Apparent Mineralocorticoid Excess Syndrome: A Case of Resistant Hypertension From Licorice Tea Consumption

Apparent mineralocorticoid excess: comprehensive overview of molecular genetics

Apparent mineralocorticoid excess is an autosomal recessive form of monogenic disease characterized by juvenile resistant low-renin hypertension, marked hypokalemic alkalosis, low aldosterone levels, and high ratios of cortisol to cortisone metabolites. It is caused by defects in the HSD11B2 gene, encoding the enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), which is primarily involved in the peripheral conversion of cortisol to cortisone. To date, over 50 deleterious HSD11B2 mutations have been identified worldwide. Multiple molecular mechanisms function in the lowering of 11β-HSD2 activity, including damaging protein stability, lowered affinity for the substrate and cofactor, and disrupting the dimer interface. Genetic polymorphism, environmental factors as well as epigenetic modifications may also offer an implicit explanation for the molecular pathogenesis of AME. A precise diagnosis depends on genetic testing, which allows for early and specific management to avoid the morbidity and mortality from target organ damage. In this review, we provide insights into the molecular genetics of classic and non-classic apparent mineralocorticoid excess and aim to offer a comprehensive overview of this monogenic disease.

Licorice-induced apparent mineralocorticoid excess causing persistent hypertension and hypokalemia

Chronic ingestion of licorice is known to cause numerous metabolic and electrolyte disturbances. Severe hyponatremia, hypertension, and hypokalemia as well as metabolic alkalosis are amongst the most common consequences of chronic ingestion resulting in an apparent mineralocorticoid excess (AME). Treatment predominantly consists of cessation of licorice ingestion, potassium replenishment and aldosterone antagonists. Given the potentially lethal effects of chronic licorice ingestion, clinicians should be made aware of the presentation of AME and the proper management. We present the rare case of a 62-year-old male with licorice-induced apparent mineralocorticoid excess secondary to excessive licorice tea intake. Initial presentation included severe hypokalemia of 2.2mmol/L and hypertension of 180/110mmHg, while eunatremic (Na, 144meq/L).