Quick facts!
Chronic hepatitis B (CHB) has a simple definition: it’s the presence of positive HBsAg for at least 6 months.
Essentially all patients with CHB have a few serology tests in common:
- positive HBsAg
- negative anti-HBs
- positive total anti-HBc
- negative IgM anti-HBc
As such, the lab monitoring of CHB largely focuses on the following:
- HBeAg
- anti-HBe
- HBV DNA
- ALT
Patients with CHB should have US monitoring for hepatocellular carcinoma (HCC) in the presence of cirrhosis, chronically elevated ALT, chronically elevated HBV DNA (>10,000 IU/mL), or a family history of HCC. There are also specific recommendations for patients of Asian and African descent, which are largely based on studies performed in southeast Asia and sub-Saharan Africa, where HBV is endemic.
The decision to treat is complex but mainly based on the presence of cirrhosis and the levels of HBV DNA and ALT.
Phases of CHB
Source: UpToDate- Phase 1: immune tolerance
- Phase 2: immune clearance (aka immune active HBeAg-positive)
- Phase 3: immune control (aka inactive carrier state, or inactive CHB)
- Phase 4: immune escape (aka reactivation, or immune active HBeAg-negative)
Key point: Not all patients with CHB go through all 4 phases. Most patients move from one phase to the next, but reversal can also occur.
We typically treat CHB in the presence of liver injury, which occurs in phases 2 and 4 (when ALT is elevated!)
Practice cases!
A 40yo man is evaluated in clinic after a recent diagnosis of hepatitis B infection, which was discovered after he donated blood. He has a history of injection drug use several years ago, but otherwise has no active medical issues and takes no medications. He has no family history of hepatitis B. His vital signs and exam are unremarkable. Labs: normal ALT, positive HBsAg, negative IgM anti-HBc, positive total anti-HBc, negative HBeAg, positive anti-HBe, and HBV DNA <20 IU/mL.
- Does this patient have acute or chronic HBV? If chronic, what is the most likely phase?
- Does this patient need to be screened for HCC?
- Does this patient need antiviral therapy?
A 3yo girl presents as a new patient in clinic. She was born in China, and recently arrived in the US following adoption. The only known history is that her biological mother had CHB and that the girl did not receive hepatitis B immunization at birth. Vital signs and exam are unremarkable. Labs: positive HBsAg, positive total anti-HBc, positive HBeAg, negative anti-HBe, and HBV DNA is 25,000 IU/mL.
- Does this patient have acute or chronic HBV? If chronic, what is the most likely phase?
- Should this patient’s adoptive family be screened for HBV?
- Among patients who acquire HBV, are children or adults more likely to develop chronic infection?