University of California San Francisco

Fibromuscular Dysplasia

What is fibromuscular dysplasia?

Fibromuscular dysplasia (FMD) is the abnormal development or growth of cells in the walls of arteries that can cause the vessels to narrow or bulge. The carotid arteries, which pass through the neck and supply blood to the brain, are commonly affected. Arteries within the brain and kidneys also can be affected. A characteristic “string of beads” pattern caused by the alternating narrowing and enlarging of the artery can block or reduce blood flow to the brain, causing a stroke or mini-stroke.

Some people experience no symptoms of the disease while others may have:

  • High blood pressure
  • Dizziness or vertigo
  • Chronic headache
  • Intracranial aneurysm
  • Ringing in the ears
  • Weakness or numbness in the face
  • Neck pain
  • Vision problems

FMD is most often seen in people 25 to 50 years of age and affects women more often than men. More than one family member may be affected by the disease. The cause of FMD is unknown.

An angiogram can detect the degree of narrowing or obstruction of the artery and identify changes such as a tear (dissection) or weak area (aneurysm) in the vessel wall. FMD can also be diagnosed using computed tomography, magnetic resonance imaging, or ultrasound.

There is no standard treatment for FMD. Any treatment to improve blood flow is based on the arteries affected and the progression and severity of the disease. The carotid arteries should be tested if FMD is found elsewhere in the body since carotid involvement is linked to an increased risk of stroke. People with minimal narrowing may take a daily antiplatelet such as an aspirin or an anticoagulant to thin the blood and reduce the chances that a clot might form. Medications such as aspirin can also be taken for headache and neck pain associated with FMD.

People with arterial disease who smoke should be encouraged to quit as smoking worsens the disease. Further treatment may include angioplasty, in which a small balloon is inserted through a catheter and inflated to open the artery. Small tubes called stents may be inserted to keep arteries open. Surgery may be needed to treat aneurysms that have the potential to rupture and cause bleeding within the brain.

Currently there is no cure for FMD. Medicines and angioplasty can reduce the risk of initial or recurrent stroke. In rare cases, FMD-related aneurysms can burst and bleed into the brain, causing stroke, permanent nerve damage, or death.

How can I or my loved one help improve care for people with fibromuscular dysplasia?

Consider participating in a clinical trial so clinicians and scientists can learn more about FMD and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with FMD at Clinicaltrials.gov.