14. Glucocorticoid deficiency and overproduction, Addison's and Chusing's Flashcards
(43 cards)
What are the physiological causes of glucocorticoid excess?
- Stress,
- pregnancy,
- prolonged and intensive physical activity
What are some pathological causes of glucocorticoid excess?
- Iatrogenic Cushing’s syndrome,
- Cushing’s syndrome
What are some complications of Cushing’s syndrome?
- Cardiovascular (MI, HT, hypokalemia),
- Neuropsychiatric (depression, anxiety),
- Metabolic (diabetes, hepatic steatosis, obesity),
- Reproductive (infertility)
- Skin (skin thinning, poor wound healing)
- Thromboembolic
- Muskuloskeletal (osteoporosis, myopathy)
What is the prevalence of Cushing’s disease? At what age does it usually occur? M/F ratio?
The prevalence is 39/million. It can occur at any age, but it is most frequent between 25-45 years. The female/male ratio is 3-4/1.
What is the prevalence of ACTH-dependent forms of endogenous Cushing’s syndrome in adulthood?
70%
What is the most common form of ACTH dependant Cushing syndrome?
Pituitary adenoma (aka Cushing’s disease)
What is the prevalence of adrenal tumours in endogenous Cushing’s syndrome?
23%
What are the most common concomitant disorders in patients with Cushing’s?
- High blood pressure
- Hyperglycemia
- Osteoporosis
What are the main signs to differenciate between Cushing’s syndrome and simple obesity?
- Skin thinning, easy bruising
- Myopathy
What are the laboratory tests used for the diagnosis of cortisol excess in Cushing’s syndrome?
- Urinary free cortisol,
- midnight serum cortisol,
- midnight salivary cortisol,
- low dose dexamethasone suppression test.
What is the interpretation in the short (overnight) dexamethasone test?
Normal if < 1,8 microg/dl (<50 nmol/l).
What are the different forms of dexamethasone suppression test?
- Once (midnight, short, overnight)
- Repeated (two days, standard, long test / liddle test)
What are the different doses of dexamethasone used in the short dexamethasone suppression test?
Low-dose: 1 mg,
High-dose: 8 mg,
What are the laboratory tests used for the differential diagnosis of ACTH-dependent hypercortisolism?
- Basal ACTH,
- high-dose dexamethasone suppression test,
- CRH test.
What does a high dose decamethasone suppression test tell us?
It tells us wether the problem is from the pituitary (Cushing’s disease) or a different site in the body (ectopic)
What is the difference in the progression of Cushing’s disease and ectopic ACTH syndrome?
- Cushing’s disease has a slow progression
- Ectopic ACTH syndrome has a rapid progression, with myopathy and hyperpigmentation
How is the serum ACTH in Cushing’s disease and in ectopic ACTH syndrome?
- Cushing’s : normal / elevated
- Ectopic : high / very high
Which of the 2 types of Cushing’s syndrome can be suppressed in dexmethasone testing?
Cushing’s disease can be suppressed (aka invisible) in high dose testing
What is inferior petrosal sinus sampling?
Sampling the ACTH levels directly from veins that drain the pituitary to then compare with peripheral blood levels
What is the treatment for ACTH-producing pituitary adenoma in Cushing’s syndrome?
- Surgical intervention with transsphenoidal adenomectomy
- Drugs : inhibition of ACTH secretion or steroid biosynthesis inhibitors
- Pituitary radiation
- Bilateral adrenalectomia
What is the medical treatment for inhibiting ACTH secretion?
- Carbergoline : D2 agonist
- Pasireotide : somatostatin analog
What are some steroid synthesis inhibitors used in the treatment of ACTH producing pituitary adenomas?
- Etomidate
- Metyrapone
- Osilodrostat
What is the potential complication of pituitary irradiation?
Panhypopituitarism.
What are some of the known ectopic tumors that can produce ACTH?
- Bronchial tumors,
- Pheochromocytoma,
- Gastrinoma,
- Other neuroendocrine tumours
