Synonyms:
Fibromuscular dysplasia FMD,
Diagnosis:
Catheter angiography:
- Affects: extracranial vessels e.g. carotid artery
- Dilated portions (larger than normal parent vessel) & stenotic portions
- +/-Pseudoaneurysm
Type 1: ‘string if pearls’ beaded appearance
Type 2: tubular stenosis (focal or multifocal)
Type 3: limited to part of the arterial wall
False negatives with MRA, CTA and ultrasound but CTA is a useful screening test
Pathology:
- Tunica media: smooth muscle cell hyperplasia, proliferation of fibroblasts, fibrosis
- Dilated portions (larger than normal parent vessel) & stenotic portions
- +/-dissection, +/-pseudoaneurysm, +/-berry aneurysm, +/- CCF, +/-rare VA arteriovenous fistula,
Vessels affected:
- Extracranial ICA (usually mid-portion), VA (mid-distal)
- Less commonly, Intracranial ICA, VA
- Renal arteries
- Other vessels may be affected
Investigations to consider:
Catheter angiography:
- Exclude other mechanisms e.g. atheroma
- Evaluate for presence of aneurysms
Treatment:
Depends on complications e.g. stroke, pseudoaneurysm, dissection etc.
No randomized controlled trials are available.