[Pitfalls in the diagnosis of hypercortisolemia]

Cushing's syndrome (CS) is relatively rare disorder affecting 2-5 per million per year, although the issue of establishing the diagnosis of CS and differential diagnosis of the disease are a significant clinical problem. CS is usually the result of excessive exogenous glucocorticoids usage (iatrogenic CS), endogenous CS can be divided into ACTH-dependent and ACTH-independent. Regardless of its etiology, the most important steps in establishing the diagnosis of CS are taking careful history and examination. The symptoms with high discriminatory value are myopathy, reddish purple striae, easy bruising and plethora. Knowledge of the pathomechanisms leading to the development of CS symptoms, facilitates establishing the diagnosis and understanding the importance of early diagnosis. Although the sensitivity and specificity of laboratory test have increased and imaging techniques developed, establishing the diagnosis of CS is still a challenging problem in clinical practice. When choosing appropriate diagnostic test we should remember of both advantages and limitations of each of them. The increasing popularity of late night/midnight salivary cortisol measurement as a first line diagnostic test is observed, also urinary free cortisol measurement, 1mg dexamethasone overnight suppression test and midnight serum cortisol measurement are used in the initial testing for hypercortisolemia. Subclinical CS as well as cyclical or episodic CS may be challenging especially. Another diagnostic problem is differentiation between functional hypercortisolism (pseudo-Cushing's syndrome) and pathological hypercortisolism with organic changes (CS). Right and early diagnosis is of vital importance in patients with CS because of large extent of complications resulting from untreated hypercortisolemia. In the course of CS many different organs and systems can be affected, leading to increase in total morbidity and mortality.