5 - Endocrine Flashcards
The CRH/ACTH/Cortisol pathway (the HPA axis) is very important in the body’s response to stress.
Describe how the adrenal gland is involved in both the short term (acute) stress response and the long term stress response.
. In acute stress, the sympathetic nervous system activates the adrenal medulla, which secretes epi and norepi. These hormones induce: glycogen breakdown to glucose, increased BP, Increased RR, increased metabolic rate, altered blood flow distribution
In chronic (long term stress), CRH (corticotropin releasing hormone) is released from the hypothalamus and travels to the anterior pituitary. The pituitary then releases ACTH – travels thru bloodstream to adrenal cortex. The Adrenal cortex responds by releasing glucocorticoids and mineralocorticoids. Glucocorticoids lead to breakdown of proteins and fats to increase blood glucose levels, and alters immune response. Mineralocorticoids lead to sodium and water retention and thereby increase blood volume and blood pressure.
What are the 3 layers of the adrenal cortex? For each layer, describe the adrenal hormones it is responsible for producing and what their major actions are.
Zona Glonerulosa – mineralocorticoids – increase salt and water retention
Zona Fasciculata – glucocorticoids – elevate blood glucose, anti-inflammatory action
Zona Reticularis – adrenal androgens – male sex hormone characteristics
List the multiple physiologic effects that occur following administration of a glucocorticoid. What are the mechanisms of the anti-inflammatory response?
Glucocorticoids lead to breakdown of proteins and fats to increase blood glucose levels, and alters immune response. Anti-Inflamm effect: Inhibition of phospholipase A2 – which leads to decreased production of prostaglandins and leukotrienes.
You are caring for a patient who has been on chronic steroid therapy for an unrelenting autoimmune process. If this individual were to experience a significant physiologic stress – like a trauma or a surgery – he might have trouble mounting the appropriate stress response. Why is that? How do you address it medically?
Chronic steroid therapy creates a negative feedback loop that shuts down release of CRH and ACTH. If the steroid is withdrawn abruptly, and the patient becomes stressed – the normal physiologic release of CRH & ACTH is not released to the degree necessary to formulate an appropriate response. Can be managed medically thru the administration of hydrocortisone (which has both mineralocorticoid and glucocorticoid actions).
Which pharmacologic steroids are primarily glucocorticoid? Which are primarily mineralocorticoid?
Which provides both actions (I am looking for one specific drug here)?
Primarily Glucocorticoid – prednisone, methylprednisolone, triamcinolone, dexamethasone, betamethasone…..
Mineralocorticoid – fludrocortisone, aldosterone
Both - Hydrocortisone
What are the adverse effects of steroid therapy? What does it mean to have Cushingoid Effects? What are the characteristic stigmata?
Adverse effects: osteoporosis, cataracts, glaucoma, impaired growth, risk of gastric ulceration, fat redistribution, immune modulation (risk for opportunistic infections), hypertension, hyperkalemia, impaired wound healing, mood changes
Cushingoid effects: characteristic appearance/ sequelae of an individual with chronic steroid exposures: emotional changes, moon facies, osteoporosis, buffalo hump, obesity, thinning skin, abdominal striae, muscle weakness, purpura, skin ulcerations, hypertension
BB is a patient who has undergone a complete thyroidectomy for thyroid cancer. She is now completely dependent on thyroid hormone supplementation.
What are the physiologic effects of thyroid hormone?
Increased metabolic rate, increased cardiac output, growth, brain development, effects secretion of other hormones
BB is a patient who has undergone a complete thyroidectomy for thyroid cancer. She is now completely dependent on thyroid hormone supplementation.
What would happen if she were to quit taking her thyroid hormone?
Signs of hypothyroidism: (short term) slow heart beat, cold intolerance, slowing of metabolism, fatigue (longer term) dry coarse hair, puffy face, depression, dry skin, muscle aches, constipation, weight gain
BB is a patient who has undergone a complete thyroidectomy for thyroid cancer. She is now completely dependent on thyroid hormone supplementation.
If her dose of thyroid hormone were too low, what would you expect her TSH to be if you checked her level? What are some of the symptoms that she might experience?
TSH would be high. See above
BB is a patient who has undergone a complete thyroidectomy for thyroid cancer. She is now completely dependent on thyroid hormone supplementation.
On a particularly busy morning, BB got to work and couldn’t remember if she took her levothyroxine. Knowing it would be bad for her to miss a dose, she chose to take a pill. What signs and symptoms might she expect if her thyroid level got too high?
Sweating, rapid heartbeat, heat intolerance, irritability, nervousness, frequent bowel movements, tremor
BB is a patient who has undergone a complete thyroidectomy for thyroid cancer. She is now completely dependent on thyroid hormone supplementation.
What are the therapies that can be employed in the treatment of hyperthyroidism? How do they work?
Beta blockers, counters the cardiac effects of hyperthyroidism
Radioactive Iodine - destroys thyroid tissues
PTU or methimazole – prevent oxidation reaction required for iodination
Blockade of Hormone Release – Iodide
PY is a 54 yo woman who has experienced hot flashes and vaginal dryness associated with menopause. She states that these symptoms are interfering with her quality of life and requests hormonal therapy.
You decide to start her on estrogen replacement therapy. What are the different dose delivery formulations that are available to deliver estrogen?
Oral, sublingual, vaginal creams, patches
PY is a 54 yo woman who has experienced hot flashes and vaginal dryness associated with menopause. She states that these symptoms are interfering with her quality of life and requests hormonal therapy.
If she were just having the vaginal symptoms, which formulation might be preferable?
Vaginal cream
What are some potential concerns about the use of estrogens. Are there certain conditions that are contraindications for the use of estrogens?
Migraine with aura, personal history or strong family history of thromboembolic events, smoking
PY is a 54 yo woman who has experienced hot flashes and vaginal dryness associated with menopause. She states that these symptoms are interfering with her quality of life and requests hormonal therapy.
Why would it matter if PY had undergone hysterectomy?
If PY has an intact uterus, she would require progestin therapy in addition to estrogen therapy. If she had a hysterectomy, she would not.
