A stroke (also called cerebrovascular accident -CVA) occurs when blood supply is interrupted to a part of the brain, depriving those brain cells of oxygen and nutrients. It is a medical emergency as brain cells start to die within a few minutes of oxygen deprivation.
TYPES OF STROKE
Ischemic Stroke
A stroke can occur due to narrowing, blockage and stiffening of arteries of the brain (cerebrovascular disease). This type of stroke is called Ischemic stroke (ischemia means lack of oxygen).
This happens due to atherosclerosis that is the formation of plaques (fatty deposits) in the blood vessels, which also causes cardiovascular disease. It can also happen due to blood clots lodging in the brain arteries, the risk of which increases significantly in patients with deep vein thrombosis, heart failure and heart rhythm abnormalities (like atrial fibrillation).
Hemorrhagic Stroke
Stroke can also occur when a brain artery leaks or ruptures, thereby inhibiting further blood supply to a part of the brain. This is called hemorrhagic stroke.
The hemorrhage may be subarachnoid (between the brain and its covering) as occurs due to weak blood vessel walls seen in aneurysms and vascular malformations, or trauma. The hemorrhage can also be intracerebral (within the brain) as seen in uncontrolled blood pressure. A decrease in clotting (coagulation disorders or high dose blood thinners) can also cause hemorrhagic stroke.
Ischemic stroke can also lead to a hemorrhagic stroke.
Transient Ischemic Attacks (TIA)
TIA (mini-stroke) occurs due to a temporary (few minutes) decrease in blood supply, and can sometimes be an early sign of cerebrovascular disease, and risk of ischemic stroke.
There may be momentary stroke-like symptoms (dizziness, blackout, unsteadiness, weakness on one side, vision blurring, confusion, or slurring of speech) with usually immediate recovery or within 24 hours and no permanent damage.
SIGNS AND SYMPTOMS
Immediate signs and symptoms can include:
- weakness, numbness, or paralysis on one side of the body
- vision problems
- confusion, memory loss or sudden blankness, altered behavior
- headache, sometimes a seizure
- loss of balance, difficulty in walking and coordination (ataxia)
- trouble in speaking or understanding language (aphasia)
- blackout or passing out (brief fainting)
Involvement of the left side of the brain usually affects speech and the right side of the body, while the stroke in the right side of the brain affects vision and the left side of the body. Memory loss and behavioral changes can occur with the involvement of either side of the brain.
Long-term or permanent problems after stroke can include:
Loss of Function: This can include weakness, paralysis, or loss of movement of one side (hemiplegia), difficulty in writing and fine tasks, difficulty in swallowing and eating, and speech impairment.
Abnormal sensations and pain: This can include tingling, numbness, or pain in the affected areas.
Memory, cognitive and behavioral problems: Difficulty in remembering, thinking, analyzing, understanding and reasoning may persist long-term, There may also be altered behavior and emotional instability.
RISK FACTORS
- Diabetes
- Hypertension (High Blood Pressure)
- Dyslipidemia (increased cholesterol +/- triglycerides in the blood)
- Lack of physical activity (sedentary lifestyle)
- Obesity or being overweight (high BMI)
- Inappropriate diet (high carbohydrate/sugar, salt and/or saturated/trans-fat intake)
- Cardiovascular disease (CVD)
- Heart failure,
- Heart rhythm abnormalities (atrial fibrillation)
- Psychosocial stress
- Chronic Insomnia
- Sleep apnea
- Smoking/tobacco use
- High alcohol consumption
- Family history of cardiovascular disease, stroke and/or hypertension.
- Personal history of TIA
- Medicines (blood thinners- anticoagulants, oral contraceptives), illegal drugs (cocaine, methamphetamine)
- Abnormalities of blood vessels like arteriovenous (AV) malformations and aneurysms (ballooning or weakened area in an artery)
- Amyloidosis (build-up and deposit of abnormal proteins called amyloid proteins)
- Recently suffered from COVID
- Asian and African race
- Male gender and increasing age > 55 years represent an overall higher stroke risk as compared to women and younger age. However, women who have risk factors, and suffer from stroke, have a greater risk of dying.
STROKE PREVENTION
Healthy diet: Reduce packaged foods, and foods high on salt, trans/saturated fats, and sugar. Switch to a healthy diet that has more fresh foods, fruits and vegetables, and whole grains, which can also help maintain appropriate weight and BMI.
Physical activity: This should include 30-45 minutes of exercise like brisk walking, swimming, yoga, aerobics, cycling, etc. at least 5 times/week.
Adequate sleep: Uninterrupted sleep of 8 hours on most nights is very important.
Healthy lifestyle: This should include stress management, stopping smoking, and reducing alcohol intake (to not more than a glass daily). Take out half to 1-hour of relaxation time daily to spend with family, pursue a hobby, including a few minutes of breathing exercises like pranayama and meditation.
Risk factor evaluation and regular medical consultation/check-up: People with mentioned risk factors should undergo a medical consultation, and be evaluated with suitable and regular tests by the physician. Conditions increasing stroke risk like hypertension, diabetes, high cholesterol/triglycerides, sleep apnea, etc. should be well controlled with appropriate medicines and treatment.
Medicines: People who have multiple risk factors, especially cardiovascular disease or past history of TIA, are prescribed medicines to prevent clots in the arteries due to plaques and their rupture. These include antiplatelet drugs like aspirin, clopidogrel, ticlopidine and in high-risk cases additional anticoagulant medicines (rivaroxaban, apixaban).
MANAGEMENT
Diagnosis
If symptoms suggestive of stroke present themselves, immediate medical attention is required with hospitalization. A physical examination, and neurological assessment, with blood pressure (BP) measurement, and basic blood tests (like blood sugar, lipids, kidney function, etc.) to evaluate comorbidities, are performed. Brain imaging tests include CT scan/ MRI with contrast dye, and sometimes a cerebral angiogram or a carotid ultrasound, to diagnose the type of stroke (ischemic or hemorrhagic), assess the extent of damage, and prognosis. Cardiac function is also evaluated by echocardiography.
Treatment
ISCHEMIC STROKE
To treat an ischemic stroke, thrombolytic agents (that break down a clot) like altepase (also called recombinant tissue plasminogen activator -tPA) are given intravenously within 3 hours. The shorter the window within which this drug is given, the better the recovery. This drug can also be given directly into the brain through a long thin tube (catheter) inserted peripherally through an artery in the groin region and threaded to the brain. This may help if the window period has been longer.
For large clots, incompletely responding to tPA, a stent retriever (fine mesh tubes) can be used for grabbing and extracting the clot. This is called mechanical thrombectomy (clot removal). A balloon inserted through the catheter can be inflated and used to expand a narrowed artery (balloon angioplasty) followed by a stent to maintain the open artery. Sometimes the plaque and clot may have to be surgically removed from the artery supplying the brain (carotid endarterectomy).
Long-term treatment with low-molecular-weight heparin (LMWH) or antiplatelet drugs like aspirin may be given to prevent early neurological deterioration and recurrent ischemic stroke.
HEMORRHAGIC STROKE
The most important steps are to reduce bleeding and pressure in the brain. Blood pressure controlling medicines are given, along with medicines (diuretics) to decrease intracranial pressure and swelling, and in some cases antiepileptics. Blood thinner medications and anticoagulants are stopped if the patient is on them, and sometimes medicines or transfusion to counteract their effects may be needed.
Surgical intervention may be needed for large areas of hemorrhage. This may include draining the accumulated blood to relieve hemorrhage, repairing bleeding vessels or arteriovenous (AV) malformations, or clipping aneurysms or bleeding vessels. Sometimes detachable coils may be guided and inserted into the brain aneurysm through the peripherally placed catheter (endovascular embolization). Stereotactic radiosurgery used focused beams of radiation to repair blood vessels and malformations.
Also read:
Cardiovascular Disease (CVD) – Understanding Atherosclerosis and Coronary Artery Disease
Reference: Stroke Guidelines (MOHFW India)