Med-Surg II Exam 4: Metabolic & Endocrine/Parathyroid Disorders

Document Content and Description Below

Function of Parathyroid Hormone (PTH) - ANSWER -Raises the level of calcium in the blood -Decreases the level of blood phosphate -Partially antagonistic to calcitonin Calcium Homeostasis - ANSWER... -PTH secretion stimulated by fall in serum calcium -Calcium mobilized from bone -Increased renal absorption of calcium; decreased renal clearance of calcium -Increased calcium absorption in intestine -Calcitonin is released by the "C" cells (parafollicular cells in the thyroid gland) in response to small increases in plasma ionic calcium -It acts on the kidney and bones to restore the level of calcium to just below a normal set point which in turn inhibits secretion of the hormone. Hypoparathyroidism - ANSWER -Too little PTH -low serum calcium -high serum phosphate -RARE endocrine disorder -Three types: -Iatrogenic hypoparathyroidism -Idiopathic hypoparathyroidism -Hypomagnesemia-induced hypoparathyroidism Hyperparathyroidism - ANSWER Too much PTH -high serum calcium -low serum phosphate -Incidence increases dramatically after the age of 50 -2 - 4 times more common in women -Single adenoma occurs in 80% of patients with primary hyperparathyroidism. -Parathyroid carcinoma is etiology in < 1% -Bone (osteitis fibrosa cystica) -Excessive PTH levels increase bone resorption by decreasing osteoblastic activity and increasing ostoclastic activity -Releases calcium and phosphate into blood -Results in decreased bone density -Chronic hypercalcemia → calcium deposits on soft tissue -Caused by nonresponse to feedback of serum calcium Hyperparathyroidism Causes - ANSWER -Benign tumor in one parathyroid gland -parathyroid adenoma -parathyroid carcinoma -Congenital hyperplasia -Neck trauma or radiation -Vitamin D deficiency -Chronic kidney disease with hypocalcemia -Parathyroid hormone-secreting carcinomas of the lung, kidney, or GI tract Hyperparathyroidism Sx's - ANSWER Bones -Resorption of distal phalanges -Distal tapering of clavicles -"salt & pepper" appearance of skull -Bone cysts and brown tumors of the long bones Kidney (20%) -Renal stones (nephrolithiasis) -Diffuse deposition of calcium/phosphate complexes in the parenchyma (nephrocalcinosis) Other Sx's: -muscle weakness & easy fatigability -peptic ulcer disease -pancreatitis -hypertension -gout -anemia -depression Hyperparathyroidism Diagnostics - ANSWER -Presence of established -hypercalcaemia in more than one serum measurement -elevated immunoreactive PTH -Lab Studies -Serum calcium → increased in primary (90%) -Serum phosphate →decreased -Serum magnesium →Increased -Serum parathyroid hormone → increased -Vitamin D (calciferol) → variable -Urine cAMP → increased (80%) -Venous sampling of thyroid for blood PTH levels -Glucocortisoid Suppression Test -Radiology -X-rays (hands & skull) -CTs -US Glucocortisoid Suppression Test - ANSWER Hypercalcemia of non-parathyroid origin generally respond to the administration of prednisolone in a dose of 40-60 mg daily for 10 days by a decrease in serum calcium level -vitamin D intoxication -sarcoidosis -lymphoproliferative syndromes Hyperparathyroidism Treatment - ANSWER -Monitor cardiac and neurologic function -Injury prevention -Patient Education -Drug Therapy Hyperparathyroidism Drug Therapy - ANSWER -Diuretic and hydration therapy -Furosemide (Lasix) with large volumes of IV NS -if unsuccessful or contraindicated, oral phosphates inhibit bone resorption and interfere with calcium absorption. -Calcium chelators -Glucocorticoids (hematological malignant neoplasms) -Mithramycin -Inhibit bone resorption -Used in hematological and solid neoplasms causing hypercalcemia -Phosphate (used as a temporary measure during diagnostic workup) -Estrogen (decreases bone resorption and can be given to postmenopausal women with primary hyperparathyroidism Parathyroidectomy (resection) - ANSWER Surgical Tx of hyperparathyroidism -calcium levels must be near normal prior to surgery -same procedure as for thyroidectomy **MONITOR CALCIUM LEVELS POST-OP** Iatrogenic hypoparathyroidism - ANSWER -most common form of hypothyroidism -caused by removal of all parathyroid tissue during total thyroidectomy or deliberate surgical removal of parathyroid glands. Idiopathic hypoparathyroidism - ANSWER -May occur spontaneously -Genetic (autosomal recessive transmission) -Cause unknown, but autoimmune is suspected -May occur with other autoimmune disorders Hypomagnesemia-induced hypoparathyroidism - ANSWER Often seen in alcoholics and in patients with malabsorption syndromes, chronic kidney disease, and malnutrition. Hypoparathyroidism Assessment - ANSWER Patient history -Damage to parathyroid glands -Serious injury from car crash -Serious strangulation injury Monitor -Signs and symptoms of hypocalcemia -Tingling, numbness, muscle cramps, seizures, AMS, tetany. Hypoparathyroidism Causes - ANSWER -Vitamin D deficiency or calcium -decreased intestinal absorption -tissue resistance to Vitamin D -drugs (phenytoin, phenobarbital, & laxatives) -Excessive phosphate intake -Severe hypomagnesemia -Chronic renal failure Hypoparathyroidism Clinical Manifestations - ANSWER Neuromuscular -paresthesia -hyperventilation -adrenergic symptoms -convulsions -tetany (Chvostek Sign, Trousseau Sign) Cardiovascular -prolonged QT interval -resistance to digitalis -hypotension -refractory heart failure with cardiomegaly Other -dental manifestation (abnormal enamel formation with delayed or absent dental eruption) -malabsorption syndrome (steatorrhea) Hypoparathyroidism Diagnosis - ANSWER -EEG -Blood tests -Serum calcium → decreased -Serum phosphate → increased -Serum magnesium → decreased -Serum parathyroid hormone → decreased -Vitamin D (calciferol) → decreased -Urine cAMP → decreased -CT Hypoparathyroidism Tx - ANSWER Correction of: -hypocalcemia -vitamin D deficiency -hypomagnesemia [Show More]

Last updated: 1 year ago

Preview 1 out of 6 pages