Endocrine Abstracts

We present two patients with significant hypokalaemia initially attributed to liquorice use.

Case 1: A 52-year-old engineer was noted to have a potassium level of 2.5 mmol/l (3.5–5.3 mmol/l) at a Well Man check-up. He had no significant past history, and took no medications. He was normotensive. The patient reported regular liquorice use. The hypokalaemia corrected with supplementation equivalent to 48 mmol K⁺ daily, and with cessation of liquorice. Two months later, the hypokalaemia recurred (2.9 mmol/l). The patient reported that his mother also had low potassium levels. Further tests showed magnesium 0.66 mmol/l (0.70–1.00 mol/l), bicarbonate 37 mmol/l (22–29 mmol/l), plasma renin activity 11.5 nmol/l per h (0.5–3.5 nmol/l per h) and urine potassium excretion 177 mmol/24 h (25–125 mmol/24 h). The patient was referred to Clinical Genetics and found to be a compound heterozygote for mutations in the SLC12A3 gene, in keeping with Gitelman’s syndrome.

Case 2: A 72-year-old gentleman was referred to A&E with increased thirst and hypokalaemia of 2.8 mmol/l. He had suffered a cardiac arrest 5 months previously, when his potassium was 2.0 mmol/l. A defibrillator had since been implanted. His medications were amlodipine (for longstanding hypertension), atorvastatin, bisoprolol and warfarin. Hypernatraemia was noted, renin was undetectable, aldosterone within the normal range. The patient admitted to eating two bags daily of Pontefract cakes and Liquorice Allsorts. He agreed to stop. The hypokalaemia corrected with oral replacement, then spironolactone. Spironolactone was stopped once potassium reached the upper normal range. However, off spironolactone, potassium fell to 3.5 mmol/l. Renin remained undetectable, aldosterone increased above normal range. Imaging revealed a likely adrenal adenoma, suggesting Conn’s syndrome.

Discussion: Whilst liquorice may cause of hypokalaemia, it may also exacerbate hypokalemia due to other causes, thus bringing them to attention. Renin and aldosterone levels were useful in these cases – hyperaldosteronism in Gitelman’s is due to hyperreninaemia caused by volume contraction; liquorice results in pseudohyperaldosteronism with renin suppression.