Fibromuscular dysplasia
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Fibromuscular dysplasia (FMD) is a medical condition characterized by abnormal cell growth in the arteries of the body. This condition primarily affects medium-sized arteries and can lead to both narrowing (stenosis) and enlargement (aneurysm) of these blood vessels. The most commonly affected arteries are those leading to the kidneys and brain, but other arteries, such as those in the legs, heart, abdomen, and occasionally the arms, can also be involved. The consequences of FMD can include reduced blood flow and impaired organ function due to the narrowed arteries.
FMD primarily occurs in women but can affect individuals of any age or gender. The symptoms experienced can vary depending on which arteries are affected. Examples of symptoms associated with FMD include migraines and blood pressure problems. In severe cases, FMD can lead to the development of aneurysms and increase the risk of stroke. While treatments exist to manage the symptoms and complications of FMD, there is currently no known cure for this condition.
There are two distinct classifications of Fibromuscular Dysplasia (FMD), based on the observed characteristics of the arteries during diagnostic examinations:
- Multifocal FMD: Which is the more prevalent form. In this case, the arteries display a distinctive appearance resembling a string of beads. This pattern is characterized by a repetitive sequence of bulging sections followed by narrowed segments.
- Focal FMD: Which is significantly less common. It involves the presence of narrowed arteries or abnormal tissue formations known as lesions on the arterial walls. These lesions represent areas of atypical tissue within the artery.
Symptoms
The symptoms of fibromuscular dysplasia (FMD) can vary depending on which arteries are affected. Some individuals with mild cases may not experience any symptoms. However, for those with restricted blood flow, the following symptoms may occur:
- Bruit: An abnormal swishing noise heard in the neck or abdomen when a healthcare provider listens to blood flow using a stethoscope.
- Dizziness or vertigo.
- High blood pressure or poorly controlled blood pressure.
- Migraine headaches.
- Neck pain.
- Whooshing or ringing sound in the ears.
FMD can also lead to serious medical complications, including:
- Aneurysm: Bulging and weakening of an artery, such as in the brain or abdomen.
- Arterial dissection: A tear in the inner wall of an artery, such as in the carotid or coronary arteries.
- Stroke.
- Transient ischemic attack (TIA) or mini-stroke.
If you have fibromuscular dysplasia (FMD), it is crucial to seek immediate medical attention if you experience signs or symptoms that could indicate a stroke, such as sudden changes in vision, speech difficulties, or new weakness in your arms or legs. If you have other concerns or symptoms related to FMD, it is advisable to consult your doctor. Make sure to inform your doctor about your family’s medical history as FMD can occur in families, although it is uncommon. It is important to note that there is currently no genetic test available for diagnosing fibromuscular dysplasia.
Causes
The exact cause of fibromuscular dysplasia (FMD) remains unknown, although several factors are believed to contribute to its development:
- Hormonal factors: Particularly in females. However, the use of birth control pills, pregnancy history, and age at childbirth do not appear to be directly linked to FMD.
- Genetic factors: They also play a role, as individuals with a family history of FMD are more likely to develop the condition.
- Injury to the artery wall: Repeated stretching of the artery wall has been associated with FMD.
- Smoking: It can exacerbate the condition.
Risk factors
There are a number of factors that could increase your risk of fibromuscular dysplasia.
- Gender. Women are affected by fibromuscular dysplasia more frequently than men.
- Age. Fibromuscular dysplasia is typically identified in adults in their 50s, despite the fact that it can afflict persons of any age.
- Smoking. Smokers tend to be more likely to experience fibromuscular dysplasia. Smoking raises the likelihood of developing a more serious illness for individuals who have already been diagnosed.
Diagnosis
The doctor may check for fibromuscular dysplasia if they detect an abnormal sound in the upper stomach area or neck, which could indicate narrowed arteries. Even in the absence of symptoms, individuals with a family history of fibromuscular dysplasia or aneurysms may be recommended to undergo screening.
To diagnose the condition, the doctor will conduct a physical examination and order blood tests, including assessments of blood sugar and cholesterol levels, to detect signs of atherosclerosis, another condition that can lead to arterial narrowing.
Diagnostic tests for fibromuscular dysplasia may include the following:
- Duplex ultrasound: This noninvasive imaging test employs a transducer pressed against the skin to send sound waves into the body. By reflecting off cells and body structures, the waves provide information on blood flow speed, as well as the size and shape of blood vessels, helping to determine if an artery is narrowed.
- CT angiogram: This test generates cross-sectional images of the body, which can reveal arterial narrowing, aneurysms, and dissections. The individual lies on a narrow table that moves through a doughnut-shaped scanner. Prior to the procedure, a dye is injected to enhance visualization of the examined areas.
- Magnetic resonance (MR) angiogram: By utilizing a magnetic field and radio waves, this test produces images of the body to identify aneurysms or dissections. The person lies on a narrow table that slides into a tube-like machine with open ends. A dye injection may be administered before the procedure to highlight the examined areas.
- Catheter-based angiography: This commonly employed test involves inserting a thin tube (catheter) into an artery and maneuvering it to the desired examination site. A small amount of dye is injected, and X-rays are used to examine the area.
After receiving a diagnosis of fibromuscular dysplasia, your doctor will provide ongoing clinical care. In certain instances, such as the presence of an aneurysm or if your symptoms undergo any changes, repeat imaging may be necessary to monitor the condition of your arteries.
Treatment
Treatment for fibromuscular dysplasia (FMD) varies depending on the symptoms, location of the narrowed artery, and other concurrent health conditions like high blood pressure. In cases where immediate treatment is unnecessary, doctors may advise a strategy of watchful waiting. Unfortunately, there is currently no cure for FMD. Therefore, treatment primarily revolves around managing symptoms and minimizing the risk of complications.
Medications
For individuals with fibromuscular dysplasia and hypertension, treatment with high blood pressure medications is highly recommended, even if they have undergone a procedure to correct the condition. There are several types of medications available for this purpose:
- Angiotensin-converting enzyme (ACE) inhibitors: Examples include benazepril (Lotensin), enalapril (Vasotec), and lisinopril (Prinivil, Zestril). These medications help relax the blood vessels.
- Angiotensin II receptor blockers: These drugs, such as candesartan (Atacand), irbesartan (Avapro), losartan (Cozaar), and valsartan (Diovan), also help relax the blood vessels.
- Diuretics: Hydrochlorothiazide (Microzide) is an example of a diuretic. These medications aid in removing excess fluid from the body and are often used in combination with other blood pressure medications.
- Calcium channel blockers: Amlodipine (Norvasc), nifedipine (Procardia), and other medications in this class help relax the blood vessels.
- Beta blockers: Metoprolol (Lopressor), atenolol (Tenormin), and other beta blockers slow down the heartbeat and block the effects of adrenaline.
In addition to the mentioned medications for high blood pressure in individuals with fibromuscular dysplasia, your doctor may suggest daily aspirin to lower the risk of stroke, but it’s crucial to consult your doctor before starting aspirin. Some blood pressure medications can impact kidney function, so your doctor may recommend regular blood and urine tests to monitor kidney function after starting these medications.
Surgery or other procedures
- Percutaneous Transluminal Angioplasty (PTA). Is a commonly preferred procedure over surgery for treating narrowed arteries. Typically performed along with a catheter-based angiogram, PTA involves injecting dye into an artery to identify narrowed areas. A wire is then guided to the affected artery, and a balloon catheter is inserted to open the narrowed section by inflating the balloon. In some cases, a stent (metal mesh tube) may be placed within the weakened part of the artery to provide additional support and prevent rupture.
- Surgical revascularization. Is not commonly recommended and is usually reserved for cases where complications arise or if PTA is not feasible. This invasive approach involves repairing or replacing the narrowed portion of the artery through surgery. The specific surgical technique employed depends on the location of the narrowed artery and the extent of damage it has incurred.
