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Cyclic Cushing's syndrome
1Department of Medicine IV, LMU University Hospital, LMU Munich, Munich, Germany.
Vitamins and Hormones
|June 3, 2026
Summary
Cyclic Cushing's syndrome (cCS) is a challenging endocrine disorder with fluctuating cortisol levels, leading to diagnostic delays. Recognizing these unpredictable cycles is key for accurate diagnosis and effective management of hypercortisolism.
Area of Science:
- Endocrinology
- Internal Medicine
- Hormone Research
Background:
- Physiological cortisol secretion follows a circadian rhythm.
- Endogenous Cushing's syndrome involves pathological cortisol excess and dysregulation.
- Cyclic Cushing's syndrome (cCS) is a subtype with alternating hypercortisolism and normal/low cortisol levels.
Purpose of the Study:
- To review the epidemiology, etiology, diagnostic approach, and management of cyclic Cushing's syndrome.
- To aid clinicians in recognizing and managing this complex, underdiagnosed disorder.
- To highlight the diagnostic challenges posed by fluctuating cortisol levels in cCS.
Main Methods:
- Serial hormonal profiling.
- Clinical correlation.
- Review of existing literature on cCS.
Main Results:
- cCS presents with unpredictable oscillations in cortisol concentrations, complicating diagnosis.
- Diagnostic procedures during eucortisolaemic phases can yield false-negative results.
- Delayed diagnosis is common due to inconsistent biochemical findings and fluctuating clinical features.
Conclusions:
- Recognition of cyclicity is essential for diagnosing cCS in patients with fluctuating Cushingoid features.
- Accurate diagnosis requires serial testing and careful clinical correlation.
- Management must account for temporal variability in cortisol excess, impacting diagnostic procedures and therapy timing.
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