Poisoning by hydantoin derivatives, undetermined, subs

This code signifies a poisoning event involving hydantoin derivatives, a class of anticonvulsant medications, where the intent (e.g., accidental, intentional self-harm, assault) cannot be determined. The "subsequent encounter" indicates that the patient is receiving follow-up care for the poisoning after the initial treatment.

Apply this code when a patient presents for ongoing management or complications related to a hydantoin derivative poisoning, and the medical record does not clearly specify whether the poisoning was accidental, intentional, or due to assault. This is appropriate for follow-up visits after the acute phase of treatment.

• Ensure documentation explicitly states "undetermined" intent for the poisoning.
• This code is for subsequent encounters only; use an "A" for initial encounters.
• Always code the specific hydantoin derivative if known, otherwise, use the general category.