Fibromuscular dysplasia (FMD) is a rare medical condition. Patients with FMD have abnormal cellular growth in the walls of their medium and large arteries. FMD is an angiopathy that affects medium-sized arteries predominantly in young women of childbearing age.
Most cases of FMD affect the carotid and renal arteries. The carotid arteries are in the neck and connect the heart and the brain. The renal arteries are the blood vessels that carry blood from the aorta to the kidneys. Among patients with identified FMD, renal involvement occurs in 60-75%, cerebrovascular involvement in 25-30%, visceral involvement in 9%, and arteries of the limbs in about 5%. FMD occurs in most other medium-to-large arteries as well, including the coronary arteries the pulmonary arteries and the aorta.
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 is most common in women between the ages of 40 of and 60, but the condition can also occur in children and the elderly. The majority (more than 90%) of patients with FMD are women. However, men can also have FMD, and those who do have a higher risk of complications such as aneurysms (bulging) or dissections (tears) in the arteries.
The cause of FMD is not yet known, but several theories have been suggested. A number of case reports in the literature have identified the disease in multiple members of the same family including twins. As a result, it is felt that there may be a genetic cause. Other possible causes of FMD include abnormal development of the arteries that supply the vessel wall with blood, resulting in inadequate oxygen supply; the anatomic position or movement of the artery within the body, certain medications, and tobacco use.
Patients with FMD experience a variety of symptoms that are largely dependent on the location of the affected arteries. However, many patients have no symptoms at all and are diagnosed when an imaging test of the arteries is performed for another reason. Patients with carotid artery FMD may experience headaches, neck pain, and a pulsatile ringing or swooshing sound in the ears. The most common sign of renal artery FMD is high blood pressure. If FMD involves the arteries of the arms or legs, patients can experience pain with exertion that is relieved by rest, also known as claudication.
There is no cure for FMD. Treatments are focused on managing symptoms and complications of FMD, including high blood pressure and headaches. Antiplatelet medications, such as aspirin, may be prescribed along with medications to treat high blood pressure (anti-hypertensives). Many patients with FMD suffer from headaches, and a number of medications are available to help control and prevent headaches. All patients with FMD who use tobacco should be encouraged to quit.