title: Cushing's syndrome: a practical approach to diagnosis and differential diagnoses.
abstract: Diagnosis of Cushing's syndrome (CS) and identification of the aetiology of hypercortisolism can be challenging. The Endocrine Society clinical practice guidelines recommends one of the four tests for initial screening of CS, namely, urinary-free cortisol, late night salivary cortisol, overnight dexamethasone suppression test or a longer low-dose dexamethasone suppression test, for 48 hours. Confirmation and localisation of CS requires additional biochemical and radiological tests. Radiological evaluation involves different imaging modalities including MRI with or without different radio-nuclear imaging techniques. Invasive testing such as bilateral inferior petrosal sinus sampling may be necessary in some patients for accurate localisation of the cause for hypercortisolism. This best practice review discusses a practical approach for the diagnostic evaluation of CS with a brief discussion on differential diagnoses, and cyclical CS, to enhance the skills of clinicians and laboratory personnel.
authors.affiliation: Department of Endocrinology & Diabetes, New Cross Hospital, The Royal Wolverhampton Hospitals NHS Trust, Wolverhampton, UK.
authors.forename: Joseph M
authors.identifier: http://orcid.org/0000-0003-0886-5255
authors.initials: JM
authors.lastname: Pappachan
authors.affiliation: Department of Endocrinology & Diabetes, New Cross Hospital, The Royal Wolverhampton Hospitals NHS Trust, Wolverhampton, UK.
authors.forename: Christian
authors.initials: C
authors.lastname: Hariman
authors.affiliation: Department of Endocrinology & Diabetes, Imperial College London Diabetes Centre, Abu Dhabi, UAE.
authors.forename: Mahamood
authors.initials: M
authors.lastname: Edavalath
authors.affiliation: Department of Clinical Biochemistry, University Hospitals of North Midlands NHS Trust, Stoke-on-Trent, UK.
authors.forename: Julian
authors.initials: J
authors.lastname: Waldron
authors.affiliation: Department of Endocrinology & Diabetes, University Hospitals of North Midlands NHS Trust & North Staffordshire University, Stoke-on-Trent, UK.
authors.forename: Fahmy W
authors.initials: FW
authors.lastname: Hanna
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D047748:Pituitary ACTH Hypersecretion / Q000175:diagnosis*; D017410:Practice Guidelines as Topic
keywords: ADRENAL GLAND; ENDOCRINE PATHOLOGY; PITUITARY; diagnostic screening