Cushing's syndrome: screening and diagnosis aspects
Corina Crista1, Anda Cismas2, Roxana Voicu3, Nagaraj Manjunath4, Maria Dana Bobu5 & Bogdan Alin Nes5
The diagnosis of Cushings syndrome, in the clinical practice, requires investigations necessary for distinguishing it from obesity with reactive hypercorticism and for differentiating its forms.
The study group was represented by 85 cases of hypercorticism (hospitalized in the Clinic of Endocrinology Timisoara during the period 20002009) divided in two groups: obesity with reactive hypercorticism (81.18%) respectively, Cushings syndrome with its forms (18.82%).
The medical history accompanied by the clinical examination is very important in revealing the clinical features of Cushings syndrome. Loss of circadian rhythm of cortisol is a sensitive screening test. The assessment of the basal plasma cortisol levels, in the study group, showed significant higher levels (P<0.01) in patients with Cushings syndrome in comparison to obesity with reactive hypercorticism. Low-dose (12 mg) overnight dexamethasone suppression tests are useful for Cushings syndrome screening (it was observed that there was no cortisol suppression in patients with Cushings syndrome in comparison to those with obesity with reactive hypercorticism (P<0.00001)); while, high-dose (8 mg) dexamethasone suppression tests helps in differentiating some Cushings syndrome forms (a lowering in the cortisol level over 50%, in patients with Cushings disease and no response in cases with Cushings syndrome caused by an adrenal adenoma/carcinoma P<0.01).
The patients with Cushings syndrome also presented a significant decreased values of the serum TSH (P<0.0001), FT4 (P<0.00001), FSH (P<0.01) and LH (P<0.00001) versus those with obesity.