Transient Ischemic Attack (TIA)

Description

• A transient episode of neurologic dysfunction due to focal brain, retinal, or spinal cord ischemia without acute infarction
• 7.5–17.4% of patients with transient ischemic attack (TIA) experience a stroke within 3 months (1).
• Synonym(s): ministroke

Epidemiology

Prevalence

• Prevalence of TIA in general population: ~2%
• Risk increases >60 years of age; highest in 7th and 8th decades of life
• Predominant sex: male > female
• Predominant race/ethnicity: African Americans > Hispanics > Caucasians

Etiology and Pathophysiology

Temporary reduction/cessation of cerebral blood flow adversely affecting neuronal function

• Carotid/vertebral atherosclerotic disease (artery-to-artery thromboembolism, low-flow ischemia)
• Lacunar infarcts: small, deep vessel disease associated with hypertension (HTN) and diabetes mellitus (DM)
• Embolism secondary to the following:
  • Valvular (mitral valve) pathology
  • Mural hypokinesias/akinesias with thrombosis (acute anterior MI/congestive cardiomyopathies)
  • Cardiac arrhythmia (atrial fibrillation accounts for 5–20% incidence)
• Hypercoagulable states (antiphospholipid antibodies, increased estrogen [e.g., oral contraceptives], pregnancy and parturition)
• Arteritis (vasculitis)
• Sympathomimetic drugs (e.g., cocaine)
• Other causes: spontaneous and posttraumatic (e.g., chiropractic manipulation) arterial dissection
• Fibromuscular dysplasia

Genetics
Inheritance is polygenic, with tendency to clustering of risk factors within families.

Risk Factors

• Older age (i.e., >60 years old)
• HTN, cardiac diseases (atrial fibrillation, MI, valvular disease)
• Atherosclerotic disease (carotid/vertebral stenosis)
• Obesity, DM, hyperlipidemia
• Cigarette smoking
• Thrombophilias

General Prevention

• Control of medical risk factors: DM, HTN, hyperlipidemia
• Anticoagulation when high risk of cardioembolism (e.g., atrial fibrillation, mechanical valves)
• Blood pressure (BP) control, with antiplatelet therapy for preventing recurrence if previous TIA (2)

Geriatric Considerations

• Older patients have a higher mortality rate—highest in 7th and 8th decades of life.
• Atrial fibrillation is a frequent cause among the elderly.

Pediatric Considerations

• Congenital heart disease is a common cause among pediatric patients.
• Genetic: Marfan syndrome, moyamoya, or sickle cell disease

Pregnancy Considerations

• Preeclampsia, eclampsia, and HELLP syndrome
• Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome
• Postpartum angiopathy
• Cerebral venous thrombosis
• Hypercoagulable states related to pregnancy

Commonly Associated Conditions

• Atrial fibrillation, uncontrolled HTN
• Carotid stenosis
• Some disease processes mimic TIA presentation (seizures, migraines, metabolic disturbances, syncope, multiple sclerosis); difference: gradual onset with nonspecific symptoms (headache, memory loss) versus acute onset with specific neurologic deficits (TIA)