Internal Medicine · Year 3 · from Internal Medicine
Case 2: Resistant Hypertension
Patient Presentation
A 58-year-old woman with hypertension for 15 years presents for follow-up. Despite taking amlodipine 10 mg, lisinopril 40 mg, and hydrochlorothiazide 25 mg daily, her blood pressure remains uncontrolled. She confirms taking her medications as prescribed. She has a history of type 2 diabetes and reports occasional headaches and fatigue.
Vital Signs
- Blood Pressure: 162/98 mmHg (average of 3 readings)
- Heart Rate: 72 bpm
- BMI: 32 kg/m²
Physical Examination
- General: Obese, cushingoid appearance not evident
- HEENT: No thyroid enlargement
- Cardiovascular: Regular rhythm, S4 present, no murmurs
- Pulmonary: Clear
- Abdomen: Obese, no bruits
- Extremities: Trace edema
Laboratory Results
- Sodium: 144 mEq/L
- Potassium: 3.2 mEq/L (low)
- Creatinine: 1.0 mg/dL
- Fasting glucose: 132 mg/dL
- Aldosterone: 22 ng/dL (elevated)
- Plasma renin activity: 0.4 ng/mL/hr (suppressed)
- Aldosterone-to-renin ratio: 55 (elevated, >30 is positive)
- 24-hour urine sodium: 180 mEq/day (adequate salt intake)
Clinical Image
Figure 2: CT scan of the abdomen demonstrating a left adrenal adenoma (arrow) in a patient with primary aldosteronism causing resistant hypertension.
Image Source: Educational illustration for teaching purposes.
Questions
- What defines resistant hypertension?
- A) BP >140/90 on one medication
- B) BP above goal despite 3 optimally dosed antihypertensives including a diuretic
- C) BP >160/100 despite any treatment
- D) Hypertension requiring hospitalization
- What is the most likely cause of this patient's resistant hypertension?
- A) Medication non-adherence
- B) Primary aldosteronism
- C) Renal artery stenosis
- D) Pheochromocytoma
- What confirmatory test should be performed for primary aldosteronism?
- A) Repeat aldosterone level
- B) Salt suppression test or fludrocortisone suppression test
- C) MRI of adrenal glands
- D) 24-hour urine catecholamines
- What is the appropriate treatment if a unilateral adrenal adenoma is confirmed?
- What medication should be added if surgery is not an option?
Answers
- B) BP above goal despite 3 optimally dosed antihypertensives including a diuretic - Resistant hypertension is defined as BP above goal despite adherence to 3 or more optimally dosed antihypertensive medications of different classes, one of which should be a diuretic.
- B) Primary aldosteronism - The combination of resistant hypertension, hypokalemia, elevated aldosterone, suppressed renin, and elevated aldosterone-to-renin ratio (>30) is highly suggestive of primary aldosteronism.
- B) Salt suppression test or fludrocortisone suppression test - Confirmatory testing is required after positive screening. Options include:
- Oral salt loading test (aldosterone remains elevated despite sodium loading)
- IV saline infusion test
- Fludrocortisone suppression test
- Captopril challenge test Imaging (CT/MRI) is for localization, not confirmation.
- Treatment for unilateral aldosterone-producing adenoma:
- Laparoscopic adrenalectomy is the treatment of choice
- Often curative for hypertension (35-60% cure rate)
- Always improves blood pressure control even if not cured
- Adrenal vein sampling should be performed to confirm lateralization before surgery
- Medical management if surgery not an option:
- Mineralocorticoid receptor antagonist (spironolactone or eplerenone)
- Spironolactone 25-100 mg daily is highly effective
- Eplerenone is an alternative with fewer anti-androgen side effects
- Amiloride can be used if MRAs not tolerated
- Often requires continuation of other antihypertensives