Cerebral hyperperfusion syndrome is a rare but potentially fatal risk of Carotid endarterectomies and Carotid artery stenting. The surgeries increase blood flow in the arteries that supply the brain, neck, and face.

CHS can lead to swelling and bleeding in your brain. The mortality rate is as high as 50 percent, and many people who survive have permanent disabilities.

The termCHS is often used with the termcerebral reperfusion injury. What causes and how it is managed are more detailed in this article.

“Hyperperfusion” meaning

Increased blood flow through an organ is called hyperperfusion. The word “hyper” means increased or excessive, and “perfusion” means the passage of blood through a blood vessel.

Cerebral hyperperfusion is defined as a greater than 100 percent increase in blood flow through the carotid artery compared with baseline. Some people develop symptoms with increases in blood flow as small as 20 to 40 percent.

CHS is a potential risk of carotid arterial revascularization surgeries. These surgeries aim to increase blood flow through the carotid artery to prevent strokes in people with carotid artery disease. Blockages in the carotid arteries account for 15 percent of all strokes.

CHS was first discovered to be a risk of a type of surgery called a carotid endarterectomy, but it can also occur after carotid artery stenting. It can develop immediately after surgery or up to a month later.

Some people develop a disease. Multiple factors are thought to contribute.

Loss of autoregulation

Normally, your brain autoregulates itself to maintain a constant pressure when blood flow changes. Researchers think that in some people with chronically low blood flow through the carotid artery, the brain may lose its ability to autoregulate itself and blood vessels may remain chronically relaxed.

When blood flow increases after surgery, the brain may not be able to protect the tiny blood vessels called capillaries.

Chronic high blood pressure

People with a severe narrowing of the carotid artery often have chronic high blood pressure. It’s thought that already present high blood pressure may contribute to the development of CHS. Chronic high blood pressure can damage small blood vessels and result in a breakdown of the blood-brain barrier.

Researchers have found evidence of leakage of the protein albumin after blood-brain barrier breakdown in animal studies. This leakage can potentially activate a pathway that causes brain swelling and Seizures..

Nitric oxide and free radical damage

Nitric oxide relaxes blood vessels and allows more blood to pass through.

It’s thought nitric oxide may contribute to dysfunction of autoregulation and the blood-brain barrier in CHS. Accumulation of harmful molecules called free radicals can damage brain tissue for up to 48 hours.

Baroreceptor dysfunction

Baroreceptors are specialized receptors that sense blood pressure and send signals to your brain to either upregulate or downregulate blood flow. During surgery, the nerves that carry information from these receptors can become damaged. This damage can lead to increased blood pressure that’s hard to control even with medication. Fluctuations in blood pressure due to baroreceptor damage can last for up to 12 weeks.

Most people with CHS have mild symptoms, but they can progress to severe and life threatening if left untreated. The most common symptoms are:

Less common symptoms include:

This condition can be fatal in some instances.

CHS is a rare risk of carotid surgery. One study of 4,689 people undergoing carotid endarterectomy and 4,446 people undergoing carotid artery stenting found an incidence of 1.9 percent and 1.16 percent, respectively.

What can increase the risk of getting CHS?

Large studies have found that the three most common conditions associated with the development of CHS are:

  • A lot of the arteries in the neck are blocked.
  • There are blood vessels in the brain.
  • High blood pressure has been a longstanding problem.

Studies have also identified the following as risk factors for developing CHS after carotid surgery:

  • Being assigned female at birth.
  • Chronic kidneys disease.
  • Left sided disease of the arteries.
  • Neurological disorders that are progressive.
  • There are recurrent hemorrhages.
  • Brain tumors or damaged areas are brain diseases.
  • The disease of small blood vessels is called microvascular disease.
  • The brain has less ability to respond to changes in blood flow.

What risks does CHS pose to your health?

If left unaddressed,CHS can lead to brain swelling, bleeding, and permanent disabilities.

A 2018 review of studies noted that 47 percent of CHS cases led to stroke and that more than half of strokes were fatal or disabling.

Treatment for CHS often includes intravenous medications to lower blood pressure, such as labetalol and clonidine.

Seizure medications may be given to prevent Seizures. or to treat Seizures. if they occur.

Mannitol and hypertonic saline may be used to treat brain swelling. However, whether these treatments are effective in the long term isn’t clear.

If bleeding occurs, surgery may be required.

High blood pressure is a risk factor for the development of chs, so taking steps to keep it in a healthy range may help you prevent it.

Quick identification and treatment of CHS are critical for preventing potentially lethal complications. It’s recommended that blood pressure should be monitored by healthcare professionals continuously at least every 15 minutes for 24 hours or more after surgery.

CHS management focuses on reducing swelling, Seizures., and bleeding, which are the main causes of brain damage.

In the early stages, swelling is usually reversible, but if it progresses to a hemorrhage, the outlook isn’t as favorable. Up to 30 percent of people remain at least partially disabled and the mortality rate is high as 50 percent.

Surgeries to increase blood flow in the Carotid are rare. It is defined as a more than 100 percent increase in blood flow through the carotid arteries.

CHS can lead to severe complications such as permanent disability or death. Early recognition of CHS is critical for receiving prompt treatment. Common initial symptoms include headaches, There is pain in the face., or Eye pain. on one side. Get immediate medical attention if you experience any of these symptoms within a month of carotid surgery.