Normal cortisol response to high dose Synacthen and insulin tolerance test in children and adults with Prader--Willi syndrome (PWS)
Stense Farholt1, Rasmus Sode-Carlsen1, Jens Sandahl Christiansen2, John Rosendahl Østergaard1 & Charlotte Høybye3
Objective: PWS is associated with hypogonadism and partial GH insufficiency. In addition partial insufficiency of the hypothalamicpituitaryadrenal (HPA) axis recently was suggested (de Lind van Wijngaarden 2008) based upon an insufficient response to an overnight single-dose metyrapone in 15 out of 25 (60%) children. We aimed at further exploring this potentially dangerous condition.
Methods: During a 1-year period genetically verified PWS patients were consecutively enrolled. Twenty-nine women and 22 men, median age 22 years (range 0.544 years) and median BMI 22.6 kg/m2 (range 13.642.7 kg/m2), were examined with a standard high dose Synacthen test (HST). Two women and 6 men, median age 26 years (range 1636 years) and median BMI 30.1 kg/m2 (range 22.753.0 kg/m2), were examined with a standard insulin tolerance test (ITT). Two out of these 8 persons were also tested using the HST. Children admitted to our department with acute illness had a spot cortisol measured.
Results: The HST median cortisol was 179 nmol/l (range 581020 nmol/l) at t0 min, and was 698 nmol/l (range 4741578 nmol/l) at t30 min. Three had a cortisol level <550 nmol/l at t30 min, and one of them even <500 nmol/l. In the latter the ITT peak cortisol was 583 nmol/l.
The ITT median cortisol was 188 nmol/l (range 175281 nmol/l) at t0 min, and was 668 nmol/l (range 502822 nmol/l) at t30 min.
Three children aged 0.424 years were admitted to the acute ward. Two had febrile illness, and one had a first episode of status asthmaticus. The spot cortisol were 1372, 775 and 1080 nmol/l, respectively.
Conclusion: In this cohort of 57 children and adults with PWS we were not able to confirm an increased risk of central adrenal insufficiency. Clinically significant insufficiency of the HPA axis in PWS is rare.