Both aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are elevated in which disease?

• A. Muscular dystrophy
• B. Viral hepatitis
• C. Pulmonary embolism
• D. Infectious mononucleosis

Answer: (B)

When liver cells are damaged, they release their enzymes into the blood. This shows up as elevated aminotransferases, specifically AST and ALT, which are commonly used as markers of hepatocellular injury.

Viral hepatitis is a classic situation where both enzymes rise markedly because the virus causes direct injury to hepatocytes and an inflammatory response that spills these enzymes into the bloodstream. ALT is more liver-specific, so its elevation tends to be pronounced, and AST also rises due to its presence in liver tissue (as well as in other tissues).

In muscular dystrophy, AST can be elevated because muscle tissue is damaged, but ALT generally does not rise as much since it is more specific to the liver; thus both enzymes are not typically elevated together to the same extent. Pulmonary embolism doesn’t typically cause hepatocellular injury, and infectious mononucleosis can cause mild liver involvement but not the characteristic, marked simultaneous rise of both enzymes seen with active viral hepatitis.

So the disease most associated with elevations of both AST and ALT is viral hepatitis.