Biochemical and imaging evaluation of Cushing's syndrome.
The diagnosis and differential diagnosis of Cushing's syndrome remains a considerable challenge in clinical endocrinology. Investigation is a two-step process, involving first diagnosis followed by differential diagnosis. Traditionally diagnosis has relied upon urinary free cortisol (UFC) collection, low-dose dexamethasone-testing, and assessment of midnight cortisol. More recently, differentiation between mild disease and pseudo-Cushing's states has been achieved using dexamethasone-suppressed corticotropin releasing hormone (CRH) and desmopressin tests. Refinements of tests used for differential diagnosis have been made including optimized response criteria for ovine and human sequence CRH tests, desmopressin tests, GHBP-testing and testing with combinations of peptides. Despite improvements in these non-invasive tests use of inferior petrosal or cavernous sinus sampling is frequently required. Imaging is guided by biochemical assessment. MRI is the investigation of choice for Cushing's disease, but is often negative. Scintigraphic investigation using radionucleotide-labeled agonists for receptors commonly expressed by neuroendocrine tumors the investigation of occult ACTH-dependent disease remains disappointing. In this review we critically analyze the tests used for this most challenging of clinical conditions.
Newell-Price
J
J
Endocrine Unit, Division of Clinical Sciences, University of Sheffield, Northern General Hospital, Sheffield, UK.
Grossman
A
A
D000182:ACTH Syndrome, Ectopic / Q000150:complications / Q000175:diagnosis; D000236:Adenoma / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism; D000306:Adrenal Cortex Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000378:metabolism; D000818:Animals; D001127:Arginine Vasopressin; D002940:Circadian Rhythm; D003346:Corticotropin-Releasing Hormone; D003480:Cushing Syndrome / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism; D003894:Deamino Arginine Vasopressin; D003907:Dexamethasone; D003937:Diagnosis, Differential; D006801:Humans; D006854:Hydrocortisone / Q000097:blood / Q000652:urine; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D009842:Oligopeptides; D017591:Petrosal Sinus Sampling; D010911:Pituitary Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D011859:Radiography; D011877:Radionuclide Imaging; D012756:Sheep
D009842:Oligopeptides; C086184:hexarelin; D001127:Arginine Vasopressin; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D003894:Deamino Arginine Vasopressin; D006854:Hydrocortisone