At the atrial fibrillation, with myocardial infarction, with prosthetic heart valves, with endocarditis infectious nature, embolus breaks, which closes the lumen of the vessel and leads to ischemia of the brain tissue. With occlusion of a small vessel with myocardial infarction, diabetes mellitus and high blood pressure, cavities of necrosis in the brain can form. Therefore, not extensive areas of ischemic lesions of the cerebral hemispheres are formed, but small cavities, and this stroke is called lacunar. Most often, the symptomatology of this form of the disease is obliterated.
This is a very serious disease - ischemic stroke, the causes of which can be reduced to the following:
- A thrombus or cholesterol plaque detaches from the wall and enters the small vessel of the brain with a blood stream.
- The thrombus detaches from the endocardium and closes the lumen of the cerebral artery.
- In case of hemodynamic disturbances, with heart failure and circulatory disturbance, embol from the heart enters the carotid artery.
- Lacunar cerebral ischemia on a background of hypertension and diabetes mellitus of severe form.
- In case of trauma, arterial stratification can occur, which leads to cerebral ischemia.
Ischemic stroke has three degrees of severity. Allocate cerebral symptoms and focal. Headache, pain in the eyeballs, which is intensified when they move, nausea, dizziness and vomiting are common symptoms.
Its consequences depend on the age of the patient, the location of the occlusion of vessels, the duration of occlusion, the development of collaterals and blood pressure. The more time has passed since the blockage and the greater the lesion, the faster irreversible processes occur. The signs of ischemic stroke depend on the localization of occlusion. When the anterior cerebral artery is blocked, lower limbs are affected, severe weakness, paresis or paralysis develops, speech is disrupted.
When the posterior cerebral arteries are affected, there is a disturbance in the functions of the cerebellum, brainstem, occipital and temporal lobes. There is difficulty in swallowing, respiratory depression and serious disorders in the work of the heart. Coordination of movements, sensitivity to pain and temperature can be disturbed. Attention is drawn to the stunned consciousness down to the coma, the distortion of the face as a result of the defeat of the trigeminal and facial nerve, paralysis of the half of the body. From the viewpoint of vision develops nystagmus, strabismus.
Ischemic stroke with obstruction of the middle cerebral artery is characterized by a violation of sensitivity and paralysis on the opposite side of the lesion. Sensitivity is broken, paresis of the gaze, upper limbs and face develops.
With carotid thromboembolism, paresis develops on the opposite side and vision falls sharply on the side of the occlusion.
With occlusion of the basilar artery, ischemic stroke can manifest itself in different ways, depending on the level of damage. There may be tinnitus and hearing loss down to its loss, nystagmus and dizziness, vomiting and nausea. With lesions in the trunk of the basilar artery or vertebral arteries, complete paralysis, bilateral paresis of the eye and coma can be observed.
The process of cerebral ischemia is reversible in 6-12 hours. Rarely, when you can count on a day. Therefore, it is extremely important to correctly and timely provide the necessary medical care to a patient if an ischemic stroke occurs. Provide him peace, stabilize the heart and lungs, prevent complications. It is important to restore blood flow, protect the brain from further damage and support its normal nutrition.