Toxic effect of hydrogen sulfide, undetermined, sequela

This code signifies the long-term or residual health problems resulting from an exposure to hydrogen sulfide, where the intent of the exposure (e.g., accidental, intentional self-harm, assault) cannot be determined. These sequelae can manifest as chronic respiratory issues, neurological deficits, or other persistent conditions that developed after the initial toxic event.

Apply this code when documenting a patient presenting with a chronic or lasting health condition directly attributable to a past hydrogen sulfide poisoning, and the circumstances surrounding the original exposure are unknown or unspecifiable. This is appropriate for follow-up encounters addressing these persistent effects, not the initial acute poisoning.

• Always sequence this sequela code after the code for the specific residual condition (e.g., chronic bronchitis, neurological disorder).
• Ensure documentation clearly links the current condition to a past hydrogen sulfide exposure.
• Only use the "S" (sequela) seventh character for conditions that are the late effects of the initial poisoning.