fibromuscular dysplasia (FMD)

introduction

an uncommon angiopathy predisposing to dissection of medium sized arteries
~1% of middle aged women may have this condition affecting either renal arteries (60-75% of cases), craniocervical arteries (25-30% of cases, 95% of whom involved internal carotid mainly extracranially at C1-2 level, while 12-43% involve the vertebral arteries), visceral arteries (9% of cases), coronary arteries(? 5% of cases), or limb arteries (5% of cases)
may also affect pulmonary arteries and aorta
a quarter have more than one region affected
affects women 3-4x men
most commonly presents in young to middle-aged adults but may affect children - in fact 1st observed in a 5 year old boy with disease of the renal arteries
patients with FMD affecting cerebrovascular system are also likely to have cerebral aneurysms which may occur in 50% of cases although causal link is not known
appears to have higher prevalence if siblings have FMD, but most are sporadic
it may cause:
- refractory renovascular hypertension
- stroke (CVA) - particularly strokes in young women
- internal carotid or vertebral dissection
  - FMD is a predisposing factor in 15% of spontaneous cervical carotid dissections
- coronary artery dissection
- mesenteric ischaemia
- limb ischaemia
diagnosis is based on angiography findings