Endocrine Flashcards
What is the preferred method of thyroid replacement therapy?
Levothyroxine (T4) Don’t forget, T4 is a prohormone. T3 is the active hormone.
Liothyronine is what?
T3 replacement
Liotrix is what?
Combination treatment of thyroid replacement.
Primary hypothyroidism is a result of what?
Problem with the thyroid gland itself
In primary hypothyroidism, what are the levels of TSH and T3, T4 like?
High TSH levels, low T3 and T4
Secondary hypothyroidism is a result of what?
Problem with the pituitary gland – decreased levels of TSH as a result.
What is the third way one can have hypothyroidism?
Hypothalamus doesn’t secrete enough TRH.
When do pts treated with T4 usually improve?
2 weeks (complete recovery can take months for severe cases)
When are steady state TSH concentrations achieved in thyroid replacement therapy?
at least 6 weeks
Thyroid preparations increase the metabolism of _______.
VItamin K-dependent clotting factors.
True or false: mineral supplements can bind with thyroid replacement therapy agents and hinder absorption.
True.
True or False: Thyroid preparations require an alkaline gastirc pH for optimal absorption.
False. They require normal gastric acid secretion, so PPIs affect absorption.
True or false: oral hypoglycemic agents may need adjustment when taking thyroid preparations.
True
What is the most common presentation of hyperthyroidism? What are the levels of TSH, T3, and T4 like?
Grave’s disease. Low TSH, high T3, T4
Diarrhea, flushing, increased appetite, muscle weakness, fatigue, irritability, heart palpitations… clinical manifestations of what??
Hyperthyroidism
Popythiouracil (PTU) and Methimazole are agents for the treatment of what?
They are anti-thyroid drugs for the treatment of hyperthyroidism. They work by inhibiting the incorporation of iodine into the thyroid hormones.
PTU has the added ability to do what?
Inhibit the conversion of T4 into T3 in peripheral circulation.
Warfarin, beta blockers, digoxin, and theophylline are the drug-drug interactions for what?
Anti-thyroid drugs
Parathyroid glands maintain adequate levels of what two things?
Calcium and phosphorus
Elevated levels of PTH cause changes in the function of renal cells, bone cells, and GI tract mucosa. This leads to what electrolyte abnormality and results in what disease?
Hypercalcemia. Also, bone breakdown is increased. This is from HYPERPARATHYROIDISM.
Secondary hyperparathyroidism is associated with what?
Low calcium; calcium or vitamin D deficiency, chronic kidney disease.
True or false: Vitamin D is a prohormone.
True (1,25 dihydroxy vitamin D is the active form)
What is an analog of fat-soluble vitamin D?
1,25 dihydroxy vitamin D (the active form, also known as calcitrol)
What is the preferred vitamin D analog for daily supplementation?
Cholecalciferol (vitamin D3). Considered 2-3x more potent than ergocalciferol (vitamin D2).
What other drug may be used to supplement vitamin D therapies?
Thiazide diuretics (work on DCT to decrease calcium excretion in urine)
What hormones are secreted by the posterior pituitary?
Vasopressin and Oxytocin.
Insufficient secretion of vasopressin leads to _______, while oversecretion leads to ________.
diabetes insipidus, SIADH.
What hormone can only be given in parenteral formulations?
Vasopressin
What drug increases plasma levels of von Willebrand factor, factor VIII, and tPA, contributing to a shortened bleeding time and aPTT? (good news for hemophiliacs!)
Desmopressin
Primary nocturnal enuresis and diabetes insipidus (as well as hemophilia) are treated with what?
Desmopressin
What does the adrenal cortex secrete?
Aldosterone and cortisol
What does the adrenal medulla secrete?
epinephrine and norepinephrine
Glucose metabolism (stimulating gluconeogensis), lipolysis, and fetal development, as well as potent inflammatory and immunosuppressive properties, are a result of what?
Glucocorticoids.
Increased appetite, insomnia, mood alterations, stress ulcers, acne, hypertension, and hyperglycemia
Short term adverse effects from systemic corticosteroid use
Cushing’s syndrome, immunosuppression, adrenal suppression, delayed wound healing, growth suppression, osteoporosis
Long Term adverse effects from systemic corticosteroid use
True or false: Corticosteroids should be taken in the morning without food.
False: morning WITH food.
Pts at high risk for infection, hypertension, heart failure, and renal failure should avoid what drug?
Corticosteroids.
When is adrenal suppression (suppression of HPA axis) with corticosteroids a threat?
When they are administered longer than 2 weeks.
What drug has an adverse effect of hypokalemia and is used to replace aldosterone?
Fludrocortisone
What drug competitively inhibits aldosterone leading to less potassium loss in the urine?
Aldosterone antagonists
What does aldosterone do?
Acts in collecting ducts and induces expression of Na/K exchangers. Na enters tubular cells, K is lost in the urine.
