Cushing’s disease

Findings and pathogenesis

Body habitus

  • Central obesity: fat accumulation centrally on neck, chest & abdomen
  • Accumulation of fat
    – in bitemporal region (moon facies)
    – between scapula (buffalo hump)
    – in supraclavicular region (a “collar” around the neck)
    – in front of sternum (“dewlap”)
  • Due to an increase in visceral fat and NOT subcutaneous fat

Hypertension

  • Due to suppressed vasodepressor system and activation of RAAS
  • Most DO NOT have positive salt and water balance

Skin findings

  • Thin skin
    – Corticosteroid induced inhibition of epidermal cell division and dermal collagen synthesis
    – To assess thin skin, measure skinfold thickness on the back of patient’s hand. Measure it using calipers. Normally in women should be >1.8mm, cutoff for men has not been established.
  • Acne
    – Increased adrenal androgens
  • Plethora
  • Striae
    – Not understood, maybe due to actual rupture of the weakened connective tissue of skin, under tension from central obesity
  • Ecchymoses
  • Hirsutism
    – Increased adrenal androgens

Muscular finding

  • Proximal myopathy

Psychiatric findings

  • Depression, difficulty with memory, suicidal attempts

Pseudocushing’s sndrome

  • Chronic alcoholism (due to overproduction of ACTH by hypothalamic-pituitary axis)
    – Physical + biochemical findings
  • HIV infection (especially on protease inhibitors)
    – Physical findings

Which findings are the most accurate?

  • Thin skin
  • Ecchymoses
  • Central obesity

Etiology of Cushing’s syndrome and bedside findings

  • Ectopic ACTH syndrome: rapid onset (months) and more prominent LOW
  • Presence of virilization eg baldness, deep voice, clitoromegaly (not hirsutism) argue strongly for adrenocortical carcinoma in females.

Reference:

Steven mcgee. Evidence Based Physical Diagnosis. Chapter 12; 109-118

 

 

 

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