stroke localisation and cerebral blood flow

1. Cerebral blood flow and
stroke localisation

4. – The anterior and middle cerebral arteries supply the
frontal and parietal lobes while the posterior cerebral
artery supplies the occipital lobe.
– The vertebral and basilar arteries supply the brain stem,
midbrain and cerebellum.

7. CLINICAL
PRESENTATION
– Most vascular lesions develop suddenly, within a matter
of minutes or hours and so should be considered in the
differential diagnosis of patients with any acute
neurological presentation.
– WEAKNESS: unilateral weakness is the classical
presentation of stroke. It is sudden, progresses rapidly and
follows a hemiplegic pattern.
– SPEECH DISTURBANCE: dysphasia and dysarthria are
the most common presentation.

8. – Dysphasia indicates damage to the frontal or parietal lobe.
Dysarthria is a non-localising feature that reflects
weakness or incoordination of the face, pharynx, lips,
tongue or palate.
– VISUAL DEFICIT : ischemia of the occipital cortex or
post chiasmic nerve tracts results in contralateral
hemianopia.

9. – ATAXIA : stroke causing damage to cerebellum and its
connections may result in acute ataxia and there may be
associated brainstem features such as diplopia , vertigo.
– Seizure and Coma is uncommon.

11. – If the entire MCA is occluded at it’s origin (blocking both
it’s cortical and penetrating branches) and the distal
collaterals are limited, the clinical findings are contralateral
hemiplegia, hemianaesthesia and homonymous hemianopia.
– Dysarthria is common because of facial weakness.
– When the dominant hemisphere is involved, global aphasia
is present.

13. – Paralysis of opposite foot and leg: motor leg area
– Cortical sensory loss over toes, foot and leg : sensory area
of foot and leg
– Urinary incontinence : sensorimotor area in paracentral
lobule