Transient Ischemic Attack (TIA) ICD-10-CM codes

G45.9 (transient cerebral ischemic attack, unspecified) is the code for TIA. More specific syndromes are available when documented: G45.0 vertebro-basilar artery syndrome, G45.1 carotid artery syndrome (hemispheric), G45.2 multiple and bilateral precerebral artery syndromes, G45.3 amaurosis fugax, G45.4 transient global amnesia, and G45.8 other transient cerebral ischemic attacks. Transient global amnesia is not a TIA clinically but is grouped in this category.

TIA is a diagnosis of exclusion once imaging rules out infarction. If the workup finds an acute infarct, code the stroke (I63.-) instead of G45.9, even when deficits resolved quickly. A TIA and a stroke are not reported together for the same event.

After the acute episode, a TIA is reported as history: Z86.73 (personal history of TIA and cerebral infarction without residual deficits). Do not continue to assign G45.9 on follow-up visits. Underlying carotid stenosis (I65.2-) or cerebral atherosclerosis (I67.2) is coded in addition when documented, along with long-term antiplatelet therapy (Z79.02 or Z79.82 for aspirin).