An ischemic stroke occurs when the blood supply to a part of the brain is blocked, leading to reduced oxygen and nutrient supply. If blood flow is not restored quickly, brain cells begin to die, making it a medical emergency.
It is the most common type of stroke, accounting for about 85% of all stroke cases, while the remaining are mainly haemorrhagic strokes.
Causes
Ischemic stroke is usually caused by blockage of an artery supplying the brain.
The blockage may occur due to:
- Thrombosis – formation of a blood clot within a brain artery.
- Embolism – a clot formed elsewhere (commonly in the heart during atrial fibrillation) travels and blocks a cerebral artery.
- Atherosclerosis – narrowing of arteries due to cholesterol plaque.
Risk Factors
Major risk factors include:
- Hypertension (most important)
- Diabetes mellitus
- High cholesterol
- Smoking
- Obesity
- Physical inactivity
- Atrial fibrillation
- Coronary artery disease
- Excessive alcohol consumption
- Increasing age
- Family history of stroke
Symptoms
Symptoms usually appear suddenly.
Common features include:
- weakness or paralysis of one side of the body
- facial drooping
- difficulty speaking or understanding speech
- sudden loss of vision
- dizziness or loss of balance
- severe difficulty in walking
- confusion
- sudden numbness of face, arm or leg
The FAST rule helps identify stroke early:
- F – Face drooping
- A – Arm weakness
- S – Speech difficulty
- T – Time to seek emergency medical care
Diagnosis
Early diagnosis is critical because treatment is highly time-dependent.
Investigations include:
- CT Scan of the brain
- MRI Brain
- CT Angiography
- MR Angiography
- Carotid Doppler
- ECG
- Echocardiography
- Blood investigations
The first priority is to distinguish ischemic stroke from haemorrhagic stroke, as treatment differs completely.
Treatment
Treatment aims to restore blood flow as quickly as possible.
Major treatment options include:
Intravenous Thrombolysis
- Tenecteplase (TNK) or Alteplase (tPA) may be administered to dissolve the clot.
- Best outcomes occur when given within the recommended therapeutic window after symptom onset.
Mechanical Thrombectomy
For large artery blockages, doctors may remove the clot using specialised catheter-based procedures.
Supportive Management
- Blood pressure control
- Blood sugar control
- Oxygen support if required
- Prevention of complications
- Early rehabilitation
Rehabilitation
Recovery often requires multidisciplinary rehabilitation.
It may include:
- physiotherapy
- occupational therapy
- speech therapy
- psychological counselling
- nutritional support
Early rehabilitation significantly improves long-term outcomes.
Prevention
Primary prevention focuses on controlling risk factors.
Important measures include:
- controlling blood pressure
- diabetes management
- cholesterol reduction
- smoking cessation
- regular physical activity
- healthy diet
- maintaining healthy body weight
- treatment of atrial fibrillation
- regular medical check-ups
Secondary prevention after a stroke often includes:
- antiplatelet drugs
- anticoagulants (when indicated)
- statins
- blood pressure control
- lifestyle modification
Difference Between Ischemic and Haemorrhagic Stroke
| Feature | Ischemic Stroke | Haemorrhagic Stroke |
| Cause | Blockage of blood vessel | Rupture of blood vessel |
| Frequency | ~85% of strokes | ~15% of strokes |
| Blood flow | Reduced | Bleeding into brain tissue |
| Treatment | Clot-dissolving drugs, thrombectomy | Bleeding control, neurosurgery (if required) |
Current Relevance
Ischemic stroke remains one of the leading causes of:
- disability
- mortality
- long-term neurological impairment
Recent research focuses on:
- faster clot-removal techniques
- AI-assisted stroke diagnosis
- advanced brain imaging
- improved thrombolytic drugs
- tele-stroke services
- neuroprotective therapies
Significance
Ischemic stroke is a time-sensitive neurological emergency. Rapid recognition, immediate hospital care and timely restoration of blood flow are critical because “time is brain”—every minute of delay results in the loss of millions of brain cells, reducing the chances of recovery.
