Cushing Syndrome Overview

What is Cushing Syndrome?

• Defined as chronic glucocorticoid excess, whatever the cause
• Symptoms and physical features are present

Causes

• ACTH-dependent
  • Pituitary adenoma (Cushing disease)
  • Non pituitary neoplasm (ectopic ACTH)
• ACTH-independent
  • Iatrogenic (glucocorticoid, megestrol acetate)
  • Adrenal neoplasm (adenoma, carcinoma)
  • Nodular adrenal hyperplasia
    • Primary pigmented nodular adrenal disease (PPNAD)
    • Massive macronodular adrenal hyperplasia
    • Food dependent (GIP mediated)
    • Factitious

Prevalence

• ACTH dependent types of Cushing’s:
  • Chronic ACTH hypersecretion,
  • Results in hyperplasia of the adrenal zonae fasciculata and reticularis and, therefore, increased secretion of cortisol and androgens.
• ACTH-independent Cushing syndrome:
  • Caused by a primary adrenal neoplasm (adenoma or carcinoma) or nodular adrenal hyperplasia.
  • The cortisol excess suppresses pituitary ACTH secretion.
• Clinical Features of Cushing’s disease:
  • Can be present for years before diagnosis

Clinical Features of Cushing’s disease:

• Facial Appearance:
  • Round plethoric complexion
  • Acne and hirsutism,
  • Thinning of scalp hair.
• Weight Gain:
  • Truncal obesity, buffalo hump, supraclavicular fat pads.
• Skin:
  • Thin and fragile due to loss of subcutaneous tissue
  • Purple striae on abdomen, breasts, thighs, axillae
  • Easy bruising
  • Tinea versicolor
  • Occasionally pigmentation due to ACTH.
• Proximal muscle weakness.
• Mood disturbance:
  • Labile, depression, insomnia, psychosis.
• Menstrual disturbance.
• Low libido and impotence.
• Venous thromboembolism: High incidence.
• Mortality: Overall mortality greater than of general population.
• Growth arrest: in children.

Associated Features:

• Hypertension: >50% due to mineralocorticoid effects of cortisol
• Impaired glucose tolerance/diabetes mellitus (30%).
• Osteopenia and osteoporosis (leading to fractures of spine and ribs).
• Vascular disease: due to metabolic syndrome.
• Susceptibility to infections.

Diagnosis

• Confirm clinical suspicion with biochemical studies
• General assessment of the patient regarding:
  • Other illnesses
  • Drugs and alcohol
  • Psychiatric problems

Laboratory findings

• CBC show:
  • High normal hemoglobin, hematocrit, and red cell counts are usual; polycythemia is rare.
  • The total white count is usually normal; however, both the percentage of lymphocytes and the total lymphocyte count may be subnormal.

This quiz provides an in-depth look at Cushing Syndrome, defined as chronic glucocorticoid excess regardless of the cause. You will explore the various causes, including ACTH-dependent and ACTH-independent types, as well as their prevalence and related symptoms. Test your knowledge about this complex endocrine disorder!