7. Extracellular fluid 40 % of body fluid Rich in : Sodium Chloride Bicarbonate Interstitial fluid : between cells, low in protein Intravascular fluid(Plasma) : High in protein Transcellular fluids – CSF, intraocular fluids, serous membranes (third space) 10/5/2009 6
8. Spacing First space: normal Second Space: interstitial - edema; Third Space: in places not normally found 10/5/2009 7
9. Fluid compartments are separated by membranes that are freely permeable to water. Movement of fluids due to: Hydrostatic pressure Osmotic pressure Examples: Capillary filtration (hydrostatic) pressure Capillary colloid osmotic pressure Interstitial hydrostatic pressure Tissue colloid osmotic pressure 10/5/2009 8
17. 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 10/5/2009 16
24. 23 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 membraneActive transport – movement of particles up a concentration gradient ; requires energy
25. Regulation of body water ADH – antidiuretic hormone + thirst Decreased amount of water in body Increased amount of Na+ in the body Increased blood osmolality Decreased circulating blood volume Stimulate osmoreceptors in hypothalamusADH released from posterior pituitaryIncreased thirst 24
26. 25 Result: increased water consumption increased water conservation Increased water in body, increased volume and decreased Na+ concentration
28. Different components of renal function occur along thenephron. A normal glomerular filtration rate of 125 mL/minwould generate 180 L/day of filtrate containing 27,000 mmolofsodium. 10/5/2009 27
29. Approximately two thirds of the filtered sodium is absorbed in the PCT, 20% in the LOH, 7% in the DCT, and 3%in the CD; the net excretion of urinary sodium per day, as a fraction of the total sodium filtered load, is less than 1%. 10/5/2009 28
34. Volume and electrolyte depletion Due to extrarenal loss of body fluid Causes : Vomiting Diarrohoea Nasogastric suction Intestinal fistulae Intestinal obstruction Peritonitis 10/5/2009 33
37. Clinical features Sunken eyes Tongue – Dry and Coated Low urinary output Lab: Normal or Slightly reduced Serum Sodium Low urinary sodium 10/5/2009 36
38. Treatment Replacement of sodium deficit in addition to volume deficit by infusion of Isotonic saline, or Ringer’s lactate Depending on the severity of hyponatremia 10/5/2009 37
39. Volume overload Conservation of sodium and water following stress like surgery If fluid intake is excessive in immediate post op fluid overload may occur. 10/5/2009 38
40. Tendency of fluid overload increases in patients with : Heart disease Liver disease Kidney disease 10/5/2009 39
45. Hypernatremia Serum Na levels > 150Mmol/l Causes: Renal dysfunction Cardiac failure Drug induced (NSAIDS, corticosteroids) 10/5/2009 44
46. Types of hypernatremia Euvolemic (pure water loss) Hypovolemic (more water lost than sodium) Hypervolemic (both gained but more sodium gained) 10/5/2009 45
47. Clinical features Pitting edema Puffiness of face Increased urination Dilated jugular veins Features of pulmonary edema 10/5/2009 46
48. Treatment Restriction of sodium and saline. Treatment of pulmonary edema. 10/5/2009 47
49. Hypokalemia Serum potassium levels <3.5 mEq/L Causes : Diarrhoea Villous tumor of rectum After trauma or surgery Gastric outlet obstruction Duodenal fistula 10/5/2009 48
50. Clinical features Slurred speech Muscular hypotonia Depressed reflexes Paralytic ileus Weakness of respiratory muscles Cardiac arrhythmias ECG shows prolonged QT interval , depessed ST segment and inversion of T waves 10/5/2009 49
51. Treatment Oral potassium 2g 6th hourly Intravenous KCl 40 mmol/litre given in 5% dextrose of normal saline, under ECG monitoring Max dose per hour = 20 mmol 10/5/2009 50
52. Hyperkalemia Normal range of K = 3.5-5 mEq/L Hyperkalemia >6 mEq/L Causes Renal failure Rapid infusion of potassium Massive blood transfusion Diabetic ketoacidosis Potassium sparing diuretics 10/5/2009 51
53. Dangerous condition, can cause sudden cardiac arrest. High serum potassium levels Peaked ‘T’ waves in ECG 10/5/2009 52
54. Treatment IV admin. Of 50 ml of 50% glucose with 10 units of soluble insulin, slowly. Hemodialysis if life threatening. Correction of acidosis. 10/5/2009 53
55. Hypermagnesimia It is rare Occurs because of renal failure or during treatment of pre eclampsia for which magnesium sulfate is given. 10/5/2009 54
56. Hypomagnesimia Causes : Malnutrition Large GI fluid loss Patients on Total Parenteral Nutrition 10/5/2009 55
57. Clinical features Hyperreflexia Muscle spasm Paraesthesia Tetany It mimics hypocalcemia Often associated with hypokalemia and hypocalcemia IV/Oral magnesium is needed. 10/5/2009 56
58. Hypocalcemia Causes Hypoparathyroidism Severe pancreatitis Severe trauma Crush injuries 10/5/2009 57
63. Treatment Expand ECF by IV normal saline Also increases urinary output and thus increasing calcium excretion. Hemodialysis in case of renal failure. 10/5/2009 62