1. Atheroma of the internal carotid, vertebral or common carotid artery.
2. Aneurysm of aorta or innominate artery
3. Infective endocarditis.
4. Mitral stenosis particularly in presence of atrial fibrillation.
5. Myocardial infarction.
6. Infected emboli from the lung.
7. Paradoxical embolism.
Left-sided vascular occlusion is common as the left common carotid artery arises directly from the aorta. Left middle cerebral artery is seen to be the commonest site.
Onset is stormy or very acute.
Clinical features of CEREBRAL EMBOLISM :- Patient may be unconscious and remains dazed. There may be headache and convulsive seizure. The site of occlusion determines the focal neurological symptoms. Hemiplegia develops usually on the right side as left side vessels are usually occluded and this is usually associated with aphasia. Symptoms and signs may increase gradually due to associated vasospasm. In some other cases again clinical features may diminish due to dislodgement of embolus more distally resulting in shifting of hemiplegia.
Immediate mortality is about 7%-10 %.
TREATMENT OF CEREBRAL EMBOLISM
Same as cerebral thrombosis.
Some prefer to give anticoagulants but it should be used with great caution. It should not be used in cases of bacterial endocarditis. The underlying cause should be treated as far as practicable.
If there is recurrent transient episodes-long term anticoagulant therapy may be used. In young individuals with atrial fibrillation, anticoagulants are preferred. Steroids are given by some to reduce vasogenic cerebral oedema. Dehydrating agents, e.g., mannitol may be used also to reduce brain swelling. Nimodipine is also used by some to reduce neural deficit. Glutamate blockade drugs may also reduce the size of infarct. This drug is under trial. Stenosis of internal carotid or vertebral artery can be relieved by surgery. For residual hemiplegia physiotheraphy can be done. In syphilitic cases antisyphilitic measure is to be given.