On angiography the vessels have a corrugated, complicated or ‘string-of-beads’ appearance. The dilated segments are larger than normal, whereas the lumen of the narrow segments is reduced to 40% of normal.
The exact cause remains unknown although genetic predisposition, trauma, hormonal factors, growth factors, underlying, connective tissue disease, skeletal factors and metabolic and immunological factors have all been proposed as cause of fibromuscular dysplasia.
The increased incidence of fibromuscular dysplasia in women as compared with men suggests a possible hormonal or genetic influence. Some authors have proposed the sex difference to be related to immune system functioning, but overt inflammation, as is observed in most classic autoimmune disease is histological lacking.
Aneurysms and dissection are not uncommon complications of fibromuscular dysplasia. Aneurysms can rupture, causing severe life-threatening bleeding. Such aneurysms are usually treated surgically or can sometimes be embolized using endovascular techniques.
Fibromuscular dysplasia
