Definition
The term “Cushing’s syndrome” is used to describe a condition resulting from long-term exposure to excessive cortisol (glucocorticoids). The term “Cushing’s disease” is reserved for Cushing’s syndrome which is caused by excessive secretion of adrenocorticotropin hormone (ACTH) by a pituitary tumor, usually an adenoma.
- Cushing’s disease is responsible for roughly two-thirds of the cases of endogenous Cushing’s syndrome. The remainder of the endogenous cases is caused by ectopic ACTH-secreting tumors and primary adrenal neoplasms.
- Cushing’s disease occurs most frequently in women of reproductive age, but it can affect males and females of any age.
- The pituitary tumors in Cushing’s disease are usually microadenomas, which, by definition, are 10 mm or less in diameter. Micro-adenomas generally do not cause symptoms by local mass effect. These tumors are most often discovered when clinical manifestations of hypercortisolism resulting from hypersecretion of ACTH prompt an appropriate diagnostic work-up. Occasionally, microadenomas are found incidentally during imaging performed for other reasons.
- Depression, obesity, alcoholism, medications, eating disorders and other conditions can cause mild clinical and laboratory findings, similar to those in Cushing’s syndrome, termed “pseudo Cushing’s syndrome.”
Signs and symptoms
- Sudden weight gain
- Central obesity
- Hypertension
- Proximal muscle weakness
- Glucose intolerance or diabetes mellitus
- Hyperlipidemia
- Decreased libido or impotence
- Menstrual disorders
- Depression or psychosis
- Facial plethora/reddish complexion
- Easy bruising
- Violaceous striae wider than 1 cm
- Acne
- Hirsutism
- Recurrent opportunistic or bacterial/fungal infections
- Osteopenia or osteoporosis
- In children, impaired growth
Causes
- ACTH dependent such as Cushing’s disease, Ectopic ACTH syndrome
- ACTH independent such as Iatrogenic, Adrenal adenoma
Tests/Labs
- Cortisol, Urinary Free (LabCorp TEST: 004432 CPT: 82530)// Normal values are less than 90 μg per 24 hours (250 nmol per day). Values more than 300 μg per day (830 nmol per day) are considered diagnostic for Cushing’s syndrome.
Treatment
- Transsphenoidal removal of the tumor is the treatment of choice for Cushing’s disease.
- Most patients are rendered hypoadrenal for months to years after the procedure. During this period, they require glucocorticoid replacement therapy.