Adrenal:Cushings Flashcards
(21 cards)
What is Cushing’s Syndrome?
Group of diseases characterised by prolonged HIGH levels of glucocorticoids (cortisol) in the body
What are common symptoms of Cushing’s Syndrome?
- ‘Round in the middle with thin limbs’
- Abdominal striae
- Enlarged fat pad on upper back
- Proximal limb muscle wasting
- Hirsutism
- Easy bruising and poor skin healing
- Skin hyperpigmentation (Cushing’s Disease)
What additional conditions may occur in Cushing’s Syndrome?
- Hypertension
- Cardiac hypertrophy
- Type 2 diabetes
- Dyslipidaemia
- Osteoporosis
- Adverse mental health issues (e.g., anxiety, depression, insomnia, psychosis)
What does ‘CAPE’ stand for in the causes of Cushing’s Syndrome?
- C - Cushing’s Disease
- A - Adrenal Adenoma
- P - Paraneoplastic syndrome
- E - Exogenous steroids
What is Cushing’s Disease?
Pituitary adenoma secreting excessive ACTH, stimulating excess cortisol
What is an adrenal adenoma?
Adrenal tumour secreting excessive cortisol
What is paraneoplastic syndrome in the context of Cushing’s Syndrome?
ACTH released from a tumour somewhere other than the pituitary gland, stimulating excessive cortisol
**Small Cells Lung Cancer **
What are the two classifications of ACTH levels in Cushing’s Syndrome?
- ACTH dependent = HIGH ACTH
- ACTH independent = Normal ACTH
What test is used to diagnose Cushing’s syndrome?
Dexamethasone Suppression Tests
What is the method for the low-dose overnight Dexamethasone test?
Method:
(1) Low-dose overnight test:
1. Give 1mg Dexamethasone at night (10/11pm)
2. Check morning cortisol at 9am
3. Failure to suppress cortisol calls for further investigation
(2) Low-dose 48hr test:
1. Give 0.5mg Dexamethasone every 6hrs for 8 doses
2. Measure cortisol at 9am on Day 1 and 9 am on Day 3
3. Faliure of dexamethasone to suppress cortisol on day 3 = Cushing’s Syndrome
(3) High-dose 48hr test:
1. Same method as low-dose 48hr but with 2mg Dexamethasone
2. Cushing’s Disease (pituitary adenoma) = cortisol suppression
3. Adrenal adenoma/ectopic ACTH = no cortisol suppression
What is the outcome of the dexamethasone supression test test in cases of Cushing’s Disease?
Pituitary Adenoma
Low dose test: High Cortisol
High dose test: LOW
What is the normal response to Dexamethasone in terms of cortisol levels?
- Dexamethasone causes an INCREASE in steroid hormones
- Negative feedback reduces CRH and ACTH
- Overall REDUCED Cortisol due to low CRH and ACTH
What does a lack of cortisol suppression in a dexamethasone test suggest?
Cushing’s syndrome
What are the pros and cons of the 24-hour urinary free cortisol test?
Pros: Measures cortisol levels
Cons: Logistically difficult + does not indicate a case with the Dexamethasone test
What blood tests are relevant for Cushing’s Syndrome?
- FBC (High WBCs)
- U&Es (low K+ with adrenal adenoma)
What imaging techniques are used to investigate Cushing’s Syndrome?
- MRI brain - pituitary adenoma
- CT chest - small cell lung cancer
- CT abdomen - adrenal tumour
What is the first step in the treatment of Cushing’s Syndrome?
Treat the underlying cause
* Pituitary adenoma - Trans-sphenoidal surgical removal
* Adrenal tumour - Surgical removal
* Ectopic ACTH Tumour - Surgical removal
What surgical procedure is performed for a pituitary adenoma?
Trans-sphenoidal surgical removal
What is adrenalectomy?
Removal of both adrenal glands when treating the underlying cause is not possible
What are the risks associated with adrenalectomy?
Nelson’s syndrome - ACTH-producing pituitary tumour develops after surgery due to loss of negative feedback
What is Metyrapone used for?
Drug which reduces the production of cortisol in the adrenals
