Gastrointestinal · Year 2 · from Gastrointestinal
Case 1: Acute Hepatitis B
Patient Presentation
Demographics: 28-year-old male
Chief Complaint: Fatigue, nausea, and dark urine for 10 days
History of Present Illness: The patient developed progressive fatigue, loss of appetite, and nausea over the past 2 weeks. He noticed his urine became dark "like cola" 10 days ago, followed by yellowing of his eyes. He reports right upper quadrant discomfort and low-grade fever. He has no prior history of liver disease.
Past Medical History: None
Social History: Reports unprotected sexual contact with new partner 3 months ago; denies IV drug use; no tattoos
Physical Examination
- Vital Signs: Temperature 37.8C, HR 78 bpm, BP 118/72 mmHg
- General: Ill-appearing jaundiced male
- HEENT: Icteric sclerae, mild pharyngeal erythema
- Abdomen: Tender hepatomegaly (liver edge 4 cm below costal margin), no splenomegaly, no ascites
- Skin: Jaundice, no spider angiomata
Workup and Results
- Liver Function Tests: AST 1,850 U/L, ALT 2,240 U/L (markedly elevated), Total bilirubin 8.4 mg/dL, Direct bilirubin 6.2 mg/dL, ALP 180 U/L
- INR: 1.2 (mildly elevated)
- Albumin: 3.6 g/dL
- Hepatitis Serologies:
- HBsAg: Positive
- Anti-HBc IgM: Positive (indicates acute infection)
- HBeAg: Positive (high replication)
- Anti-HBs: Negative
- HBV DNA: 8.2 x 10^7 IU/mL
Hepatitis B serologic markers over time during acute infection, showing the appearance and disappearance of HBsAg, anti-HBc IgM, HBeAg, and the eventual development of protective anti-HBs in patients who clear the infection.
Image Source: Wikimedia Commons, Public Domain
Diagnosis
Acute Hepatitis B Infection
Clinical Correlation
Hepatitis B virus is a partially double-stranded DNA virus transmitted through blood and body fluids. The incubation period is 6 weeks to 6 months. Acute infection is diagnosed by presence of HBsAg (surface antigen indicating active infection) and anti-HBc IgM (core antibody indicating acute infection). High HBeAg and HBV DNA levels indicate active viral replication. In immunocompetent adults, 95% clear the virus spontaneously. The marked transaminase elevation reflects immune-mediated hepatocyte destruction. Monitoring INR and mental status is critical to detect progression to acute liver failure, which occurs in <1% of acute HBV but has high mortality.
Treatment
- Supportive care for most acute HBV (high spontaneous clearance rate)
- Avoid hepatotoxic substances (alcohol, acetaminophen)
- Monitor for signs of acute liver failure: worsening coagulopathy (INR >1.5), hepatic encephalopathy
- Antiviral therapy (entecavir or tenofovir) indicated only if severe/fulminant course
- Sexual contacts and household members should be tested and vaccinated
- Follow-up serology at 6 months to confirm clearance (HBsAg negative, anti-HBs positive)
- If HBsAg persists >6 months: chronic hepatitis B requiring treatment evaluation