Fibromuscular Dysplasia
Related Subjects:Migraine
|Basilar Migraine
|Takayasu arteritis (pulseless disease)
|Fibromuscular Dysplasia
⚠️ Fibromuscular Dysplasia (FMD) can cause four vascular changes:
stenosis, aneurysm, dissection, or occlusion.
Always consider in young stroke patients or those with refractory hypertension.
🧠 Introduction
- FMD is an idiopathic, non-inflammatory, and non-atherosclerotic disease of small- and medium-sized arteries.
- It leads to segmental arterial abnormalities affecting flow and structure.
- Most often affects the renal arteries and distal extracranial carotid arteries, but may involve multiple vascular beds.
- More common in young and middle-aged females (female:male ≈ 3:1).
- Accounts for a proportion of childhood strokes and young-onset renovascular hypertension.
🔍 Aetiology
- Found in ≈1% of carotid arteries at post-mortem studies.
- Segmental in nature: alternating areas of stenosis and dilation.
- Does not arise from atherosclerosis or vasculitis.
- Consider in ischaemic stroke or saccular aneurysms (with or without subarachnoid haemorrhage).
📑 Classification
- 💢 Medial fibroplasia (≈80%) – Most common.
Classic “string-of-beads” appearance on angiography. Multiple webs → stenosis with post-stenotic dilatation. Aneurysms frequent.
- 🧱 Intimal fibroplasia (≈10%) – Collagen deposition in intima. Appears as long tubular stenosis or concentric band-like narrowing.
- 👧 Perimedial fibroplasia (<10%) – Seen in young girls (5–15 years). Often presents with hypertension and renal dysfunction.
- 🔬 Medial hyperplasia (<1%) – Only confirmed pathologically.
- 🧩 Adventitial fibroplasia (<5%) – Seen on intravascular ultrasound (IVUS); angiography mimics intimal disease.
💡 Clinical Features
- Stroke or TIA due to carotid/vertebrobasilar infarction.
- Carotid/vertebral dissection causing headache, neck pain, or stroke.
- Renal artery stenosis → refractory hypertension.
- Carotid stenosis (with or without stroke).
- Spontaneous coronary artery dissection (SCAD) (link).
- Rare: pulmonary artery involvement.
- May present with subarachnoid haemorrhage from aneurysm rupture.
🧪 Investigations
- Bloods: FBC, U&E, creatinine (renal function).
- CT/MRI Brain: To detect infarction or SAH.
- Angiography (CTA / MRA / DSA): Shows stenosis with “string-of-beads”, dissections, or aneurysms.
- Histology (post-mortem/biopsy): Collagen deposition in intima/media, thinned media with beading.
- No validated genetic/ante-mortem biomarkers currently available.
🩺 Management
- 🚑 Ischaemic stroke: Follow standard stroke protocols (antiplatelets, BP control).
- 🩹 Dissections: Managed with antiplatelets short/long term.
- 🩻 Renal artery stenosis: May require percutaneous intervention or surgery.
- 💊 Hypertension: Treat with antihypertensive drugs.
- 🔁 Long-term follow-up with vascular imaging as disease can recur or progress.
📚 References & Further Reading
