Stroke and Other Vessel Disorders in the Brain

Has this article been insightful? Share it!

What is a Blood Vessel Disorder?

The human brain requires a constant supply of blood and oxygen to function. Any disruption in these will have a significant impact on brain function and can lead to severe complications such as strokes. Since blood vessels are responsible for delivering oxygen and blood supply, a blood vessel disorder is a serious condition that can potentially cause damage to the rest of the body and be fatal. Neurovascular conditions specifically refer to all blood vessel disorders in the brain and spine that cause bleeding or limited blood flow in a specific area of the brain, leading to temporary or permanent damage.

Blood flow may be affected by:

● The narrowing of the vessel walls by hardening or abnormalities of the blood vessels
● A blockage caused by a clot or atheromatous plaque
● A ruptured blood vessel (haemorrhage)

What are the Types of Blood Vessel Disorders?

Cerebral Vascular Abnormalities

● Brain Aneurysm

A brain aneurysm is the localised dilation or ballooning of a blood vessel in the brain. The ballooning is caused by a weakening of the blood vessel wall, which can lead to a rupture and haemorrhage. A ruptured aneurysm can be treated with brain aneurysm surgery or endovascular treatment. However, there are also various other surgical procedures that can redirect blood flow away from an aneurysm that is liable to rupture and treat the damaged blood vessel.

● Arteriovenous Malformation (AVM)

An arteriovenous malformation, or AVM, is a congenital anomaly in the formation of the arteries and veins, which can lead to a rupture or bleeding. This interferes with blood flow, preventing tissues from receiving oxygen. An AVM can form anywhere in the body, including the brain, and it typically occurs during pregnancy or shortly after birth.

● Cavernomas

Cavernomas, also known as cavernous angiomas or cavernous malformations, involve the enlargement and deformities of blood vessels. They are abnormal clusters of thin-walled blood vessels in the brain and spinal cord that form wide ‘caverns’ of slow-flowing blood. Over time, the clusters can grow in size and number, as well as cause seizures, headaches, haemorrhages and numbness.

● Sinus AV Fistula

Sinus AV fistula refers to the abnormal connections between an artery and vein within the venous sinus wall, which is the tough covering that surrounds the brain or spinal cord.

● Cerebral Venous Sinus Thrombosis (CVST)

When a blood clot forms in the venous sinuses of the brain, it is known as cerebral venous sinus thrombosis (CVST). The clot prevents blood from draining out of the brain. Consequently, pressure accumulates in the blood vessels, leading to swelling and bleeding in the brain.

All these conditions can cause a haemorrhage, bleeding, or blockage, all of which can result in a stroke.

Spontaneous Bleeding in the Brain (haemorrhagic stroke)

A hemorrhagic stroke occurs when there is bleeding in or around the brain as a result of blood vessel rupture. There are two main types of hemorrhagic strokes.

● Bleeding within the brain

When an artery in the brain ruptures and leaks out into brain tissue at high pressure, causing brain cells to die or swell, the condition is known as an intracerebral haemorrhage.

● Bleeding on the surface of the brain

A subarachnoid haemorrhage occurs when blood vessels close to the brain’s surface rupture and flow into the subarachnoid space, which is a cushion of membranes that surround the brain.

Subdural Hematoma

Damage to a blood vessel in the subdural space – the area between the skull and the brain – causes a subdural hematoma. When blood leaks from the blood vessel, it forms a blood clot (haematoma), which applies pressure to the brain and causes harm. Subdural haematomas often occur due to severe head injuries, such as those sustained in violent assaults, vehicle crashes, or falls.

What Causes Blood Vessel Disorders?

Although there is no clear cause of neurovascular disease, certain conditions may put one at greater risk of developing it. These are:

● High Blood Pressure (Hypertension)
High blood flow pressure can damage artery and blood vessel walls over time, increasing the likelihood of blood vessels bursting in the brain.

● Congenital blood vessel abnormalities
People are rarely born with malformed blood vessels. These vascular malformations are tangles of blood vessels or enlarged blood vessels that induce bleeding in the brain if the vessel walls rupture.

● Atherosclerosis
The narrowing or ‘hardening’ of the arteries occurs when a fatty substance called plaque builds up inside them. This is known as atherosclerosis and causes blood vessels to narrow, which slows or blocks blood flow. Smaller arteries in the brain are more prone to bleeding and could lead to haemorrhagic strokes.

● Cerebral Amyloid Angiopathy (CAA)
CAA, a type of small vessel disease that is more common among elderly persons with dementia, occurs when a protein called amyloid accumulates inside the small blood vessels near the surface of the brain. The resulting damage can cause a blood vessel to tear, leading to bleeding.

What are the Risk Factors for a Blood Vessel Disorder?

Risk factors may include diabetes, high blood pressure, high cholesterol, smoking, lack of physical activity, and genetic factors. Blood-thinning medication could also increase the risk of bleeding in the brain.

What are the Symptoms of a Blood Vessel Disorder?

The FAST model is helpful in detecting haemorrhagic strokes.

● F – Facial weakness: Take note of drooping mouth or eyes

● A – Arm weakness: Check the mobility of both arms

● S- Speech problems: Is the speech slurred or incomprehensible?

● T- Time to call 999: If you see any of these signs

● Arteriovenous malformation (AVM)
An AVM is a congenital defect between the arteries and veins. This condition affects the connection between these blood vessels and disrupts the flow of blood between them.

If the patient’s bleeding is severe, they may experience unbearable thunderclap headaches followed by a loss of consciousness and coma.

Other general symptoms of blood vessel disorders can include:

● Sudden, intense headache
● Nausea and vomiting
● Stiff neck
● Blurred or double vision
● Sensitivity to light
● Seizures
● A drooping eyelid
● Loss of consciousness
● Problems with balance

When Should You See a Doctor?

Since blood vessel disorders can be life-threatening and require immediate medical intervention, it is advised that you consult a doctor without delay if you experience any of the above symptoms.

What Can I Expect During My First Consultation?

During your consultation, the specialist will assess your medical history and your symptoms, as well as conduct a physical examination focusing on your brain and nerves. Medical tests ordered may include blood and urine tests and imaging tests.

How are Blood Vessel Disorders Diagnosed?

● MRI/MRA Stroke Protocol

Magnetic Resonance Imaging (MRI) is a test that employs powerful magnets, radio waves, and a computer to create detailed images, including that of soft tissues and the nervous system. The MRI protocol for stroke assessment is a group of MRI sequences assembled to visualise the brain and blood vessel damage.

● CT/MR Venogram

CT (computer tomography) cerebral venography is a contrast-enhanced examination with an acquisition delay that provides an accurate and detailed depiction of the cerebral venous system, while MR (magnetic resonance) venography uses magnetic resonance technology and intravenous (IV) contrast dye to visualise the veins.

● Cerebral Angiogram (DSA)

Digital Subtraction Angiography (DSA) provides an image of the blood vessels in the brain to detect problems with blood flow. The procedure involves inserting a catheter into an artery in the leg and sending it up to the blood vessels in the brain. A contrast dye is injected through the catheter, and X-ray images of the blood vessels are obtained.

● Transcranial Doppler

Transcranial Doppler (TCD) ultrasound is a test that uses sound waves to detect blood vessel disorders that affect blood flow in your brain. For example, strokes caused by blood clots, narrowed sections of blood vessels and tiny blood clots can be visualised.

● CT / MRI Perfusion Scans

CT perfusion and MRI perfusion imaging reveal which areas of the brain are adequately supplied or perfused with blood and provide detailed information on blood delivery or flow to the brain. Thus, these can be used to evaluate acute stroke and blood vessel constriction.

How are Blood Vessel Disorders Treated?

The treatment for your neurovascular condition depends on its type. This could come in the form of medication and/or minimally invasive procedures such as:

● Mini-Craniotomy and Clipping or Reinforcement/Reconstruction of Cerebral Aneurysm

A bone flap with a diameter of 3-4cm is created in the skull via a mini-craniotomy, and brain aneurysm surgery is performed to repair the disorder by placing coils of thin metal wires into the aneurysm. Blood clots that form around this coil prevent the aneurysm from rupturing.

A mini-craniotomy procedure

● Microsurgical Excision of Brain AVM and Cavernomas

A craniotomy is performed, where a part of the bone from the skull is surgically removed to expose the brain. The microscope is used to isolate and remove the AVM and cavernoma from the tissues around the brain.

● Microanastomosis of Extra-Intracranial Vessels (EC-IC bypass) for Stroke

Extracranial to intracranial (EC-IC) bypass surgery is performed to improve blood supply to the brain by surgically connecting the external carotid artery in your neck with the internal carotid artery inside your skull, thus bypassing the blocked area.

● Carotid Endarterectomy for Carotid Stenosis

During endarterectomy, the inner lining of the carotid artery is surgically removed together with any obstructive deposits, which prevents narrowing (stenosis) of the blood vessel.

● Endoscopic Evacuation of Intracranial Haemorrhage

Summary

Arteries carry and deliver nutrients and oxygen-rich blood to the brain and spine. Neurovascular disorders can cause vessel obstruction, limiting blood flow to the brain and potentially leading to severe disability or even death.

These blood vessel disorders are often treated with surgery. If you or a loved one is experiencing symptoms of a neurovascular disease or require guidance regarding brain aneurysms in Singapore, reach out to us today.

Dr Sein Lwin is an experienced Senior Consultant Neuro & Spine Surgeon and the Neurosurgical Director at the Advanced Brain and Spine Surgical Centre.

He is highly experienced in spine surgery and in minimally invasive approaches for spinal cord tumours and degenerative spine surgery. His specialised interests lie in endoscopic endonasal and open skull base surgery, pituitary tumours, vascular surgery, cranial nerve disorders and peripheral nerve conditions.

Urgent Care

Many neurological conditions may require urgent attention. If you require immediate care, please contact us.