5 5 meqliter normal hyperkalemia increased plasma k

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ce from tumors • Treatment – often just water restriction – may prescribe intake of salt Sodium Sodium • Regulated along with water – it is the major ion regulating plasma volume and, therefore, total fluid volume • 135-145 mEq/liter = normal Other Electrolytes Other • K+, Ca++, Mg++ – All three ions affect neuromuscular function • explains major side effects when imbalance occurs Normal Ion Distribution Normal Potassium Potassium 3.5-5 mEq/liter = normal • Hyperkalemia (increased plasma K+) – causes: • • • • decreased aldosterone renal failure cellular damage (burns, crushing, etc.) metabolic acidosis (causes K+ shift from cells) – symptoms: • decreased neuromuscular function – weakness, abdominal distention, diarrhea • A-V block, cardiac arrest – Note: mental function usually remains normal although mental confusion is possible – treatment: • calcium, sodium bicarbonate, dextrose plus insulin – all move K+ into cells; • resins work more slowly. Hypokalemia Hypokalemia + Decreased plasma K+ • causes: – decreased K+ intake • starvation or intestinal blockage – increased G.I. loss • vomiting, diarrhea – metabolic alkalosis • causes K+ shift into cell and • K+ secretion due to H+ unavailability – increased aldosterone secretion Hypokalemia Decreased plasma K+ • symptoms: – decreased neuromuscular function • muscle cramps,jitteriness • decreased ventilation and small muscle function – increased HR, impaired conduction (fibrillation) • Note: mental function usually remains normal • treatment: – Oral intake preferred unless an emergency – Parenteral -- usually use chloride salt (bicarbonate, acetate, gluconate also available). • Often 40 mEq/L I.V. fluid with 40-150 mEq/day being given (i.e. normal dietary intake). Calcium Calcium • Uses – keeps cell membranes less permeable • especially muscle and nerve – initiates muscle contraction • will see direct effect on heart – works with enzyme systems such as those in blood clotting Hypercalcemia Hypercalcemia • causes: – Hyperparathyroidism • or tumor mimicking PTH – vitamin D intoxication – excessive "mineral" intake – acidosis – bone cancer Hypercalcemia • symptoms: – nerve membranes less excitable • stupor, muscle flaccidity, weakness, peripheral vasodilation – direct action on heart • increases heart contractions – stones and calcium deposits – Polyuria • impaired concentrating ability Hypocalcemia Hypocalcemia • causes: – hypoparathyroidism – too little vitamin D – chronic renal insufficiency • kidneys retain phosphate which combines with Ca++ • also, kidneys activate vitamin D – bed rest and inactivity (long term only) – alkalosis – stored blood (calcium binds to citrate) Hypocalcemia Hypocalcemia • symptoms: – nerve membranes more excitable • (irritability, tetany, convulsions) – heart weak • treatment: – if parenteral treatment required, calcium gluconate is least irritating Magnesium • Uses – activator for many enzyme systems – mimics Ca++ effects on nervous system (seems to affect acetylcholine release) Hypermagnesemia Hypermagnesemia Too much magnesium • causes: – renal insufficiency • especially if increased intake – acidosis may make worse • shift out of cells • symptoms: – sedation and depression – muscle weakness Hypomagnesemia Hypomagnesemia Too little magnesium • causes: – starvation – diarrhea – over intake of Ca++ • symptoms: – increased irritability – convulsions – cardiac arrhythmia Pharmacology Unit 9: Pharmacology End of Slides...
View Full Document

Ask a homework question - tutors are online