Toxic effect of hydrogen cyanide, undetermined, subs encntr

This code signifies a patient presenting with symptoms or complications from a previous exposure to hydrogen cyanide, where the intent of the exposure (e.g., accidental, intentional self-harm, assault) cannot be determined. The "subsequent encounter" indicates that the patient is receiving follow-up care for the toxic effects after the initial treatment of the acute poisoning.

Apply this code when a patient is seen for ongoing management of health issues directly resulting from an earlier hydrogen cyanide poisoning, and the circumstances surrounding the exposure remain unclear. This includes follow-up appointments for organ damage, neurological sequelae, or other chronic conditions linked to the initial toxic event.

• Ensure documentation clearly states the encounter is for follow-up care related to a past hydrogen cyanide exposure.
• Verify that the intent of the poisoning is explicitly documented as "undetermined" by the provider.
• Do not use for the initial treatment of the acute poisoning; refer to codes with the "A" (initial encounter) seventh character for that scenario.