Definition of Stroke
(What is stroke?)
According to World Health Organization, stoke is defined as “a neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours, with no apparent cause other than that of vascular origin.
A stroke is a condition that is typically referred to as a cardivasuclar accident or a CVA. During a stroke, blood supply to the brain cells in interrupted leading to cell death. This interruption of regular blood flow could be due to a blockage in the blood vessels (ischemic stroke) or due to the rupturing and bleeding of the blood vessel (hemorrhagic stroke). Lack of oxygen from blood damages the brain cells leading to cell death within minutes. This makes it very important for a person having a stroke to get immediate medical attention and treatment.
Etiology of Stroke
(What is/are causes of stroke?)
Based on the etiology, stroke is classified into two types, which are as under,
- Ischemic Stroke
As the name suggest, ischemic stroke occurs as a result of ischaemia (decreased supply of blood) in certain areas of the brain, which could occur due to the following reasons.
- Formation of a thrombus (blood clot) in a blood vessel might obstruct the flow of blood to the brain. IN this case, it is referred as thrombotic stroke.
- It can occur as a result of an emboli/embolus reaching the brain, in which case it is referred as embolic stroke or cerebral embolism. An embolus is a clot of blood, fat, air or a foreign body that is carried by the blood from one point to another which finally lodges itself at a place.
- It can also occur as a result of decreased blood supply to the brain under certain circumstances such as shock. This phenomenon is reffered as systemic hypoperfusion.
2. Haemorrhagic Stroke
As the name suggests, hemorrhagic stroke occurs as a result of haemorrhage i.e., escape or leakage of blood from a ruptured blood vessel in the brain, which can occur due to the following reasons,
- Use of certain drugs like anticoagulants may lead to leakage of blood from the blood vessels.
- Blood vessels may rupture due to highly elevated blood pressure.
- Certain normalities of the blood vessels like presence of arteriovenous malformations (AVM) and aneurysm which are abnormal balloon-like swellings in the arteries may also lead to haemorrhagic stroke.
Pathophysiology of Stroke (Ischemic Stroke)
(What are stages, causes or process that a person goes through during stroke?)
Ischemic stroke occurs due to decreased supply of blood to the brain due to various factors which have been discussed under the etiological classification. This condition triggers an ischemic cascade as described below:
Due to decreased supply of blood, the amount of oxygen the brain cells receive also decreases and eventually the brain cells resort to anaerobic metabolism to produce energy (ATP). The end products of anaerobic metabolism are lactic acid and very less amounts of ATP. Lactic acid distrubs the acid-base equilibrium in the brain and also damages the neurons. Due to decreased ATP production, the NA+ – K+ ATPase pump fails leading to deplorization of the cell membrane resulting in an efflux of K+ and an influx of cell membrane and mitochondria break down releasing toxins and apoptotic factors (substances that cause programmed cell death) into the cell, causing neurosis and neuronal damage.
Pathophysiology of Hemorrhagic stroke
In haemorrhagic stroke, there is leakage of blood from the blood vessels due to various etiological factors as described previously. As a result, there is a formation of haematoma (accumulation of blood within the tissues that clots to form a solid swelling), which keeps enlarging causing compression of the brain tissues, resulting in injury and development of an infarct (dead tissue) due to decreased supply of blood to the tissues.
Signs and Symptoms of Stroke
(What are signs of Stroke?)
(What are symptoms of Stroke?)
Symptoms of stroke include :
- Difficulty in swallowing
- Reading or writing
- Memory loss
- Urinary incontinence
- Dizziness, confusion
- Altered sensorium
- Loss of balance
- Extreme weakness in the muscles of face
- Arms or legs
- Numbness and impaired co-ordination of the muscles.
Complications of Stroke
(What are complications of stroke?)
- Speech problems : When certain parts of the brain that control facial muscles are affected, the person suffers from aphasia (disorder of language that affects the generation and content of speech).
- Dysphagia : The person might face difficulty in swallowing in case the muscles of the neck are affected and this could lead to withdrawal of food particles into the lungs.
- Memory Loss : Since stroke affects the brain, loss of memory is an obvious complication
- Loss of motor function
Treatment for Stroke
(What is treatment for stroke?)
- Surgery – Carotid endarterectomy
- Therapies – Speech therapy, Rehabilitation, Physiotherapy.
Prevention for Stroke
(How to prevent stroke?)
- Quit smoking
- Regular Physical Exercise.
Some more related diseases can be found below :
Ischemic Heart Disease – http://pharmadiagnosis.com/ischemic-heart-disease/
Hypertension (High Blood Pressure) – http://pharmadiagnosis.com/hypertension-high-blood-pressure/
Jaundice – http://pharmadiagnosis.com/jaundice-icterus/
Tuberculosis – http://pharmadiagnosis.com/tuberculosis/
Gonorrhoea – http://pharmadiagnosis.com/gonorrhoea/
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