Anatomy, Physiology, and Pathophysiology of Stroke Flashcards

What is a stroke?

Answer: A disruption of blood supply to the brain

A stroke, also known as a cerebrovascular accident (CVA), occurs when the blood flow to a part of the brain is interrupted or severely reduced. This deprives brain tissue of oxygen and nutrients, causing brain cells to die within minutes. This disruption can be due to a blocked artery (ischemic stroke) or a ruptured blood vessel (hemorrhagic stroke).

What is ischemic stroke?

Answer: A stroke due to reduced blood flow caused by a clot

Ischemic stroke is the most common type of stroke, occurring when a blood clot blocks or narrows an artery that supplies blood to the brain. This blockage prevents oxygen and nutrients from reaching brain cells, leading to their damage or death. The clot can form in the brain's arteries (thrombotic) or travel from elsewhere in the body (embolic).

What is hemorrhagic stroke?

Answer: A stroke caused by bleeding in the brain

A hemorrhagic stroke occurs when a blood vessel in the brain ruptures and bleeds into the surrounding brain tissue. This bleeding directly damages brain cells and increases pressure on the brain, further impairing function. It is often associated with high blood pressure, aneurysms, or arteriovenous malformations (AVMs).

Which part of the brain is most commonly affected by a stroke?

Answer: The brainstem

The brainstem is a crucial part of the brain that connects the cerebrum with the spinal cord and controls many vital functions, including breathing, heart rate, and consciousness. A stroke affecting the brainstem can have severe and life-threatening consequences due to its role in these essential bodily processes. While other areas are also affected, the brainstem's role is critical.

What are the main causes of ischemic stroke?

Answer: Fatty deposits and blood clots

The primary causes of ischemic stroke are atherosclerosis, which involves the buildup of fatty deposits (plaque) in the arteries, and the formation of blood clots. These plaques can narrow arteries, reducing blood flow, or rupture, leading to clot formation that blocks the vessel. Clots can also travel from other parts of the body, such as the heart, to the brain.

What role does the carotid artery play in stroke risk?

Answer: It supplies blood to the brain, and blockage increases stroke risk

The carotid arteries are major blood vessels located on each side of the neck that supply a significant portion of the blood to the brain. Atherosclerosis, or the buildup of plaque in these arteries, can narrow them (carotid artery stenosis) or lead to the formation of blood clots. This severely increases the risk of an ischemic stroke by impeding blood flow to the brain.

What is transient ischemic attack (TIA)?

Answer: A temporary blockage or reduced blood flow to the brain

A Transient Ischemic Attack (TIA), often called a 'mini-stroke,' occurs when blood flow to the brain is temporarily interrupted, causing stroke-like symptoms that typically last only a few minutes to an hour and resolve completely. Although symptoms are temporary, a TIA is a serious warning sign that a full-blown stroke may occur soon, necessitating immediate medical evaluation.

What is the significance of early intervention in stroke management?

Answer: Early intervention helps restore blood flow and prevent brain damage

Time is critical in stroke management, often summarized as 'time is brain.' Early intervention, particularly within the first few hours of symptom onset, allows for treatments like thrombolytic drugs (tPA) or mechanical thrombectomy to restore blood flow to the affected brain area. This rapid action can significantly limit the extent of brain damage, improve patient outcomes, and reduce long-term disability.

What is the role of the blood-brain barrier in stroke?

Answer: It prevents the passage of harmful substances but limits drug access in stroke

The blood-brain barrier (BBB) is a highly selective semipermeable membrane that protects the brain from circulating toxins and pathogens while allowing essential nutrients to pass. In stroke, while it helps protect against further damage from systemic substances, its integrity can be compromised. It also poses a challenge by limiting the delivery of therapeutic drugs to the affected brain tissue, making treatment more complex.