Cushing's and Addison's Flashcards
What is the function of the adrenal glands?
Produce hormones that react to stressors (illness/injury), regulate how fats, proteins and CHO are converted to energy, regulate BP, help control BG, and help control kidney function
Stress Response
metabolism
Blood Glucose, Blood Pressure
Kidney Function
What hormones are produced by the adrenal glands?
The 2 major hormones produced are cortisol and aldosterone; others are androgens and adrenaline
Where is adrenaline produced in the adrenals?
Adrenal Medulla
What is cortisol?
The “stress hormone”
Is secreted in higher levels in response to stress, and in normal release, it helps restore homeostasis after stress
What are some of the actions of cortisol?
Has many actions which may or may not be beneficial in excess ranging from immunosuppressive properties, to anti-inflammatory activity, to actions on BG and bone
What is the major mineralcorticoid secreted by the adrenals?
ALDOSTERONE
What controls aldosterone secretion? How is it’s release stimulated?
Secretion is mainly controlled by the RAAS; less so by potassium, then ACTH (decreasing importance)
It’s release is stimulated by: bp lowering, salt depletion, & CNS excitation
What is the main functions of aldosterone?
Helps maintain the right balance of salt and water while helping control BP
What are the actions of aldosterone and its result?
It maintains electrolyte (potassium, magnesium, sodium) and volume homeostasis
↑’s Na & H2O retention and K+ excretion in dct’s of kidney
Result: expanded plasma volume, elevated BP, hypokalemia
The adrenal are a ________ production site for ___________
Secondary site for androgen synthesis (primary site is the testes and ovaries)
What is the main androgen produced by the adrenal glands? When is it released?
Primarily DHEA (Dehydroepiandrosterone)
Release is increased with puberty, decreased with aging
What are androgens responsiblefor?
- Androgens help with bone density, sexual desire and function, sex and body maturation amongst others
What is cushing’s syndrome?
A disorder caused by persistent exposure to excessive glucocorticoids (exogenous or endogenous) – orally or body production
What is the primary cause of Cushings? The rate of incidence is highest in……
- Exogenous corticosteroid usage
- Women > Men
What is the etyiology of Cushings?
Cushings results from the effects of excess cortisol levels originating from:
- Endogenous overproduction
A. ACTH dependent; 80% (main)
… a benign pituitary tumour over-producing ACTH (Cushing’s Disease)
… by an ectopic ACTH source (e.g. non-pituitary tumour in the lungs – may or may not be cancerous)
B. ACTH independent; 20%
… by adrenal gland tumours
- Exogenous administration of corticosteroids
How is Cushings diagnosed?
Often difficult and delayed because it mimics other conditions
Based on clinical history and testing of HPA axis
Must know their medical history
A 2-step process if Cushing’s Syndrome is suspected:
- Establish if hypercortisolism is present
Urinary free cortisol
Midnight serum cortisol [ ] or salivary cortisol [ ]
Low-Dose dexamethasone suppression test - Establish the cause
High-dose dexamethasone suppression test
Plasma ACTH via radioimmunoassay
CRH stimulation test
Metyrapone stimulation test
Others…..
What are some clinical features of cushings?
Obesity/Weight Gain
Facial Plethora
Rounded Face/Buffalo Hump
Decreased Libidio
Thin Skin
Decreased linear growth in children
Menstrual Irregularity
HTN
Hirutism (excess hair growth)
Depression
Muscle Weakness
Osteosoporosis
Poor Skin Healing (Skin Ulcers)
(progressive obesity and skin changes, acne, straie, fatigue, erectile ndysfunction)
What are some signs that may help distinguish Cushings from obesity?
Protein wasting:
Thin skin
Unusual bruising
Muscle weakness
Suddenly appearing red striae
Children: decreased linear growth especially evident
What are the tx goals of Cushings?
Remove the source of hypercortisolism
Restore cortisol secretion to normal
Reverse clinical features
Prevent dependency on medications
What is the prognosis of cushings? When will sx resolve?
Left untreated –> high morbidity and mortality (5yr survival rate of 50%)
With appropriate tx, most signs and sx’s will resolve within 2-12 months (20yr survival rate of 87%)
Overall, what is the main purpose of treatment of Cushings?
Treatment is aimed at removing the cause
What is the tx of a pituitary adenoma? What may pt’s need afterwards? What if it fails?
Surgical (transphenoidal) resection
Patients may require glucocorticoid-replacement therapy post-surgery if there is HPA axis suppression
When patients are not cured by transsphenoidal resection, the following options are available:
a) repeat the transsphenoidal surgery
b) medication therapy
c) radiation therapy
d) bilateral adrenalectomy
What is the tx of adrenal tumours? Which has more favourable outcomes: adenomas and carcinomas? What if metasteses?
Surgical resection
Adenomas (benign) have a favorable outcome; carcinomas do not (malignant)
If there are metastases – can try radiation, chemotherapy
What is the tx of ectopic ACTH syndrome?
Multiple tumour sites often exist; therefore 10-30% are cured with surgical removal and remaining 70-90% require post-op medication
Hypercortisolism can be controlled with pharmacologic therapy
What is the tx of drug induced cushings syndrome?
Removal of the cause (tapering the medication)
When are medications used in Cushings?
Medications are used:
To ↓ cortisol levels pre-surgery
As adjunct tx after unsuccessful surgery or radiation
For non-resectable tumours
To help treat severe sx’s
What are examples of pharmacotx of Cushing’S?
- Steroidogenesis Inhibitors
- Ketoconazole
- Metyrapone
- Mitotane - Inhibitors of ACTH Secretion
- Pasireotide
MOA of ketoconazole in Cushing’s
Blocks the synthesis of cortisol in the adrenal gland via inhibition of 11 beta and 17 alpha hydroxylase
11 Beta –> 11-deoxycortisol - cortisol
17 Alpha –> progesteron –> 17 hydroxyprogesterone
What is the DOC for cushings?
Ketoconazole - effective and adverse effect profile not as bad as others
Why is ketoconazole the DOC for Cushings?
Effective and a/e profile not as bad as others