Suggested approach to the etiologic evaluation of ischemic stroke

AVM: arteriovenous malformation; CBC: complete blood count; CT: computed tomography; CTA: computed tomography angiography; ECG: electrocardiogram; ED: emergency department; INR: international normalized ratio; LP: lumbar puncture; MRA: magnetic resonance angiography; MRI: magnetic resonance imaging; PACNS: primary angiitis of the central nervous system; PT: prothrombin time; TEE: transesophageal echocardiography; TTE: transthoracic echocardiography.

* Findings from the standard evaluation may raise suspicion for uncommon or rare causes of stroke.

¶ Cardiac echo (TTE or TEE) may not be necessary if probable mechanism known from immediate evaluation (eg, arterial dissection in young patient with no cardiovascular risk factors).

Δ Cryptogenic stroke is a diagnosis of exclusion, made when a standard evaluation reveals no definite evidence of cardioembolism, large artery atherosclerosis, small artery disease, or other determined etiology, and no evidence of atrial fibrillation on a 12-lead ECG and on 24-hour cardiac monitoring.

◊ Monitor with insertable loop recorder or external cardiac monitor for at least 30 days, particularly for patients at higher risk for atrial fibrillation (eg, due to older age or history of heart disease); we generally do not monitor young patients (eg, age <30 years) in absence of heart disease or strong family history of heart disease.

§ Test for antiphospholipid syndrome and hyperhomocysteinemia, particularly for younger patients or those with a family history of hypercoagulability.