Ischemic stroke
Ischemic stroke is a pathological condition of a person that is not an independent disease, but is considered an intermediate development of a general (or local) vascular lesion of a progressive nature. Ischemic stroke accompanies various diseases of the cardiovascular system.
The content of the article:
Classification of ischemic strokes
Etiology and pathogenesis of ischemic stroke
Clinical picture of ischemic stroke
Diagnosis of ischemic stroke
Treatment of ischemic stroke
Prognosis for ischemic stroke
Prevention of ischemic stroke
Ischemic stroke
Usually, ischemic stroke is accompanied by diseases such as:
atherosclerosis;
arterial hypertension;
rheumatic heart disease;
diabetes mellitus;
coronary heart disease;
and other abnormalities associated with vascular lesions.
The symptoms of ischemic stroke are based on focal and cerebral manifestations, which depend on the location of vascular abnormalities. Diagnosis of ischemic stroke involves CT or MRI of the brain. This technique also helps to differentiate ischemic stroke from hemorrhagic stroke.
In its anatomy, an ischemic stroke is nothing more than a violation of cerebral circulation, which is characterized by a spontaneous manifestation of cerebral (or neurological) symptoms of the focal type. Usually, the clinic is maintained for a whole day or even more, which leads to frequent deaths of patients.
Classification of ischemic strokes
Since ischemic stroke is often the outcome of one of the suffered cardiovascular diseases, several types of it are distinguished in neurology:
Cardioembolic is a type of ischemic stroke that occurs due to arrhythmia, a previous myocardial infarction or a valvular heart defect present.
Lacunar is a type of ischemic stroke, the cause of which was a minor occlusion of the arteries.
Atherothrombotic — the cause of it is atherosclerosis of large arteries, which causes arterial embolism.
Unknown genesis — ischemic stroke, the root cause of which has not been established, several reasons that could lead to the development of this disease are not excluded, so it is difficult to immediately make an accurate diagnosis.
Ischemic stroke, which is related to rare causes: dissection of arterial walls; hypercoagulation of blood or non-atherosclerotic diseases.
Ischemic stroke is also classified depending on the time of occurrence. For example, there are 5 periods of ischemic stroke:
Acute: occurs in the first three days. It should be said that in the first three hours after the stroke, thrombolytic drugs that are administered systemically can help the patient. If the symptoms begin to regress, then a transient ischemic attack is diagnosed on the first day of the disease.
Acute: lasts up to 4 weeks.
Early recovery period: may last up to 0.5 years.
Late recovery period: lasts up to two years.
Time of residual phenomena: manifests itself after 2 years from the moment of the disease.
It should also be noted that in practice, a small stroke is also common, which is characterized by regressive symptoms observed for 3 weeks from the onset of the disease.
Etiology and pathogenesis of ischemic stroke
Since in medical practice, ischemic stroke is not considered as an independent disease, it is not necessary to talk about any etiological cause that causes it.
However, doctors mention risk factors that affect the incidence of this disease, among them:
Modifiable factors: arterial hypertension, diabetes mellitus, asymptomatic carotid artery disease, myocardial infarction.
Unmodifiable factors: heredity.
In addition to these two large groups of risk factors, there are also lifestyle factors: stressful situations, prolonged psycho-emotional stress, poor standard of living, low physical activity, excess weight, bad habits.
A special sequence of biochemical changes occurring in the patient’s body, and in particular in the brain substance, is usually caused by focal cerebral ischemia (acute form), which entails various kinds of disorders at the tissue level, which causes the death of brain cells or a brain infarction.
If we talk about the nature of changes occurring during an ischemic stroke, it depends on the level and duration of reduced activity in the cerebral bloodstream, as well as on how sensitive the brain substance is to ischemic processes.
Interestingly, the degree of reversibility of changes occurring in the tissue will be determined at each pathological stage by the level of decrease in cerebral blood flow, as well as by such an indicator as its duration, together with those factors that affect the sensitivity of the brain to damage of a hypoxic nature.
There are several medical terms that cause controversy in their definition. In order to debunk all doubts, let’s call them.
The core of a heart attack in neurology is called the zone of irreversible damage, whereas the penumbra is usually called the zone of ischemic lesion, which is characterized by a reversible character. In the study of a particular case of ischemic stroke, doctors devote considerable attention to the duration of the existence of penumbra, since over time those changes that previously had a reversible character become irreversible.
Another important term is the “oligemia zone”, which is called the area with a preserved balance between the needs of the tissue and the processes that provide it with these needs, even despite the reduced cerebral blood flow. Such zones usually exist for a very long time, while not passing into the core of a heart attack. This term should not be confused with the term “penumbra”.
Clinical picture of ischemic stroke
Clinical manifestations in ischemic stroke are quite diverse, depending on the location of the focus and the area of brain damage. Most often, the lesion is located in the carotid basin (it accounts for more than 80% of cases of ischemic stroke), less often — in the vertebral-basilar department.
The main feature of a heart attack in the blood supply zone of the cerebral artery of the middle type is the presence of a collateral blood supply system. If we talk about such a phenomenon as occlusion of the proximal part, then in the cavity of the middle cerebral artery it contributes to the subcortical type of infarction, while the cortical part will not be affected by blood supply. If there are no collateral data, a massive infarction may develop in the part where the blood supply to the middle cerebral artery occurs.
If the infarction occurred in the part characterized by blood supply to the superficial branches of the cerebral artery of the middle type, then the fact of the development of deviation of the eyeballs in the direction of the affected part of the hemisphere is not excluded. If the dominant hemisphere was affected, then the development of the ipsilateral form of ideomotor apraxia begins. In addition, total aphasia can be traced. If the subdominant hemisphere was affected, then we are talking about anosognosia. In addition, the development of dysarthria or aprosody is not excluded. A contralateral kind of ignoring of space may also occur.
Symptoms of myocardial infarction of the brain
The main symptom of a cerebral infarction (in the area of the branch of the middle cerebral artery) is contralateral hemianesthesia, as well as the so-called contralateral type of hemiparesis.
If the patient is characterized by lesions with a large area, then the formation of conjugate removal of the eyeballs is not excluded, which is characterized by fixation of the gaze in the direction of the damaged hemisphere of the brain.
Subdominant hemisphere infarction
If a subdominant hemisphere infarction has occurred, then emotional disturbances and spatial non-response will be inherent in the disease.
How much paresis will spread during a heart attack into the cavity of the blood supply basin (striatocapsular arteries) will depend on the location and area of the lesion itself (usually the upper part of the body: face, limbs or cotralateral part of the body). Speaking of extensive striatocapsular infarction, the main symptom is occlusion of the cerebral (middle) artery, which is expressed in aphasia or homonymous lateral hemianopia.
Symptoms of lacunar infarction
If we talk about lacunar infarction, then clinically it is manifested by the unfolding of lacunar syndromes, which is reflected in hemihypesthesia, hemiparesis, both individually and in combination.
Most often, a heart attack that occurred in the blood supply pool of the anterior cerebral artery, symptomatically expresses itself in the form of movement disorders. With the occlusion of the cortical branches, the development of motor deficiency begins in the area of the feet or on the lower extremities. In addition, there is an implicit paresis of the upper extremities, which is also manifested in a strong lesion of the tongue and face as a whole.
Infarctions of the occipital part of the temporal lobe
Due to occlusion of the posterior side of the cerebral artery, infarcts of the characteristic occipital part of the temporal lobe begin to occur. In addition, there may be infarcts in the area of just the temple. In this case, the clinic is such a defect of the visual fields as homonymous hemianopsia of a contralateral nature. A combination of the latter with photopsias or manifested hallucinations is not excluded.
Infarcts in the vertebrobasilar pool of blood supply
The cause of infarcts occurring in the vertebrobasilar pool of blood supply is the occlusion of the perforating branch of the artery, which is called the basilar. The main symptoms of such infarcts are lesions of the CHN from the ipsipateral part. The process of occlusion of the vertebral artery type, as well as branches that are often called penetrating, that is, directed from the distal part, often contributes to the occurrence of lateral medullary syndrome, which in neurology is called Wallenberg syndrome.
Diagnosis of ischemic stroke
Immediately before the start of the anamnesis collection, doctors determine changes in cerebral circulation that have occurred during the onset of the disease. Specialists determine the rate and level of progression of the symptoms that have begun.
Ischemic stroke is characterized by a sharp appearance of neurological symptoms. Important risk factors to pay attention to when making a diagnosis of ischemic stroke are: atrial fibrillation, diabetes mellitus, atherosclerosis, arterial hypertension.
Diagnosis of ischemic stroke involves a physical examination, which is carried out according to the accepted rules. When assessing the neurological status of a patient, attention should be paid to the presence of so-called general cerebral symptoms:
headache;
generalized seizures;
violation of consciousness.
In addition, patients may have meningeal and neurological symptoms. If we talk about the types of laboratory tests, they are represented by urine and blood analysis (biochemical), coagulogram.
The main methods of instrumental diagnosis of ischemic stroke are CT and MRI, which also help to make a differential diagnosis, distinguishing ischemic stroke from various forms of intracranial lesions or control by dynamics in tissue changes during the treatment of this disease.
The most important ischemic symptom indicating damage in the area of the middle cerebral artery, which can be detected during CT diagnostics, is a weak severity of the lenticular nucleus and cortex, which subsequently leads to the development of cytotoxic edema.
In addition, during the course of an ischemic stroke, the doctor may detect changes associated with the hyperdensity of the areas of the posterior or middle artery located on the affected side (for example, it may be thrombosis or embolism of a vessel).
For the first week of the disease, the area of gray matter with ischemic lesion is characterized by an increase in the density level, up to an isodensive or weakly hyperdensive state. The latter indicates the beginning of the development of the process of neovasogenesis or restoration of blood flow. Doctors also call this process the “blurring” effect, because at this time it is not always possible to determine the boundaries of ischemic damage, especially if the brain infarction has reached the subacute period.
MRI allows you to detect a diffusion-weighted image of the affected area with high accuracy. Due to the cytotoxic edema that has appeared, water molecules usually move into the intracellular space (from the extracellular), which leads to a slowdown in the rate of diffusion process. All these changes occurring in the human body can be detected on a diffuse-weighted image obtained during MRI. It is this type of diagnosis that helps to identify the irreversibility of damage occurring in the structures of the substance of the brain.
Differential diagnosis
First of all, an ischemic stroke should be distinguished from a hemorrhagic type of stroke. A significant role in differential diagnosis is assigned to neuroimaging methods of studying the disease. In some cases, it may be necessary to distinguish between ischemic stroke and hypertensive encephalopathy of the acute type. Ischemic stroke should also be distinguished from toxic or metabolic types of encephalopathy, from brain tumors, abscesses, encephalitis and other brain lesions of an infectious nature.
Treatment of ischemic stroke
A person with even the slightest suspicion of an ischemic stroke should be hospitalized in a special department as soon as possible. If the first symptoms of an ischemic stroke were detected no later than 6 hours from the beginning of their manifestation, then the patient is sent to the intensive care unit. Usually, the patient is transported in a reclining position, with his head raised up to 30 degrees.
Hospitalization is not indicated for those patients who are in a terminal coma, suffer from cancer or have a history of dementia with pronounced disability.
Treatment of ischemic stroke, as a rule:
non-drug treatment (involves taking measures aimed at caring for the patient, as well as regulating the swallowing reflex, treating infectious diseases that often manifest themselves in the form of pneumonia or infection of the genitourinary system);
medication (this type of therapy will be most effective only at the initial stage of the disease, in the first 6 hours from the onset of symptoms; drug treatment involves a multidisciplinary approach that can be performed within the walls of a special vascular department, usually located in the intensive care unit, where CT, MRI or ECG can be performed at any time, as well as blood and urine analysis.
Maintenance of body functions is the main stage of treatment
The main goal of any type of treatment of ischemic stroke is the correction of particularly important body functions and the mandatory maintenance of homeostasis. To achieve this goal, all important physiological components are monitored, as well as measures aimed at maintaining hemodynamics, respiratory processes, and water-electrolyte balance. When treating a patient, his intracranial pressure should also be normalized in order to get rid of brain edema in the future. In addition, regular prevention of this disease and therapy aimed at combating the possible consequences of ischemic stroke should be carried out.
The main infusion solution during the treatment of this disease is a solution of sodium chloride. As for the use of glucose-containing solutions, in recent years doctors have refused them because of the possible development of hyperglycemia.
If an ischemic stroke develops against the background of diabetes mellitus, then the patient is given subcutaneous injections of insulin (short-acting). The exception is cases when specialists establish glycemic control while the patient is lucid and does not suffer from impaired swallowing function.
In the first 2 days after the onset of the disease, doctors regularly measure the level of oxygen saturation of hemoglobin in the blood. If the indicator reaches 90-92%, then doctors conduct oxygen therapy (usually starting with 2 liters per minute).
If the patient’s level of consciousness decreases to 8 or less points (calculated on the Glasgow scale), then this indicates an indicator for tracheal incubation. The decision whether to use a ventilator in the future or not will be made on the basis of the available resuscitation provisions. If the patient’s level of wakefulness is noticeably reduced, there are clinical and other neuroimaging characteristics indicating cerebral edema (or increased intracranial pressure), then it will be mandatory to maintain the head in an elevated state so that the neck does not bend at the same time. It is necessary to minimize the cough that has arisen or the signs of an incipient epileptic seizure, as well as curb muscle arousal. It should be remembered that infusions of hypoosmolar solutions are contraindicated in this case.
Nutrition of patients with ischemic stroke
The main task of ischemic stroke therapy is considered to be proper nutrition of the patient, control of the water-elictrolytic balance. This requirement should be implemented regardless of where the patient is being treated: whether in the intensive care unit or in the neurological department.
The main indicator for carrying out enteral-probe nutrition will be the progress of the swallowing function. The amount of the dose of the administered nutrients is calculated on the basis of data on the metabolic needs of the patient’s body, as well as his physiological losses. If food is administered orally (or with a probe), then the patient should take a semi-sitting position.
To prevent deep vein thrombosis (in the case of ischemic stroke), the use of compression bandages or stockings is prescribed. This method also helps to prevent the development of pulmonary embolism. In addition, direct anticoagulants can be used.
Neuroprotection
Speaking about the treatment of ischemic stroke, we should also mention such a type of therapy as neuroprotection. Its main focus is the use of special drugs with neurotrophic and neuromodulatory functions. The most well-known such drug today is cerebrolysin (it belongs to the neurotrophic series of drugs). As you know, there is no such important property as deposition in the central nervous system and spinal cord. In other words, if you suspend blood flow in these areas for 5 minutes, the neurons will begin to die. Therefore, the need for the introduction of neuroprotectors is mandatory. It should be carried out in the first minutes after the onset of an ischemic stroke.
Treatment of ischemic stroke will be crowned with success with an integrated approach: basic therapy, rehabilitation, neuroprotection and reperfusion.
Surgical treatment
If we talk about the surgical type of treatment of ischemic stroke, first of all, it includes surgical decompression, which implies a decrease in intracranial pressure and at the same time an increase in perfusion pressure against the background of preserved cerebral blood flow. According to statistics, the death rate in ischemic stroke has now been reduced to 30%.
The rehabilitation period after an ischemic stroke will be aimed at restoring previously lost motor and speech functions of the patient. This is the main task of neurologists who perform electromyostimulation, physical therapy, regular massage of paretic limbs or mechanotherapy. To correct the patient’s speech, he is also referred to a speech therapist.
Prognosis for ischemic stroke
The prognosis in the case of ischemic stroke will be determined by the location and area of the brain lesion. In addition, important indicators here will be the age of the patient and the severity of parallel diseases. The most difficult period in ischemic stroke is the first 5 days. It is at this time that there is an increase in brain edema in the area of its lesion, after which there comes a time of stabilization, when the impaired functions of the central nervous system gradually return to normal. To date, the percentage of deaths of patients with ischemic stroke is no more than 20%.
Prevention of ischemic stroke
The most important thing in the prevention of ischemic stroke is taking measures to prevent thrombosis of blood vessels, which is formed at the time of occurrence of cholesterol plaques in the blood. To this end, doctors prescribe a set of procedures to maintain a healthy lifestyle, excluding smoking, alcohol and fatty foods. As is known, the risk group for ischemic stroke is primarily those patients who suffer from chronic diseases of the cardiovascular system, diabetes mellitus or hypertension.
Secondary prevention of ischemic stroke includes the implementation of a comprehensive program in the form of: hypotensive therapy with the use of inhibitors, diuretics; hypolipidemic therapy with statins; surgical intervention (carotid endaterectomy is performed); antithrombotic therapy (antiplatelet agents and anticoagulants of indirect action).
