11-beta-hydroxysteroid-dehydrogenase type 2 deficiency (11bHSD2) or syndrome of apparent mineralocorticoid excess is an autosomal recessive condition that characteristically presents with hypokalaemia and hypertension. In this condition, cortisol is not inactivated to cortisone and thus the excess cortisol cross reacts with the mineralocorticoid receptors in the kidney leading to hypertension, hypokalaemia and suppressed plasma renin activity (PRA) and aldosterone levels. The diagnosis and treatment options in a 15 year old girl were reviewed and adjusted. She was born at 37+5 weeks gestation to Pakistani parents with a low birth weight of 1.54 kg. At 2 years of age, hypokalaemia was noted during routine investigations. Given the family history of 11bHSD2 she had a urine steroid profile which showed a high urinary cortisol:cortisone ratio suggestive of 11bHSD, along with a suppressed PRA (0.4 pmol/ml per hr) and aldosterone (<55 pmol/l). Treatment was commenced on spironolactone, amiloride, amlodipine and oral potassium to control the blood pressure and hypokalaemia. At 13 years she represented to endocrine services with a height of 0.19 SDS, weight −1.53 SDS, and BMI −2.44 SDS. She has bilateral hearing loss and dry cracked skin on the heels. Further investigations revealed nephrocalcinosis and elevated ambulatory blood pressures (daytime and nighttime averages of 126/83 and 125/72 respectively). Thus she would be at risk of end stage renal disease and these individuals may require a renal transplant. Treatment was then changed to low dose dexamethasone 0.5 mg at night suppress the endogenous cortisol in the kidney and thus aiming for measurable PRA and aldosterone levels. This resulted in improved electrolyte control and successful stopping of other medications and weaning of potassium supplements. Remarkably it also improved her life long dry cracked heels. Education about steroid stress dosing for illness was provided. Repeat ambulatory blood pressure will dictate whether she is a candidate for the addition of a mineralocorticoid receptor antagonist. Despite the elevated cortisol levels, individuals with 11bHSD deficiency typically have a low birth weight, and low BMI along with hypokalaemia and hypertension. This is an important and treatable cause for hypertension and consideration should be given to instituting dexamethasone to suppress the endogenous steroids.
22 - 24 Nov 2017
British Society for Paediatric Endocrinology and Diabetes