Q.22 AST / ALT ratio is decreased in
1. myocardial infarction
2. acute hepatocellular damage
3. damaged kidney
4. both damaged kidney and heart
AST/ALT Ratio Decrease: Key Conditions and MCQ Insights
The AST/ALT ratio, also known as the De Ritis ratio, is a clinical marker where AST (aspartate aminotransferase) levels are typically compared to ALT (alanine aminotransferase) levels. A decreased ratio (AST/ALT <1) often signals specific patterns of tissue damage, particularly in acute liver injury scenarios.
Correct Answer
2. acute hepatocellular damage
In acute hepatocellular damage, such as viral hepatitis or toxin-induced liver injury, ALT rises more sharply than AST because ALT is predominantly liver-specific, resulting in an AST/ALT ratio below 1. This pattern contrasts with chronic liver conditions or alcoholic liver disease, where the ratio often exceeds 1 or 2.
Option Analysis
Myocardial Infarction (Option 1)
AST elevates significantly due to cardiac muscle damage, as AST is present in heart tissue, while ALT remains relatively unchanged or mildly elevated. Thus, the AST/ALT ratio increases (often >2), not decreases.
Acute Hepatocellular Damage (Option 2)
Here, both enzymes rise, but ALT increases disproportionately due to its cytosolic location in hepatocytes and higher concentration in liver cells during acute injury. This leads to a decreased AST/ALT ratio (<1), making it the correct choice.
Damaged Kidney (Option 3)
Kidney damage primarily affects other markers like creatinine; AST and ALT are not significantly released from renal tissue. The ratio typically remains normal or unaffected, with no characteristic decrease.
Both Damaged Kidney and Heart (Option 4)
Heart damage raises the ratio (as in option 1), while kidney damage does not lower it notably. No combined effect produces a decreased ratio.
| Condition | AST/ALT Ratio Pattern | Reason |
|---|---|---|
| Myocardial Infarction | Increased (>2) | AST from cardiac tissue |
| Acute Hepatocellular Damage | Decreased (<1) | ALT-dominant liver injury |
| Damaged Kidney | Normal | Minimal enzyme release |
| Both Kidney & Heart | Increased | Dominated by heart effect |
Clinical Relevance
Monitoring the AST/ALT ratio aids in differentiating liver from cardiac or other injuries, guiding diagnosis in emergencies. For exams like medical entrance tests, recognizing acute liver damage as the key for decreased ratio is crucial.
