A 27-year-old man with a history of intravenous drug use is known to have been infected with the hepatitis B virus for the past 6 years and has not been ill. He is seen in the emergency department because he has had nausea, vomiting, and passage of dark-colored urine for the past week. Physical examination shows scleral icterus and mild jaundice. Neurologic examination shows a confused, somnolent man-oriented only to person. He exhibits asterixis. Laboratory studies show total protein, 5 g/dL; albumin, 2.7 g/dL; AST, 2342 U/L; ALT, 2150 U/L; alkaline phosphatase, 233 U/L; total bilirubin, 8.3 mg/dL; and direct bilirubin, 4.5 mg/dL. Superinfection with which of the following viruses has most likely occurred in this man?
A 27-year-old man with a history of intravenous drug use is known to have been infected with the hepatitis B virus for the past 6 years and has not been ill. He is seen in the emergency department because he has had nausea, vomiting, and passage of dark-colored urine for the past week. Physical examination shows scleral icterus and mild jaundice. Neurologic examination shows a confused, somnolent man-oriented only to person. He exhibits asterixis. Laboratory studies show total protein, 5 g/dL; albumin, 2.7 g/dL; AST, 2342 U/L; ALT, 2150 U/L; alkaline phosphatase, 233 U/L; total bilirubin, 8.3 mg/dL; and direct bilirubin, 4.5 mg/dL. Superinfection with which of the following viruses has most likely occurred in this man?
💡 Explanation
**Core Concept**
The patient in question has a history of hepatitis B infection and is now presenting with signs of acute liver injury, including elevated liver enzymes, jaundice, and asterixis. This clinical presentation suggests the development of a superinfection with another virus that is capable of causing acute liver injury.
**Why the Correct Answer is Right**
The patient's presentation is consistent with acute liver failure, characterized by coagulopathy (indicated by low albumin), elevated liver enzymes (AST and ALT), and jaundice. The presence of asterixis and somnolence suggests hepatic encephalopathy. Given the patient's history of hepatitis B infection, the most likely cause of his acute liver failure is superinfection with the hepatitis D virus (HDV). HDV is a defective virus that requires the presence of the hepatitis B virus (HBV) to replicate and cause disease. HDV infection can lead to severe acute liver injury and fulminant hepatic failure.
**Why Each Wrong Option is Incorrect**
**Option A:** Cytomegalovirus (CMV) is a herpesvirus that can cause a range of clinical syndromes, including hepatitis, but it is not the most likely cause of acute liver failure in this patient.
**Option B:** Epstein-Barr virus (EBV) is another herpesvirus that can cause infectious mononucleosis, a condition characterized by fever, sore throat, and lymphadenopathy. While EBV can cause hepatitis, it is not typically associated with acute liver failure.
**Option C:** Hepatitis C virus (HCV) is a flavivirus that can cause chronic liver disease, but it is not typically associated with acute liver failure, especially in the context of a pre-existing HBV infection.
**Option D:** Herpes simplex virus (HSV) is a herpesvirus that can cause a range of clinical syndromes, including encephalitis and hepatitis. However, it is not typically associated with acute liver failure.
**Clinical Pearl / High-Yield Fact**
HDV infection is a significant cause of acute liver failure in patients with chronic HBV infection. The presence of HDV antigen in the serum is a strong indicator of HDV infection.
**Correct Answer:** . Hepatitis D virus (HDV)
✓ Correct Answer: C. HDV
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