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Question

Difficulty: MediumMedical History Evaluation

A 52-year-old woman comes to the clinic for follow-up of hypertension and new-onset muscle cramps. Her blood pressure was previously well-controlled on amlodipine and lisinopril, but over the past two months, it has consistently been above 160/100 mmHg. Today, her blood pressure is 168/104 mmHg and her heart rate is 76/min. Laboratory results show:

Sodium: 144 mEq/L
Potassium: 2.7 mEq/L
Bicarbonate: 31 mEq/L
Creatinine: 0.9 mg/dL

Subsequent endocrinologic evaluation reveals profoundly suppressed plasma renin activity and undetectable serum aldosterone levels. The patient reports absolute adherence to her prescribed antihypertensive regimen and denies illicit drug use. She mentions that she recently adopted a "natural" holistic lifestyle to help manage occasional indigestion and promote weight loss. To ascertain the etiology of this patient's current clinical and laboratory findings, the physician should specifically question the patient about her daily consumption of which of the following?

  1. A
    Over-the-counter nonsteroidal anti-inflammatory drugs
  2. B
    Grapefruit juice and related citrus beverages
  3. Licorice-containing herbal productsAnswer
  4. D
    St. John's wort extracts
  5. E
    Ephedra-based weight loss supplements

Answer

Licorice-containing herbal products
The correct answer identifies licorice-containing herbal products because licorice root contains glycyrrhizin, which inhibits the enzyme 11-beta-hydroxysteroid dehydrogenase type 2. This inhibition prevents the conversion of cortisol to cortisone, allowing cortisol to chronically bind to and activate mineralocorticoid receptors in the kidney. This produces a syndrome of apparent mineralocorticoid excess characterized by hypertension, hypokalemia, metabolic alkalosis, and suppressed renin and aldosterone levels. Given the patient's new-onset symptoms and her history of adopting a holistic lifestyle to manage indigestion (a common reason for using licorice), inquiring about licorice consumption is the critical next step in her medical history evaluation.

Step-by-Step Solution

1
Analyze the patient's laboratory and clinical findings.
The patient has resistant hypertension, severe hypokalemia, metabolic alkalosis, and suppressed renin and aldosterone levels.
Identifying this specific constellation of findings narrows the differential diagnosis to the syndrome of apparent mineralocorticoid excess or exogenous mineralocorticoid administration.
2
Correlate the syndrome of apparent mineralocorticoid excess with the patient's recent history.
The patient recently started a "natural" lifestyle for indigestion, which strongly suggests the ingestion of licorice root.
Licorice contains glycyrrhizic acid, a known inhibitor of 11-beta-hydroxysteroid dehydrogenase type 2, which perfectly explains all her symptoms.
3
Determine the most appropriate historical element to evaluate.
Question the patient about her daily consumption of licorice-containing herbal products.
Eliciting this specific dietary history confirms the diagnosis and avoids unnecessary and invasive diagnostic workups.

Key Concept

Patients presenting with resistant hypertension, hypokalemia, metabolic alkalosis, and suppressed renin and aldosterone should be carefully evaluated for the ingestion of licorice root. Glycyrrhizin in licorice inhibits 11-beta-hydroxysteroid dehydrogenase type 2, causing apparent mineralocorticoid excess.
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Topics

Medical History Evaluation

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