From the Guidelines
Cushing's syndrome is characterized by a constellation of symptoms resulting from prolonged exposure to excessive cortisol, including weight gain, purple stretch marks, thin skin, hirsutism, acne, and metabolic disturbances such as high blood pressure and elevated blood sugar. The symptoms of Cushing's syndrome can be divided into several categories, including:
- Physical symptoms: weight gain, particularly in the face, trunk, and upper back, while the arms and legs remain thin, purple stretch marks (striae) on the abdomen, thighs, and breasts, thin, fragile skin that bruises easily, facial redness, excess facial hair in women (hirsutism), and acne.
- Metabolic disturbances: high blood pressure, elevated blood sugar (potentially leading to diabetes), muscle weakness, bone loss (osteoporosis), and increased susceptibility to infections.
- Psychological symptoms: depression, irritability, anxiety, and cognitive difficulties.
- Reproductive symptoms: menstrual irregularities and decreased fertility in women, and decreased libido and erectile dysfunction in men. These symptoms develop gradually and may be subtle at first, making diagnosis challenging 1. The underlying cause is excessive cortisol production, usually from a pituitary tumor (Cushing's disease), adrenal tumor, or prolonged use of corticosteroid medications 1. Early recognition is important as untreated Cushing's syndrome can lead to serious complications including heart disease, stroke, and blood clots 1. It is essential to note that the diagnosis and management of Cushing's syndrome require a comprehensive approach, including laboratory tests, imaging studies, and medical therapy, to optimize patient outcomes and minimize the risk of complications.
From the Research
Symptoms and Signs of Cushing's Syndrome
The symptoms and signs of Cushing's syndrome vary and can be related to the extent and duration of cortisol excess. Some common symptoms and signs include:
- Proximal muscle weakness
- Wide purple striae
- Hypertension
- Weight gain
- Cardiovascular disease
- Thromboembolic disease
- Psychiatric and cognitive deficits
- Infections 2
Biochemical Screening
Recommended tests to screen for Cushing's syndrome include:
- 1 mg dexamethasone suppression test
- Urine free cortisol
- Late night salivary cortisol 2, 3 These tests may be slightly elevated in patients with physiologic hypercortisolism, which should be excluded, along with exogenous glucocorticoid use.
Diagnostic Tests
Other diagnostic tests that may be used to diagnose Cushing's syndrome include:
- Overnight dexamethasone suppression test
- Low-dose dexamethasone suppression test
- Midnight serum cortisol
- Plasma ACTH measurement
- MRI scan of the pituitary
- Corticotrophin releasing hormone (CRH) test
- Bilateral petrosal sinus sampling 4, 5, 6
Pitfalls of Screening Tests
Each screening test has its own distinctive features and pitfalls, making it preferable in specific clinical conditions. For example, the overnight 1 mg dexamethasone suppression test and urinary free cortisol demonstrate high sensitivity and specificity for the diagnosis of Cushing's syndrome, but each test has its own limitations 3.