Q&A: Coding adverse effects versus poisonings

Q: I’m trying to decide between the codes F14.121 (Cocaine abuse with intoxication with delirium) and T40.5X5A (Adverse effect of cocaine, initial encounter). The patient presented to the emergency department with altered mental status. The physician documented that the patient's delirium is likely due to toxidrome from cocaine. Which code would be more appropriate?

A: There are chapter specific guidelines in the Official Guidelines for Coding and Reporting that must be followed for appropriate code assignment related to substance consumption. Code assignment is always based solely on the documentation in the medical record by the provider, which would include the provider stating the patient “uses, “abuses,” or is “dependent” on a substance, and also whether the patient is currently “intoxicated.” In ICD-10-CM, poisonings and adverse effects use expanded combination codes that identify the substance, whether it’s an adverse effect, poisoning or related to under-dosing (including reason if know), the intent (if not indicated by the provider, this will default to accidental), and the type of encounter (initial, subsequent, or sequela).  

So, one of the first questions we need to ask is, “Was the substance taken correctly?” The answer will determine the principle diagnosis for the encounter and the sequencing of the appropriate codes. A poisoning is a reaction to improper use of medication, could be wrong drug, wrong route, wrong patient, overdose or toxicity due to non-medicinal chemical substance. When a patient is admitted for a poisoning, the poisoning is sequenced first followed by a code for the manifestation caused by the poisoning.

An “adverse effect” is a reaction to a therapeutic substance correctly prescribed and administrated. This can include allergic reactions, medication toxicity, or side effects. If the encounter is for an adverse effect, then the appropriate sequencing would be a code for the manifestation caused by the adverse effect, followed by the appropriate code for the drug responsible for the adverse effect.

Based on the little information provided, this scenario would likely be coded as a poisoning and not an adverse effect, which would mean the code for poisoning would be sequenced first followed by a code for the manifestation(s), and/or when available we would use a combination code. In addition, we would need to query the provider regarding the usage of the substance to apply an additional code that represents whether the patient “uses, abuses, or is dependent on” the substance.

Editor’s Note: Sharme Brodie RN, CCDS, CDI education specialist and CDI Boot Camp instructor for HCPro in Middleton, Massachusetts, answered this question. For information, contact her at sbrodie@hcpro.com. For information regarding CDI Boot Camps offered by HCPro, visit www.hcprobootcamps.com/courses/10040/overview.