Many conditions raise the serum aminotransferases (AST and ALT, enzymes released from injured liver cells) and reproduce the course of viral hepatitis, so the differential is broad. The pattern of the liver tests helps narrow it: most of the mimics raise the aminotransferases without raising bilirubin, whereas viral hepatitis itself tends to raise both once jaundice appears.
Infections
Several infections can mimic the clinical course of viral hepatitis:
- infectious mononucleosis
- CMV (cytomegalovirus)
- HSV (herpes simplex virus)
- Coxsackie virus
- toxoplasmosis
- VZV (varicella-zoster virus)
- yellow fever
Like viral hepatitis, these infections raise the liver aminotransferases, but mostly without a rise in bilirubin. In fact, elevation of serum aminotransferases can accompany any systemic viral disease, such as SARS-CoV-2 infection.
Drugs, inflammatory and genetic liver disease
The drugs a patient is using should always be considered, because some drugs mimic the symptoms and signs of acute and even chronic hepatitis. Other inflammatory liver diseases, and genetic disorders, also belong in the differential for acute hepatitis.
Cardiac and vascular causes
Right ventricular failure can mimic acute hepatitis, because a failing right heart raises hepatic venous pressure and congests the liver. The same applies to any disorder that impairs right atrial venous return, such as veno-occlusive disorders and hepatic vein occlusion.
Once these mimics have been set aside, a diagnosis of viral hepatitis leads to the question of what can be done for each virus.