Nursing 105

Essentials of Nursing Study Guide

• Signs and symptoms: polyuria; hypotension; weight loss; tachycardia; fatigue; irritability; lethargy; coma; nausea; vomiting; initially signs of hyperkalemia are dry flushed skin, dry mucus membranes, and hypokalemia after insulin administration • Treatment: rehydration usually with Normal Saline, which is given until glucose levels begin to fall; then IV is changed to D5W to avoid rebound hypoglycemia Diabetes insipidus is caused most often by too little ADH produced by the pituitary gland or occasionally by the inability of the kidneys to respond to ADH. Patients will excrete large amounts of extremely dilute urine (5 to 40 liters per day). They are at risk of serious complications as vascular volume quickly falls, serum osmolarity rises, and hyponatremia results. Also as serum osmolarity rises, patients become prone to thromboemboli. Diabetes insipidus is most often caused by tumors, injury of the pituitary gland, or cerebral death. • Risk factors: head injury; pituitary tumors; brain death; increased ICP • Signs and symptoms: include polyuria; signs of dehydration such as dry mucous membranes, poor skin turgor hypotension, tachycardia, and urine osmolarity; decreased (less than 200); urine specific gravity greater than 300; serum sodium greater than 147 mEq/L • Treatment: rapid rehydration with hypotonic saline to correct fluid losses; then replacement is tailored to urinary losses, exogenous vasopressin (DDAVP), and Chlorpropamide (stimulates ADH release) Syndrome of inappropriate secretion of anti-diuretic hormone (SIADH) is stimulated by increased plasma, decreased plasma volume as sensed by stretch receptors located in the left atrium and pulmonary vasculature, and decreased blood pressure as sensed by pressure receptors located in the carotid arteries. During these times, increased ADH release occurs, which causes the kidneys to conserve water. This extra water expands in the serum and decreases serum osmolarity and sodium levels. Decreased serum osmolarity causes water to move first into the extracellular space, then the intracellular spaces causing the brain to swell, which causes increased intracranial pressure. The increase in ECF causes an increase in aldosterone secretion, which further reduces serum sodium levels. Without prompt treatment, the patient will experience increased ICP due to cerebral edema and severe hyponatremia, which may be fatal. • Risk factors: oat cell carcinoma of the lung; carcinoma of the pancreas, duodenum, prostate, or thymus; some forms of leukemia; fear; pain or stress; head trauma; brain tumors; intracranial hemorrhage; meningitis; positive pressure ventilation (stimulates pressure receptors in the carotid sinus and aortic arch); medications such as Chlorpropamide, acetaminophen, morphine, amitriptyline, thiazide diuretics, and cancer chemotherapy drugs; SIADH causes serum and cellular fluid overload but not interstitial overload; can be seen by fingerprint edema (when a finger is pressed over the sternum a fingerprint will be left)

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