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Difficulty: HardMedical History Evaluation

During a routine continuity clinic visit, a physician evaluates a 54-year-old female patient for persistent, resistant hypertension. She was initially diagnosed with essential hypertension 5 years ago. Three months ago, due to uncontrolled readings, her medication regimen was maximized to include amlodipine 10 mg daily, olmesartan 40 mg daily, and chlorthalidone 25 mg daily. Despite confirmed adherence, her home blood pressure logs consistently show systolic values >160 mm Hg. Today, she reports new-onset generalized muscle weakness and occasional palpitations. She denies headaches, episodic diaphoresis, or chest pain. Vital signs show a blood pressure of 168/104 mm Hg and a heart rate of 78/min. Physical examination reveals normal heart sounds, clear lungs, and trace bilateral pedal edema. There are no abdominal bruits.

Laboratory studies reveal the following:
Serum sodium: 144 mEq/L
Serum potassium: 2.7 mEq/L
Serum bicarbonate: 30 mEq/L
Serum creatinine: 0.9 mg/dL
Plasma renin activity: markedly decreased
Serum aldosterone: markedly decreased

Which of the following targeted history questions is most appropriate to identify the underlying etiology of this patient's condition?

  1. Are you consuming any herbal preparations or candies for digestive issues?Answer
  2. B
    Have you been taking over-the-counter nonsteroidal anti-inflammatory drugs regularly?
  3. C
    Do you have a family history of adrenal tumors or early-onset hypertension?
  4. D
    Do you frequently snore loudly or awaken gasping for air?
  5. E
    Have you been using oral decongestants for seasonal allergies?

Answer

The correct inquiry focuses on the consumption of herbal preparations or candies for digestive issues.
The correct targeted question asks about the consumption of herbal preparations or candies for digestive issues. This patient's presentation of resistant hypertension, severe hypokalemia, metabolic alkalosis, and profoundly suppressed levels of both renin and aldosterone is the hallmark of the syndrome of apparent mineralocorticoid excess (AME). Glycyrrhizic acid, a compound commonly found in natural black licorice and various herbal supplements used for gastrointestinal discomfort, inhibits the renal enzyme 11-beta-hydroxysteroid dehydrogenase type 2 (11β-HSD2). This enzyme is responsible for converting active cortisol to inactive cortisone. When it is inhibited, cortisol (which circulates at much higher concentrations than aldosterone) binds to and strongly activates mineralocorticoid receptors in the distal tubule. This leads to massive sodium and water retention, potassium wasting, and a subsequent feedback suppression of both endogenous renin and aldosterone. Eliciting this specific dietary and supplement history is the critical diagnostic step.

Step-by-Step Solution

1
Analyze the patient's clinical presentation.
The patient has resistant hypertension accompanied by new-onset muscle weakness and palpitations.
Identifying the clinical syndrome guides the interpretation of the subsequent laboratory findings.
2
Interpret the basic metabolic panel.
The labs show severe hypokalemia (2.7 mEq/L) and metabolic alkalosis (bicarbonate 30 mEq/L).
The combination of hypertension, hypokalemia, and metabolic alkalosis strongly suggests a state of mineralocorticoid excess.
3
Evaluate the endocrine laboratory findings.
Both plasma renin activity and serum aldosterone are markedly decreased.
Primary hyperaldosteronism would show low renin but high aldosterone. Secondary hyperaldosteronism would show high renin and high aldosterone. When both are low, it indicates an exogenous mineralocorticoid effect or a defect in cortisol metabolism.
4
Identify the historical trigger matching the pathophysiology.
The biochemical profile is diagnostic of the syndrome of apparent mineralocorticoid excess (AME), commonly caused by glycyrrhizic acid.
Glycyrrhizic acid, found in natural black licorice and herbal preparations for dyspepsia, inhibits the enzyme 11-beta-hydroxysteroid dehydrogenase type 2 in the kidneys, allowing normal cortisol levels to continuously activate mineralocorticoid receptors.

Key Concept

Identifying occult sources of glycyrrhizic acid (licorice root) in a patient presenting with resistant hypertension, hypokalemia, and suppressed renin/aldosterone.
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Topics

Medical History Evaluation

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