Cardiovascular · Year 1 · from Cardiovascular

Case 3: Renovascular Hypertension - Fibromuscular Dysplasia

Clinical Image

Source: Wikimedia Commons - FMD angiography - CC BY-SA 3.0

Patient Presentation

A 28-year-old woman presents to her primary care physician after being told her blood pressure was elevated at a routine gynecology visit. She has no symptoms and was previously healthy. Her mother has hypertension but developed it in her 50s. On review of systems, she mentions occasional unilateral headaches and a "whooshing" sound in her ears.

Demographics

  • Age: 28 years
  • Sex: Female
  • Past Medical History: None
  • Medications: None
  • Family History: Maternal hypertension (age 50s)
  • Social History: Non-smoker, occasional alcohol

Chief Complaint

Newly discovered hypertension at age 28

Physical Examination

  • Blood pressure: 162/98 mmHg (right arm), 158/96 mmHg (left arm)
  • Heart rate: 74 bpm
  • BMI: 22 kg/m2
  • General: Healthy appearing young woman
  • Cardiovascular: Normal heart sounds, grade 2/6 systolic bruit heard in right upper quadrant/flank
  • Peripheral pulses: Normal and symmetric

Workup

  • Basic metabolic panel: Normal creatinine, potassium normal
  • Plasma renin activity: Elevated
  • Plasma aldosterone: Elevated (secondary to elevated renin)
  • Renal duplex ultrasound: Elevated velocities in right renal artery suggestive of stenosis
  • CT angiography: "String of beads" appearance in mid-portion of right renal artery, consistent with fibromuscular dysplasia (medial fibroplasia subtype)
  • Evaluation for FMD in other vascular beds:
  • CTA head/neck: No carotid or intracranial FMD
  • Normal abdominal aorta

Diagnosis

Renovascular Hypertension due to Fibromuscular Dysplasia of Right Renal Artery

Treatment

  1. Blood pressure control with ACE inhibitor (if tolerated with close creatinine monitoring)
  2. Percutaneous transluminal renal angioplasty (PTRA):
  • First-line treatment for FMD
  • High success rate (cure or improvement in 80-90%)
  • Stenting usually not required for FMD
  1. Post-procedure BP monitoring
  2. Screening for FMD in other vascular territories
  3. Family screening not routinely recommended (low familial occurrence)
  4. Avoid oral contraceptives (thrombotic risk with hypertension)

Physiological Principles Demonstrated

  • Renovascular hypertension mechanism: Renal artery stenosis reduces renal perfusion pressure, activating the renin-angiotensin-aldosterone system. Angiotensin II causes systemic vasoconstriction, and aldosterone causes sodium retention, together elevating blood pressure.
  • FMD vs. atherosclerotic renal artery stenosis: FMD affects the middle and distal renal artery with characteristic "string of beads" appearance; it typically occurs in young women. Atherosclerotic disease affects the ostium and proximal renal artery, typically in older patients with cardiovascular risk factors.
  • Renin-angiotensin feedback: The elevated renin and aldosterone in this case represent an appropriate physiological response to reduced renal perfusion, unlike primary aldosteronism where renin is suppressed.
  • ACE inhibitor considerations: ACE inhibitors can be used but require monitoring; in bilateral disease or solitary kidney, they can cause AKI by removing the efferent arteriolar tone needed to maintain GFR.

All cases for this lecture as Markdown