What are the main action of the thyroid gland? What are the 2 active hormones?
- Stimulation of energy use, heart, and promotion of growth and development.
- Triiodothyronine (T3)-- synthetic T3 is liothyronine.
- Thyroxine T4 tetraiodothyronine-- Synthetic T4 is levothyroxine.
Regulation of thyroid function?
Hypothyroidism? diseases? Clinical Manifestations? Causes? treatment?
- Severe deficiency of thyroid hormone.
- Myxedema (adults): rare but serious from persistently low thyroid production by ilness/rapid withdrawal of thyroid medication/surgery.
- TX: levothyroxine (synthroid), glucose and corticosteroids.
- Cretinism (infants).
- CM: weight gain, cold and dry skin, lethargy and fatigue, intolerance to cold, brittle hair or loos of hair.
- Causes: Malfunction of the thyroid, Hashimoto's disease-chronic autoimmune thyroiditis, insufficient iodine in the diet, surgical removal of the thyroid and destruction of thyroid with radioactive iodine. (in adults) insufficient secretion of TSH and TRH.
- TX: Therapeutic strategy and lifelong replacement therapy (levothyroxine (T4) and Liothyronine (T3)).
hypothyroidism in lifespan issues? pregnancy and infants?
- Pregnancy: in frist trimester can result in permanent neuropsychologic deficits in the child.
- Infants: may be permanent or transient, can cause retardation and derangement of growth.
Levothyroxine (synthroid)? half-life? TU? AE? checks? DI?
- it is the synthetic preparation of thyroxine (T4) and drug of choice for hypothyroidism.
- Conversion to T3.
- Half-life: 7days.
- TU: hypothyroidism. Should be taken on empty stomach in the morning at least 30 mins before breakfast.
- AE: Tachycardia, angina, tremors, can intensify effects of warfarin.
- Checks: T3, T4, and TSH for therapeutic levels.
- DI: drugs that reduce or accelerate the absorption, Warfarin, catecholamines.
Forms of hyperthyroidism?
- Grave's disease
- Toxic diffuse goiter or plummer's disease.
- Thyrotoxic crisis (thyroid storm)
Grave's disease? CM? TX?
- Most common form of hyperthyroidism.
- affects women 20-40 yrs.
- Causes exophthalmos (abnormal protrusion of the eyeball or eyeball)
- CM: tachycardia, dysrhythmia, angina, appetite increased, weight loss.
- TX: surgical removal of thyroid tissue, destruction of thyroid tissue with radioactive iodine, methimazole or propylthiouracil.
What is thyrotoxicosis? exophthalmos?
- Another name for hyperthyroidism.
- Abnormal protrussion of the eyeball or eyeballs.
Toxic diffuse goiter or plummer's disease?
- Similar clinical manifestations as Grave's disease.
- Treatment is similar to Grave's disease.
Thyrotoxic Crisis (thyroid storm) CM?
- Major surgery or severe intercurrent illness.
- CM: Profound hyperthermia, Tachycardia, restless, agitation, tremor.
- TX: potassium iodise, PTU, beta blocker, sedation, cooling, glucocorticoids, IV fluids.
- *Could infect WCB.
AE: agranulocytosis (deficiency of granulocytes), hypothyroidism, pregnancy and lactation.
Radioactive Iodine-131? Half-life? TX? TU? Candidates? MOA?
- Radioactive isotope of stable iodine, emits gamma and beta rays.
- HL: 8 days.
- TX: 2-3 months for full effect.
- TU: used in Grave's disease.
- Candidates: Pts over the age of 30.
- MOA: produces clinical remission with destruction of thyroid gland.
Nonractive Iodine? TU? AE? DON'T NEED TO KNOW IT.
- Strong iodine solution (lug's solution).
- TU: used to suppress thyroid function in preparation for thyroidectomy.
What do the adrenal cortex hormones affect?
- Maintenance of glucose availability.
- Regulation of water and electrolyte balance.
- Development of sex characteristics.
- Life-preserving response to stress.
What are the classes of steroid hormones from the adrenal cortex?
What are 2 most familiar forms of adrenocortical dysfunction?
- Crusing's syndrome: adrenal hormone excess.
- Addison's disease: adrenal hormone deficiency.
Negative feedback regulation of glucocorticoids synthesis and secretion.
What do mineralocorticoids do? example.
- Influence renal processing of sodium, potassium, and hydrogen.
- EX: aldosterone.
- Promotes sodium and potassium hemostasis.
- Maintains intravascular volume.
- Harmful cardiovascular effects with high levels.
- Regulated by RAAS.
- Minimal physiological effect at normal levels.
- In excess (congenital adrenal hyperplasia) --> excess of the androgens, sex characteristics in early age (kind of a rare thing) most of the time is a tumor growth.
- Responsible for how we look like.
Cushing's syndrome? causes? CM? TX?
- Adrenal hormone excess.
- Causes: hypersecrition of ACTH (adrenocorticotropic hormone) or/and glucocorticoids.
- Administering glucocorticoids in large doses.
- CM: Obesity.
- hyperglycemia, hypernatremia (electrolyte probs), HTN.
- Hypokalemia, hypocalcemia.
- TX: Carcinoma/adenoma: surgical removal of adrenal gland.
- replacement therapy with glucocorticoids and mineralocorticoids -- for Bilateral adrenalectomy.
- Drugs are adjunct for surgical treatment.
- beta blockers (to calm them down).
- * This is the main reason why glucocorticoids should start high and slowly go down.
Primary huperaldosteronism? Causes? TX?
- Excessive secretion of aldosterone.
- Causes: Hypokalemia (low potassium), metabolic alkalosis, HTN.
- TX: surgery or aldosterone antagonist (spironolactone).
- *Aldosterone keeps homeostasis b/t potassium (hypokalemia) and sodium (hyponatremia)
Addison's disease? CM and causes? TX?
- Adrenal hormone insufficiency (primary adrenocortical insufficiency).
- CM and causes: weakness and hypotension.
- Hypoglycemia, hyponatremia, hypotension.
- Hyperkalemia, hypercalcemis.
- Increased pigmentation of skin and mucous membranes.
- TX: Replacement therapy with adrenocorticoids.
- Hydrocortisone is the drug of choice. Both glucocorticoids and mineralcorticoids.
Acute adrenal insufficiency (adrenal crisis)? CM? Causes? TX?
- It is when they are not producing adrenal hormones at all.
- CM: hypotension, dehydration, weakness, lethargy, GI symptoms (vomiting and diarrhea).
- Causes: adrenal failure, pituitary failure, inadequate doses of corticosteroid or abrupt withdrawal.
- TX: rapid replacement of fluid, salt, and glucocorticoids (hydrocortisone).
- Glucose: normal saline with dextrose bc of the hypoglycemia.
What are the glucocorticoids employed for 2nd and 3th adrenocortical insufficiency? TU?
- -SONE suffix.
- Hydrocortisone, dexamethasone, prednisone.
- TU: Five entire rose at bedtime (high level during sleep, peak at waking time).
- Doses for endocrine disorder are much smaller than for nonendocrine disorders.
- Increase dosage in time of stress.
Hydrocortisone? TU? AE?
- Synthetic steroid w structure identical to cortisol (it could be considered as a glucocorticoid).
- TU: adrenal insufficiency, allergic rxn to inflammation, and Cancer.
- AE: Adrenal suppression, and cushing's disease.
Fludrocortisone (florinef)? TU? AE?
- Potent mineralocorticoid.
- TU: addison's disease, primary hypoaldosteronism, congenital adrenal hyperplasia.
- AE: HTN, edema, Cardiac enlargement, hypokalemia (low potassium).
- Synthetic steroid, primarily glucocorticoids properties; very little mineralcorticoid activity.
- Overnight dexamethasone test to diagnose cushing's syndrome.