Stroke: Clinical

A stroke is a when there’s a sudden focal neurological deficit due to a part of the brain losing its blood supply.

There are two types of strokes - ischemic strokes and hemorrhagic strokes.

The majority are ischemic strokes and there are three types: thrombotic, embolic, and hypoxic strokes.

Thrombotic strokes are caused by local arterial obstruction due to inflammatory diseases like atherosclerosis, and non-inflammatory diseases like fibromuscular dysplasia.

Thrombotic strokes affect large vessels like the internal carotid artery, as well as small vessels like the penetrating arteries that branch off of the basilar artery.

When they affect these small arteries they’re called lacunar strokes, and they typically cause symptoms like hemiparesis, ataxia, dysarthria, and numbness in the contralateral face, arm, and leg.

An embolic stroke is when the blood vessel is blocked by an embolus.

If it arises from the heart, it’s called cardioembolic, and that usually occurs in the setting of atrial fibrillation.

That’s because in atrial fibrillation, blood stagnates in the atria and can become clotted.

That clot can then travel up to the blood vessels supplying the brain.

Alternatively, an embolus might dislodge from a thrombus or atherosclerotic plaque in the carotid artery, and that results in a thromboembolic or atheroembolic stroke.

More rarely, there might be a paradoxical embolus which dislodges from a thrombus in the veins - like a deep vein thrombosis, and then slips through an atrial septal defect or patent foramen ovale.