Transient ischemic attack
Overview (summary)
A Transient Ischemic Attack (TIA) is a brief loss of neurologic function. In a TIA, the affected brain cells were not killed, but only transiently deprived of blood supply and the signs of what seems to be a stroke, (or black-out), pass quickly and completely. A TIA is often a warning sign of an impending stroke, however, and like a true stroke, is a neurologic emergency. None the less, a TIA is not a true stroke.
Prognosis
Patients diagnosed with a TIA are sometimes said to have had a warning for an approaching cerebrovascular accident. If the time period of blood supply impairment lasts more than a few minutes, the nerve cells of that area of the brain die and cause permanent neurologic deficit. One third of the people with TIA later have recurrent TIAs and one third have a stroke due to permanent nerve cell loss.
The ABCD2 score can predict likelihood of subsequent stroke.[1][2]
The score is calculated as:
- Age ≥ 60 years = 1 point
- Blood pressure at presentation ≥ 140/90 mm Hg = 1 point
- Clinical features
- unilateral weakness = 2 points
- speech disturbance without weakness = 1 point
- Duration of attack
- ≥ 60 minutes = 2 points
- 10–59 minutes = 1 point
- Diabetes = 1 point
Interpretation of score, the risk for stroke:
- Score 0-3 (low)
- 2 day risk = 1.0%
- 7 day risk = 1.2%
- Score 4-5 (moderate)
- 2 day risk = 4.1%
- 7 day risk = 5.9%
- Score 6–7 (high)
- 2 day risk = 8.1%
- 7 day risk = 11.7%
References
- ↑ Johnston SC, Rothwell PM, Nguyen-Huynh MN, et al (2007). "Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack". Lancet 369 (9558): 283-92. DOI:10.1016/S0140-6736(07)60150-0. PMID 17258668. Research Blogging.
- ↑ Rothwell PM, Giles MF, Flossmann E, et al (2005). "A simple score (ABCD) to identify individuals at high early risk of stroke after transient ischaemic attack". Lancet 366 (9479): 29-36. DOI:10.1016/S0140-6736(05)66702-5. PMID 15993230. Research Blogging.