Cushings syndrome Flashcards
define cushings syndrome?
syndrome associated with chronic inappropriate elevation of free circulating cortisol
how can we categories the causes of cushings syndrome?
- ACTH Dependent
* ACTH Independent
what are ACTH dependent causes of cushings syndrome?
o Cushing’s disease: Excess ACTH from a pituitary adenoma
o Lung cancer, Ectopic ACTH
what are ACTH independent causes of cushings syndrome?
o Iatrogenic: steroids – MOST COMMON CAUSE
what is the epidemiology of cushings syndrome?
• Peak incidence 20-40 yrs
presenting symptoms of cushings?
- Increasing weight
- Fatigue
- Muscle weakness
- Myalgia (pain in muscles)
- Thin skin
- Easy bruising
- Poor wound healing
- Fractures
- Hirsuitism
- Acne
- Frontal balding
- Oligomenorrhoea/amenorrhoea
- Depression or psychosis
signs of cushings?
- Moon face
- Flushed face
- Interscapular fat pad
- Proximal muscle weakness
- Thin skin
- Bruises
- Central obesity
- Pink/purple striae on abdomen/breast/thighs
- Kyphosis (due to vertebral fracture)
- Poorly healing wounds
- Hirsuitism, acne, frontal balding
- Hypertension
- Ankle oedema (due to salt and water retention from the mineralocorticoid effect of excess cortisol)
- Pigmentation in ACTH dependent cases
what is the first line investigation for cushings syndrome?
o 24 hour urinary free cortisol
o Overnight dexamethasone suppression test
what might the blood show for cushings syndrome?
o U&Es - hypokalaemia due to mineralocorticoid effect
o BM - high glucose
o ABG – hypokalaemia metabolic alkalosis
how to localise the cause of the high cortisol?
we can use both a low does dex and a high dose dex test
what will a normal person show with
low dose dex
high dose dex
ACTH
↓
↓
↓
what will a adrenal adenoma person show with
low dose dex
high dose dex
ACTH
↔
↔
↓
what will a cushings disease person show with
low dose dex
high dose dex
ACTH
↔
↓
↑
what will a ectopic ACTH disease person show with
low dose dex
high dose dex
ACTH
↔
↔
↑
what extra tests might be used for adrenal adenomas?
• CT or MRI of adrenals
what extra tests might be used for pituitary adenomas?
- Pituitary MRI
* Inferior petrosal sinus sampling
what extra tests might be used for ectopic ACTH?
• If lung cancer suspected: CXR, sputum cytology, bronchoscopy, CT scan
management plan for iatrogenic cushings?
discontinue steroids, use lower dose or use a steroid-sparing agent
how to medically treat cushings?
o Inhibit cortisol synthesis with metyrapone or ketoconazole
o Treat osteoporosis
o Physiotherapy for muscle weakness
how to surgically treat cushings?
o Pituitary Adenomas - trans-sphenoidal adenoma resection
o Adrenal adenoma/carcinoma - surgical removal of tumour
o Ectopic ACTH - treatment directed at the tumour
complications of cushings syndrome?
- Diabetes
- Osteoporosis
- Hypertension
- Pre-disposition to infections
prognosis for cushings syndrome?
- Untreated - 5 yr survival = 50%
* Depression persists for many years following treatment
