Sunday 17 October 2010

MRCP revision battle 32.3: TIA

TIA (=transient ischaemic attack) = sudden onset of focal CNS phenomena which last <24 hours.  Caused by temporary occlusion of part of the cerebral circulation.



Causes of TIAs:
  • thromboembolism
    • chiefly from carotids
    • may be from heart - AF, mural thrombus etc)
  • hyperviscosity
    • myeloma
    • polycythaemia
    • sickle cells
    • very high white cells


Management depends on the ABCD2 score, which is calculated as shown below:
  • age >60 : 1 point
  • BP greater or equal to 140/90 : 1 point
  • clinically:
    • unilateral weakness : 2 points
    • speech disturbance without weakness : 1 point
  • duration
    • >60 mins : 2 points
    • 10 - 59 mins : 1 point
  • diabetes : 1 point


ABCD2 score of 4 or more, or crescendo TIAs (=2 or more in one week):
  • specialist review within 24 hrs
  • start 300mg aspirin OD


ABCD2 score of 3 or below, or symptoms >1 week ago:
  • specialist review within a week
  • start 300mg aspirin od

After specialist review, usually 75mg aspirin OD and dipyridamol OD for 2 yrs.
If pt is aspirin intolerant, prescribe monotherapy of clopidogrel.




If assessed to be a candidate for carotid endarterectomy, imaging should be performed within 1 week of symptom onset and if carotid stenosis of:
  • 50–99% according to NASCET criteria, or 
  • 70–99% according to ECST criteria 
carotid endarterectomy should be performed within 2 weeks of symptom onset.



Remember pt must inform DVLA and no driving for 1 month (car) or 1 yr (lorry).  This increases to 3 months for car if multiple TIAs.



Of course other risk factors (hypertension, alcohol, smoking, etc etc etc) should also be addressed.




Differentials for TIA may include:
  • migraine
  • epilepsy
  • hypoglycaemia
  • malignant hypertension 
  • MS


Lets move on to tackle epilepsy...