinically recognised in only a small proportion of cases

• less that 10% of children and 30-50% of adults show icteric disease
• in patients with clinical illness, the onset is usually insidious with a prodrome of non-specific symptoms such as fever, joint pain, urticarial or maculopapular rashes, malaise, and non-specific gastrointestinal symptoms such as nausea, often progressing to jaundice.
• the acute episode may be similar to that seen in HAV or HAC but more severe. Jaundice rarely persists for more than 4 weeks and usually, is not severe.
• in many patients, the disease is subclinical. Non-jaundiced patients are more likely to develop chronic disease than icteric ones.

A fulminant course may indicate superimposed infection in a symptomless HBV carrier with a new agent such as HDV or HAV. Manifestations include fatigue, jaundice, encephalopathy and ascites. Urgent and immediate referral is indicated in following patients:

• worsening symptoms/signs of liver failure (e.g., encephalopathy)
• laboratory tests indicating deteriorating liver function or liver failure
  • elevated or rising INR
  • elevated or rising bilirubin
  • low or falling platelet count (1)

Recovery and lifelong immunity for acute infection is seen in majority (95%) of immunocompetent adults. The reminder of patients will develop chronic infection

• a flare of chronic HBV may present like acute HBV, and should be included in the differential diagnosis (1)

Circulating immune complexes containing HBsAg may produce extra-hepatic complications such as:

• glomerulonephritis - especially in children
• polyarteritis - usually affecting the medium and small arteries
• peripheral neuropathy
• polymyalgia rheumatica

Reference:

1. Public Health Agency of Canada. Primary care management of hepatitis B – Quick reference 2013
2. NICE (February 2006). Adefovir dipivoxil and peginterferon alfa-2a for the treatment of chronic hepatitis B