Adrenal Disorders Flashcards
In what way might excess cortisol cause diabetes insipidus?
It can result in increased muscle proteolysis and hepatic gluconeogenesis that may lead to hyperglycaemia with associated polyuria (urinated a lot) and polydipsia ( feeling thirsty a lot )
Why does someone with excess cortisol (Cushing’s syndrome) have a ‘moon-shaped’ face?
Because they have increase lipogenesis in adipose tissue leading to deposition of fat in face (and neck and abdomen)
Why would someone with Cushing’s syndrome have purple striae on their body and increased easy bruising?
Because the cortisol is having catabolic effects on protein structures in the skin (causing striae) and causes thinning of skin and subcutaneous tissue (leads to easy bruising)
Why might some with Cushing’s syndrome have back pain and collapsed ribs?
Due to osteoporosis caused by disturbances in calcium metabolism and loss of bone matrix protein
Many signs and symptoms of Cushing’s syndrome are seen in patients receiving long term treatments with glucocorticoids for various chronic inflammatory conditions. Give an example of such a drug.
Hydrocortisone
Prednisone
What is the difference between Cushing’s syndrome and Cushing’s disease?
Cushing’s syndrome refers to the general constellation of symptoms resulting from chronic excessive exposure to cortisol whereas
What can cause Addison’s disease?
- Disease of the adrenal cortex (auto-immune destruction)
2. Disorders in pituitary or hypothalamus that leads to decreased secretion of ACTH or CRH
What are the symptoms and signs of an Addisonian crisis?
- Insidious onset with initial non-specific symptoms: tiredness, extreme muscular weakness, anorexia, vague abdominal pain, weight loss and occasional dizziness
- Extreme muscular weakness and dehydration
- Increased skin pigmentation
- Decreased Blood pressure (Na+ and fluid depletion)
- Postural hypotension
- Hypoglycaemic episode (especially on fasting due to lack of glucocorticoid)
What are the clinical tests that can be done to investigate suspected adrenocortical diseases? (3)
- Plasma cortisol levels
- Plasma ACTH levels
- 24hr urinary excretion of cortisol and its products
What are the clinical investigations used in the differential diagnosis of adrenocortical diseases?
Dynamic function tests:
- Dexamethasone suppression test
- ACTH stimulation test
What is a dexamethasone suppression test?
The drug dexamethasone is given oral and should (by feedback inhibition) suppress the secretion of ACTH and therefore cortisol
What is a ACTH stimulation test?
Synacthen (a synthetic analogue of ACTH) is given intramuscularly and this should increase plasma cortisol levels
