Bone mineral density at diagnosis and following successful treatment of pediatric Cushing's disease

Abstract

Bone mineral density (BMD) is frequently reduced in children and adolescents with Cushing's disease (CD), but there is little follow-up data after cure. BMD was determined by dual energy X-ray absorptiometry (DEXA) in two groups of patients with CD. Group 1 comprised 8 patients, 5 males and 3 females, aged 12.4 yr (8.2-16.8), assessed at diagnosis. Group 2 comprised 11 subjects, 6 males and 5 females, diagnosed at age 13.3 yr (6.4-17.4), cured by transsphenoidal surgery (TSS) (no.=7) or TSS + pituitary irradiation (no.=4). They had measurement of BMD, at mean age of 18.3 yr (11.1-28.5), i.e. 4.5 yr (0.8-11.4) after cure. Four patients, mean age 20.2 yr (17.6-22.4), had repeated DEXA'scans, 1-4 times, for up to 5.8 yr. After cure, GH deficiency was present in 9 patients and treated with hGH in 8. In Group 1, patients' L2-L4 volumetric (v)BMD Z-score was variable with a mean of -1.04 (-3.21-0.11). L2-L4 vBMD Z-score values correlated negatively with midnight cortisol (p < 0.05). In Group 2, mean L2-L4 vBMD was -0.38 (-1.0-0.13); and in 7/11, mean femoral neck (FN) areal (a)BMD Z-score was 0.14 (-1.62-2.46). FN aBMD Z-score was higher than L2-L4 aBMD Z-score (p < 0.05). In patients with repeated scans, mean change in L2-L4 vBMD Z-score was 0.20 (-0.15-0.45), and mean change in FN aBMD Z-score 0.03 (-0.53-0.38). These findings show variability of BMD at diagnosis and near normal BMD after cure of pediatric CD, suggesting that with appropriate replacement of pituitary hormone deficiency normal peak bone mass is achievable.