Stroke

Today we discussed a case of stroke. Some points:

Differential diagnosis of stroke:
Any structural abnormality, seizure, migraine (esp migraine sensory aura- ascending paresthesias over minutes), MS, hypoglycemia, TIA, dissection (esp young), vasculitis, venous sinus thrombosis. Any underlying brain abnormality with something that can cause delirium can cause focal sx.

Etiology:
20% hemorrhagic: HTN (basal ganglia, thalamus, cerebellum, internal capsule); AVM; aneurysm (SAH), amyloid angiopathy (large, lobar)
80% ischemic: Embolic (cardio-embolic: a-fib, valves, akenesis; artery to artery- carotid stenosis), thrombotic (in-situ thrombosis), lacunar (same as HTN areas- lipohyalinosis).
Hemorrhagic conversion of ischemic also occurs.

Stroke syndromes
MCA dominant (usu. means left, where speech function is)
inferiolat frontal lobe: R hemiparesis (arm greater than leg), expressive language.
superior temporal: word-finding
inf. parietal: receptive aphasia, homonymous hemianopsia
MCA non-dominant: L hemiparesis (arm greater than leg), apraxia, sensory neglect, visuospatial
ACA dominant: R hemiparesis (leg greater than arm), verbal problem-solving
ACA non-dominant: L hemiparesis (leg greater than arm), apraxia, lack of insight
PCA: Occipetal lobe- hemianopsia, post. parietal- sensory changes, basal ganglia, cerebellar findings
PICA: (Wallenberg)- Lat. medulla. 1) Ataxia/vertigo from inf. cerebellar peduncle (pt falls towards affected side), 2) ipsilateral loss of pain/temp on face, 3) contralat loss of pain/temp on body (STT). Possible Horners syndrome. Possible contralateral weakness of extremities, ipsilateral facial if 7th nerve nucleus involved. Also associated with dysphagia, hiccups...
Lacunar: subcortical, internal capsule (face=arm=leg weakness), basal gangla involvement (variable)

Cortical vs. subcortical:
Important from etiological standpoint; cortical more likely to be embolic; subcortical more commonly lacunar. Some cortical signs: aphasia, visual field loss, apraxia, neglect.

Prognosis:
Small vessel (Lacunar)- recurrence risk is ~3%/ yr
Cardioembolic: 10-15% /yr.
Carotid: 30% recurrence risk/yr, all front-loaded. This is why carotid dopplers are often done prior to discharge decision. NNT for endarterectomy is 3 in first 2 weeks. Patients often await surgery admitted to hospital, sometimes on heparin infusion.

Some references
Click here for ABCD2 TIA score
Click here for original paper describing ABCD2 score
Click here for the NASCET trial of carotid endarterectomy in carotid stenosis