Fibromuscular Dysplasia and Stroke: String of Beads, Dissection Risk, and the One-Time Screen
A middle-aged woman with a carotid dissection, resistant hypertension, or whooshing in one ear — FMD ties those threads together. It isn't atherosclerosis, it isn't vasculitis, and once found anywhere it deserves one good look everywhere.
FMD found in one artery earns one good look at all of them — once.
- →FMD is an idiopathic, non-atherosclerotic, non-inflammatory arteriopathy of medium-sized arteries — overwhelmingly in women in mid-life — most often involving the renal and extracranial carotid/vertebral arteries.
- →Two forms: multifocal ("string of beads" — the common one) and focal (a single smooth stenosis, younger patients). Neither is plaque; neither is vasculitis — so statin-and-ESR reflexes both miss.
- →FMD earns its place in a stroke library through its complications: cervical artery dissection, intracranial aneurysm, and pulsatile tinnitus. In the US registry, most patients had cerebrovascular involvement, and dissections and aneurysms were common enough to change surveillance.
- →Consensus care includes a one-time head-to-pelvis vascular survey (brain-to-renal CTA or MRA) in every FMD patient — dissection and aneurysm elsewhere are what you are looking for.
- →Management is mostly antiplatelet therapy, blood-pressure control, and dissection/aneurysm-specific care; revascularization is for select renal disease, not for asymptomatic cervical beads.
Three chief complaints, one diagnosis. A 47-year-old woman with a vertebral dissection after yoga. A 52-year-old whose hypertension shrugs off three drugs. A 44-year-old who hears her own pulse whooshing in one ear at night. Fibromuscular dysplasia can stand behind all three — and once it is found in any artery, the next question is always the same: where else?
What FMD is — and is not
FMD is an idiopathic arteriopathy of medium-sized arteries that is neither atherosclerotic nor inflammatory.1 It is a disease of the arterial wall's architecture — fibrous and muscular tissue laid down where it does not belong — producing webs, ridges, and redundancy. Roughly 90% of registry patients are women, typically diagnosed in their 40s–60s; the renal arteries and the extracranial carotid and vertebral arteries are the two great territories, and involvement of both is common.12
Because it is not plaque, the lesions sit in un-plaque-like places — the mid-to-distal cervical ICA, well above the bulb where atherosclerosis lives. Because it is not vasculitis, inflammatory markers are normal and immunosuppression has no role. Both look-alike errors happen in real charts.
Multifocal versus focal
| Multifocal FMD | Focal FMD | |
|---|---|---|
| Angiographic look | "String of beads" — alternating stenosis and dilation | Single smooth concentric or tubular stenosis |
| Who | The common adult form; mid-life women | Rarer; younger patients, more often children/men than multifocal |
| Trap | Beads read as "irregularity" or missed above the imaged field | Mistaken for atherosclerosis or vasculitis at an atypical site |
Why a stroke service cares
- Dissection. FMD is the classic arteriopathy underneath "spontaneous" cervical dissection — and the thing to think of when dissection is multivessel, recurrent, or paired with resistant hypertension. In the US registry, a large minority of patients had suffered arterial dissection, most commonly carotid.2 The dissection itself is managed as dissection — imaging pearls, CADISS/TREAT-CAD, and all — in the dissection chapter; FMD changes the surveillance around it.
- Aneurysm. Intracranial and visceral aneurysms travel with FMD often enough that finding them is a stated purpose of whole-body screening.3
- Pulsatile tinnitus and dizziness. A common, under-attributed symptom cluster — the whoosh of turbulent carotid flow — and worth asking about directly; posterior-circulation symptoms belong in the same triage frame as any vertigo with vascular features.
- Renovascular hypertension. Not a neurologic symptom — but resistant hypertension in a young woman is both an FMD clue and a stroke risk factor in its own right.
A second dissection, a young woman's resistant hypertension, or a one-sided whoosh — each is FMD raising its hand.
The one-time screen, and everyday management
The international consensus position is straightforward: every patient with FMD anywhere deserves a one-time cross-sectional survey from head to pelvis (CTA or MRA — including intracranial vessels) to find the dissections, aneurysms, and additional beds that change follow-up.3 After that, surveillance is individualized to what was found — an aneurysm gets aneurysm follow-up; a dissected artery gets restudied like any dissection.
Day-to-day management is unglamorous and mostly medical:13
- Antiplatelet therapy (commonly aspirin) is reasonable in cerebrovascular FMD for ischemic protection — consensus-based, not trial-proven.
- Blood-pressure control, with renal-FMD angioplasty reserved for the right renovascular cases — a vascular-medicine decision, not a neurology one.
- No statins for the FMD itself (it is not plaque), no steroids (it is not vasculitis) — prescribe them only for the indications the patient actually has.
- Stroke events managed on their own merits — dissection per the dissection chapter; the rest of the young-stroke evaluation per the tiered workup and workup checklist.
- Counseling with proportion: most patients do well; the point of the label is surveillance and dissection-awareness (avoid high-torque neck manipulation), not fear.
The bottom line
FMD is the arteriopathy hiding behind a meaningful slice of "spontaneous" dissections, young resistant hypertension, and pulsatile tinnitus — non-atherosclerotic, non-inflammatory, and overwhelmingly a disease of mid-life women. Recognize the beads (and where they live, above the bulb), give every FMD patient their one-time head-to-pelvis survey, treat with antiplatelets and blood-pressure control, and reserve intervention for the specific lesions that earn it. The diagnosis is less a treatment than a map — of where this patient's arteries need watching.
Frequently asked questions.
What is fibromuscular dysplasia?
An idiopathic disease of medium-sized artery walls that is neither atherosclerosis nor vasculitis, most common in women in mid-life. It most often affects the renal and extracranial carotid/vertebral arteries, producing the classic "string of beads" (multifocal type) or a single smooth stenosis (focal type).
How is FMD related to stroke?
Mainly through its complications: cervical artery dissection (FMD is the classic underlying arteriopathy, especially when dissection is multivessel or recurrent), associated intracranial aneurysms, and — indirectly — renovascular hypertension. The FMD lesions themselves sit in the mid-to-distal cervical arteries, above where atherosclerotic plaque usually forms.
What screening does an FMD patient need?
International consensus recommends a one-time cross-sectional vascular survey from head to pelvis (CTA or MRA, including intracranial vessels) in every patient with FMD, to detect dissections, aneurysms, and disease in other arterial beds. Subsequent surveillance is tailored to what that survey finds.
How is cerebrovascular FMD treated?
Mostly medically: antiplatelet therapy (commonly aspirin) is considered reasonable, blood pressure is controlled, and complications are managed on their own merits — dissection as dissection, aneurysm as aneurysm. Statins and immunosuppression treat diseases FMD is not. Revascularization has a role in selected renal-artery FMD with renovascular hypertension, not in asymptomatic cervical disease.
Is pulsatile tinnitus a symptom of FMD?
Yes — a one-sided, heartbeat-synchronous whoosh is a recognized and under-attributed FMD symptom, produced by turbulent flow in a beaded carotid. New pulsatile tinnitus deserves vascular imaging rather than reassurance, particularly in a mid-life woman.
References.
- Olin JW, Gornik HL, Bacharach JM, et al. Fibromuscular dysplasia: state of the science and critical unanswered questions: a scientific statement from the American Heart Association. Circulation. 2014;129(9):1048-1078. PubMed
- Olin JW, Froehlich J, Gu X, et al. The United States Registry for Fibromuscular Dysplasia: results in the first 447 patients. Circulation. 2012;125(25):3182-3190. PubMed
- Gornik HL, Persu A, Adlam D, et al. First International Consensus on the diagnosis and management of fibromuscular dysplasia. Vasc Med. 2019;24(2):164-189. PubMed
Related guides
Keep building the picture.
- Cervical artery dissection The complication that brings most FMD to a stroke service.
- Stroke in young adults The cluster map: whose arteries earn the zebra workup.
- Stroke workup checklist Where dedicated vessel imaging sits in the evaluation.
- Dizziness can be a stroke Pulsatile tinnitus and posterior-circulation symptoms share a triage frame.
Article written by