What is Cerebral Amyloid Angiopathy?

It’s called amyloid angiopathy because the amyloid protein clogs within the walls of the artery that goes into your brain that causes hemorrhage.

Graphics illustrating issues in the brain

Cerebral Amyloid Angiopathy (CAA), also known by its medical term of congophilic angiopathy, is a degenerative vasculopathy that’s linked with intracranial hemorrhage. This condition happens when a protein called amyloid congests within the walls of brain arteries that may lead to stroke. If not given immediate medical attention during the first signs of the symptoms, prolonged bleeding increases the risk of the rapid development of dementia.

The symptoms are frequently diagnosed to people fifty years and above and become more prevalent as a person grows older. There are other cases of cerebral amyloid angiopathy that is hereditary, meaning that the parent could transfer the defective gene to its children’s.

Documentation of cerebral amyloid angiopathy has been done since the early 1900s. However, in those early years, there were only a few studies conducted on CAA and its causes were still inconclusive until in 1984 when Wong and Glanner found protein congestion within brain arteries of Alzheimer’s patients when they sequenced and isolated the amyloids. In the past few years, the development of neuroimaging and molecular biological techniques has prompted researchers’ interest in cerebral amyloid angiopathy and results in publications of more studies regarding this subject.

 

Causes

It’s called amyloid angiopathy because the amyloid protein clogs within the walls of the artery that goes into your brain that causes hemorrhage. The accumulation of proteins weakens the artery wall causing the bleeding and leads to stroke or dementia or even death if not treated properly. This amyloid protein is also linked to the inflammation caused when the body reacts to infections or injuries.

Areas affected by the intracranial hemorrhage are called petechial hemorrhage. And when observed under CT scan results they have a distinctive appearance that doctors can spot and base their evaluations. Bleedings caused by amyloid proteins usually occurs in an area near the brain called lobar.

Normally, the intracranial hemorrhage caused by cerebral amyloid angiopathy affects only small areas of the blood vessels and minimum bleeding is expected. However, if proper medical attention was not given, severe bleedings may happen that leads to a life-threatening situation.

Faulty genes pass down to children may also be the culprit for the development of CAA. But a person who doesn’t have a family background of this disease can still have it.

Up until now the definitive cause of this disease is still unknown but research shows that this disease is common to people older than 50 and progressively developing as the person age.

 

Symptoms

The bleeding caused by cerebral amyloid angiopathy usually happens in the outer regions of the brain. Symptoms happen when the bleeding damages blood tissues. However, detecting cerebral amyloid angiopathy can be challenging because the symptoms may depend on the state of bleeding within the artery walls. We may not notice any symptom at all if the intracranial hemorrhage is only to a minimum. If the bleedings become more frequent and starts to clog the artery then we may observe some symptoms and have similarities with stroke.

Early signs of intracranial hemorrhage are as follows:

  • Periods of confusion
  • Mild headaches
  • Unusual feeling of fatigue or weakness

Enlisted below are common symptoms when bleeding becomes severe:

  • Lethargy
  • Migraine
  • Seizures
  • Nausea
  • Loss of consciousness
  • Hemiparesis
  • Hemiplegia
  • In rare instances, coma may happen if bleeding becomes serious.
  • Abnormal function of the nervous system. This includes delusion, confusion, vision problems, and difficulty in speech.

 

How Cerebral Amyloid Angiopathy is Diagnosed

Cerebral amyloid angiopathy is difficult to diagnose because you will need brain tissues to detect signs of it. And collecting brain tissues is only possible for the deceased person.

We can definitively diagnose cerebral amyloid angiopathy through brain biopsy; however, this is not a practical approach because brain biopsy is a surgical procedure that may lead to other potential risks like bleeding and exposure to infections. Brain biopsy is only conducted upon doctors’ order or it has become a necessity.

Doctors’ evaluation may start by asking you several questions like your medical history, family background, and symptoms.

Several brain imaging scans will also be conducted to detect any anomalies in your brain. These imaging tests may include:

Positron Emission Tomography

This is to detect any amyloid protein congestion in your brain. A result of a study suggest that diagnosis through a PET scan could provide doctors’ from moderate to good accuracy of the condition of the protein build-up in the patients’ brain.

Magnetic Resonance Angiogram

MRA is used to evaluate the damage of the bleeding.

Computed Tomography/Magnetic Resonance Imaging

This provides a complete mapping of patients’ brain. CT scans can detect signs of bleeding in any area of the brain, however, a regular MRI scan may not detect signs of CAA because of its limited function and poor imaging resolutions unless placed under MR scanners with higher resolutions that allow them to detect any bleeding.

The doctor may also order a type of Magnetic Resonance Imaging (MRI) scan known as the gradient echo or GRE. It provides the doctor signs that help them detect whether the patient has an intracranial hemorrhage or not. According to a few medical practitioners, this procedure is an effective way to spot any bleeding in the brain. It can identify whether the bleeding is small or large and it what region of the brain’s affected. It could also tell the length of the period since the bleeding has occurred. The image result of cerebral amyloid angiopathy from the gradient echo is usually called cortical cerebral micro-bleeding.

 

Treatments

As the cause of cerebral amyloid angiopathy is unknown, there’s also no cure for CAA. The aim of the treatment is to manage and delay the development of the symptoms. Rehabilitation may also be needed if physical movement is affected by CAA. Medication may also be advised to support brain activities and prevent seizures from happening.

When the intracranial hemorrhage starts, its treatment is the same as other intracranial hemorrhage cases.

Continuous bleeding may cause swelling within the artery and may lead to a condition called increased intracranial pressure (ICP), and if it does occur your doctor will conduct an emergency procedure or if other methods are possible to reduce the swelling. There may be instances that your doctor will prescribe you an anti-seizure medicine to prevent any seizure caused by the bleeding.

What is Cerebral Amyloid Angiopathy?

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