Endocrine System Supplemental Handouts - Part 1 PDF

12/10/2024 Endocrine System 1 Hormones Alter the function of the target tissue by interacting with chemical receptors located either on the cell membrane or in the interior of the cell. 2 1 ...

12/10/2024 Endocrine System 1 Hormones Alter the function of the target tissue by interacting with chemical receptors located either on the cell membrane or in the interior of the cell. 2 1  12/10/2024 3 Pituitary Gland Anterior Pituitary Gland Follicle Stimulating Hormone (FSH) Luteinizing Hormone (LH) Prolactin (PRL) Adrenocorticotropic Hormone (ACTH) – acts in the adrenal glands (imbalance can cause Addison’s Disease – hypoproduction/ Cushing’s Syndrome – hyperproduction) Thyroid-Stimulating Hormone (TSH) Growth Hormone (GH) *secretion of these hormones is controlled by releasing factors from the hypothalamus 4 2  12/10/2024 Pituitary Gland Posterior Pituitary Gland Vasopressin / Antidiuretic Hormone (ADH) – controls the excretion of water by the kidney Oxytocin - facilitates milk ejection during lactation and increases the force of uterine contractions during labor and delivery. *these hormones are produced/synthesized in the Hypothalamus and are stored in the Posterior Pituitary Gland for secretion 5 6 3  12/10/2024 Diseases related to Pituitary Gland Hypopituitarism Hypofunction of the pituitary gland Can be cause by problem in the: Pituitary Gland (due to head and neck radiation therapy, destruction due to trauma, tumor, vascular lesions) Hypothalamus 7 Diseases related to Anterior Pituitary Gland Oversecretion/Hypersecretion Cushing’s Syndrome (excess levels of ACTH) Acromegaly (excess levels of GH in adults) - enlargement of peripheral body parts and soft tissue, after the fusion of the epiphyseal plates has occurred, without increase in height Pituitary Gigantism (excess levels of GH before closure of epiphysial growth plates) 8 4  12/10/2024 Diseases related to Anterior Pituitary Gland Hyposecretion/Undersecretion Pituitary Dwarfism Panhypopituitarism (undersecretion of all hormones in APG) – causes shrinking of thyroid gland, adrenal cortex, gonads 9 Diseases related to Posterior Pituitary Gland Hyposecretion/Undersecretion Diabetes Insipidus (DI) abnormally large volumes of dilute urine are excreted and extreme thirst as a result of deficient production of vasopressin. Causes may include: following surgical treatment of a brain tumor, secondary to nonsurgical brain tumors, traumatic brain injury, infections of the nervous system, post hypophysectomy (removal of the pituitary), failure of renal tubules to respond to ADH. 10 5  12/10/2024 Diseases related to Posterior Pituitary Gland Hyposecretion/Undersecretion Diabetes Insipidus (DI) Central (due to head trauma, surgery, infection, inflammation, brain tumors, cerebral vascular disease, idiopathic) Nephrogenic (kidney injury, medications such as lithium, hypokalemia, and hypercalcemia) Dispogenic (defect in the hypothalamus and may be the result of damage to the pituitary gland from a head injury, surgery, infection, inflammatory process, or a tumor) Gestational 11 Diseases related to Posterior Pituitary Gland Hyposecretion/Undersecretion Diabetes Insipidus (DI) Clinical manifestations: Excessive Urination (>250 mL/hour) Low Urine Specific Gravity (1.001 to 1.005) Extreme Thirst (2-20 Liters/day) 12 6  12/10/2024 Diseases related to Posterior Pituitary Gland Hyposecretion/Undersecretion Diabetes Insipidus (DI) Assessment and Diagnostic Findings: Fluid Deprivation Test withholding fluids for 8 to 12 hours or until 3% to 5% of the body weight is lost Patient has inability to increase the specific gravity and osmolality of the urine (increased serum osmolality, elevated serum sodium, weight loss) test is terminated if tachycardia, excessive weight loss, or hypotension develops 13 Diseases related to Posterior Pituitary Gland Hyposecretion/Undersecretion Diabetes Insipidus (DI) Assessment and Diagnostic Findings: Measurement of plasma ADH Plasma and urine osmolality Trial of desmopressin therapy and IV infusion of hypertonic solution 14 7  12/10/2024 Diseases related to Posterior Pituitary Gland Hyposecretion/Undersecretion Diabetes Insipidus (DI) Medical Management ADH replacement therapy (long term) Adequate fluid replacement Identification of correct underlying cause (Nephrogenic causes will have different management approaches) 15 Diseases related to Posterior Pituitary Gland Hyposecretion/Undersecretion Diabetes Insipidus (DI) Medical Management Pharmacologic Therapy: Desmopressin synthetic ADH and drug of choice for DI (given orally or intranasal) can cause vasoconstriction – use cautiously for patients with Coronary Artery Disease Chlorpropamide and thiazide diuretics Used in mild forms of DI Can potentiate the action of vasopressin/ADH Use with caution due to high risk for hypoglycemia 16 8  12/10/2024 Diseases related to Posterior Pituitary Gland Hyposecretion/Undersecretion Diabetes Insipidus (DI) Medical Management Pharmacologic Therapy: For DI with renal origin (nephrogenic): Thiazide diuretics, mild salt depletion, and prostaglandin inhibitors (e.g., indomethacin and aspirin) are used 17 Diseases related to Posterior Pituitary Gland Hyposecretion/Undersecretion Diabetes Insipidus (DI) Nursing Management/Considerations Assessment Monitor for signs of dehydration (severe dehydration can lead to decreased cardiac output resulting to decreased perfusion of vital organs such as brain and kidney) Monitor V/S and I&O 18 9  12/10/2024 Diseases related to Posterior Pituitary Gland Hyposecretion/Undersecretion Diabetes Insipidus (DI) Nursing Management/Considerations Education Specific verbal and written instruction on how medicines should be given (dose, action, side effects, proper administration) Signs and symptoms of hyponatremia Demonstrate and observe return demonstration of medication administration (ensures that patient receives prescribed dose) 19 Diseases related to Posterior Pituitary Gland Hypersecretion Syndrome of Inappropriate Antidiuretic Hormone (SIADH) A condition wherein one cannot excrete a dilute urine, retain fluids, and develop a sodium deficiency known as dilutional hyponatremia. 20 10  12/10/2024 Diseases related to Posterior Pituitary Gland Hypersecretion Syndrome of Inappropriate Antidiuretic Hormone (SIADH) failure of the negative feedback system that regulates the release and inhibition of ADH which can be due to the following: Malignant cells or tumors in the body that synthesize and secrete ADH Disorders in the central nervous system that might have directly stimulated the pituitary gland (head injury, brain surgery, tumor, infection) Certain medications/substances that either directly stimulate the pituitary gland or increase the sensitivity of the kidneys to ADH (E.g. vincristine, phenothiazines, tricyclic antidepressants, thiazide diuretics, nicotine) 21 Diseases related to Posterior Pituitary Gland Hypersecretion Syndrome of Inappropriate Antidiuretic Hormone (SIADH) Medical Management Focused on eliminating the underlying cause (SIADH is generally self-limiting) Diuretic agent (E.g. Furosemide) with fluid restriction For severe hyponatremia, hypertonic NaCl (3%) may be prescribed and administered IV 22 11  12/10/2024 Diseases related to Posterior Pituitary Gland Hypersecretion Syndrome of Inappropriate Antidiuretic Hormone (SIADH) Nursing Considerations/Management: Close monitoring of fluid I&O, daily weight, urine and blood chemistries, and neurologic status 23 Thyroid Gland Largest endocrine gland Blood flow to the thyroid is very high (approx. 5x the blood flow of the liver) Produces 3 hormones: Thyroxine (T4) Triiodothyronine (T3) Calcitonin 24 12  12/10/2024 Thyroid Hormones T4 and T3 (amino acids that contain iodine molecules) Needed for metablosim Iodine is essential for the synthesis of these hormones, thus, iodine deficiency can cause alteration of thyroid function Iodide (from diet) is converted to iodine in the thyroid gland. Iodine + tyrosine (amino acid) = thyroid hormone Controlled by Hypothalamic-Pituitary-Thyroid Axis (works through negative feedback mechanism): Thyrotropin Releasing Hormone (TRH) from the Hypothalamus modulates TSH levels Thyroid Stimulating Hormone (TSH) or thyrotropin from the Anterior Pituitary Gland controls thyroid hormone secretion T4 - a relatively weak hormone, maintains body metabolism in a steady state T3 - about five times as potent as T4 and has a more rapid metabolic action Calcitonin (thyrocalcitonin) reduces plasma Calcium levels, secreted in response to high plasma levels of calcium by increasing deposition in the bone 25 26 13  12/10/2024 Hypothyroidism Congenital Hypothyroidism occurs when there is inadequate secretion of thyroid hormone during fetal and neonatal development results in intellectual disability and stunted physical growth because of general depression of metabolic activity Hypothyroidism (adult onset) manifests as lethargy, slow mentation, weight gain, constipation, cold intolerance, and generalized slowing of body functions 27 Hypothyroidism 28 14  12/10/2024 Hypothyroidism Clinical manifestations: 29 Hypothyroidism Myxedema coma a rare life-threatening condition and a decompensated state of severe hypothyroidism in which the patient is hypothermic and unconscious Clinical Manifestations patient may initially show signs of depression, diminished cognitive status, lethargy, and somnolence Increasing lethargy may progress to stupor. The patient’s respiratory drive is depressed, resulting in alveolar hypoventilation, progressive carbon dioxide retention, narcosis, and coma. Can also exhibit hyponatremia, hypoglycemia, hypoventilation, hypotension, bradycardia, and hypothermia, cardiovascular collapse and shock (require aggressive and intensive supportive and hemodynamic therapy) Causes: may develop with undiagnosed hypothyroidism and may be precipitated by infection or other systemic disease or by use of sedatives or opioid analgesic agents Forgot to take thyroid replacement medication 30 15  12/10/2024 Hypothyroidism Medical Management: Pharmacologic Therapy - Synthetic levothyroxine (drug of choice) Prevention of Cardiac Dysfunction Prolonged hypothyroidism is associated with elevated serum cholesterol, atherosclerosis, and coronary artery disease Angina or arrhythmias can occur when thyroid replacement is initiated because thyroid hormones enhance the cardiovascular effects of catecholamines. If this occurs, DISCONTINUE medication immediately 31 Hyperthyroidism a form of thyrotoxicosis resulting from an excessive synthesis and secretion of endogenous or exogenous thyroid hormones by the thyroid Clinical manifestations are related to a greatly increased metabolic rate and oxygen consumption: Patient may appear anxious, seem restless and irritable, and exhibit fine tremors of the hands. Cardiac manifestations: Tachycardic and complain of palpitations, arrhythmias (may be related to increased sensitivity to catecholamines) Heat intolerance with increased perspiration Increase in appetite, diarrhea, weight loss, and thin skin Exophthalmos (Graves Disease) and may exhibit reduced blinking and lid retraction 32 16  12/10/2024 Hyperthyroidism a form of thyrotoxicosis resulting from an excessive synthesis and secretion of endogenous or exogenous thyroid hormones by the thyroid Possible causes (Graves disease, toxic multinodular goiter, and toxic adenoma, thyroiditis or inflammation of the thyroid gland, and excessive ingestion of thyroid hormone) Usually associated with enlarged thyroid gland (Goiter) Goiter commonly occurs with iodine deficiency where lack of iodine causes low levels of circulating thyroid hormones. This results to increased release of TSH and causing overproduction of thyroglobulin (a precursor of T3 and T4) and hypertrophy of the thyroid gland 33 Hyperthyroidism Graves Disease autoimmune disorder that results from an excessive output of thyroid hormones caused by abnormal stimulation of the thyroid gland by circulating immunoglobulins. 34 17  12/10/2024 Hyperthyroidism: Management Pharmacologic Therapy 35 Hyperthyroidism: Management Adjunctive Therapy Potassium iodide (SSKI) may be used in combination with antithyroid agents (propylthiouracil) or beta-adrenergic blockers (propranolol) to prepare the patient with hyperthyroidism for surgery Surgical Management Surgery to remove thyroid tissue is reserved for special circumstances, for example, in pregnant women who are allergic to antithyroid medications, in patients with large goiters, or in patients who are unable to take antithyroid agents. 36 18