Cushing’s disease

Excessive cortisol due to an ACTH secreting tumour. In children, Cushing’s syndrome usually due to steroid treatment.

Manifests as dramatic weight gain, usually with angry striae, growth arrest (in terms of height), change in facial appearance, buffalo hump, hypertension.

These findings are hard to spot given that obesity with striae (and hypertension) in children common. Main clue is height centile below mean (and below MPH). Delayed bone age also a clue, as both of these things tend to be above normal in obese children.

Investigation is tricky as pituitary adenomas are not always seen on MRI and petrosal sinus sampling for cortisol is sometimes required! Even exclusion is tricky, requiring 24hr urinary cortisol collection over 3 days, low dose dexamethasone suppression testing.

CRH test done as part of work up, to see if ACTH is ectopic, which is exceptionally rare. Increased response to CRH test is almost diagnostic for Cushing’s though! High dose dexamethasone suppression rarely done.