Stroke: Symptoms, Causes, Treatment & Types

Types of Stroke

A brain stroke may occur due to a number of reasons. While most symptoms overlap for all the different types, some symptoms are distinct & stroke management & rehabilitation may differ accordingly. The different types of the brain stroke are:

• Transient Ischemic Attack (TIA) or ‘Ministroke’: Mild & short strokes caused by temporary reduction in blood flow. They can be considered to be a pre-stroke stage.
• Ischemic Stroke: Brain strokes caused by impeded blood flow. It is the most common type of stroke.
• Hemorrhagic Stroke: Brain strokes caused by vascular damage, & consequent bleeding into the brain tissue or nearby.
• Brain Stem Stroke: Brain strokes affecting the lower parts of the brain, namely the medulla, pons & midbrain.
• Cryptogenic Stroke: Brain strokes without an apparent cause.

Causes of Stroke

Stroke is caused by reduced blood flow to the brain, which in turn causes a lack of nutrients & the accumulation of metabolic waste such as carbon dioxide. Such circumstances cause neuronal death & since they have limited regenerating ability, strokes can result in significant loss of function.

The different types of brain stroke are caused by different mechanisms.

Cause of Transient Ischemic Attack

TIA results when a clot temporarily blocks blood vessels, which reduces blood flow to brain tissue. Even though it does not cause permanent brain damage, overlooking this serious warning can cause stroke in the near future.

Cause of Ischemic Stroke

Ischemic stroke results from a clot that is firmly lodged in an artery supplying the brain with blood. It is the most common cause of brain stroke. The clot could be formed due to vascular damage from atherosclerotic plaque (Cholesterol Deposition).

The clot or thrombus may have formed within the vessel, resulting in thrombosis, or may have originated elsewhere in the body’s circulatory system, eventually reaching the brain’s blood vessels, causing an embolism. The resulting blocked or narrowed lumen prevents blood from flowing to the brain tissue.

Cause of Hemorrhagic Stroke

A hemorrhage occurs when blood leaks into tissue as a result of vascular damage. A brain stroke can occur due to hemorrhage in two possible locations:

• Intra-cerebral, which is within the brain tissue
• Subarachnoid or subdural, which is between the brain & skull

A blood vessel may be weakened due to aneurysm or high blood pressure. In very old patients, amyloid deposit weakens blood vessels & is a common cause of cerebral hemorrhage. The brain stroke itself is caused by a large hematoma (blood clot) that impinges on the brain, exerting pressure. It also causes increased intracranial pressure, which can cause vomiting alongside the usual symptoms.

Cause of Brain Stem Stroke

A brain stem stroke can be caused by either hemorrhage or clot. It is associated with the same risk factors & symptoms as brain strokes affecting other regions, with the additional risk of complete paralysis of both sides of the body. It can affect vital functions, such as heart rate, respiration & blood pressure, since the control centers for these functions are located in the brain stem.

Cause of Cryptogenic Stroke

A brain stroke without an obvious cause is called a cryptogenic stroke. While it may be caused by ischemia or hemorrhage, diagnostic tools usually fail to find signs of either. 

Risk Factors for Stroke

Many factors contribute to increasing the chances of suffering from a brain stroke. Unmodifiable factors include:

• Age
• Race (E.g., African Americans, Hispanics & certain Asian groups are more at risk)
• Sex (E.g., men are more likely patients)
• Family history of heart disease or diabetes

Your lifestyle & related conditions also heavily influence the possibility of a brain stroke:

• High sodium or fat intake
• Obesity
• Inactivity
• High cholesterol levels
• Uncontrolled high blood pressure
• Mismanaged diabetes
• High alcohol consumption
• Smoking
• Use of recreational drugs such as cocaine
• Use of oral contraceptives