An ischaemic stroke is a serious medical emergency that occurs when blood flow to the brain is interrupted. This prevents brain tissue from receiving the oxygen and nutrients it needs. The consequences can be severe, leading to rapid damage to brain cells and affecting various bodily functions. Recognizing its signs and ensuring timely intervention is paramount.
What is an Ischaemic Stroke?
An ischaemic stroke, accounting for about 87% of all strokes, happens when a blood vessel supplying the brain becomes blocked. This blockage, often a blood clot, prevents blood flow, starving brain cells of oxygen and nutrients. Without adequate blood supply, brain cells can begin to die within minutes.
Atherosclerosis, or hardening of the arteries, is a common underlying cause. This involves the buildup of fatty deposits (plagues) on artery walls. These plaques can narrow vessels or break off, leading to clot formation. Blood clots can also originate from the heart, especially due to atrial fibrillation, an irregular heartbeat that allows blood to stagnate and form clots. These clots can then travel to the brain and block smaller vessels.
Risk factors for ischaemic stroke include high blood pressure, diabetes, high cholesterol, and advancing age. Conditions like carotid artery disease and transient ischaemic attacks (TIAs), often called mini-strokes, also increase risk. While some factors like age are not modifiable, many others can be managed to reduce stroke likelihood.
Recognizing the Signs
Recognizing the signs of an ischaemic stroke quickly is important for immediate action. The acronym FAST is widely used to help identify common symptoms: Face drooping, Arm weakness, Speech difficulty, and Time to call emergency services. Checking for a facial droop involves asking the person to smile, observing if one side of their face sags.
Arm weakness can be assessed by asking the person to raise both arms; if one arm drifts downward, it may indicate a stroke. Speech difficulty might manifest as slurred words or an inability to speak clearly, which can be checked by asking the person to repeat a simple sentence. If any of these signs are present, call emergency services immediately, even if symptoms seem to disappear.
Other sudden symptoms warranting immediate medical attention include numbness or weakness on one side of the body, sudden blurred vision or loss of sight, or a sudden severe headache. The concept of “time is brain” underscores the urgency, as approximately 1.9 million brain cells can die each minute a stroke goes untreated. Prompt medical care improves survival and reduces long-term disability.
Emergency Treatment and Recovery
Upon arrival at the hospital, diagnostic procedures confirm an ischaemic stroke and determine the blockage’s location and size. This often includes brain imaging like a CT scan or MRI. Blood pressure is also carefully monitored and may be lowered to safe levels if thrombolytic treatment is planned, typically below 185 mmHg systolic and 110 mmHg diastolic.
Immediate treatment aims to restore blood flow to the affected brain area. One common acute treatment is intravenous thrombolysis using medication like tissue plasminogen activator (tPA), also known as alteplase. This clot-busting drug is administered through an IV and works by dissolving the blood clot, ideally within 3 to 4.5 hours of symptom onset.
For patients with a large vessel occlusion, mechanical thrombectomy may be performed. This procedure involves threading a catheter through an artery, typically in the groin, up to the blocked artery in the brain. A device, such as a stent retriever, is then used to physically grab and remove the clot. This procedure can be performed up to 6 hours after symptom onset, and in some cases, up to 24 hours if brain imaging shows salvageable tissue.
Following acute treatment, post-stroke care includes comprehensive rehabilitation tailored to individual needs. Rehabilitation typically begins as soon as the patient is medically stable, sometimes within 24 to 48 hours after the stroke.
Physical Therapy
Physical therapy focuses on regaining strength, mobility, balance, and motor function, helping patients relearn movements like sitting, standing, and walking.
Occupational Therapy
Occupational therapy assists with daily living activities such as dressing, bathing, and eating, often incorporating adaptive equipment and exercises to retrain the brain.
Speech Therapy
Speech therapy addresses communication difficulties, including slurred speech, understanding language, and swallowing problems, through various exercises to improve vocal cord and mouth muscle coordination.
Preventing Ischaemic Stroke
Preventing ischaemic stroke involves managing modifiable risk factors and adopting healthy lifestyle changes. High blood pressure is a leading cause of stroke, and keeping it under control through medication and lifestyle adjustments is important. Managing high cholesterol levels, especially LDL cholesterol, and controlling diabetes are important to reduce stroke risk.
Lifestyle modifications play a role in prevention. Adopting a healthy diet low in saturated fats, trans fats, sodium, and added sugars, while increasing consumption of fruits, vegetables, and whole grains, can improve cardiovascular health. Regular physical activity, aiming for at least 150 minutes of moderate-intensity aerobic activity per week, helps maintain a healthy weight and lowers blood pressure and cholesterol.
Quitting smoking is an impactful step, as it damages blood vessels and increases clot formation likelihood. Limiting alcohol consumption, typically to one drink per day for women and two for men, also contributes to stroke prevention. Managing conditions like atrial fibrillation with appropriate medical treatment can reduce stroke risk by preventing blood clots from forming in the heart.