Specific stroke-related conditions, how they affect the brain, and the treatment options available

Your care team is the best source of guidance for your individual situation.

If you have questions about your diagnosis or treatment, contact the Tahoe Forest Stroke Care Coordinator at (530) 550-6715 (available Wednesday, Thursday, and Friday).

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Stroke and brain function

The brain is divided into two nearly identical halves called hemispheres, left and right, each consisting of four lobes: frontal, parietal, temporal, and occipital. Each lobe controls different mental and physical functions. Damage to the left side of the brain primarily affects the right side of the body, and damage to the right side primarily affects the left.

Left brain functions and effects of stroke

  • Controls the right side of the body
  • Problem solving, knowledge, and facts
  • Numbers and letters
  • Understanding words
  • Effects of stroke on the left side may include weakness on the right side of the body, problems seeing objects to the right, communication problems, slow or cautious behavior, memory loss, and behavior changes.

Right brain functions and effects of stroke

  • Controls the left side of the body
  • Creativity, imagination, and intuition
  • Shapes and symbols
  • Recognizing emotions
  • Effects of stroke on the right side may include weakness on the left side of the body, problems seeing objects to the left, problems with depth perception, difficulty concentrating, and impulsive behavior or poor judgment.

Ischemic stroke conditions

Ischemic strokes occur when blood flow to the brain is blocked, depriving brain cells of the oxygen and nutrients they need to survive.

Acute ischemic stroke (AIS)

An acute ischemic stroke occurs when an artery carrying blood to the brain becomes blocked, causing brain cells in the affected area to begin dying within minutes. Restoring blood flow as quickly as possible is critical to minimizing damage.

Treatment options

  • Clot-busting medications: Tissue plasminogen activator (tPA) and tenecteplase (TNK) are drugs infused into a vein in the arm that work by dissolving the clot. They must be administered as quickly as possible, typically within 4.5 hours of symptom onset. Not all patients are eligible, and they may be less effective for larger vessel blockages.

  • Mechanical thrombectomy: A minimally invasive procedure in which a catheter is inserted into an artery at the groin or wrist and guided through the body to the blocked vessel in the brain. The catheter uses suction or a stent retriever to remove the clot. This may be the only option for patients who are ineligible for clot-busting medications or who have large vessel occlusions.

Carotid artery stenosis (CAS)

The carotid arteries on either side of the neck are the main vessels carrying blood and oxygen to the brain. Carotid artery stenosis occurs when plaque builds up on the inside of these arteries, causing them to narrow. When blood flow is significantly reduced or blocked, the risk of ischemic stroke increases.

Carotid artery stenosis often has no symptoms until it is serious enough to cause a stroke or transient ischemic attack (TIA). When symptoms do occur, they are the same as stroke: sudden weakness or numbness in the face, arm, or leg; slurred speech; vision problems; or dizziness and loss of balance.

Risk factors include high blood pressure, tobacco use, diabetes, high cholesterol, family history, age, obesity, sleep apnea, and lack of exercise.

Treatment options

  • Carotid stenting: A catheter is inserted through an artery at the groin or wrist and guided to the affected carotid artery in the neck. A small wire mesh coil called a stent is placed to keep the artery open.

  • Carotid endarterectomy: A surgical procedure in which an incision is made in the neck at the site of the affected artery. The artery is opened, the plaque is removed to restore normal blood flow, and the incision is closed.

Hemorrhagic stroke conditions

Hemorrhagic strokes occur when a blood vessel in or around the brain ruptures or leaks, causing bleeding that damages surrounding tissue. The following conditions are types of or closely related to hemorrhagic stroke.

Diagnosing hemorrhagic stroke

Because hemorrhagic strokes require prompt treatment, diagnosis typically happens quickly. Your doctor may ask about your symptoms, risk factors, and medical history, and conduct a physical examination. Diagnostic tests may include:

  • Computed tomography (CT): A specialized X-ray scanner creates detailed images of the brain. CT angiography (CTA) uses a contrast dye injected into the bloodstream to visualize blood vessels.
  • Magnetic resonance imaging (MRI): Uses radio waves and a magnetic field to create detailed images of the brain. MR angiography (MRA) can provide detailed images of brain vessels with or without contrast dye.
  • Cerebral angiography: Contrast dye is injected via a catheter threaded through an artery to create detailed images of the arteries in the neck and brain.
    Cerebrospinal fluid analysis: A small amount of fluid is collected from the spinal cord to check for signs of bleeding around the brain.

Intracerebral hemorrhage (ICH)

Intracerebral hemorrhage is the most common type of hemorrhagic stroke. It occurs when a blood vessel inside the brain leaks or ruptures, allowing blood to seep into surrounding tissue. ICH is most often caused by chronic high blood pressure and is a serious condition associated with a high risk of disability and death. Early treatment is critical.

Treatment focuses on stopping the bleeding, removing the clot, and relieving pressure on the brain.

Treatment options

  • Medical management: Monitoring and controlling breathing, blood pressure, intracranial pressure, blood sugar, temperature, and seizure activity.

  • Decompressive craniectomy: A section of the skull is removed to relieve pressure on the swollen brain. Craniectomy with evacuation involves removing pooled blood from the affected area.

  • Endoscope-assisted minimally invasive surgery: A small camera and thin tube are used to remove the clot through a dime-sized hole in the skull.

  • Stereotactic aspiration: A catheter guided by imaging is inserted into the hematoma to suction out blood. Small doses of a clot-dissolving agent may be delivered through the catheter over several days to clear remaining clot.

Subarachnoid hemorrhage (SAH)

A subarachnoid hemorrhage occurs when an artery on the outer surface of the brain ruptures, allowing blood to leak into the fluid-filled space between the brain and the skull. The most common cause is a ruptured cerebral aneurysm. The first sign of SAH is typically a sudden, severe headache with no known cause. A ruptured aneurysm is a medical emergency requiring immediate treatment.

Treatment options

  • Endovascular coiling: A catheter is guided to the aneurysm and soft platinum coils are released into it to block blood flow and allow clotting. Intracranial stents may be used alongside coiling to hold the coils in place.

  • Flow diversion devices: Flexible mesh stents placed within the affected vessel to redirect blood flow away from the aneurysm.

  • Surgical clipping: An open surgical procedure in which a small clip is placed at the base of the aneurysm to cut off blood flow to it.

  • Additional treatments may include medications to prevent seizures, calcium channel-blocking drugs to reduce the risk of further stroke from vasospasm, and a shunt to manage excess cerebrospinal fluid buildup.

Brain aneurysm

A brain aneurysm occurs when a weakened section of a blood vessel wall bulges and fills with blood. Aneurysms can form anywhere in the brain and may put pressure on surrounding nerves and tissue. Some leak or rupture, leading to intracerebral or subarachnoid hemorrhage.

Aneurysms are most common in adults between the ages of 30 and 60 and are more common in women than men. Not all aneurysms require treatment. Physicians often choose to monitor unruptured aneurysms that are not causing symptoms.

Types of aneurysm:

  • Saccular (berry) aneurysm: The most common type, a rounded blood-filled sac most often found at the base of the brain
  • Fusiform aneurysm: Expands in all directions in the affected section of the artery
  • Mycotic aneurysm: Caused by an infection in the blood vessel wall, most commonly associated with endocarditis

Complications of a ruptured aneurysm can include rebleeding, changes in sodium levels that cause brain swelling, hydrocephalus (buildup of cerebrospinal fluid), vasospasm (narrowing of an artery that can cause further stroke), and seizures.

People at higher than average risk of aneurysm, including those with two or more first-degree relatives who have had a ruptured aneurysm, may be candidates for screening through brain imaging such as MRA or CTA. Contact your healthcare provider if you think you may be a candidate for screening.

Other cerebrovascular conditions

The following conditions affect the blood vessels of the brain and can increase the risk of stroke or cause stroke-like symptoms.

Arteriovenous malformation (AVM)

An arteriovenous malformation is a tangle of abnormal blood vessels that creates irregular connections between arteries and veins, bypassing the network of small vessels that normally deliver oxygen to brain cells. In most cases, AVMs cause damage by reducing oxygen to brain tissue or by compressing surrounding areas. Over time, increased blood flow can cause an AVM to grow, weaken, and rupture, resulting in hemorrhagic stroke.

AVMs may be present at birth and often cause few or no symptoms until a complication occurs. When symptoms are present they may include headache, weakness, seizures, or problems with speech, vision, or movement.

Treatment must be discussed with your doctor, as the risks and benefits vary significantly depending on the individual. One option is endovascular embolization, a minimally invasive procedure in which a catheter is guided to the AVM and a substance such as coils or fast-drying material is released to block blood flow to the affected area.

Carotid-cavernous fistula (CCF)

A carotid-cavernous fistula is an abnormal connection between the carotid artery and the cavernous sinus, a complex collection of veins located behind the eyes. Because the carotid artery carries blood at higher pressure than veins, this connection prevents the veins serving the eyes from draining properly.

CCFs are rare but can cause significant symptoms including deteriorating or double vision, eye pain or pressure, a red or bulging eye that may pulse, drooping eyelid, ringing in the ears, and pink eye-like symptoms.

There are two types:

  • Direct CCF, often caused by trauma, which develops rapidly
  • Indirect CCF, associated with atherosclerosis, high blood pressure, or collagen vascular disease, which develops more gradually

Treatment

  • Endovascular embolization is the preferred treatment for symptomatic CCFs. A catheter is guided through the femoral artery to the fistula, and coils or embolic agents are placed in the cavernous sinus to close off the abnormal connection while preserving normal blood flow in the carotid artery.

Subdural hematoma (SDH)

A subdural hematoma forms when blood collects between the protective layers surrounding the brain. This buildup of blood damages cells in the brain lining and causes inflammation. The most common cause is a head injury such as a fall, car accident, or other trauma. In older adults, chronic subdural hematomas can develop from relatively minor injuries due to age-related brain shrinkage that stretches and weakens the veins.

A subdural hematoma may cause symptoms right away or may develop gradually over time. Symptoms can include headache, confusion, drowsiness, weakness or numbness in the face, arms, or legs, balance or walking problems, vision difficulties, nausea or vomiting, aphasia, and seizures.

Treatment options

  • Embolization of the middle meningeal artery: A catheter is guided to the artery that supplies blood to the membrane covering the hematoma. Coils, particles, or liquid embolic material are released to block blood flow to that area, causing the hematoma to shrink.

  • Burr hole craniostomy: One or more small holes are drilled into the skull and a tube is inserted to drain the blood. A shunt may be used to continue drainage over several days.

  • Craniotomy: A section of the skull is removed to access and extract the hematoma.