1. Fluid and Electrolyte Imbalances 1

2. 2

3. Body Fluid Compartments 2/3 (65%) of TBW is intracellular (ICF) 2/3 (65%) of TBW is intracellular (ICF) 1/3 extracellular water 1/3 extracellular water –25 % interstitial fluid (ISF) – 5- 8 % in plasma (IVF intravascular fluid) –1- 2 % in transcellular fluids – CSF, intraocular fluids, serous membranes, and in GI, respiratory and urinary tracts (third space) 3

4. 4

5. 5

6. Fluid compartments are separated by membranes that are freely permeable to water. Fluid compartments are separated by membranes that are freely permeable to water. Movement of fluids due to: Movement of fluids due to: – hydrostatic pressure – osmotic pressure Capillary filtration (hydrostatic) pressure Capillary filtration (hydrostatic) pressure Capillary colloid osmotic pressure Capillary colloid osmotic pressure Interstitial hydrostatic pressure Interstitial hydrostatic pressure Tissue colloid osmotic pressure Tissue colloid osmotic pressure 6

7. 7

8. Balance Fluid and electrolyte homeostasis is maintained in the body Fluid and electrolyte homeostasis is maintained in the body Neutral balance: input = output Neutral balance: input = output Positive balance: input > output Positive balance: input > output Negative balance: input < output Negative balance: input < output 8

9. 9

10. Solutes – dissolved particles Electrolytes – charged particles Electrolytes – charged particles –Cations – positively charged ions Na +, K +, Ca ++, H + Na +, K +, Ca ++, H + –Anions – negatively charged ions Cl -, HCO 3 -, PO 4 3- Cl -, HCO 3 -, PO 4 3- Non-electrolytes - Uncharged Non-electrolytes - Uncharged Proteins, urea, glucose, O 2, CO 2 Proteins, urea, glucose, O 2, CO 2 10

11. Body fluids are: Body fluids are: –Electrically neutral –Osmotically maintained Specific number of particles per volume of fluid Specific number of particles per volume of fluid 11

12. Homeostasis maintained by: Ion transport Ion transport Water movement Water movement Kidney function Kidney function 12

13. 13 MW (Molecular Weight) = sum of the weights of atoms in a molecule mEq (milliequivalents) = MW (in mg)/ valence mOsm (milliosmoles) = number of particles in a solution

14. 14 Tonicity Isotonic Hypertonic Hypotonic

15. 15

16. 16 Cell in a hypertonic solution

17. 17 Cell in a hypotonic solution

18. 18 Movement of body fluids “ Where sodium goes, water follows.” Diffusion – movement of particles down a concentration gradient. Osmosis – diffusion of water across a selectively permeable membrane Active transport – movement of particles up a concentration gradient ; requires energy

19. 19

20. Regulation of body water ADH – antidiuretic hormone + thirst ADH – antidiuretic hormone + thirst Triggered by Triggered by –Decreased amount of water in body –Increased amount of Na+ in the body –Increased blood osmolality –Decreased circulating blood volume Stimulate osmoreceptors in hypothalamus ADH released from posterior pituitary Increased thirst Stimulate osmoreceptors in hypothalamus ADH released from posterior pituitary Increased thirst 20

21. 21

22. 22 Result: increased water consumption increased water conservation Increased water in body, increased volume and decreased Na+ concentration

23. 23 Dysfunction or trauma can cause: Decreased amount of water in body Increased amount of Na + in the body Increased blood osmolality Decreased circulating blood volume

24. 24 Edema is the accumulation of fluid within the interstitial spaces. Causes: increased hydrostatic pressure lowered plasma osmotic pressure increased capillary membrane permeability lymphatic channel obstruction

25. 25 Hydrostatic pressure increases due to: Venous obstruction: thrombophlebitis (inflammation of veins) hepatic obstruction tight clothing on extremities prolonged standing Salt or water retention congestive heart failure renal failure

26. 26 Decreased plasma osmotic pressure: ↓ plasma albumin (liver disease or protein malnutrition) plasma proteins lost in : glomerular diseases of kidney hemorrhage, burns, open wounds and cirrhosis of liver

27. 27 Increased capillary permeability: Inflammation immune responses (allergic reactions) Lymphatic channels blocked: surgical removal infection involving lymphatics lymphedema

28. 28 Fluid accumulation: increases distance for diffusion may impair blood flow = slower healing increased risk of infection pressure sores over bony prominences Psychological effects

29. 29 Edema of specific organs can be life threatening (larynx, brain, lung) Water is trapped, unavailable for metabolic processes. Can result in dehydration and shock. (severe burns)

30. Electrolyte balance Na + (Sodium) Na + (Sodium) –90 % of total ECF cations – 136 -145 mEq / L –Pairs with Cl -, HCO 3 - to neutralize charge –Low in ICF –Most important ion in regulating water balance –Important in nerve and muscle function 30

31. 31

32. Regulation of Sodium Renal tubule reabsorption affected by hormones: Renal tubule reabsorption affected by hormones: –Aldosterone –Renin/angiotensin –Atrial Natriuretic Peptide (ANP) Increased secretion of Na, decreased lood volume Increased secretion of Na, decreased lood volume 32

33. Potassium Major intracellular cation Major intracellular cation ICF conc. = 150- 160 mEq/ L ICF conc. = 150- 160 mEq/ L Resting membrane potential Resting membrane potential Regulates fluid, ion balance inside cell Regulates fluid, ion balance inside cell pH balance pH balance 33

34. Regulation of Potassium Through kidney Through kidney –Aldosterone –Insulin 34

35. Isotonic alterations in water balance –Loses plasma or ECF –Isotonic fluid loss ↓ ECF volume, weight loss, dry skin and mucous membranes, ↓ urine output, and hypovolemia ( rapid heart rate, flattened neck veins, and normal or ↓ B.P. – shock) ↓ ECF volume, weight loss, dry skin and mucous membranes, ↓ urine output, and hypovolemia ( rapid heart rate, flattened neck veins, and normal or ↓ B.P. – shock) 35

36. Isotonic fluid excess Isotonic fluid excess –Excess IV fluids –Hypersecretion of aldosterone –Effect of drugs – cortisone Hypervolemia – weight gain, decreased hematocrit, diluted plasma proteins, distended neck veins, ↑ B.P. Can lead to edema ( ↑ capillary hydrostatic pressure) pulmonary edema and heart failure 36

37. Electrolyte imbalances: Sodium Hypernatremia (high levels of sodium) Hypernatremia (high levels of sodium) –Plasma Na+ > 145 mEq / L –Due to ↑ Na + or ↓ water –Water moves from ICF → ECF –Cells dehydrate 37

38. 38

39. Hypernatremia Due to: Hypernatremia Due to: –Hypertonic IV soln. –Oversecretion of aldosterone –Loss of pure water Long term sweating with chronic fever Long term sweating with chronic fever Respiratory infection → water vapor loss Respiratory infection → water vapor loss Diabetes – polyuria Diabetes – polyuria –Insufficient intake of water (hypodipsia) 39

40. Clinical manifestations of Hypernatremia Thirst Thirst Lethargy Lethargy Neurological dysfunction due to dehydration of brain cells Neurological dysfunction due to dehydration of brain cells Decreased vascular volume Decreased vascular volume 40

41. Treatment of Hypernatremia Lower serum Na+ Lower serum Na+ –Isotonic salt-free IV fluid –Oral solutions preferable 41

42. Hyponatremia Overall decrease in Na+ in ECF Overall decrease in Na+ in ECF Two types: depletional and dilutional Two types: depletional and dilutional Depletional Hyponatremia Depletional Hyponatremia Na+ loss: –diuretics, chronic vomiting –Chronic diarrhea –Decreased aldosterone –Decreased Na+ intake 42

43. Dilutional Hyponatremia: Dilutional Hyponatremia: –Renal dysfunction with ↑ intake of hypotonic fluids –Excessive sweating → increased thirst → intake of excessive amounts of pure water –Syndrome of Inappropriate ADH (SIADH) or oliguric renal failure, severe congestive heart failure, cirrhosis all lead to: Impaired renal excretion of water Impaired renal excretion of water –Hyperglycemia – attracts water 43

44. Clinical manifestations of Hyponatremia Neurological symptoms Neurological symptoms –Lethargy, headache, confusion, apprehension, depressed reflexes, seizures and coma Muscle symptoms Muscle symptoms –Cramps, weakness, fatigue Gastrointestinal symptoms Gastrointestinal symptoms –Nausea, vomiting, abdominal cramps, and diarrhea 44

45. Hypokalemia Serum K + < 3.5 mEq /L Serum K + < 3.5 mEq /L Beware if diabetic Beware if diabetic –Insulin gets K + into cell –Ketoacidosis – H + replaces K +, which is lost in urine β – adrenergic drugs or epinephrine β – adrenergic drugs or epinephrine 45

46. Causes of Hypokalemia Decreased intake of K + Decreased intake of K + Increased K + loss Increased K + loss –Chronic diuretics –Acid/base imbalance –Trauma and stress –Increased aldosterone –Redistribution between ICF and ECF 46

47. Clinical manifestations of Hypokalemia Neuromuscular disorders Neuromuscular disorders –Weakness, flaccid paralysis, respiratory arrest, constipation Dysrhythmias, appearance of U wave Dysrhythmias, appearance of U wave Postural hypotension Postural hypotension Cardiac arrest Cardiac arrest Treatment- Treatment- –Increase K + intake, but slowly, preferably by foods 47

48. Hyperkalemia Serum K+ > 5.5 mEq / L Serum K+ > 5.5 mEq / L Check for renal disease Check for renal disease Massive cellular trauma Massive cellular trauma Insulin deficiency Insulin deficiency Addison’s disease Addison’s disease Potassium sparing diuretics Potassium sparing diuretics Decreased blood pH Decreased blood pH Exercise causes K+ to move out of cells Exercise causes K+ to move out of cells 48

49. Clinical manifestations of Hyperkalemia Early – hyperactive muscles, paresthesia Early – hyperactive muscles, paresthesia Late - Muscle weakness, flaccid paralysis Late - Muscle weakness, flaccid paralysis Change in ECG pattern Change in ECG pattern Dysrhythmias Dysrhythmias Bradycardia, heart block, cardiac arrest Bradycardia, heart block, cardiac arrest 49

50. Treatment of Hyperkalemia Decrease intake and increase renal excretion Decrease intake and increase renal excretion Insulin + glucose Insulin + glucose Bicarbonate Bicarbonate Ca ++ counters effect on heart Ca ++ counters effect on heart 50

51. Calcium Imbalances Most in ECF Most in ECF Regulated by: Regulated by: –Parathyroid hormone ↑ Blood Ca ++ by stimulating osteoclasts ↑ Blood Ca ++ by stimulating osteoclasts ↑ GI absorption and renal retention ↑ GI absorption and renal retention –Calcitonin from the thyroid gland Promotes bone formation Promotes bone formation ↑ renal excretion ↑ renal excretion 51

52. Hypercalcemia Results from: Results from: –Hyperparathyroidism –Hypothyroid states –Renal disease –Excessive intake of vitamin D –Milk-alkali syndrome –Certain drugs –Malignant tumors – hypercalcemia of malignancy Tumor products promote bone breakdown Tumor products promote bone breakdown Tumor growth in bone causing Ca ++ release Tumor growth in bone causing Ca ++ release 52

53. Hypercalcemia Usually also see hypophosphatemia Usually also see hypophosphatemia Effects: Effects: –Many nonspecific – fatigue, weakness, lethargy –Increases formation of kidney stones and pancreatic stones –Muscle cramps –Bradycardia, cardiac arrest –Pain –GI activity also common Nausea, abdominal cramps Nausea, abdominal cramps Diarrhea / constipation Diarrhea / constipation –Metastatic calcification 53

54. Hypocalcemia Hyperactive neuromuscular reflexes and tetany differentiate it from hypercalcemia Hyperactive neuromuscular reflexes and tetany differentiate it from hypercalcemia Convulsions in severe cases Convulsions in severe cases Caused by: Caused by: –Renal failure –Lack of vitamin D –Suppression of parathyroid function –Hypersecretion of calcitonin –Malabsorption states –Abnormal intestinal acidity and acid/ base bal. –Widespread infection or peritoneal inflammation 54

55. Hypocalcemia Diagnosis: Diagnosis: –Chvostek’s sign Chvostek’s signChvostek’s sign –Trousseau’s sign Trousseau’s signTrousseau’s sign Treatment Treatment –IV calcium for acute –Oral calcium and vitamin D for chronic 55