Investigation for Paediatric Cushing's Syndrome Using Twenty-Four-Hour Urinary Free Cortisol Determination.
OBJECTIVE
Paediatric Cushing's syndrome (CS) remains a challenge to diagnose and exclude. We assessed the accuracy of 24-hour urinary free cortisol (UFC) determination in children referred for suspected CS.


METHODS
We conducted a retrospective study of paediatric patients referred to our centre with suspected CS between 1982 and 2014.


METHODS
Of 66 subjects (mean age 12.9 years; range 4.4-16.9), there were 47 cases of CS (29 males), which included Cushing's disease (CD; 39 patients, 25 males), primary pigmented nodular adrenocortical disease (8 patients, 4 males) and 19 'controls' (6 males) in whom the diagnosis of CS was excluded.


METHODS
The subjects had between one and five 24-hour UFC collections analysed by radioimmunoassay, chemiluminescent immunoassay or liquid chromatography-mass spectrometry. The data were normalised, corrected for body surface area (m2) and assessed using receiver operating characteristic analysis and an independent two-tailed t test.


RESULTS
The diagnostic accuracy of 24-hour UFC for CS was excellent (area under the curve 0.98, 95% CI 0.946-1.00, sensitivity 89%, specificity 100%).


CONCLUSIONS
Twenty-four-hour UFC is a reliable and practical investigation with high diagnostic accuracy for paediatric CS. However, further investigations may be required if the UFC is normal but there is a high diagnostic suspicion of CS.
Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Lucy
L
Shapiro
Shezan
S
Elahi
Fiona
F
Riddoch
Leslie A
LA
Perry
Lee
L
Martin
Scott A
SA
Akker
John P
JP
Monson
William M
WM
Drake
Ashley B
AB
Grossman
Martin O
MO
Savage
Helen L
HL
Storr
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003480:Cushing Syndrome / Q000175:diagnosis / Q000652:urine*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000652:urine*; D008297:Male; D012189:Retrospective Studies
D006854:Hydrocortisone