CIOMS/RUCAM scale

The CIOMS/RUCAM scale is a tool to predict whether liver damage can be attributed to a particular medication.

Hepatotoxicity
Determining hepatotoxicity (toxic effects of a substance on the liver) remains a major challenge in clinical practice due to lack of reliable markers. Many other conditions lead to similar clinical as well as pathological picture. To diagnose hepatotoxicity, a causal relationship between the use of the toxin or drug and subsequent liver damage has to be established, but might be difficult, especially when idiosyncratic reaction is suspected. Simultaneous use of multiple drugs may add to the complexity. As in acetaminophen toxicity, well established dose dependent pharmacological hepatotoxicity is easier to spot.

Interpretation
The CIOMS/RUCAM scale has been proposed to establish causal relationship between offending drug and liver damage. The CIOMS/RUCAM scale involves a scoring system which categorizes the suspicion into "definite or highly probable" (score > 8), "probable" (score 6-8), "possible" (score 3-5), "unlikely" (score 1-2) and "excluded" (score ≤ 0). In clinical practice physicians put more emphasis on the presence or absence of similarity between the biochemical profile of the patient and known biochemical profile of the suspected toxicity ( e.g. cholestatic damage in amoxycillin-clauvonic acid ).

Elements of the scale

 * Concomitant therapy:
 * Time to onset incompatible: +0
 * Time to onset compatible but with unknown reaction: -1
 * Time to onset compatible but known reaction: -2
 * Role proved in this case: -3
 * None or information not available: +0


 * Exclusion of nondrug-related causes:
 * Rule out: +2
 * “Possible” to “not investigated”: -2 to +1
 * Probable: -3


 * Previous information on hepatotoxicity:
 * Reaction unknown: +0
 * Reaction published but unlabeled: +1
 * Reaction labeled in the product's characteristics: +2


 * Response to re-administration:
 * Positive: +3
 * Compatible: +1
 * Negative: -2
 * Not available or not interpretable: +0
 * or plasma concentration of drug known as toxic: +3
 * or validated laboratory test with high specificity, sensitivity, and predictive values:
 * Positive: +3
 * Negative: -3
 * Not interpretable or not available: +0

Score analysis
Points are summed and the total compared to this chart:


 * 0 or lower: relationship with the drug excluded
 * 1-2: unlikely
 * 3-5: possible
 * 6-8: probable
 * >8: highly probable

If the results are incompatible with a connection, then the case is considered "unrelated". In some cases, insufficient information is available; these cases are recorded as "insufficiently documented".