Fibromuscular dysplasia (FMD) is a condition that causes narrowing (stenosis) and enlargement (aneurysm) of the medium-sized arteries in your body. The areas of narrowing and bulging occur next to each other and can cause the artery to narrow so much that organs that receive blood from the artery are damaged.
Fibromuscular dysplasia can cause a number of complications, such as high blood pressure or tears of the artery (dissection), if left untreated.
Fibromuscular dysplasia appears most commonly in the arteries leading to the kidneys. Fibromuscular dysplasia can also affect the arteries leading to your brain, abdomen, arms and legs. While there isn't a cure for fibromuscular dysplasia, it can be treated effectively.
Most people who have fibromuscular dysplasia don't have any symptoms. Still, it's possible you could have some signs or symptoms of the disease, depending on what artery is affected by fibromuscular dysplasia.
Kidney signs and symptoms
If the arteries to your kidneys (renal arteries) are affected, you may have:
High blood pressure
Tissue damage in your kidney (ischemic renal atrophy)
Chronic kidney failure, rarely
Brain signs and symptoms
If the arteries to your brain (carotid arteries) are affected, you may have:
Blurred vision or temporary loss of vision
Pulsating ringing in your ears (tinnitus)
Facial weakness or numbness
Abdominal signs and symptoms
If the arteries to your abdomen (mesenteric arteries) are affected, you may have:
Abdominal pain after eating
Unintended weight loss
Arm and leg signs and symptoms
If the arteries to your arms or legs (peripheral arteries) are affected, you may have:
Discomfort when moving your arms, legs, hands or feet
Skin changes in color or appearance
Some people with fibromuscular dysplasia have more than one narrowed artery.
When to see a doctor
If you have fibromuscular dysplasia and have any sudden changes in your vision, ability to speak, or new weakness in your arms or legs, seek medical attention immediately.
If you have any of the other signs or symptoms listed and are concerned about your risk of fibromuscular dysplasia, see your doctor. Because fibromuscular dysplasia can be hereditary, tell your doctor about your family history of the disease, even before you show any symptoms so that he or she can be alert to changes that might suggest you have fibromuscular dysplasia. There's currently no genetic test for fibromuscular dysplasia.
While the cause of fibromuscular dysplasia is unknown, it's believed that several factors may play a role.
Genetics. Genetics may play a role in the development of fibromuscular dysplasia. But, if another family member has fibromuscular dysplasia, you or a relative may never get fibromuscular dysplasia, or you might get the condition in a different artery or have a milder case or a more severe case than your family member's fibromuscular dysplasia. In addition, not everyone who has fibromuscular dysplasia has a relative with the disease.
Hormones. Because women have fibromuscular dysplasia more often than men do, hormones may be linked to the development of fibromuscular dysplasia. However, fibromuscular dysplasia is not linked to how many pregnancies a woman has had, when she gives birth or whether she's taken birth control pills.
Abnormally formed arteries. Fibromuscular dysplasia could be caused by inadequate oxygen to the arteries that supply your blood vessel walls with blood, which causes the vessels to form abnormally. It could also be caused if the position of your arteries in your body is abnormal, or if a medication or tobacco causes your arteries to develop abnormally. Once the artery develops abnormally, a cluster of cells builds in the artery wall, narrowing it and reducing blood flow.
Although the cause of fibromuscular dysplasia is unknown, there are several factors that appear to increase the risk of developing the disorder, including:
Sex. Women have a much greater risk of fibromuscular dysplasia than do men.
Age. Fibromuscular disorder tends to be diagnosed in people in their early 50s.
Smoking. People who smoke appear to have an increased risk of developing fibromuscular dysplasia. For those already diagnosed with the disease, smoking is a risk factor for more serious fibromuscular dysplasia.
Fibromuscular dysplasia can cause a number of complications. These include:
High blood pressure. A common complication of fibromuscular dysplasia is high blood pressure. The narrowing of the arteries causes higher pressure on your artery walls, which can lead to further artery damage, heart disease or heart failure.
Chronic kidney failure. If the artery to the kidney is narrowed by fibromuscular dysplasia, you may not get enough blood flow to your kidney, causing permanent kidney injury.
Dissected artery. Fibromuscular dysplasia can cause tears in the walls of your arteries, causing blood to leak into the artery wall. This process, called arterial dissection or spontaneous coronary artery dissection (SCAD), can limit blood flow to the organ supplied by the injured artery.
Aneurysms. Fibromuscular dysplasia can weaken the walls of your arteries, creating a bulge called an aneurysm. If an aneurysm ruptures, it can be a life-threatening emergency. An aneurysm can occur in any artery affected by fibromuscular dysplasia.
Stroke. If you have a dissected artery leading to your brain or if an aneurysm in an artery to your brain ruptures, you can have a stroke. High blood pressure can also increase your risk of a stroke.
Generally, fibromuscular dysplasia isn't preventable. However, if you're a smoker, quitting smoking may reduce your likelihood of developing fibromuscular dysplasia.
If you have a family history of fibromuscular dysplasia, tell your doctor. Because most people who have fibromuscular dysplasia don't have any symptoms, it's unlikely your doctor would first check for fibromuscular dysplasia unless you have a family history of the condition or he or she hears an abnormal sound in your upper abdomen.
To diagnose fibromuscular dysplasia, your doctor may order one or more imaging tests to see your arteries. You may need to fast for several hours before the tests, depending on where the narrowed arteries are in your body. Ask your doctor if you need to do anything specific to prepare for your test.
Because appointments can be brief and because there's often a lot of ground to cover, it's a good idea to be prepared for your appointment. Here's some information to help you get ready for your appointment, and know what to expect from your doctor.
What you can do
Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
Write down any symptoms you're experiencing, including any that may seem unrelated.
Write down key personal information, including a family history of fibromuscular dysplasia, heart disease, stroke, high blood pressure, and any major stresses or recent life changes.
Make a list of all medications, as well as any vitamins or supplements, that you're taking.
Take a family member or friend along, if possible. Sometimes it can be difficult to soak up all the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
Be prepared to discuss your diet and your smoking and exercise habits. If you don't already follow a diet or exercise routine, be ready to talk to your doctor about any challenges you might face in getting started.
Write down questions to ask your doctor.
Your time with your doctor is limited, so preparing a list of questions will help you make the most of your time together. List your questions from most important to least important, in case time runs out. For fibromuscular dysplasia, some basic questions to ask your doctor include:
What is likely causing my symptoms or condition?
What are other possible causes for my symptoms or condition?
What kinds of tests will I need?
What's the best treatment?
What foods should I eat or avoid?
What's an appropriate level of physical activity?
How often should I be screened or monitored for fibromuscular dysplasia?
What are the alternatives to the primary approach that you're suggesting?
I have other health conditions. How can I best manage them together?
Are there any restrictions that I need to follow?
Should I see a specialist?
Is there a generic alternative to the medicine you're prescribing?
Are there any brochures or other printed material that I can take home with me? What websites do you recommend?
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time that you don't understand something.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:
When did you begin experiencing symptoms?
Have your symptoms been continuous or occasional?
How severe are your symptoms?
What, if anything, seems to improve your symptoms?
What, if anything, appears to worsen your symptoms?
Do you have a family history of fibromuscular dysplasia, heart disease, high blood pressure or other serious illness?
What you can do in the meantime
It's never too early to make healthy lifestyle changes, such as quitting smoking, eating healthy foods and becoming more physically active.
Before you're tested for fibromuscular dysplasia, your doctor may also want to check for atherosclerosis, another condition that can narrow your arteries.
Tests for atherosclerosis usually include:
A physical exam
A fasting blood test to check your blood sugar and cholesterol levels
The tests you'll have to diagnose fibromuscular dysplasia could include:
Catheter-based angiography. During this commonly used test for fibromuscular dysplasia, a thin tube (catheter) is inserted into one of your arteries and moved until it reaches the location your doctor wants to examine. A tiny amount of dye is injected and X-rays are used to examine the location.
Doppler ultrasound. Doppler ultrasound can determine if an artery is narrowed by fibromuscular dysplasia. In this noninvasive test, an instrument called a transducer is pressed to your skin to send sound waves into your body. The sound waves bounce off red blood cells, and the ultrasound can estimate how fast your blood flows. If your blood is moving slowly through an artery, it may be due to fibromuscular dysplasia.
Computerized tomography (CT) angiogram. A CT angiogram allows your doctor to check your arteries to see if they're narrowed or blocked. You'll receive an injection of a dye, and the doughnut-shaped CT scanner will be moved to take images of the artery your doctor believes is narrowed.
Magnetic resonance imaging (MRI). This test allows your doctor to see the soft tissues in your body. During an MRI, you lie on a table inside a long tube-like machine that uses a magnetic field and radio waves to capture images from inside your body. Using the images from the test, your doctor may be able to see the cluster of cells narrowing your artery.
The most common form of fibromuscular dysplasia looks like a "string of beads" on imaging tests. Other, more-aggressive forms of fibromuscular dysplasia have a smooth appearance.
Once you've been diagnosed with fibromuscular dysplasia, your doctor may repeat a Doppler ultrasound exam, a CT angiogram or an MRI angiogram from time to time to see if your condition is getting worse.
Treatment for fibromuscular dysplasia depends on your health, the location of the narrowed artery and other underlying conditions you have, such as high blood pressure. Treatment options include medical procedures, surgery and medications.
Medical procedures and surgery
For otherwise healthy people with fibromuscular dysplasia, repairing the affected artery is often recommended. The procedures to improve blood flow can include:
Percutaneous transluminal renal angioplasty (PTRA). This procedure is usually preferred over surgery. It is often performed at the same time as a catheter-based angiogram. Once the dye from the angiogram shows the narrowed area of the artery, a wire is threaded to the artery and a catheter with a balloon is inserted in the narrowed area. The balloon is then inflated to open the narrowed part of the artery. Unlike the angioplasty procedures performed on people with heart disease, a stent may not be necessary to keep the artery open.
PTRA is usually performed while you're awake, although you'll be given a sedative to relax during the procedure. The procedure takes about one to two hours.
Surgical revascularization. If PTRA is not an option, and the narrowing of your arteries is severe, your doctor may recommend more invasive surgery to repair the narrowed portion of the artery. The type of surgery you'll need depends on the location of the narrowed artery and how damaged the artery is. These procedures require general anesthesia, meaning you'll be unconscious during the surgery.
If your doctor finds serious damage related to fibromuscular dysplasia, such as an aneurysm, he or she may recommend placing a metal mesh tube (stent) inside the weakened part of the artery to help prevent it from rupturing.
Treatment with high blood pressure medications is recommended for most people with fibromuscular dysplasia, even if you also have a procedure to correct your condition. These could include medications from several categories:
Angiotensin-converting enzyme (ACE) inhibitors, such as benazepril (Lotensin), enalapril (Vasotec) or lisinopril (Prinivil, Zestril), stop the narrowing of your blood vessels.
Angiotensin II receptor blockers. These medications help relax blood vessels by blocking the action of a natural chemical that narrows blood vessels. Examples of this class of medications include candesartan (Atacand), irbesartan (Avapro), losartan (Cozaar) and valsartan (Diovan).
Diuretics. These drugs, such as hydrochlorothiazide (Microzide, others), help remove excess fluid from your body and may be used in conjunction with other blood pressure medications.
Calcium channel blockers, such as amlodipine (Norvasc) or nifedipine (Procardia) and others, help relax your blood vessels.
Beta blockers, such as metoprolol (Lopressor, Toprol-XL) or atenolol (Tenormin) and others, slow your heartbeat and block adrenaline.
Because some of these drugs can affect the way your kidneys work, your doctor may recommend blood tests and a urine test (urinalysis) to make sure your kidneys work normally once these medications have been started.
Your doctor also may suggest you take a daily aspirin to reduce your risk of stroke. But don't start taking an aspirin without discussing it with your doctor first.
If you're a smoker, another part of your treatment plan is to stop smoking. Smoking may make fibromuscular dysplasia worse.