Cushing's Syndrome Flashcards
Define Cushing’s syndrome
Chronic elevation of free circulating cortisol
What are the causes/risk factors of Cushing’s syndrome?
• Exogenous steroid use
ACTH dependent
• Cushing’s disease – excess
ACTH from pituitary adenoma
• Ectopic ACTH e.g. small cell lung carcinoma, pulmonary carcinoid tumours
ACTH independent
• Adrenal hyperplasia/adenoma/carcinoma – excess cortisol
What are the symptoms of Cushing’s syndrome?
- Increasing weight
- Fatigue
- Muscle weakness
- Myalgia
- Thin skin
- Easy bruising
- Poor wound healing
- Fractures
- Hirsutism
- Acne
- Frontal balding
- Oligo-/amenorrhoea
- Decreased libido
- Depression/psychosis
What are the signs of Cushing’s syndrome?
- Facial plethora
- Facial fullness/rounding
- Interscapular fat pad
- Proximal myopathy
- Thin skin
- Bruises
- Central obesity
- Purple striae
- Kyphosis – premature osteoporosis and fractures
Mineralocorticoid effect
• Hypertension
• Ankle oedema
Glucose intolerance/diabetes
What investigations are carried out for Cushing’s syndrome?
• Urinary free cortisol – elevated
• Late night salivary cortisol –elevated
• Dexamethasone suppression test
- LDDST – 0.5mg every 6h for 48h, >50nmol/L (failure of suppression)
- HDDST – 2mg every 6h for 48h, suppression <50% suggests pituitary origin,
no suppression suggests other causes of Cushing’s syndrome
• Inferior petrosal sinus sampling – elevated central:peripheral ACTH ratio suggests
pituitary origin
• Plasma ACTH
- >4pmol/L = pituitary/ectopic
- <1pmol/L = adrenal
• Adrenal CT/MRI
• MRI brain
• CXR/bronchoscopy/CT
What is the management for Cushing’s syndrome?
Iatrogenic
• Discontinue steroids
• Lower steroid dose
• Use steroid sparing agents
Medical
• Metyrapone
• Ketoconazole
Surgical • Transsphenoidal resection • Adrenal tumour resection/unilateral adrenalectomy • Ectopic tumour resection or therapy or bilateral adrenalectomy
What are the complications of Cushing’s syndrome?
- Diabetes
- Osteoporosis
- Hypertension
- ↑ susceptibility to infection