Lecture on Cushing Syndrome and Cushing's Disease

Introduction

• Cushing Syndrome vs. Cushing's Disease: Part of clinical medicine
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Definitions

• Cushing Syndrome: Primary hypercortisolism
  • Problem with adrenal gland (adrenal cortex)
  • Hyperfunctioning leading to excess cortisol
  • Feedback loop suppression (low ACTH, high cortisol)
• Cushing's Disease: Secondary hypercortisolism
  • Pituitary gland problem
  • Excess ACTH causing high cortisol

Causes

Cushing Syndrome

• Hyperfunctioning Adrenal Cortex: Often due to adrenal adenoma
• Exogenous Steroid Use: Mimics cortisol effects
  • Common in autoimmune diseases

Cushing's Disease and Ectopic ACTH Production

• Pituitary Problem: Often a pituitary microadenoma
  • Produces excess ACTH
• Ectopic ACTH Production
  • Often due to tumors such as small cell lung cancer
  • Produces hormones outside usual glands

Symptoms and Pathophysiology

• Common Symptoms: Fat redistribution leading to buffalo hump, moon face, trunk obesity
• Skin Changes: Striae and atrophy due to proteolysis
• Cushing's Disease Specific
  • Hyperpigmentation due to increased melanocyte activity
  • Masulinization in females due to elevated androgens
• Complications
  • Secondary hypertension due to increased vascular resistance
  • Diabetes mellitus exacerbation
  • Osteoporosis and pathological fractures
  • Immunosuppression leading to infections (e.g., fungal infections like candidiasis)
  • Psychological effects like agitation and psychosis

Diagnostic Workup

• Tests for High Cortisol
  • 24-hour urinary cortisol
  • Low-dose dexamethasone test
  • Late-night salivary cortisol
• ACTH Level Testing
  • Determines if problem is pituitary, ectopic, or adrenal
  • CRH stimulation test or high-dose dexamethasone test to differentiate source
• Imaging
  • Pituitary MRI for pituitary microadenoma
  • CT/PET scan for ectopic tumors

Treatment

Cushing Syndrome

• Steroid Taper: If due to exogenous steroids
• Ketoconazole: Suppresses cortisol synthesis
  • Used to reduce cortisol levels if surgical treatment is not an option
• Surgical: Adrenalectomy for adrenal adenoma

Cushing's Disease

• Ketoconazole: Temporarily suppresses cortisol
• Surgical: Transsphenoidal resection for pituitary tumor
• Cancer Treatment: Chemotherapy/radiation for small cell lung cancer

Conclusion

• Key Findings: Fat redistribution, skin changes, risk of hypertension, osteoporosis, and infections

• Diagnostic Strategy: Multistep testing to confirm diagnosis

• Treatment: Depends on underlying cause and involves medical and sometimes surgical interventions

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