Acute Hepatitis

Today we discussed a case of acute hepatitis NYD with moderate-severe liver enzyme elevation. This is not an uncommon referral to Internal Medicine.

Here's a very useful review from CMAJ in 2005 on elevated liver enzymes.

Some points about marked liver enzyme elevation (>5x the upper limit of normal):

1. Remember that the "liver function tests" are bilirubin, INR, albumin +/- glucose and can reflect the synthetic function of the liver. Conversely, the "liver enzymes" - AST, ALT, ALP and GGT are NOT liver function tests as they offer no information on the liver's synthetic function but merely are a marker of hepatocyte integrity and/or cholestasis.

2. The differential diagnosis of moderate to severe transaminitis includes: viral hepatitis, toxic hepatitis, ischemic hepatitis, severe obstruction, autoimmune and alcoholic hepatitis.

3. Decide what the predominant pattern is to help you guide investigations:
a) Hepatic (increased AST, ALT > ALP)
b) Cholestatic (increased ALP > AST, ALT)

4. How elevated are the enzymes? 5x vs. 5-10x vs. >10x of normal? What is the trend? Is there synthetic dysfunction (increased INR, bilirubin, decreased albumin)? Typically liver enzyme values at this level represent acute liver injury.

5. In acute viral hepatitis, the liver enzymes often peak before the bilirubin and the patient may have non-specific symptoms such as fatigue, arthralgias and a low grade fever (as in our patient) .

6. Consider ischemic hepatitis in the right clinical context and an ALT/LDH ratio of less than 1.

7. Hepatitis screen: Hep A IgM Ab, Hep B core Ab (IgM), Hep B surface Ag and Ab, Hep C Ab.

8. Always ask about Tylenol use, herbal and over the counter medications, periods of illness (hypotension), autoimmune symptoms and alcohol.

9. Some form of abdominal imaging (usually ultrasound) is often appropriate to assess for evidence of hepatitis and/or obstruction.

10. Once the common causes of moderate to severe transaminitis have been ruled out, consider testing for auto-immune hepatitis and other viral causes such as EBV and CMV.