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Transmission
Humans are the only host. Following routes are common for the transmission:
- Sexual/intimate contact
- Vaginal birth and breast feeding
- Blood transfusion or contact with patient’s blood (needles, bloody clothes, razor blades, etc.)
Antigens and Antibodies
Hepatitis B Virus has 3 antigen types from clinical point of view:
- Surface antigen called HBsAg (Hepatitis B surface Antigen)
- Core antigen called HBcAg (Hepatitis B core Antigen)
- Early antigen called HBeAg (Hepatitis B early Antigen)
Our body’s immune system defends and makes antibodies to each kind of antigen:
- Anti surface-antigen called HBsAb (Hepatitis B surface Antibody)
- Anti core-antigen called HBcAb (Hepatitis B core Antibody)
- Anti early-antigen called HBeAb (Hepatitis B early Antibody)
Considerations for the Labs Data
- In case of vaccination only the HBsAb will be detected without any other antibodies or antigens. This is because the vaccine is HBsAb.
- Presence of an antigen depicts infection with the virus.
- Presence of the HBeAg means high infectivity and virality.
- Presence of Antibodies means resolved state.
- Presence of IgM antibodies means acute infection.
- Presence of IgG antibody means chronic infection.
- Resolved state will usually have labs with no antigens and at least HBsAb antibody present.
Incubation Time
Incubation time is the duration between the infection by the virus to the appearance of the symptoms. Usually 2 months for Hepatitis B virus.
Window Period
Window period is when HBsAg and HBsAb are absent in the labs. If no other antigen or antibody is present then there may not be an infection. Presence of another antigen, however, depicts active infection.
Reason for the HBsAg and HBsAb to appear as zero is following: at this stage of the infection antigens produced by the virus and antibodies produced by our body are equal in amount and are bound to each other (complexed). The labs measurement apparatus does not pick up these immune complexes and registers zero antigen and antibodies. This is why the window period is also called zone of equivalence.
Clinical
Signs and Symptoms
- Ranges from asymptomatic without jaundice to fulminant hepatitis leading to death within days.
- There may be an onset for malaise (tired), myalgia (muscle aches), arthralgia (join pains), easy fatigue, upper respiratory tract symptoms, anorexia.
- GIT symptoms may be abdominal pain in the upper right quadrant or epigastrium, nausea, vomiting, and diarrhea or constipation.
- Low grade fever
- Jaundice may occur
When to refer?
Patients that require liver biopsy for diagnosis.
When to admit?
- INR > 1.6
- Encephalopathy is observed
- Patient is not able to hydrate themselves
Treatment
- Bed rest
- 10% IV glucose if patient is unable to eat or hydrate, or if the vomiting is pronounced.
- Strenuous exercise, alcohol, other hepatotoxic substances/drugs should be stopped/reduced.
- Steroids usually have no benefit even in the fulminant stage.
- Antiviral therapy is usually given in the fulminant cases or spontaneous flare up in the chronic hepatitis.