Achieve Mastery of Medical Concepts

Study for medical school and boards with Lecturio

Fibromuscular Dysplasia

Fibromuscular dysplasia Dysplasia Cellular Adaptation (FMD) is a nonatherosclerotic, noninflammatory, medium-sized angiopathy due to fibroplasia of the vessel wall. The condition leads to complications related to arterial stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS), aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms, or dissection. The clinical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor can differ depending on which arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology are affected, but may include secondary hypertension Secondary hypertension Hypertension from renal artery Renal artery A branch of the abdominal aorta which supplies the kidneys, adrenal glands and ureters. Glomerular Filtration stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) ( RAS RAS Renal artery stenosis (RAS) is the narrowing of one or both renal arteries, usually caused by atherosclerotic disease or by fibromuscular dysplasia. If the stenosis is severe enough, the stenosis causes decreased renal blood flow, which activates the renin-angiotensin-aldosterone system (RAAS) and leads to renovascular hypertension (RVH). Renal Artery Stenosis), neurologic deficits Neurologic Deficits High-Risk Headaches from cerebrovascular involvement, claudication due to limb involvement, and intestinal angina Intestinal Angina Mesenteric Ischemia from mesenteric artery disease. The diagnosis is confirmed with imaging, such as computed tomography with angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery. Treatment includes lifestyle modifications, antihypertensive therapy for RAS RAS Renal artery stenosis (RAS) is the narrowing of one or both renal arteries, usually caused by atherosclerotic disease or by fibromuscular dysplasia. If the stenosis is severe enough, the stenosis causes decreased renal blood flow, which activates the renin-angiotensin-aldosterone system (RAAS) and leads to renovascular hypertension (RVH). Renal Artery Stenosis patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship, and potential revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease).

Last updated: 8 Jan, 2021

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Definition

Fibromuscular dysplasia Dysplasia Cellular Adaptation (FMD) is a noninflammatory, nonatherosclerotic angiopathy characterized by stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS), aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms, dissection, and tortuosity of medium-sized arteries Medium-Sized Arteries Kawasaki Disease.

Fibromuscular dysplasia Dysplasia Cellular Adaptation primarily affects the renal (most common), carotid, visceral, external iliac, and vertebral arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology.

Epidemiology

  • Common, and often found incidentally
  • Women > men
  • Affects all ages, but primarily young to middle-aged adults
  • Caucasians Caucasians Esophageal Cancer are more commonly affected.
  • Frequent cause of renal artery Renal artery A branch of the abdominal aorta which supplies the kidneys, adrenal glands and ureters. Glomerular Filtration stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) ( RAS RAS Renal artery stenosis (RAS) is the narrowing of one or both renal arteries, usually caused by atherosclerotic disease or by fibromuscular dysplasia. If the stenosis is severe enough, the stenosis causes decreased renal blood flow, which activates the renin-angiotensin-aldosterone system (RAAS) and leads to renovascular hypertension (RVH). Renal Artery Stenosis) in young patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship

Pathophysiology

The cause of this disease is unknown.

  • Possibly due to a combination of genetics Genetics Genetics is the study of genes and their functions and behaviors. Basic Terms of Genetics, hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types, and an underlying connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology defect → arterial wall weakness → arterial dilation and injury → compensatory fibroplasia (development of fibrous Fibrous Fibrocystic Change tissue) in the vessel wall
  • This can result in:
    • Stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS)
    • Artery dissection
    • Aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms formation
  • Disease manifestations result from:
    • Disruption in blood flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure through affected vessels
    • Aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms rupture
    • Intravascular thrombi and embolization Embolization A method of hemostasis utilizing various agents such as gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and intracranial arteriovenous malformations, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage. Gastrointestinal Bleeding
  • In RAS RAS Renal artery stenosis (RAS) is the narrowing of one or both renal arteries, usually caused by atherosclerotic disease or by fibromuscular dysplasia. If the stenosis is severe enough, the stenosis causes decreased renal blood flow, which activates the renin-angiotensin-aldosterone system (RAAS) and leads to renovascular hypertension (RVH). Renal Artery Stenosis: FMD results in arterial stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) → ↓ renal perfusion → ↑ renin Renin A highly specific (leu-leu) endopeptidase that generates angiotensin I from its precursor angiotensinogen, leading to a cascade of reactions which elevate blood pressure and increase sodium retention by the kidney in the renin-angiotensin system. Renal Sodium and Water Regulation production through activation of the renin-angiotensin-aldosterone system Renin-angiotensin-aldosterone system A blood pressure regulating system of interacting components that include renin; angiotensinogen; angiotensin converting enzyme; angiotensin i; angiotensin ii; and angiotensinase. Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming angiotensin I. Angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to angiotensin II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal vascular smooth muscle, leading to retention of salt and water in the kidney and increased arterial blood pressure. In addition, angiotensin II stimulates the release of aldosterone from the adrenal cortex, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down bradykinin, a powerful vasodilator and component of the kallikrein-kinin system. Adrenal Hormones ( RAAS RAAS A blood pressure regulating system of interacting components that include renin; angiotensinogen; angiotensin converting enzyme; angiotensin i; angiotensin ii; and angiotensinase. Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming angiotensin I. Angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to angiotensin II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal vascular smooth muscle, leading to retention of salt and water in the kidney and increased arterial blood pressure. In addition, angiotensin II stimulates the release of aldosterone from the adrenal cortex, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down bradykinin, a powerful vasodilator and component of the kallikrein-kinin system. Adrenal Hormones) → secondary hypertension Secondary hypertension Hypertension
Fibromuscular dysplasia

Diagram showing fibroplasia of the tunic media, which can result in narrowing of the arterial lumen: Aneurysms may form as well, with thinning of the vessel wall.

Image by Lecturio.

Classification

  • Multifocal Multifocal Retinoblastoma FMD 
    • Most common type
    • “String of beads” appearance on angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery
    • Primarily corresponds to medial fibroplasia Medial fibroplasia Renal Artery Stenosis
      • Due to alternating collagen-containing fibromuscular webs and aneurysmal dilation
      • Internal elastic Elastic Connective Tissue: Histology lamina may be absent in the dilated areas. 
    • May also be due to perimedial fibroplasia
      • Outer zone of the media is replaced with collagen Collagen A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of skin; connective tissue; and the organic substance of bones (bone and bones) and teeth (tooth). Connective Tissue: Histology, resulting in irregular thickening.
      • Aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms formation is less common.
  • Focal FMD 
    • Tubular or circumferential stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) on angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery
    • Primarily corresponds to intimal fibroplasia (caused by circumferential collagen Collagen A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of skin; connective tissue; and the organic substance of bones (bone and bones) and teeth (tooth). Connective Tissue: Histology deposition in the intima)
    • Rare manifestations:
      • Medial hyperplasia Hyperplasia An increase in the number of cells in a tissue or organ without tumor formation. It differs from hypertrophy, which is an increase in bulk without an increase in the number of cells. Cellular Adaptation (smooth muscle hyperplasia Hyperplasia An increase in the number of cells in a tissue or organ without tumor formation. It differs from hypertrophy, which is an increase in bulk without an increase in the number of cells. Cellular Adaptation)
      • Periarterial hyperplasia Hyperplasia An increase in the number of cells in a tissue or organ without tumor formation. It differs from hypertrophy, which is an increase in bulk without an increase in the number of cells. Cellular Adaptation ( fibrous Fibrous Fibrocystic Change adventitia expansion)
Multifocal and focal fibromuscular dysplasia

Representations of multifocal Multifocal Retinoblastoma FMD and focal FMD

Image by Lecturio.

Clinical Presentation

The clinical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor depends on the affected vessels and the degree of blood flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure disruption. Most patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship are asymptomatic. 

  • Cerebrovascular arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology (most common presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor in women):
    • Headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess
    • Pulsatile tinnitus Tinnitus A nonspecific symptom of hearing disorder characterized by the sensation of buzzing, ringing, clicking, pulsations, and other noises in the ear. Objective tinnitus refers to noises generated from within the ear or adjacent structures that can be heard by other individuals. The term subjective tinnitus is used when the sound is audible only to the affected individual. Tinnitus may occur as a manifestation of cochlear diseases; vestibulocochlear nerve diseases; intracranial hypertension; craniocerebral trauma; and other conditions. Cranial Nerve Palsies
    • Neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
    • Cervical bruit
    • Transient ischemic attack Transient ischemic attack Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA) ( TIA TIA Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA)) or stroke
    • Amaurosis fugax Amaurosis fugax Transient complete or partial monocular blindness due to retinal ischemia. This may be caused by emboli from the carotid artery (usually in association with carotid stenosis) and other locations that enter the central retinal artery. Carotid Artery Stenosis ( vision Vision Ophthalmic Exam loss due to a lack of blood flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure to the eye)
    • Horner’s syndrome Horner’S Syndrome Pupil: Physiology and Abnormalities ( ptosis Ptosis Cranial Nerve Palsies, miosis Miosis Pupil: Physiology and Abnormalities, and anhidrosis)
  • Renal arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology (most common presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor in men):
    • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
    • Abdominal bruit Abdominal Bruit Abdominal Examination
    • Flank pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Mesenteric arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology:
  • Limb arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology:
    • Claudication 
    • Cyanotic toes 
    • Asymmetric pulses
    • Weakness
    • Paresthesias Paresthesias Subjective cutaneous sensations (e.g., cold, warmth, tingling, pressure, etc.) that are experienced spontaneously in the absence of stimulation. Posterior Cord Syndrome
    • Femoral bruit

Diagnosis

When to suspect FMD

  • Young, hypertensive patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship (especially women < 60 years of age) with:
    • Severe, resistant, or sudden worsening of hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
    • Onset of hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension < 35 years of age
    • Significant rise in creatinine with the initiation of:
      • Angiotensin-converting enzyme (ACE) inhibitors
      • Angiotensin receptor Receptor Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors blockers ( ARBs ARBs Agents that antagonize angiotensin receptors. Many drugs in this class specifically target the angiotensin type 1 receptor. Heart Failure and Angina Medication
    • Abdominal bruit Abdominal Bruit Abdominal Examination
  • Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship < 60 years of age without risk factors for atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis and:  
    • Carotid bruit Carotid bruit Carotid Artery Stenosis
    • TIA TIA Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA) or stroke
    • Aortic aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms
  • Significant headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess or tinnitus Tinnitus A nonspecific symptom of hearing disorder characterized by the sensation of buzzing, ringing, clicking, pulsations, and other noises in the ear. Objective tinnitus refers to noises generated from within the ear or adjacent structures that can be heard by other individuals. The term subjective tinnitus is used when the sound is audible only to the affected individual. Tinnitus may occur as a manifestation of cochlear diseases; vestibulocochlear nerve diseases; intracranial hypertension; craniocerebral trauma; and other conditions. Cranial Nerve Palsies with no explanation
  • Peripheral or coronary arterial dissection Arterial dissection Arterial dissection is a violation of the structural integrity of the arterial wall that results in blood accumulating between the layers. Dissection of the Carotid and Vertebral Arteries or aneurysms
  • Subarachnoid hemorrhage Subarachnoid Hemorrhage Subarachnoid hemorrhage (SAH) is a type of cerebrovascular accident (stroke) resulting from intracranial hemorrhage into the subarachnoid space between the arachnoid and the pia mater layers of the meninges surrounding the brain. Most SAHs originate from a saccular aneurysm in the circle of Willis but may also occur as a result of trauma, uncontrolled hypertension, vasculitis, anticoagulant use, or stimulant use. Subarachnoid Hemorrhage
  • Renal infarction Renal Infarction Imaging of the Urinary System

Diagnosis

Imaging is used to confirm the diagnosis.

  • Noninvasive testing (preferred):
    • Computed tomography with angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery ( CTA CTA A non-invasive method that uses a ct scanner for capturing images of blood vessels and tissues. A contrast material is injected, which helps produce detailed images that aid in diagnosing vascular diseases. Pulmonary Function Tests
    • Magnetic resonance imaging with angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery ( MRA MRA Imaging of the Heart and Great Vessels)
      • Used when CTA CTA A non-invasive method that uses a ct scanner for capturing images of blood vessels and tissues. A contrast material is injected, which helps produce detailed images that aid in diagnosing vascular diseases. Pulmonary Function Tests is contraindicated
      • More useful in detecting aneurysms and dissections
      • Vessel resolution tends to be inconsistent.
    • Duplex ultrasonography Duplex ultrasonography Ultrasonography applying the doppler effect combined with real-time imaging. The real-time image is created by rapid movement of the ultrasound beam. A powerful advantage of this technique is the ability to estimate the velocity of flow from the doppler shift frequency. Hypercoagulable States
  • Invasive testing:

Management

Management of renal FMD

  • Lifestyle modifications
    • Diet
    • Exercise
    • Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases cessation
    • Has not shown much benefit as an isolated therapy
  • Antihypertensive therapy
    • Multifocal Multifocal Retinoblastoma FMD can be controlled with medication therapy.
    • 1st line: 
      • ACE inhibitors ACE inhibitors Truncus Arteriosus
      • ARBs ARBs Agents that antagonize angiotensin receptors. Many drugs in this class specifically target the angiotensin type 1 receptor. Heart Failure and Angina Medication
      • Goal is to block the RAAS RAAS A blood pressure regulating system of interacting components that include renin; angiotensinogen; angiotensin converting enzyme; angiotensin i; angiotensin ii; and angiotensinase. Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming angiotensin I. Angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to angiotensin II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal vascular smooth muscle, leading to retention of salt and water in the kidney and increased arterial blood pressure. In addition, angiotensin II stimulates the release of aldosterone from the adrenal cortex, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down bradykinin, a powerful vasodilator and component of the kallikrein-kinin system. Adrenal Hormones.
      • Use may be limited by a decrease in glomerular filtration Glomerular filtration The kidneys are primarily in charge of the maintenance of water and solute homeostasis through the processes of filtration, reabsorption, secretion, and excretion. Glomerular filtration is the process of converting the systemic blood supply into a filtrate, which will ultimately become the urine. Glomerular Filtration rate ( GFR GFR The volume of water filtered out of plasma through glomerular capillary walls into Bowman’s capsules per unit of time. It is considered to be equivalent to inulin clearance. Kidney Function Tests) or hyperkalemia Hyperkalemia Hyperkalemia is defined as a serum potassium (K+) concentration >5.2 mEq/L. Homeostatic mechanisms maintain the serum K+ concentration between 3.5 and 5.2 mEq/L, despite marked variation in dietary intake. Hyperkalemia can be due to a variety of causes, which include transcellular shifts, tissue breakdown, inadequate renal excretion, and drugs. Hyperkalemia.
    • 2nd line: 
  • Revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease)
    • Indications:
      • Recent-onset hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension in younger patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with low risk of atherosclerotic disease (particularly with focal FMD)
      • Resistant hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension despite appropriate 3-drug therapy
      • Progressive renal insufficiency thought to be from RAS RAS Renal artery stenosis (RAS) is the narrowing of one or both renal arteries, usually caused by atherosclerotic disease or by fibromuscular dysplasia. If the stenosis is severe enough, the stenosis causes decreased renal blood flow, which activates the renin-angiotensin-aldosterone system (RAAS) and leads to renovascular hypertension (RVH). Renal Artery Stenosis
      • Children with hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
    • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension can be cured in focal FMD, but not in multifocal Multifocal Retinoblastoma FMD.
      • May be due to the younger age of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship and shorter duration of hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension at onset
    • Goal is to prevent renal atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation and chronic kidney disease Chronic Kidney Disease Chronic kidney disease (CKD) is kidney impairment that lasts for ≥ 3 months, implying that it is irreversible. Hypertension and diabetes are the most common causes; however, there are a multitude of other etiologies. In the early to moderate stages, CKD is usually asymptomatic and is primarily diagnosed by laboratory abnormalities. Chronic Kidney Disease (of particular concern in focal FMD).
    • Options:
      • Percutaneous transluminal angioplasty Angioplasty Reconstruction or repair of a blood vessel, which includes the widening of a pathological narrowing of an artery or vein by the removal of atheromatous plaque material and/or the endothelial lining as well, or by dilatation (balloon angioplasty) to compress an atheroma. Except for endarterectomy, usually these procedures are performed via catheterization as minimally invasive endovascular procedures. Cardiac Surgery (preferred)
      • Aortorenal bypass surgery Aortorenal bypass surgery Renal Artery Stenosis (usually reserved for complex cases)
  • Followup and serial monitoring
    • Blood pressure
    • Serum creatinine 
    • Renal ultrasound

Management of non-renal FMD

  • Most patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship are asymptomatic and do not require intervention.
  • Lifestyle and risk factor modifications 
    • Goal is to reduce the risk of atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis, which could accelerate arterial stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS).
    • Diet, exercise, and smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases cessation
    • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus, hyperlipidemia, and hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension management
  • Aspirin Aspirin The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. Nonsteroidal Antiinflammatory Drugs (NSAIDs) for stroke prophylaxis Prophylaxis Cephalosporins in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with cerebrovascular FMD
  • Revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease):
    • TIA TIA Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA) or stroke
    • Claudication
    • Mesenteric ischemia Mesenteric Ischemia Mesenteric ischemia is a rare, life-threatening condition caused by inadequate blood flow through the mesenteric vessels, which results in ischemia and necrosis of the intestinal wall. Mesenteric ischemia can be either acute or chronic. Mesenteric Ischemia

Differential Diagnosis

  • Atherosclerotic disease: narrowing of arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology due to patchy intimal plaques. Risk factors include diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus, hyperlipidemia, hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, and smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship tend to be older. The clinical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor depends on the vessels involved, but can include heart disease, stroke, RAS RAS Renal artery stenosis (RAS) is the narrowing of one or both renal arteries, usually caused by atherosclerotic disease or by fibromuscular dysplasia. If the stenosis is severe enough, the stenosis causes decreased renal blood flow, which activates the renin-angiotensin-aldosterone system (RAAS) and leads to renovascular hypertension (RVH). Renal Artery Stenosis, and peripheral artery disease Peripheral artery disease Peripheral artery disease (PAD) is obstruction of the arterial lumen resulting in decreased blood flow to the distal limbs. The disease can be a result of atherosclerosis or thrombosis. Patients may be asymptomatic or have progressive claudication, skin discoloration, ischemic ulcers, or gangrene. Peripheral Artery Disease. Diagnosis is based on clinical history, duplex ultrasound, or angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery. The characteristic appearance of FMD on angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery will not be seen. Treatment includes risk factor modification, antiplatelet agents Antiplatelet agents Antiplatelet agents are medications that inhibit platelet aggregation, a critical step in the formation of the initial platelet plug. Abnormal, or inappropriate, platelet aggregation is a key step in the pathophysiology of arterial ischemic events. The primary categories of antiplatelet agents include aspirin, ADP inhibitors, phosphodiesterase/adenosine uptake inhibitors, and glycoprotein IIb/IIIa inhibitors. Antiplatelet Drugs, and revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease).
  • Vasculitis Vasculitis Inflammation of any one of the blood vessels, including the arteries; veins; and rest of the vasculature system in the body. Systemic Lupus Erythematosus: a vascular inflammatory disease, often resulting in ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage, necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage, and organ damage. Any vessel can be involved. Etiologies include autoimmune disorders, drugs, and infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease. Unlike FMD, patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, arthralgias, arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis, and potential end-organ damage. Diagnosis involves inflammatory markers, autoimmune serology Serology The study of serum, especially of antigen-antibody reactions in vitro. Yellow Fever Virus, infectious Infectious Febrile Infant workup, and biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma, which will differentiate this condition from FMD. Management depends on the underlying cause.
  • Primary hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension: idiopathic Idiopathic Dermatomyositis elevation in blood pressure, and most commonly associated with increasing age (unlike RAS RAS Renal artery stenosis (RAS) is the narrowing of one or both renal arteries, usually caused by atherosclerotic disease or by fibromuscular dysplasia. If the stenosis is severe enough, the stenosis causes decreased renal blood flow, which activates the renin-angiotensin-aldosterone system (RAAS) and leads to renovascular hypertension (RVH). Renal Artery Stenosis, which is due to FMD). Most patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship are asymptomatic, but severe elevations can cause headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess and dizziness Dizziness An imprecise term which may refer to a sense of spatial disorientation, motion of the environment, or lightheadedness. Lateral Medullary Syndrome (Wallenberg Syndrome). Diagnosis is based on history and 3 separate blood pressure readings. Treatment includes lifestyle modifications and antihypertensive therapy. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship who do not respond to treatment should be evaluated for secondary hypertension Secondary hypertension Hypertension, such as RAS RAS Renal artery stenosis (RAS) is the narrowing of one or both renal arteries, usually caused by atherosclerotic disease or by fibromuscular dysplasia. If the stenosis is severe enough, the stenosis causes decreased renal blood flow, which activates the renin-angiotensin-aldosterone system (RAAS) and leads to renovascular hypertension (RVH). Renal Artery Stenosis.

References

  1. Olin, J.W. (2020). Clinical manifestations and diagnosis of fibromuscular dysplasia. In Forman, J.P. (Ed.), Uptodate. Retrieved December 1, 2020, from https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-fibromuscular-dysplasia
  2. Olin, J.W. (2020). Treatment of fibromuscular dysplasia of the renal arteries. In Forman, J.P. (Ed.), Uptodate. Retrieved December 1, 2020, from https://www.uptodate.com/contents/treatment-of-fibromuscular-dysplasia-of-the-renal-arteries
  3. Wilson, J.A., and Hughes, R.L. (2018). Fibromuscular dysplasia. In Lutsep, H.L. (Ed.), Medscape. Retrieved December 1, 2020, from https://emedicine.medscape.com/article/1161248-overview
  4. Teo, K.K. (2019). Fibromuscular dysplasia. [online] MSD Manual Professional Version. Retrieved December 1, 2020, from https://www.msdmanuals.com/professional/cardiovascular-disorders/peripheral-arterial-disorders/fibromuscular-dysplasia
  5. Kasper, D.L., Fauci, A.S., Hauser, S.L., Longo, D.L., Lameson, J.L., and Loscalzo, J. Harrison’s Principles of Internal Medicine. New York, NY: McGraw-Hill Education; 2018.

USMLE™ is a joint program of the Federation of State Medical Boards (FSMB®) and National Board of Medical Examiners (NBME®). MCAT is a registered trademark of the Association of American Medical Colleges (AAMC). NCLEX®, NCLEX-RN®, and NCLEX-PN® are registered trademarks of the National Council of State Boards of Nursing, Inc (NCSBN®). None of the trademark holders are endorsed by nor affiliated with Lecturio.

Study on the Go

Lecturio Medical complements your studies with evidence-based learning strategies, video lectures, quiz questions, and more – all combined in one easy-to-use resource.

Learn even more with Lecturio:

Complement your med school studies with Lecturio’s all-in-one study companion, delivered with evidence-based learning strategies.

User Reviews

¡Hola!

Esta página está disponible en Español.

🍪 Lecturio is using cookies to improve your user experience. By continuing use of our service you agree upon our Data Privacy Statement.

Details