Patients with different subtypes of Cushing’s syndrome (CS) have distinct plasma steroid profiles. This could be used as a test for diagnosis and classification, a German study says.
The study, “Plasma Steroid Metabolome for Diagnosis and Subtyping Patients with Cushing Syndrome,” appeared in the journal Clinical Chemistry.
A quick diagnosis of CS is crucial so that doctors can promptly give therapy. However, diagnosing CS is often complicated by the multiple tests necessary not just to diagnose the disease but also to determine its particular subtype.
Cortisol, which leads to CS when produced at high levels, is a steroid hormone. But while earlier studies were conducted to determine whether patients with different subtypes of CS had distinct steroid profiles, the methods researchers used were cumbersome and have been discontinued for routine use.
Recently, a technique called LC-MS/MS has emerged for multi-steroid profiling in patients with adrenocortical dysfunction such as congenital adrenal hyperplasia, adrenal insufficiency and primary aldosteronism.
Researchers at Germany’s Technische Universität in Dresden used that method to determine whether patients with the three main subtypes of CS (pituitary, ectopic and adrenal) showed differences in plasma steroid profiles. They measured levels of 15 steroids produced by the adrenal glands in single plasma samples collected from 84 patients with confirmed CS and 227 age-matched controls.
They found that CS patients saw huge increases in the plasma steroid levels of 11-deoxycortisol (289%), 21-deoxycortisol (150%), 11-deoxycorticosterone (133%), corticosterone (124%) and cortisol (122%), compared to patients without the disease.
Patients with the ectopic subtype had the biggest jumps in levels of these steroids. However, plasma 18-oxocortisol levels were particularly low in ectopic disease. Other steroids demonstrated considerable variation.
Patients with the adrenal subtype had the lowest concentration of dehydroepiandrosterone (DHEA) and DHEA-SO4, which are androgens. Patients with the ectopic and pituitary subtype had the lowest concentration of aldosterone.
Through the use of 10 selected steroids, patients with different subtypes of CS could be identified almost as closely as with other tests, including the salivary and urinary free cortisol test, the dexamethasone-suppressed cortisol test, and plasma adrenocorticotropin levels. The misclassification rate using steroid levels was 9.5 percent, compared to 5.8 percent in other tests.
“This study using simultaneous LC-MS/MS measurements of 15 adrenal steroids in plasma establishes distinct steroid metabolome profiles that might be useful as a test for CS,” the team concluded, adding that using LC-MS/MS is advantageous, as specimen preparation is simple and the entire panel takes 12 minutes to run. This means it could be offered as a single test for both identification and subtype classification.