A stroke is a condition where a part of the brain is deprived of blood supply. It is a common disorder, and numbers suggest that one in six people will have a stroke at some point in time.
Ischemic stroke is one of the two types of strokes and is caused by the blockage of an artery supplying the brain. This blockage reduces the blood and oxygen supply to the brain cells, resulting in their damage or death. The blockage is due to a blood clot which prevents the blood from going into a portion of the brain.
Failure to timely restore circulation may permanently damage the brain. Here time is the most important factor, the upper limit of stroke treatment time window is 24 hours. Beyond this time only supportive treatment can be given and the chance of salvaging the brain tissue decrease drastically.
Acute Ischemic Stroke
Acute ischemic stroke (AIS) is a sudden loss of blood flow to an area of the brain associated with the loss of neurological functions. Thrombosis or embolism obstructs a blood vessel supplying a specific part of the brain.
During an ischemic stroke, the damage to the core area is irreversible, but that to the surrounding area (penumbra) can be reversed. Evidence-based treatments, such as endovascular clot retrieval or intravenous thrombolysis, can restore the blood circulation by removing the obstruction and are seen to improve the outcome when used for appropriate patients.
Acute Ischemic Stroke Symptoms
The acronym BE FAST (Balance, Eyes, Face, Arm, Speech, Time) is typically used to diagnose stroke. Loss of balance, the difficulty in seeing, Face drooping, arm/leg weakness, and speech difficulty are signs that it is time to seek emergency treatment.
The symptoms depend on the location and severity of the stroke. Some people do not have any have multiple symptoms, while others may have only one symptom. However, most people have a combination of symptoms
Some common symptoms include:
- Weakness on one side of the body
- Difficulty in swallowing
- Change in alertness
- Loss of balance or dizziness
- Abnormal vision like seeing double or blurred
Acute Ischemic Stroke Risk Factors
Some factors that may increase your risk of getting a stroke are:
- High blood pressure
- High cholesterol levels
- Atrial fibrillation
- Sickle cell anemia
- Congenital heart defects
- A history of heart attack/li>
- Clotting disorders
- Being overweight
- Alcohol or drug abuse
- Old age
- A family history of stroke
Acute Ischemic Stroke Causes
The leading cause of AIS is blockage of the artery supplying your brain with a plaque (fatty buildup) or clot.
Acute Ischemic Stroke Imaging and Intervention
The following tests aids in stroke imaging:
- Computed tomography scan
- Magnetic resonance imaging
- CT or MR angiography
- Cerebral Angiography(DSA)
Acute Ischemic Stroke Management
Acute ischemic stroke treatment mainly consists of the following therapies.
Clot buster drugs (Can be given till 4.5 hrs after stroke onset)
Clot-buster or thrombolytic medicines restore blood flow by dissolving the clot. The most common drug used for this purpose is tissue plasminogen activator or tPA. tPA is an enzyme found in your body and dissolve clots. Your doctor may inject tPA in your blood to speed up the process.
Individuals receiving tPA within the first three to four hours of stroke are more likely to recover faster with little or no disability.
Mechanical Thrombectomy(Can be given till 24 hrs of stroke onset)
Large blood clots that block large arteries may not dissolve fast enough with tPA. In such cases, a minimally invasive procedure, which uses clot retrieval devices to pull out the clot, leaving the artery open, is recommended.
This procedure is done during an angiogram, where a catheter is introduced in a blood vessel through a small hole in the groin. It is called Mechanical Thrombectomy.
Acute Ischemic Stroke Recovery
The recovery time is different for everyone and depends on the size and location of the brain area affected by the stroke. It may take from several hours to several months for complete recovery from acute ischemic stroke.
Two most important predictors of recovery are time and reopening of blood vessel status. The patients where treatment is given early (0-6 hrs) show better recovery as compared to patients who are treated late (12-24hrs). The second factor is re-opening of the blood vessels, the patients where full blood supply is restored either by t-PA injection or mechanical thrombectomy generally will do better than those in whom either partial or no restoration of blood supply is achieved.
Other factors like pre-existing conditions, age etc may also affect the recovery process.
All stroke patients need supportive therapies like physiotherapy, speech therapy, swallowing therapy etc which aid in better recovery and functional status.