Vertical (mother to child in-utero), shared needles
Needle sticks in health care workers
Unscreened blood transfusion
Symptoms
Most (2/3) are asx w/acute hep B infection
Incubation is 1-4m
1/3 of those w/acute infxn have symptoms: n, v, jaundice, RUQ pain, puritus, icterus, dark urine, light colored stool, malaise
Other acute sx: occasionally symmetric inflammatory arthritis mcps, pips, knees, ankles x few weeks
Acute symptoms are typically self limited, w/resolution in 2-3m
Majority clear infection w/o sequelae; 5% develop chronic infxn w/risk cirrhosis (fatigue, edema, GI bleeding), spread to others, and hepatocellular carcinoma (w/chronic Hep B, 20% develop HCC w/o cirrhosis)
Small # of those w/chronic Hep B will develop PAN, membranous nephropathy, mucocutaneous vasculitis
Physical Exam Findings
Acute hep B (findings in 1/3): jaundice, icterus, RUQ pain, hepatomegaly, joint pain and swelling
Chronic hep B: asymptomatic until develop cirrhosis w/portal hypertension (ascites, edema, jaundice, spider angioma, muscle wasting, upper GI bleeding, etc)
HCC: RUQ mass, mets
Tests
Acute Hepatitis B: Alt and Ast elevated > 10x nl, + Hep B S Agn, + Hep B Core Ab (IgM and IgG)
S/P vaccination: Alt and Ast normal, + Hep B S Ab, - Hep B Core Ab, - Hep B S Agn
S/P Hep B infection (cleared): Alt and Ast normal, + Hep B S Ab, + Hep B Core Ab (IgG), - Hep B S Agn
Chronic Hep B infection: Alt and Ast mildly elevated, + Hep B S Agn, - Hep B S Ab, + Hep B Core Ab (IgG), + Viral Load
Inactive Hep B (risk of reactivation w/immunosuppression): Alt and Ast normal, - Hep B S Agn, - Hep B S Ab, + Hep B Core Ab (IgG), low level or undetectable VL