Stroke and Transient Ischemic Attack Overview

Study Notes

A heterogeneous group of disorders causing sudden, focal interruption of cerebral blood flow leading to neurological deficits.
Results from ischemic infarction or bleeding into the brain.
Manifests with rapid onset of focal CNS signs and symptoms (focal neurological defects), often including hemiplegia with or without other neurological signs.
A major neurological disease with a 12% mortality rate within 56 days after the first stroke.

Hemorrhage (10-20%): Resulting from vascular rupture (subarachnoid hemorrhage).
Brain Ischemia (Infarct) (80-90%):
- Thrombus
- Other types of embolism
- Systemic hypoperfusion

A minor stroke presenting with stroke-like symptoms (limb weakness, dysphagia, visual defects) that completely resolve within 24 hours.
Usually, a result of microemboli (80%) but not always.
Sometimes, a mass lesion can mimic a TIA.
Other times, it's caused by temporary reduced blood flow, for example, with massive postural hypotension or decreased blood flow through a stenosed artery.

Clinical effects reach their maximum within 6 hours of onset.
Prognosis:
- Mortality of 20% in the first 2 months, then roughly 10% per year.
- Age of 65 is the biggest risk factor.
- Gender: Men at higher risk than women.

Modifiable:
- Hypertension
- Cigarette smoking
- Dyslipidemia
- Diabetes Mellitus
- Insulin resistance
- Abdominal obesity
- Excess alcohol consumption
- Lack of physical activity
- High-risk diet
- Heart disorders
- Intracranial aneurysms
- Use of certain drugs
- Vasculitis
Unmodifiable:
- Prior stroke
- Older age
- Family history of stroke
- Genetic factors

Anterior Circulation:
- Likely thrombus from carotid artery, affecting cerebral function.
- Symptoms: Aphasia/dysphasia, hemiparesis, amaurosis fugax, hemisensory loss, hemianopic visual loss.
- Amaurosis fugax: Sudden loss of vision in one eye, caused by an infarct in the retinal artery.
Posterior Circulation:
- Likely thrombus from vertebrobasilar system, affecting cerebellar/brainstem function.
- Symptoms: Diplopia, vertigo, vomiting, choking, dysarthria, hemianopic visual loss, sensory loss, transient global amnesia, tetraparesis, loss of consciousness.
- Transient global amnesia: Episodes of amnesia, primarily in those over 65, that completely resolve within 24 hours.

Within 5 years after a TIA, 30% of patients have a stroke, with 15% experiencing a myocardial infarction (MI).
Within the first year after a TIA, 30% of patients will have a stroke.

If symptoms do not resolve after 24 hours or a serious condition is suspected, follow the stroke protocols.
Otherwise, patients are often admitted to the hospital based on their ABCD2 score.
This score predicts the likelihood of a further cerebrovascular event.
Patients with an ABCD2 score greater than 4 should be admitted to the hospital and investigated within 24 hours.