Question: A patient reported to the ED suffering from exertional heatstroke they suffered while playing in a baseball game. What diagnosis code(s) should I report for this patient? Florida Subscriber Answer: Report T67.02XA (Exertional heatstroke, initial encounter) for the heatstroke. Also, include Y93.64 (Activity, baseball) as a secondary diagnosis to indicate the activity the patient was engaged in when heatstroke occurred. More on heatstroke and sunstroke: The ICD-10 code set for conditions related to heatstroke and sunstroke is surprisingly deep. Here are all of the codes listed under the T67.0- (Heatstroke and sunstroke) heading: