STROKE (LacI)

---

Refer ischaemic stroke card for other detail.

---

AETIOLOGY
One cause:
Lipohyalinosis related to hypertension.

Pathogenesis
Over time, with hypertension, small penetrating branches of cerebral vessels become impregnated with hyaline-lipid material (arteriolar sclerosis).
These are vulnerable to thrombosis.
Brain undergoes ischaemia in single or multiple small 'lake'-like pockets.
Gives rise to 'lacunar' infarcts.
Undergo liquefactive cavitation, just a few mm wide.
top D I A B M I M home

---

BIOLOGICAL BEHAVIOUR
Pathophysiology
Depends on the area hypoperfused.
See ischaemic stroke for functional anatomy and hence clinicopathological correlations.
The specific areas that may be affected by the LacI (due to supply by deeper penetrating arteries) are (decreasing order of frequency).
The lenticular nucleus.
Thalamus.
Internal capsule.
Deep white matter.
Caudate nucleus.
Pons.

Classification
Typically, the LacI syndrome can be one of 5 major types:
1. Pure motor hemiparesis.
Posterior limb or internal capsule/ crus cerebri of midbrain/ basis pontis damage).
2. Pure sensory stroke.
Infarct in ventrolateral thalamus.
3. Ataxic hemiparesis.
Infarct in the base of the pons.
4. Dysarthria and a clumsy hand or arm.
Infarction in the base of the pons or in the genu of the internal capsule.
5. Motor 'aphasia'.
Lenticulostriate branch supplying genu and anterior limb of internal capsule + adjacent white matter of corona radiata.
No visual field defect.
No abnormality of higher cerebral function.
No signs of brain stem abnormality.
No impairment of consciousness.
3% die in 30 days.
35% probability of death or disability at 6 months.
top D I A B M I M home

---

MANIFESTATIONS

Symptoms
Local
See explanation above.
One or a number of:
Unilateral motor weakness/ paralysis (face, arm, leg, foot, toes almost always involved).
Pure sensory loss to pain and temperature (light touch OK) unilaterally.
Inability to smoothly coordinate muscle activity during voluntary movement (ataxia).
Dysarthria and a clumsy hand or arm.
Motor 'aphasia' - loss of voluntary movements unilaterally.

No visual defect.
No higher brain function defects.
No signs of brain stem abnormality.
No impairment of consciousness.

Signs
As for ischaemic stroke but especially:
Look for:
Neuro exam
Isolated hemisensory deficits.
Dysarthria.
Ataxic hemiparesis.
top D I A B M I M home

---

INVESTIGATIONS
CT - Small infarct (dense areas) shown on imaging in basal ganglia, internal capsule. top D I A B M I M home

---