What is a Transient Ischemic Attack (TIA)?

What is a Transient Ischemic Attack (TIA)?

A transient ischemic attack (TIA) is a brief episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction, with clinical symptoms typically lasting less than one hour. 1 This medical emergency serves as a critical warning sign of impending stroke, with risk highest in the first week after the event.

Definition and Characteristics

TIA was traditionally defined as neurological symptoms lasting less than 24 hours, but modern definitions emphasize:

• Temporary neurological dysfunction (typically <1 hour)
• Caused by focal ischemia to brain, spinal cord, or retina
• No evidence of permanent infarction on imaging
• Complete symptom resolution

Clinical Presentation

TIA symptoms mirror those of ischemic stroke but are transient:

• Unilateral limb weakness or numbness
• Speech disturbances (dysphasia, slurred speech)
• Visual disturbances (including monocular blindness/amaurosis fugax)
• Sensory symptoms
• Gait difficulties

Some symptoms are particularly characteristic of TIA rather than stroke:

• Monocular blindness (amaurosis fugax)
• Limb shaking 2

Risk Factors

Major risk factors for TIA include:

• Age over 55 years
• Male sex
• Hypertension
• Diabetes mellitus
• Tobacco use
• Family history of stroke/TIA
• Dyslipidemia
• Carotid artery stenosis 3

Stroke Risk After TIA

TIA represents a medical emergency due to the high risk of subsequent stroke:

• Up to 13% risk in first 90 days after the event
• Up to 30% within 5 years 4
• Highest risk in the first week after TIA

Evaluation and Management

Urgent Assessment

TIA requires immediate medical attention:

• Brain imaging (MRI with diffusion-weighted imaging preferred) within 24 hours 4
• Vascular imaging of cervical and intracranial vessels
• Cardiac evaluation (ECG, possible extended monitoring)
• Laboratory testing

Risk Stratification

Clinical scores such as ABCD² help identify high-risk patients:

• Age ≥60 years
• Blood pressure ≥140/90 mmHg
• Clinical features (focal weakness, speech impairment)
• Duration of symptoms (>1 hour)
• Diabetes 4

Treatment

Immediate interventions focus on preventing stroke:

• Antiplatelet therapy
• Management of vascular risk factors (hypertension, diabetes, dyslipidemia)
• Carotid endarterectomy for significant carotid stenosis (>70%) 3
• Anticoagulation for atrial fibrillation

Importance of Rapid Care

Specialized TIA clinics and urgent assessment protocols have demonstrated significant reduction in subsequent stroke risk. Studies show that immediate evaluation and treatment in specialized centers can reduce relative risk of subsequent stroke by up to 80% 4.

Common Pitfalls

1. Delayed evaluation: Failing to recognize TIA as a medical emergency requiring immediate assessment
2. Misdiagnosis: Confusing TIA with mimics such as syncope, migraine, or seizures
3. Inadequate imaging: Not obtaining appropriate brain and vascular imaging
4. Incomplete risk factor assessment: Failing to identify and address all modifiable risk factors
5. Lack of follow-up: Not ensuring appropriate secondary prevention measures

TIA should be viewed as part of the spectrum of acute cerebrovascular disease, similar to how angina and myocardial infarction are understood as part of acute coronary syndromes 4.