Fibromuscular dysplasia (FMD) is a disorder that affects the walls of blood vessels. It's non-atherosclerotic and non-inflammatory, meaning fatty buildup in the vessels or inflammation cause it.
Abnormal growth, called fibroplasia, forms in the artery walls, causing them to narrow or look beaded.
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What Is Fibromuscular Dysplasia (FMD)?
FMD is a disorder that affects the walls of blood vessels or arteries. It is not a result of inflammation or plaque buildup.
Arteries are blood vessels that carry blood to different parts of the body. They often consist of strong, flexible cells.
But with FMD, the artery's cells become:
- Weak.
- Stiff.
- Fibrous.
- Easier to damage.
What are the types of FMD?
There are three types of FMD:
- Multifocal FMD – This is the most common type, in which the arteries look like a string of beads.
- Focal FMD – This affects about 10% of people with FMD. This type involves the narrowing of the arteries or lesions in the arterial wall.
- Adventitial FMD – A rare type that affects the outer layer of the artery.
FMD can happen in any artery but most commonly affects the:
- Renal arteries – which bring blood to your kidneys.
- Carotid arteries – which bring blood to your brain.
- Subclavian arteries – which bring blood to the upper part of your body.
- Vertebral arteries – which bring blood to the back of the brain.
In most cases, FMD can occur in more than one artery.
What causes FMD?
FMD can happen to anyone but is most common in women ages 25 to 50.
Doctors don't know exactly what causes FMD, but it likely has underlying factors like:
- Hormones – Most people with FMD are women.
- Mechanical stress from trauma – which places a physical strain on the arteries.
- Genes – FMD can run in families, although many people with FMD have no family history of it.
- Ehlers-Danlos syndrome (type IV) – FMD can sometimes go hand in hand with this genetic connective tissue disorder.
- A lack of oxygen supplying the blood vessel walls – This causes the vessels to form fibrous lesions.
- Environment – Smoking and estrogen have known links to FMD.
What are FMD risk factors and complications?
Some people with FMD have no symptoms. Symptoms depend on the blood vessels involved.
Even without symptoms, FMD can lead to severe, even life-threatening, complications. It can narrow the arteries that supply blood to the kidneys and brain.
Some complications of FMD include:
- Changes in kidney function – Reduced blood flow from narrowed arteries can damage the kidneys. You may have flank pain.
- High blood pressure – When the blood vessel narrows, the pressure on the artery walls increases.
- Torn arteries – Fibrous cells in the artery make them more prone to tears.
- Aneurysm – or a bulge or weak spot in an artery. Cell changes can weaken the artery walls, making them more likely to bulge.
- Stroke – When FMD affects the carotid or vertebral arteries, you may have a mini-stroke or stroke-like symptoms.
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What Are The Signs And Symptoms Of Fibromuscular Dysplasia?
Symptoms of FMD vary based on the arteries where they are occurring. Many people have no symptoms.
Kidney (renal) artery FMD symptoms
- High blood pressure.
- Abnormal kidney function.
- Flank pain.
- Bruit ((pronounced broo-ee) an abnormal sound in the neck or belly heard with a stethoscope.
- Headaches, especially migraines.
- Whooshing sounds or ringing in the ears.
- Neck pain.
- Lightheadedness.
- Dizziness or vertigo.
- A transient ischemic attack (TIA) also known as a mini-stroke.
Abdominal artery FMD symptoms
- Stomach pain after eating.
- Weight loss.
Arm and leg artery symptoms
- Pain with exercise.
- A lack of blood flow to the limbs (limb ischemia) or blocked arteries.
- Discoloration of the fingertips.
Heart (coronary) artery symptoms
- Chest pain.
- Heart attack.
- Spontaneous coronary artery dissection (SCAD).
Carotid and vertebral artery FMD symptoms
- Headaches.
- Ringing in the ears.
- Dizziness.
When Should I see a doctor about my FMD Symptoms?
See a doctor if you have symptoms related to the affected artery of your FMD. They can help you find what you need to feel better.
Call 911 or go to the nearest ER right away if you're showing signs of a stroke, including:
- Confusion
- Dizziness
- Vision problems
- Trouble speaking
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How Do You Diagnose Fibromuscular Dysplasia?
FMD can be hard to diagnose since no specific signs and symptoms exist.
Your doctor will first do a physical exam and take a detailed medical history.
In some cases, they can diagnose FMD after:
- Taking an x-ray or other imaging test that shows a beaded appearance in the arteries.
- Hearing a whooshing sound — called a bruit — during a routine exam.
To diagnose FMD, your UPMC vascular surgeon may order one or more of the following imaging tests:
- Angiography — uses a catheter and x-rays to create images of your arteries.
- Duplex ultrasound — uses sound waves to take pictures of the blood flow through your blood vessels.
- Computerized tomography angiogram (CTA) — uses cross-sectional x-rays and a computer to create detailed 3D images.
- Magnetic resonance angiogram — uses a large magnet, radio waves, and computers to make detailed images. This test looks for a bulge or tear in the artery.
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How Do You Treat Fibromuscular Dysplasia?
Doctors can treat FMD with medicine. In some cases, you may need surgery or other treatment.
Most people do well with treatment and routine checkups.
Your UPMC vascular surgeon will create a treatment plan based on your needs and the blood vessels involved.
FMD treatment may include:
- Lifestyle changes that lower your risk for high blood pressure, high cholesterol, and diabetes, which contribute to vascular disease.
- Follow-up imaging tests to check the health of your arteries.
- Drugs to prevent blood clots, control blood pressure and treat headaches.
- Endovascular balloon angioplasty a catheter-based procedure that uses a balloon to open narrowed or blocked arteries.
- Surgery to repair damaged, bulging, or weak arteries.
By UPMC Editorial Staff. Last reviewed on 2024-10-01.
