Fibromuscular dysplasia (FMD) is a rare vascular disease that causes extra cells to grow within the walls of a person’s arteries. This can cause the arteries to narrow and may cause them to tear.
FMD can affect different arteries and cause a variety of signs and symptoms.
This article explains what FMD is, outlines its signs and symptoms, and explains treatment options. It also highlights possible causes, risk factors, complications, and more.
FMD is a rare disease that affects the arteries. It causes abnormal cell development in the walls of the arteries.
This causes the affected arteries to narrow. It may also cause tears to appear in the artery wall. Tears and narrowing of arteries can restrict blood flow through these arteries.
The disease can affect any artery in the body, but it most commonly affects the renal and carotid arteries.
The renal arteries carry blood to the kidneys. The carotid arteries carry blood to the brain, neck, and face.
Other arteries that FMD can affect include:
- the arteries in the abdomen that supply the liver, spleen, and intestines with blood
- the arteries in the arms and legs
More than 50% of people with FMD will have evidence of the disease in more than one artery.
FMD can affect people of varying ages. However, the median age for the disease is
A person with FMD may have no symptoms at all. Symptoms will usually depend on which arteries FMD has affected.
A person who has FMD of a renal artery may have the following signs and symptoms:
- high blood pressure
- pain in the sides
- hematuria, or the presence of blood in the urine
- disrupted or restricted blood supply to the kidneys
- hypokalemia, or low levels of potassium in the blood
- abdominal bruit, which is a swishing sound a doctor hears through a stethoscope that they place over the spleen, renal arteries, or abdominal aorta
A person who has FMD of the carotid arteries may have the following symptoms:
- high blood pressure
- chest pain
- shortness of breath
- weakness and numbness, especially on one side of the body
- slurred speech
- facial droop on one side
If a person has FMD in their abdomen, they may have the following symptoms:
- weight loss
- abdominal pain after eating
The subclavian arteries supply blood to the head, neck, and arms. If a person has FMD of their subclavian arteries, they may have the following signs and symptoms:
- weakness in the upper arms
- paresthesia, a burning or prickling sensation in the hands, arms, legs, or feet
- pain in the arms
- steal syndrome, which is the name for the diversion of blood away from the arm, which can cause fainting
If a person has FMD in the arteries that supply blood to the legs, they may have the following symptoms:
- pain in the legs when walking
- cold legs
- lack of blood flow to the feet, which can cause a loss of function, gangrene, and sores
If a person has FMD in the arteries that supply blood to the heart, they may have chest pain and shortness of breath.
FMD in this case can be a sign of acute coronary syndrome. Symptoms of acute coronary syndrome can include chest pain that spreads to neck, jaw, or arm, which may indicate a heart attack. A person with these symptoms needs immediate medical attention.
The exact causes of FMD are unknown. However, there are some common theories as to what causes FMD.
FMD is far more common in females than males. Some scientists theorize hormones may play an important role in the development of the disease.
However, more research is needed to confirm whether hormones play a role in FMD.
- being female and below age 50
- having family members who have FMD
FMD can cause a person to develop renal artery stenosis. It accounts for
Renal artery stenosis is the narrowing of one or both of the renal arteries. The renal arteries carry blood to the kidneys.
Renal artery stenosis is the most common cause of secondary hypertension, or high blood pressure due to an underlying medical condition.
Other complications of FMD include:
- steal syndrome
- acute coronary syndrome
To diagnose FMD, a doctor must carry out a test to observe the blood vessels.
Below are three tests a doctor may use to produce images of the arteries:
- Duplex ultrasound: This test uses high frequency sound waves to create images of the blood vessels. It can measure the speed of blood flow through the blood vessels.
- CT scan: A CT scan uses images from several X-rays to produce a detailed picture of structures inside the body. A doctor can use a CT scan to take detailed images of the arteries.
- MRI scan: An MRI scan uses a strong magnetic field and radio waves to create a detailed image of the arteries.
A healthcare professional may also do an arteriography. This procedure involves inserting a wire into or near the affected artery. The healthcare professional then injects contrast material into the artery. The contrast material is a dye that a healthcare professional can detect using an X-ray.
After injecting the dye, the healthcare professional will take an X-ray of the affected area. The X-ray can show how the dye moves through a person’s artery, helping a doctor make a diagnosis.
The procedure usually lasts 1–2 hours. A person typically recovers within 6 hours of the procedure.
There is no cure for FMD. However, some treatment options can help a person manage the disease.
Treatment options for FMD tend to focus on the following:
- controlling risk factors
- managing blood pressure
- preventing the restriction of blood flow to certain parts of the body
Treating acute symptoms of FMD
If a person’s FMD causes them to experience a TIA, a doctor will need to treat the TIA to improve blood flow to the brain.
A doctor may treat a TIA using thrombolytics. Thrombolytics are medications that work by quickly dissolving a major clot to improve blood supply.
In some cases, a surgeon may do a percutaneous thrombectomy. This surgical procedure uses a catheter or other devices to remove a blood clot from a blood vessel.
Arterial dissection refers to the formation of a tear along the inner wall of an artery. This tear can create a small pouch in the artery wall. This pouch can fill up with blood.
Blood accumulating within the pouch may lead to blood clots and block blood flow.
If a person’s FMD causes them to experience arterial dissection, a doctor may treat it with anticoagulation medications. These medications aim to prevent blood clots, help blood flow, and lower the risk of stroke.
Treating high blood pressure
If a person’s FMD causes them to have high blood pressure, medications can help.
- Angiotensin-converting enzyme (ACE) inhibitors: Angiotensin II is a hormone that increases blood pressure. ACE inhibitors lower the levels of this hormone, causing the blood vessels to expand. This allows blood to flow more easily, reducing blood pressure.
- Angiotensin receptor blockers (ARBs): ARBs do not reduce the amount of angiotensin II, but they prevent the hormone from affecting the heart and blood vessels. This prevents blood pressure from rising.
If a person takes these medications, a healthcare professional may monitor their kidney function. Acute kidney injuries may complicate treatment.
Other medications that may help reduce a person’s blood pressure include:
- Diuretics: These medications rid the body of excess fluids by increasing urination. Diuretics remove water from the blood, decreasing the fluid flow through the person’s veins and arteries. This reduces blood pressure.
- Beta-blockers: These medications decrease a person’s heart rate and the force of the heart’s contractions. This causes the heart to beat more slowly and with less force, which lowers blood pressure.
- Calcium channel blockers: These medications prevent calcium from entering the cells of the heart and arteries. This helps reduce blood pressure because calcium causes the heart and arteries to contract with greater strength. Blocking calcium causes the blood vessels to relax and open, lowering blood pressure.
Treatment to widen narrowed arteries
In some instances, a doctor may want to treat FMD-induced narrowed arteries. These treatments aim to improve the blood flow through the artery.
The specific treatment depends on which artery is narrowed.
During this procedure, a healthcare professional passes special tubing with an attached, deflated balloon through the arterial system until it reaches the affected artery. They then inflate the balloon, which widens the area of the artery, improving blood flow.
In some rare cases, a person may require a stent to help prop the artery open and reduce the chances of another blockage.
Healthcare professionals often consider FMD to be a benign disorder. Many people with the disease do not experience severe symptoms and live for a long time.
Long-term data regarding the outlook for people with FMD
The following may increase the likelihood of a poor outcome:
- FMD affecting the cranial nerve of a young person
- FMD that causes a dissection of the arteries
A person with FMD can incorporate certain lifestyle strategies to help manage their symptoms.
- Regularly checking blood pressure: A person with FMD will need to monitor their blood pressure closely. If their blood pressure is elevated, they will need to contact a doctor who may prescribe blood pressure medications.
- Stopping smoking: People with FMD need to stop smoking. Smokers may develop a more aggressive form of FMD than nonsmokers. A doctor can help create a quit plan.
- Getting regular exercise: Regular exercise can help reduce blood pressure. It can also help a person improve heart health and lower stress levels, which can also help reduce high blood pressure.
- Eating a heart-healthy diet: A person can eat a diet high in foods that help reduce high blood pressure. These foods
- fruits and vegetables
- whole grains
- low fat dairy products
- skinless poultry and fish
- non-tropical vegetable oils, such as olive oil and sunflower oil
If a person experiences any FMD symptoms, they should speak with a doctor. Early diagnosis and treatment are important for a good outcome.
A person should seek emergency medical attention if they experience the symptoms of a stroke, such as sudden:
- numbness or weakness in the face, arm, or leg, especially on one side of the body
- trouble speaking or understanding speech
- problems seeing in one or both eyes
- trouble walking, dizziness, loss of balance, or lack of coordination
- severe headache with no known cause
If a person experiences the above symptoms, they, or someone nearby, should call 911 or local emergency services immediately.
Ehlers-Danlos syndrome is a group of genetic disorders that affect the body’s connective tissues.
The vascular subtype of this disorder affects the blood vessels. Healthcare professionals associate the vascular subtype of Ehlers-Danlos syndrome with FMD.
There are also other isolated reports of FMD associated with other disorders, including:
More research is needed to identify a direct link between FMD and the above disorders.
FMD is a rare disease that causes abnormal cell development in the walls of the arteries. This can cause the arteries to narrow, which restricts blood flow.
The disease most commonly affects the renal and carotid arteries. Symptoms of FMD vary depending on the affected artery.
Treatment for FMD usually aims to control risk factors, reduce blood pressure, and prevent the restriction of blood flow to certain parts of the body.