Isolated Angiitis of the Central Nervous System (IACNS)

Angiitis is the inflammation of the walls of small blood vessels. When the condition affects only the vessels in the brain, it is known as isolated angiitis of the central nervous system (IACNS).

This condition causes narrowing of the blood vessels, which reduces the blood flow through the vessel to the brain. This can result in serious complications such as a stroke.


The most common symptom of IACNS is a headache due to limited blood flow (ischemia) to the brain. Ischemia can result in an ischemic stroke or transient ischemic attacks (TIA). Symptoms of an ischemic stroke include:

  • Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
  • Sudden confusion
  • Sudden trouble speaking
  • Sudden trouble seeing in one or both eyes
  • Sudden trouble walking
  • Sudden dizziness, loss of balance or coordination
  • Sudden, severe headache with no known cause

If you notice one or more of these signs in another person or in yourself, do not wait to seek help. Call 9-1-1 immediately.

Other symptoms of IACNS include:

  • Headaches
  • Confusion or difficulty understanding
  • Seizures
  • Behavioral changes
  • Difficulty with coordination or balance
  • Inability to control muscle movement (ataxia)
  • Changes in vision
  • Pinched nerve in the spinal cord (myelopathy)
  • Muscle pain, weakness or numbness

Causes and Risk Factors

The cause of IACNS is unknown, but some cases may be related to tumors or an infection. The condition most often affects men around age 50.

Symptoms of IACNS can be very similar to other conditions, including:

  • Certain infections, including viral and bacterial
  • Abnormal tissue growth, such as Hodgkin's or non-Hodgkin's lymphoma
  • Moyamoya disease


Diagnosis of IACNS usually begins with a physical exam and a review of the patient’s medical history and symptoms. A positive diagnosis is based on a biopsy of the area. However, the medical team will also consider the patient’s symptoms as well as the findings of diagnostic tests.

Biopsy is the removal and examination of biological tissue, cells or fluids. A muscle biopsy is the most definitive way to diagnose IACNS. During a biopsy, the medical team will use a needle to remove a small amount of tissue, which team members will study under a microscope.

Imaging tests, including magnetic resonance imaging (MRI), can be used to diagnose the condition and observe the area affected by constricted blood vessels. An angiogram may be used to view the arteries. The fluid surrounding the brain and spinal cord also may be tested for abnormalities.


IACNS can be fatal and treatment options depend on the severity of the condition.

For severe cases, treatment will begin with medication known as cyclophosphamide, a chemotherapy drug. Because this medication can be very toxic, it is used only for a short period of time when the condition is critical. A medication such as prednisone also may be used to suppress the immune system and manage the body’s response to the condition. Once the patient’s condition is not as critical, an alternative medication that is less damaging to the body will be prescribed.

For patients who have experienced a stroke, the Stroke Program at Cedars-Sinai provides a multidisciplinary treatment approach through a treatment plan tailored to each patient. Patient care is generally broken down into three categories: stroke prevention, treatment immediately after a stroke and post-stroke rehabilitation.

© 2000-2021 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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