Transient Ischemic Attack (TIA) is often used as a catchall diagnosis for patients with transient neurological events.  However, stroke specialists establish a non-TIA/stroke diagnosis for up to half of Stroke Prevention Clinics patients.1-3 Arbitrary TIA diagnosis and a surplus of non-TIA referrals impedes rapid stroke services for patients truly at risk of further events.    

Our retrospective chart review included 1894 patients referred to The Ottawa Hospital Stroke Prevention Clinic in 2015.  Descriptive statistics were used to define patient and referral characteristics, features of the presenting neurological event and final diagnosis by a stroke neurologist (classified as definitely, possibly, or definitely not TIA/stroke).  Multinomial logistic regression analysis with backwards elimination and a significance level of staying in the model of α 0.15 was used to identify variables associated with the final diagnosis.

The final model included 20 variables.  The odds of a final diagnosis of definite TIA/stroke (vs definitely not) was more than 50% lower for patients with two or more events in the past month or stereotyped features.  Loss of consciousness, amnesia, lightheadedness, jerking, situational triggers, and positive visual phenomena were associated with an 83% to 98% reduced odds of final TIA/stroke diagnosis.

Identification of presenting variables associated with a reduced likelihood of TIA/stroke diagnosis is important to consider when determining the provisional diagnosis for a transient neurological event.  Judicious attention to features less commonly associated with TIA/stroke may influence a broader differential diagnosis, guide initial testing to enhance discrimination, and may reduce unnecessary demands for urgent stroke services.

AVERTING TRANSIENT ISCHEMIC ATTACK MISDIAGNOSIS: DISCRIMINATING FEATURES FROM A RETROSPECTIVE CHART REVIEW