Fibromuscular dysplasia (FMD) was first observed in 1938 by Leadbetter and Burkland in a 5-year-old boy, and described as a disease of the renal arteries. Involvement of the craniocervical arteries was recognized in 1946 by Palubinskas and Ripley. FMD is an angiopathy that affects medium-sized arteries predominantly in young women of childbearing age. FMD most commonly affects the renal arteries and can cause refractory renovascular hypertension. Of patients with identified FMD, renal involvement occurs in 60-75%, cerebrovascular involvement occurs in 25-30%, visceral involvement occurs in 9%, and arteries of the limbs are affected in about 5%. Case reports have shown FMD in most other medium-to-large arteries as well, including the coronary arteries, the pulmonary arteries, and the aorta. In 26% of patients, disease is found in more than one arterial region.
Although early autopsy and radiologic series suggested that FMD involving the craniocervical arteries occurs at a frequency of approximately 1%, a more recent large series looking at FMD in the carotid arteries only suggests a lower frequency, on the order of 0.02%. FMD generally follows a benign course and is frequently an incidental finding. However, cranial involvement bears worse prognosis because of the occurrence of dissection and strokes and the coexistence of saccular aneurysms. Specific mortality and morbidity data are lacking. Regarding the risk of recurrent carotid artery dissection, de Bray et al prospectively reviewed 103 consecutive patients with carotid artery dissection with follow-up for an average of 4 years. Of those, 5 had recurrent dissections and 4 of the 5 patients with recurrent dissections were diagnosed with FMD. If considering the presentation of recurrent dissection of the carotid artery, FMD was associated in 80% of their series. FMD most commonly presents in young to middle-aged adults. One angiographic series found a mean age of 48 years with a range of 24-70 years. Cases have even been described in the pediatric population, including infantile-onset cases.
The primary symptoms are associated with FMD are hypertension, aneurysms, dissections and occlusion of the renal artery. The carotid and vertebral arteries are also affected. Symptoms of craniocervical involvement include headaches (mostly migraine), pulsatile tinnitus, dizziness, and neck pain, although patients are often asymptomatic. Patients may experience abdominal pain after eating or weight loss. Treatments depend on the symptoms that develop during the disease period. Medical management is the most common form of treatment. Blood pressure control is the primary concern when treating patients with renal FMD. Patients with carotid or vertebral FMD should be medically managed to reduce the risk of a stroke. Aspirin 81 mg is typically prescribed for patients with carotid FMD. Medical therapy for pediatric population may involve the use of angiotensin-converting enzyme inhibitor (ACE inhibitors) and/or angiotensin II receptor blockers, multiple anti-hypertensive medications, diuretics, calcium channel blockers, and beta-blockers. Prevention of thrombosis of affected arteries may be taken through administration of an antiplatelet medication such as aspirin.