Data

Copy and paste the text below. It is read-only. Select All

Magnesium Causes vasodilatation Decreases peripheral vascular resistance Balance - closely related to K and Ca balance Intracellular compartment electrolyte Hypomagnesemia - < 1.5 mEq/L Hypermagnesemia - > 2.5 mEq/L *chronic alcoholism* Hypomagnesemia Causes Acute pancreatitis, starvation, malabsorption syndrome, _______, burns, prolonged hyperalimentation without adequate Mg Hypoparathyroidism with hypocalcemia Diuretic therapy Signs/Symptoms hypomg Tremors, tetany, ↑ reflexes, paresthesias of feet and legs, convulsions Positive Babinski, Chvostek and Trousseau signs Personality changes with agitation, depression or confusion, hallucinations ECG changes (PVC'S, V-tach and V-fib Treatment hypomg Mild Diet - Best sources are unprocessed cereal grains, nuts, legumes, green leafy vegetables, dairy products, dried fruits, meat, fish Magnesium salts More severe MgSO4 IM MgSO4 IV slowly Calcium Approximately 99% found in bone, 1% found in extracellular fluid 50% free (active) ionized form (1-1.15 mmol/L) 40% bound to protein (predominantly albumin) 10% complexed with anions (eg, citrate) Intracellular calcium regulates cAMP - mediated messenger systems and most cell organelle functions Ion pumps control lvels Extracellular levels maintained at 8.7-10.4 mg/dL Total body levels controlled by complex feedback system PTH directly targets bone and kidneys to increase serum calcium levels Indirectly, through vitamin D, PTH causes intestinal calcium absorption Vitamin D directly targets GI absorption of calcium to increase calcium levels Calcitonin lowers calcium by targeting bone, renal, and GI losses Hypercalcemia 90% due to hyperparathyroidism or malignancy All etiologies due to a combination of increased bone resorption, increased GI absorption, and decreased renal excretion Primary hyperparathyroidism mostly commonly due to adenoma; occasionally due to parathyroid hyperplasia; rarely due to parathyroid carcinoma Hypocalcemia Paresthesias, tetany (especially carpopedal spasm) Lethargy, confusion, seizures Trousseau's sign (carpal spasm occurring after the occlusion of the brachial artery with a blood pressure cuff for three minutes) Chvostek's sign (contraction of the facial muscle in response to tapping the facial nerve anterior to the ear) QT prolongation Severe, symptomatic _______ may result in cardiovascular collapse, hypotension unresponsive to fluids & vasopressors, and dysrhythmias Clinically evident _____ generally presents in milder forms and is usually the result of a chronic disease state PhosphorusFunctions of phosphorus The major intracellular negatively charged electrolyte Required for fluid balance Critical role in bone formation (85% of body's phosphorus is found in bone) Regulates biochemical pathways by activating or deactivating enzymes Found in ATP, DNA, RNA Recommended intake RDA for ____ is 700 mg/day Sources of ____ Found widespread in many foods Found in high amounts in foods that contain protein (e.g., meat, milk, eggs) What if you consume too much ___? High blood levels of ____ can occur with kidney disease or when taking too many vitamin D supplements Causes muscle spasms, convulsions What if you don't consume enough ___? Deficiencies of ___ are rare Seen in severe alcoholism Iodine -body normally has 20-30 mg of ___ and more than 75% is in the thyroid gland -the rest is in the mammary gland, gastric mucosa, and blood -it's only function is related to thyroid hormone Required for synthesis of thyroid hormone Thyroxine (T4) - 4 atoms of__ per molecule Triiodothyronine (T3) - 3 atoms of__ per molecule bile Absorption and Excretion -iodine is absorbed in the form of iodide -occurs both as free and protein-bound iodine in circulation -iodine is stored in the thyroid where it is used for the synthesis of T3 and T4 -the hormone is degraded in target cells and in the liver and the iodine is conserved if needed -excretion is primarily via urine -small amts from ___are excreted in the feces Deficiency iodine goiter—enlargement of the thyroid gland -deficiency may be absolute—in areas of deficiency, or relative—adolescence, pregnancy, lactation -goiters are more prevalent in women and with increased age cretinism -goitrogens occurring naturally in foods can cause goiter by blocking absorption or utilization of iodine (cabbage, turnips, peanuts, soybeans) -***severe deficiency during gestation and early postnatal growth: ______ —mental deficiency, spastic diplegia, quadriplegia, deaf mutism, dysarthria, shuffling gait, short stature, hypothyroidism Iodine _________deficiency is the most common nutrient deficiency in the world! Paradoxical goiter Iodine Excess and Toxicity Humans are remarkably tolerant to high iodine intakes In iodine deficiency, repletion must be done slowly to prevent hyperthyroidism _______(enlarged thyroid as a result of very high intakes of iodine) Occurs in Japan and China with high intake of seaweed (50,000 - 80,000 mg/day) -iodine has wide margin of safety Selenium deficiency Goiter Endemic to parts of S. America and India Sporadic cases in U.S. ___________ (needed to convert T4 to T3 ceruloplasmin Copper Metabolism Intestinal absorption/membrane translocation mediated by specific transporters Copper circulates bound to _____ Relative tissue distribution of copper reflects levels of cuproenzymes Excretion occurs via transport of copper into bile and elimination in feces Copper: Biochemical Functions Essential catalytic cofactor for many cuproenzymes Hypochromic microcytic anemia Neutropenia Hypopigmentation of hair and skin Structural abnormalities in connective tissue (hair, teeth, bone demineralization, vascular system with arterial aneurysms with risk of hemorrhage and thrombosis) Fetal and neonatal deprivation leads to neurologic dysfunction Reduced levels of circulating copper and ceruloplasmin Copper Physiology/Deficiency Acquired deficiency is rare. Causes include: Omission from TPN High intake of Zinc Renal dialysis patients Use of copper chelating agents (penicillamine) Manifestations: __________________- Food Sources copper organ meats, seafood, nuts, seeds, cereals, whole grains, cocoa Chromium--Functions -required for normal lipid and CHO metabolism and for the fxn of insulin -?can supplementation raise HDL Deficiency chromium altered CHO metabolism, impaired glucose tolerance, glycosuria, fasting hyperglycemia, increased insulin levels and decreased insulin binding -impaired growth, peripheral neuropathy, negative nitrogen balance -increased chromium losses in stress -hyperglycemia and wt loss reverse with IV supplementation in TPN chromium toxicity -chronic renal failure Cobalt most stored with vitamin B12 -component of B12—cobalamin -essential for maturation of RBC's and normal function of all cells Absorption and Excretion cobalt -shared with Fe -absorption is increased in pts with deficient Fe intake, portal cirrhosis with Fe overload, and hemochromatosis -excretion is mainly thru the urine -small amts in feces, hair, sweat animal foods such as organ and muscle meat Sources and Intakes cobalt -microorganisms are able to synthesize B12 -***humans must obtain B12 and cobalt from _______________ -***takes a long time to become deficient—happens in vegetarians *macrocytic anemia* Deficiency cobalt -related to vit B12 deficiency -**_______- -genetic defect: pernicious anemia -tx: massive doses Toxicity cobalt polycythemia -hyperplasia of BM -reticulocytosis -increased blood volume Selenium glutathione peroxidase -acts with other antioxidants and free radical scavengers -overlaps with vit E for antioxidant effects -fxn with vit E to protect cell and organelle membranes from oxidative damage Selenium Deficiency Diseases Major problem in livestock Human deficiency is rare except in areas with low Se content in soil Keshan disease occurs in Keshan China: endemic cardiomyopathy and muscle weakness (due to oxidized lipids) Aggressive supplementation has eliminated disease Iatrogenic deficiency TPN without supplemental Se Selenium Toxicity Range of dietary Se intake without toxicity is narrow Acute selenium poisoning can result in cardiorespiratory collapse (gram amounts) Chronic toxicity (selenosis) changes in nail structure and loss of hair (intakes ~6x UL) Hair and nail brittleness Selenium and Cancer Prevention Epidemiologic evidence indicates low intakes of Se are associated with higher risk of prostate cancer Prospective study of Se supplementation demonstrated 42% reduction in cancer incidence Small sample size and other confounding factors have diminished enthusiasm for the results of these studies Molybendum -relationship with copper and sulfate -cofactor of many enzymes involved in the catabolism of sulfur AA, purines and pyridines -Toxicity: gout-like syndrome, reproductive SE's -Deficiency: increased risk with co-existing copper deficiency, TPN Normal: 136-145 mEq/L or mmol/L Critical values: Na < 125 Na >160 Na level is major determinant of osmolality Serum osmolality _____________-2 x Na + BUN/3 + glucose/18; you calculate this -Usually in range of 280-290 It is driven by sodium Severe acute hyponatremia (<120 over <24 Hours): cerebral edema Hyponatremia: symptoms Most patients are asymptomatic Symptoms usually occur with [Na+] < 125 Nausea, vomiting, headache Seizures, coma, respiratory arrest ____________________ copper reduced in wilsons (ring in eye)