About Fibromuscular Dysplasia • FMD

By Kevin on

Name of the medical condition and other names that it’s been known by

  • Fibromuscular Dysplasia

  • FMD

  • Fibromuscular Hyperplasia

What is Fibromuscular Dysplasia (FMD)?

Fibromuscular Dysplasia (FMD) is a rare disorder that affects the walls of medium-sized arteries. Instead of the usual smooth, elastic walls, these arteries develop abnormal growths, often causing them to narrow, bulge, or even tear.

Key Points

  • Abnormal Growth: The core issue is the abnormal growth of tissue within the artery walls, primarily an overgrowth of fibrous tissue.

  • Consequences: This abnormal growth can lead to:

    • Stenosis: Narrowing of the artery, restricting blood flow.

    • Aneurysms: Bulges or weakened areas in the artery wall.

    • Dissections: Tears within the artery wall.

Types of Fibromuscular Dysplasia (FMD)

  • Medial Fibroplasia (most common): The artery walls have thick and thin spots that make them look like a "string of beads" on X-ray pictures. This happens in the middle layer of the artery wall.

  • Intimal Fibroplasia (less common): The inner layer of the artery wall gets too thick, making smooth narrowing instead of beads.

  • Adventitial Fibroplasia (rarest): The outer layer of the artery wall thickens, causing smooth narrowing.

What are its Symptoms?

  • High Blood Pressure: Often the first and most common symptom.

  • Headaches

  • Dizziness

  • Weakness

  • Chest pain

  • Heart attack

  • Stroke

  • Mini-stroke (Transient Ischemic Attack - TIA)

  • Ringing in the ears (Pulsatile Tinnitus): A rhythmic sound in the ears that matches the heartbeat.

  • Kidney problems

  • Abdominal pain

  • No symptoms: Many people with FMD have no noticeable symptoms.

How is it Diagnosed?

  • Angiography: Special X-ray using dye to visualize blood flow within the arteries. Often considered the gold standard for diagnosing FMD.

  • Computed Tomography (CT) Angiography: CT scan with contrast dye to create detailed images of blood vessels.

  • Magnetic Resonance Imaging (MRI) Angiography: MRI with contrast dye to visualize blood vessels.

  • Ultrasound: Uses sound waves to image blood vessels, including Doppler ultrasound to assess blood flow.

How is it Treated?

  • Medications:

    • Antihypertensive drugs: To control high blood pressure.

    • Antiplatelet agents: Such as aspirin, to reduce the risk of blood clots.

    • Medications for pain and other symptoms.

  • Procedures:

    • Angioplasty: A balloon is inflated within the narrowed artery to widen it.

    • Stent Placement: A small mesh tube is inserted to keep the artery open.

    • Surgery: In severe cases, such as for ruptured aneurysms.

  • Conservative Management: Often preferred for asymptomatic or minimally symptomatic cases, with medications and lifestyle changes being the first line of treatment.

Additional Information

  • FMD is often associated with other connective tissue disorders like Marfan, Loeys-Dietz, or Ehlers-Danlos syndromes.

  • The condition can affect multiple blood vessels, and screening for FMD in other arteries is recommended when found in one location.

Trend

  • In the US, it's estimated to be around 12 per 100,000 individuals, which could mean millions of Americans might have FMD. However, many cases are underdiagnosed due to its perceived rarity and the nonspecific nature of its symptoms.

  • There isn't specific data on the number of new cases in the last five years, but the US Registry for FMD has been actively enrolling patients since 2009, suggesting an increase in awareness and diagnosis.

  • Projection: Given the underdiagnosis and the potential for millions of Americans to have FMD, the number of diagnosed cases is expected to rise as awareness and diagnostic capabilities improve.

History of Fibromuscular Dysplasia (FMD)

FMD was first described in 1938 by Leadbetter and Burkland when they found it in the renal arteries. The term "fibromuscular hyperplasia" was first used by McCormack and colleagues in 1958. The term "fibromuscular dysplasia" was introduced by Hunt et al. in 1965.

Over the years, more research has been done, especially in the last decade, with the establishment of the US Registry for FMD in 2009. This registry has helped better understand the disease, showing that FMD is not as rare as once thought and can affect multiple circulatory system parts.

Fibromuscular Dysplasia (FMD) - Source of Information

For informational purposes only. Consult a medical professional for advice.


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