Fibromuscular dysplasia (FMD) is a condition that causes narrowing (stenosis) and enlargement (aneurysm) of the medium-sized arteries in the body. The areas of narrowing occur next to each other and can cause the artery to narrow significantly and as a result organs that receive blood from the artery are damaged.
Fibromuscular dysplasia can cause numerous 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 the brain, abdomen, arms and legs. There is no cure for this condition but there are effective treatments.
Most people with fibromuscular dysplasia do not experience any symptoms. However, it is possible to have some symptoms of the disease, depending on what artery is affected by fibromuscular dysplasia.
Kidney (renal arteries) symptoms include:
- High blood pressure
- Tissue damage in the kidney (ischemic renal atrophy)
- Chronic kidney failure (rare)
Brain (carotid arteries) symptoms include:
- Blurred vision or temporary vision loss
- Pulsating ringing in the ears (tinnitus)
- Neck pain
- Chronic headaches
- Facial weakness or numbness
Abdominal (mesenteric arteries) symptoms include:
- Abdominal pain after eating
- Unintended weight loss
Arm and leg (peripheral arteries) symptoms include:
- Discomfort when moving the arms, legs, hands or feet
- Cold limbs
- Skin changes in color and appearance
It is possible for some people with fibromuscular dysplasia to have more than one narrowed artery.
The exact cause of fibromuscular dysplasia is unknown; however, the following factors may play a role:
- Genetics: genetics may play a role in the development of fibromuscular dysplasia. However, it is not an inherited disease and one might also develop the condition in a different artery or have a milder or a more severe case of the disorder.
- Hormones: fibromuscular dysplasia is more common in women, therefore it is believed that certain hormones may be associated with the development of fibromuscular dysplasia.
- Abnormally formed arteries: inadequate oxygen to the arteries that supply the blood vessel walls with blood may cause the vessels to form abnormally, which may lead to fibromuscular dysplasia. It can also be caused by an abnormal position of the arteries in the body or medications or tobacco that cause the arteries to develop abnormally. Once the artery develops abnormally, a cluster of cells builds in the artery wall causing a narrowing and reducing blood flow.
Factors that increase the risk of developing fibromuscular dysplasia include:
- Being female
- Age: most cases of fibromuscular dysplasia develop in the early 50s
Complications associated with fibromuscular dysplasia include:
- High blood pressure: common complication due to narrowing of the arteries, which can lead to further artery damage, heart disease or heart failure.
- Chronic kidney failure: insufficient blood flow to the kidney due to narrowing of the renal arteries may cause permanent kidney damage.
- Dissected artery: tears in the walls of the arteries causing blood to leak into the artery wall. This can limit blood flow to the organ supplied by the damaged artery.
- Aneurysms: bulges or aneurysms may form in the weakened walls of the arteries. A ruptured aneurysm is a life-threatening emergency.
- Stroke: a dissected artery leading to the brain or if an aneurysm in an artery close to the brain ruptures it can cause a stroke.
In general, fibromuscular dysplasia is not preventable. However, quitting smoking may reduce the risk of developing the disease.