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Cushing’s syndrome

Background knowledge ๐Ÿง 

Definition

  • Cushing’s syndrome is a disorder caused by prolonged exposure to high levels of cortisol
  • Cortisol is a glucocorticoid hormone produced by the adrenal cortex
  • Can be ACTH-dependent or ACTH-independent
  • Most common cause is exogenous steroid use

Epidemiology

  • Rare condition, with an estimated incidence of 1-2 per 100,000 people per year
  • More common in females than males
  • Peak incidence occurs in adults aged 20-50 years
  • Endogenous Cushing’s syndrome is less common than exogenous

Aetiology and Pathophysiology

  • Exogenous: prolonged use of corticosteroid medications
  • Endogenous: ACTH-secreting pituitary adenoma (Cushing’s disease), ectopic ACTH secretion, adrenal adenomas or carcinomas
  • Pathophysiology: excess cortisol leads to increased gluconeogenesis, protein catabolism, and lipolysis
  • Results in characteristic physical and metabolic changes

Clinical Features ๐ŸŒก๏ธ

Symptoms

  • Weight gain (central obesity)
  • Facial rounding (moon face)
  • Muscle weakness
  • Fatigue
  • Depression or mood swings
  • Menstrual irregularities in women
  • Decreased libido

Signs

  • Cushingoid faces
  • Posterior neck fat pad
  • Central obesity
  • Purple striae on the abdomen and thighs
  • Thin skin and easy bruising
  • Proximal muscle weakness
  • Hypertension
  • Osteoporosis
  • Hyperglycemia
  • Hirsutism in women
  • Psychiatric disturbances (e.g., depression, anxiety)

Investigations ๐Ÿงช

Tests

  • 24-hour urinary free cortisol test
  • Dexamethasone suppression test (low-dose and high-dose)
  • Midnight salivary cortisol test
  • Plasma ACTH levels
  • MRI of the pituitary gland (if ACTH-dependent)
  • CT scan of the adrenal glands (if ACTH-independent)

Management ๐Ÿฅผ

Management

  • Surgical resection of the causative tumor (e.g., transsphenoidal surgery for pituitary adenomas)
  • Adrenalectomy for adrenal tumors
  • Radiotherapy (if surgery is not feasible or as adjunct therapy)
  • Pharmacological therapy (e.g., ketoconazole, metyrapone) to control cortisol production
  • Gradual tapering of exogenous steroids if iatrogenic
  • Management of complications (e.g., hypertension, diabetes)

Complications

  • Cardiovascular disease (e.g., hypertension, myocardial infarction)
  • Diabetes mellitus
  • Infections (due to immunosuppression)
  • Osteoporosis and fractures
  • Psychiatric disorders (e.g., depression, anxiety)
  • Venous thromboembolism
  • Adrenal insufficiency after treatment

Prognosis

  • Depends on the cause and successful treatment of the underlying condition
  • Prognosis generally good with appropriate management
  • Long-term follow-up necessary to monitor for recurrence or complications
  • Quality of life may improve significantly after treatment
  • Patient education on potential complications and lifestyle modifications is essential

Key Points

  • Cushing’s syndrome is caused by prolonged exposure to high levels of cortisol
  • Common features include central obesity, facial rounding, and skin changes
  • Diagnosis involves clinical evaluation and biochemical tests
  • Management includes surgical, medical, and supportive therapies
  • Early diagnosis and treatment are crucial to prevent complications

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