Fibromuscular Dysplasia (FMD): 10 Common Signs and When to See a Doctor

Fibromuscular Dysplasia (FMD): 10 Common Signs and When to See a Doctor

Fibromuscular Dysplasia (FMD) is a rare vascular condition where cells grow abnormally in the walls of medium-sized arteries. This growth causes the arteries to narrow (stenosis), bulge (aneurysm), or tear (dissection).

Because FMD restricts blood flow to vital organs—primarily the kidneys and the brain—early detection is vital to preventing strokes or organ failure.

10 Common Signs and Symptoms of FMD

FMD is often called a “silent” condition because many people have no symptoms until a complication occurs. When symptoms do appear, they vary based on which artery is affected.

1. Resistant High Blood Pressure: Blood pressure that remains high despite taking three or more medications (typically a sign of renal artery involvement).

2. Pulsatile Tinnitus: A rhythmic “whooshing” or thumping sound in the ears that matches your heartbeat.

3. Chronic Headaches: Migraine-like headaches are the most common neurological symptom of FMD.

4. Neck Pain: Specific pain along the sides of the neck, often associated with carotid artery issues.

5. Dizziness or Vertigo: Feeling lightheaded or unsteady due to reduced blood flow to the brain.

6. Visual Disturbances: Temporary blurred vision or “spots” in the eyes.

7. Bruit (Vessel Noise): A doctor may hear a “swishing” sound when placing a stethoscope over your neck or abdomen.

8. Abdominal Pain After Eating: If FMD affects the arteries supplying the intestines (mesenteric arteries).

9. Weakness or Numbness: Sudden weakness in the limbs, which can be a warning sign of a TIA (mini-stroke).

10. Changes in Kidney Function: Detected through blood tests showing unexplained Acute Kidney Injury (AKI; usually in someone with a single kidney). It is a rare cause of chronic kidney disease (CKD).

When to See a Doctor Immediately

FMD can lead to sudden arterial tears (dissections) or ruptures. Seek emergency medical care (call 999 or go to A&E) if you experience:

• Signs of a Stroke: Sudden facial drooping, inability to raise both arms, or slurred speech (FAST).

• Sudden, “Thunderclap” Headache: An excruciatingly painful headache that comes on instantly.

• Sudden Chest Pain: Which could indicate a tear in the coronary arteries (SCAD).

• Sudden Loss of Vision: In one or both eyes.

Causes and Risk Factors

While the exact cause of FMD is unknown, researchers have identified several key patterns:

• Gender: FMD disproportionately affects women, who make up roughly 90% of cases.

• Age: Whilst it can affect any age, it is most commonly diagnosed in women between 40 and 70.

• Genetics: There is evidence that FMD can run in families, though a single “FMD gene” has not yet been identified.

• Smoking: Tobacco use does not cause FMD but significantly increases the risk of the disease progressing and becoming more severe.

Diagnosis: Visualising the “String of Beads”

Diagnosis requires specialized vascular imaging to identify the characteristic “string of beads” appearance caused by alternating narrowing and enlarging of the artery.

• CTA or MRA Scans: Non-invasive imaging (CT or MRI) that visualises blood flow using contrast dye.

• Duplex Ultrasound: Uses sound waves to measure how fast blood is moving through the neck or kidney arteries.

• Catheter-Based Angiogram: The “gold standard” where a specialist inserts a thin tube into the vessels to take high-resolution X-ray images.

Treatment and Management Strategies

The goal of treatment is to manage blood pressure and prevent arterial damage.

• Blood Pressure Management: Using ACE inhibitors or ARBs to protect the kidneys and lower pressure.

• Antiplatelet Therapy: Daily low-dose aspirin is often prescribed to prevent blood clots from forming in narrowed vessels.

• Angioplasty: A procedure where a balloon is inflated inside the artery to widen the narrowed section. Unlike other heart conditions, stents are rarely used in FMD unless there is a tear.

• Surgery: Traditional bypass surgery may be required for complex aneurysms or severe arterial damage.

Trusted External Resources

• NHS England: Understanding Vascular Diseases

• FMDSA: Fibromuscular Dysplasia Society of America

• Mayo Clinic: FMD Patient Information