Transient Ischemic Attack Flashcards
1
Q
What is a TIA?
A
- A transient episode of neurologic dysfunction caused by focal brain, spinal cord or retinal ischemia WITHOUT acute infarction.
- The old, benign definition of TIA is now replaced by an understanding that even a brief period of ischemia can cause permanent brain injury as found by more modern imaging techniques
2
Q
What are the 3 types of TIA?
A
A TIA should be considered a syndrome with the symptoms dependent upon the pathophysiologic subtype which are divided into 3 main mechanisms:
- Embolic TIA – focal neurologic symptoms lasting hours; embolus arising usually exracranial
- Lacunar or small vessel TIA – caused by atherothrombotic obstructive lesions at the origin of the penetrating vessel; symptoms may be step-wise and progressive instead of abrupt
- Large artery, low flow TIA – associated with tightly stenotic atherosclerotic lesions of the extracranial or intracranial arteries if collateral flow to the potentially ischemic brain is also impaired; symptoms are usually short lived (minutes) and often recurrent
3
Q
What can cause TIA’s?
A
Atherosclerotic Disease
- Carotid arteries, intracranial atherosclerosis, vertebral arteries, aorta
Cardiac emboli
- Atrial fibrillation
- MI
- Valvular disease
Vasculitis disorders
Hematologic disorders
- RBC disorders such as polycythemia
Platelet disorders
- Thrombocytopenia
- Increased viscosity/hypercoagulable conditions
- Antiphospholipid antibody syndrome
- Oral contraceptive or estrogen use
- Antithrombin III deficiency
- Protein S and C deficiency
Patients at increased risk:
- Older than 45 years’ old
- History of thrombolytic event
- History of spontaneous miscarriage
- Related autoimmune conditions such as lupus
- Stoke of unknown cause
- Family history of thrombotic events
Intracranial Causes:
- Brain tumor
- Focal seizure
- Hemorrhage – subdural hematoma, subarachnoid hemorrhage, intracerebral hemorrhage
Subclavian steal syndrome
- Localized stenosis of subclavian artery proximal to source of vertebral artery so that blood is ‘stolen’ from that artery
- BP is significantly lower in affected arm than in opposite arm
4
Q
What is the risk of stroke after having a TIA?
A
- 17% of TIA patients had a stroke within 90 days of TIA
- Greatest risk of stroke is 1st week after TIA
- 1/3 of stroke patients have a history of TIA
