Fibromuscular Dysplasia (FMD): Complete Guide to Symptoms, Diagnosis, and Treatment
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
What Is Fibromuscular Dysplasia?
Fibromuscular dysplasia, often abbreviated as FMD, is a condition that causes the medium-sized arteries in the body to narrow and grow larger at the same time. In affected arteries, the muscle and fiber tissues within the artery wall thicken. This thickening narrows the artery, a problem called stenosis.
Narrowed arteries can reduce blood flow to the organs they supply, and over time this can cause organ damage. The arteries that grow larger can weaken and balloon outward.
FMD shows up most often in the arteries leading to the kidneys (the renal arteries) and the arteries that supply the brain. But it can also affect the arteries in the legs, the heart, the belly area, and, rarely, the arms. More than one artery can be involved in the same person.
The most common form of FMD produces a distinctive appearance on imaging tests that doctors describe as a "string of beads." Other forms of the condition may look smooth instead.
One fact matters more than anything else: there is no cure for fibromuscular dysplasia. But treatments are available to control symptoms and help prevent complications, including stroke.
What Does Fibromuscular Dysplasia Feel Like? (Symptoms)
Symptoms depend entirely on which artery or arteries are affected. Some people with FMD never have any symptoms at all.
When the kidney (renal) arteries are affected, the two most common signs are:
High blood pressure: The most frequent symptom; often appears in younger people or is unusually hard to control.
Problems with kidney function: The reduced blood flow can gradually damage the kidneys.
When the arteries to the brain are affected, possible symptoms include:
Headache: Can be new, frequent, or different from your usual headaches.
Pulsing or ringing in the ears (tinnitus): A rhythmic pulsing or ringing sound.
Dizziness: A sense of unsteadiness or lightheadedness.
Sudden neck pain: A new pain in the neck that appears without injury.
Stroke or TIA: A stroke, or a transient ischemic attack (a temporary blockage that causes stroke-like symptoms).
When to Get Emergency Help
If you have FMD or suspect you might, seek emergency medical help immediately if you experience any symptom of a stroke:
Sudden changes in vision
Sudden changes in the ability to speak
Sudden or new weakness in the arms or legs
If you are concerned about your risk of FMD, make an appointment for a health checkup. The condition can rarely run in families, but it is important to know that there is no genetic test for fibromuscular dysplasia.
What Causes Fibromuscular Dysplasia?
The cause of fibromuscular dysplasia is not known. Researchers believe changes in genes might play a role.
Because the condition is more common in women than in men, researchers also think female hormones may be involved, although exactly how is unclear. One point of reassurance: FMD is not linked to women's use of birth control pills.
Risk Factors
Three factors raise the likelihood of having FMD:
Sex: More common in women than in men.
Age: Tends to be diagnosed in people in their 50s, but can affect anyone of any age.
Smoking: Smokers appear to have an increased risk, and smoking can also make the disease worse.
What Happens If Fibromuscular Dysplasia Goes Untreated?
Left untreated, FMD can lead to four main complications.
High blood pressure: Narrowed kidney arteries raise pressure on artery walls; artery damage may eventually lead to heart disease or heart failure.
Artery wall tears (dissection): FMD and tears in artery walls often occur together. A tear in a heart blood vessel is called a spontaneous coronary artery dissection (SCAD). A dissection can slow or block blood flow, so emergency treatment is needed.
Aneurysm: A bulge or ballooning of a weakened, damaged artery wall. If an aneurysm breaks open (rupture), it can be life-threatening and requires emergency care.
Stroke: An artery tear or a ruptured aneurysm in the brain can cause a stroke. High blood pressure itself also raises stroke risk.
How Is Fibromuscular Dysplasia Diagnosed?
Diagnosis begins with a physical exam. A healthcare provider uses a stethoscope to listen to blood flow through the arteries in the neck and belly area. If you have FMD, the provider might hear an irregular sound caused by narrowed arteries.
If someone in your family has or had FMD, you may need tests to check for it even if you have no symptoms.
Tests Used to Diagnose FMD
Blood tests: A simple blood draw checks for other conditions that can narrow arteries, along with blood sugar and cholesterol levels.
Duplex ultrasound: A wand-like device pressed against the skin uses sound waves to produce pictures of blood flow and the shape of blood vessels.
Angiogram: A thin tube (catheter) is guided into an artery and dye is injected into a vein, producing X-ray pictures of the arteries; the dye makes them show up clearly.
CT angiogram: A cross-sectional CT scan after contrast dye is given shows narrowing in the arteries, plus aneurysms and dissections.
MR angiogram: A magnetic field and radio waves create images after possible contrast dye, showing whether you have an aneurysm or an artery tear.
On these imaging tests, the most common form of FMD shows the classic "string of beads" pattern.
How Is Fibromuscular Dysplasia Treated?
Treatment depends on three things: which artery is narrowed, your symptoms, and any other health conditions you have, such as high blood pressure.
Some people need only regular health checkups. Other people need medicines or procedures. If your symptoms change, or if you have an aneurysm, you may need repeated imaging tests to monitor your arteries over time.
Blood Pressure Medicines
If you have FMD with high blood pressure, medicines are usually given to bring blood pressure under control.
ACE inhibitors: Relax blood vessels. Examples: benazepril, enalapril, lisinopril.
Angiotensin 2 receptor blockers (ARBs): Also relax blood vessels. Examples: candesartan, irbesartan, losartan, valsartan.
Diuretics ("water pills"): Remove excess fluid from the body. Example: hydrochlorothiazide; often used with other blood pressure medicines.
Calcium channel blockers: Relax blood vessels. Examples: amlodipine, nifedipine.
Beta blockers: Slow the heartbeat. Examples: metoprolol, atenolol.
An important monitoring note: some blood pressure medicines can affect kidney function. You may need regular blood and urine tests to make sure your kidneys are working properly.
Your doctor might also recommend a daily aspirin to reduce your risk of stroke. However, never start taking aspirin on your own — talk to your healthcare team first.
Procedures and Surgery
When medicines are not enough, treatments can repair a narrowed or damaged artery.
Angioplasty (percutaneous transluminal angioplasty, or PTA). This procedure uses a thin flexible catheter and a tiny balloon to widen a narrowed artery and improve blood flow. A metal mesh tube called a stent may be placed inside the weakened part of the artery to keep it open.
Surgery (surgical revascularization). Repairing or replacing the damaged artery surgically is rarely recommended. It may be suggested if you have severe narrowing and angioplasty is not an option. The type of surgery depends on the location of the narrowed artery and the amount of damage.
How to Prepare for Your Appointment
When you make the appointment, ask if you need to do anything in advance — for example, you might be told not to eat or drink for several hours before certain tests.
Before the visit, prepare a list of the following:
Your symptoms: What they are and when they began.
Important personal information: Any family history of FMD, aneurysms, heart disease, stroke, or high blood pressure.
All medicines: Every medication, vitamin, and supplement you take, including doses.
Questions to ask: See the questions below.
Useful questions to bring with you: What is the most likely cause of my symptoms? What tests will I need? What treatments are available and what do you recommend? What level of physical activity is appropriate? How often should I have checkups? How can my other health conditions be managed together with FMD? Should I see a specialist? Are there printed materials or recommended websites?
Expect your doctor to ask questions too: Do your symptoms always occur, or do they come and go? How severe are they? Does anything seem to improve them? What makes them worse?
Conclusion
Fibromuscular dysplasia is a subtle condition — often discovered only when high blood pressure appears unusually early, or when headaches, ringing in the ears, or dizziness lead to imaging. The "string of beads" pattern on an angiogram or CT scan usually settles the question.
While there is no cure, the outlook for most people is manageable: blood pressure medicines protect the organs, a simple balloon procedure can restore blood flow when needed, and regular imaging keeps a watch on the arteries over time.
What to do next: If you are a woman in your 40s or 50s with hard-to-control blood pressure, unexplained headaches, or ringing in your ears — especially with any family history of FMD or aneurysms — ask your healthcare provider whether imaging for fibromuscular dysplasia makes sense. Bring a written symptom timeline and your family history to the appointment. If you smoke, stopping is one of the few changes shown to help, both because smoking raises FMD risk and because it can worsen the disease. And if you ever notice sudden changes in vision, speech, or strength in your arms or legs, call for emergency help immediately.
Frequently Asked Questions
What is fibromuscular dysplasia in simple terms?
Fibromuscular dysplasia (FMD) is a condition in which the walls of medium-sized arteries thicken unevenly, causing the arteries to narrow and sometimes balloon outward. It most often affects the arteries going to the kidneys and brain.
What causes fibromuscular dysplasia?
The exact cause is not known. Researchers think gene changes and possibly female hormones may play a role. The condition is more common in women than men and is not linked to birth control pill use.
Who gets fibromuscular dysplasia?
FMD is more common in women and tends to be diagnosed in people in their 50s, though it can affect anyone of any age. Smoking increases risk and can worsen the condition.
What are the symptoms of fibromuscular dysplasia?
Symptoms depend on the affected arteries. Kidney artery FMD usually causes high blood pressure and kidney function problems. Brain artery FMD can cause headaches, ringing in the ears, dizziness, sudden neck pain, or stroke. Some people have no symptoms at all.
Is fibromuscular dysplasia curable?
No. There is no cure for fibromuscular dysplasia. However, treatments control symptoms and help prevent complications such as stroke, and many people with mild FMD need only regular checkups.
How is fibromuscular dysplasia treated?
Treatment ranges from regular monitoring to blood pressure medicines (ACE inhibitors, ARBs, diuretics, calcium channel blockers, beta blockers), daily aspirin in some cases, balloon angioplasty with a possible stent, or, rarely, surgery to repair the artery.
When should I seek emergency care for fibromuscular dysplasia?
Get emergency medical help immediately if you have sudden changes in vision, sudden changes in the ability to speak, or sudden or new weakness in the arms or legs — these are stroke warning signs.
References
Health information, not medical advice. This article is for general education and is not a substitute for professional diagnosis or treatment. Always consult a qualified healthcare provider about your own health, and seek emergency care for urgent symptoms.
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