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Disturbances of body fluids Renata Péčová Dept. of Pathophysiology 2009.

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Presentation on theme: "Disturbances of body fluids Renata Péčová Dept. of Pathophysiology 2009."— Presentation transcript:

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2 Disturbances of body fluids Renata Péčová Dept. of Pathophysiology 2009

3 TOTAL BODY FLUID (TBF) water - 60 % of the weight of men - 50 % of the weight of women - more fat and a smaller muscle mass  smaller amount of water in relation to total body weight (TBW 

4 Major Compartments of Body Fluid 1. intracellular fluid (ICF) - 40 % (2/3) TBW (in the adult) 2. extracellular fluid (ECF) - 20 % (1/3) –a. interstitial fluid (ISF) - compartment between the cells (15 %) –b. intravascular fluid (IVF) in addition to the ISF and IVF, special secretions (cerebrospinal fluid, intraocular fluid, and gastrointestinal secretions) form a small proportion (1 % to 2 % of body weight) of the extracellular fluid called transcellular fluid

5 Major compartments of body fluids TBF 60-65% of body weight; ECT:ICT=1:2; IVT:IST =1:4

6 Compartments of total body fluid INTRACELLULAR FLUID PLASMAPLASMA PERITONEAL CAVITY PLEURAL CAVITY PERICARDIAL CAVITY TRANSCELLULAR FLUID thick connective tissue bones lymph INTERSTITIAL FLUID „third space“

7 TBF 40 l IVF (3 l) volume of erythrocytes (2 l) ECF (15 l) ICF (25 l) blood volume (5 l)

8 Normal water balance (24 h) IntakeLoss Cellular metabolism0,5 lUrine1-2 l Normal water intake1 lStool0,1 l 1 lSweat0,6-0,8 l Pulmonary0,5 l TOTAL2,5 lTOTAL2,5 l

9 Sumit Kumar & Tomas Berl Principles of normal water balance

10 Major electrolytes and their distribution - 1 sodium (Na+) - chief cation of the ECF potassium (K+) - the chief cation of the ICF calcium (Ca++) magnesium (Mg++) chloride (Cl-) - chief anion of the ECF bicarbonate (HCO 3 - ) - chief anion of the ECF phosphate (HPO ) - chief anion of the ICF sulfate(SO4 2- )

11 Major electrolytes and their distribution - 2 Sodium plays a major role in controlling total body fluid volume; potassium is important in controlling the volume of the cell The law of electrical neutrality states that the sum of negative charges must be equal to the sum of positive charges (measured in milliequivalents) in any particular compartment

12 Major electrolytes and their distribution - 3 Ionic composition of the ISF and IVF is very similar. The main difference is that ISF contains very little protein as compared with the IVF. The protein in plasma plays a significant role in maintaining the volume of the IVF.

13 Major electrolytes and their distribution

14 MOVEMENT OF BODY FLUIDS AND ELECTROLYTES there is a continual intake and output within the body as a whole, and between the various compartments the composition and volume of the fluid is relativelly stable, a states called dynamic equilibrum or homeostasis.

15 Movement of Solutes Between Body Fluid Compartments - 1 Several factors affect how readily a solute diffuses across capillary and cell membranes 1. membrane permeability refers to the size of the membrane pores. 2. concentration and electric gradients interact to influence the movement of electrolytes termed the electrochemical potential. 3. electrical potential

16 Movement of Solutes Between Body Fluid Compartments pressure gradients - hydrostatic pressure gradient increases the rate of diffusion of solutes through the capillary membrane - active transport systems - NaK-activated - ATPase system (sodium-potassium pump) located in cell membranes (3 Na+ ions out of the cell in exchange for two K+)

17 Movement of Water Between Body Fluid Compartments - controlled by 2 forces: - 1. hydrostatic pressure - 2. osmotic pressure Osmotic pressure refers to the drawing force for water exerted by soluted particles. Osmosis is the process of the net diffusion of water caused by a concentration gradient. Net diffusion of water occurs from an area of low solute concentration (dilute solution) to one of high solute concentration (concentrated solution).

18 Movement of Water Between the Plasma and Interstitial Fluid - Na + does not play an important role in the movement of water between the plasma and interstital fluid compartments - the distribution is determined by o hydrostatic pressure of the capillary blood produced, mainly by the pumping action of the heart o colloid osmotic pressure produced primarily by serum albumin The accumulation of excess fluid in the interstitial spaces = edema

19 Starling forces

20 Factors favor edema formation: 1.  capillary hydrostatic pressure (  Pc) 2.  plasma oncotic pressure (  c ) 3.  capillary permeability (Kf) resulting in an  in interstitial fluid colloid osmotic pressure 4. lymphatic obstruction (  interstitial oncotic pressure)

21 Starling forces ICF ISF IVF KfKf Lymph capillary cell Pc cc PiPi ii Jr = Kf [(Pc – Pi) – (  c -  i)]

22 Pathogenesis of edema formation 1.  gradient of hydrostatic pressures ( P c – P i ) -Heart failure; venous insufficiency -  EABV  R-A-A (SAS, ADH)

23 Starling forces ICF ISF IVF KfKf Lymph capillary cell Pc cc PiPi ii Jr = Kf [(Pc – Pi) – (  c -  i)]

24 Pathogenesis of edema formation 2.  gradient of oncotic pressures (  c -  i ) -  plasma protein level -  EABV  R-A-A (SAS, ADH)

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26 Pathogenesis of edema formation 3.  capillary permeability (Kf) resulting in an  interstitial fluid colloid osmotic pressure 4. lymphatic obstruction (  interstitial oncotic pressure)

27 Pathogenesis of ascites Disturbance of liver  plasma albumin Portal hypertension  inactivation of ADH and aldosteron  plasma oncotic pressure  capillary pressure in splanchnic region  plasma volume (retention of Na and water) Ascites  plasma volume volumoreceptor stimulation ADH secretion Aldosteron secretion

28 Movement of Water Between the ECF and the ICF determined by osmotic forces: - because Na + composes over 90 % of the particles in the ECF, it has a major effect on TBW and its distribution -  ECF osmolality (becomes hyperosmotic)  water shifts from the ICF to the ECF, decreasing cell volume: hypertonic solution (3 % saline)  cell shrinkage

29 Movement of Water Between the ECF and the ICF - 2 Cell in hypertonic solution –water shifts from the ICF to the ECF –decreasing cell volume (cell shrinkage) –active  of intracellular osmotic pressure - water shifts from the ECF to the ICF –increasing cell volume (general decreasing)

30 Movement of Water Between the ECF and the ICF determined by osmotic forces: -  ECF osmolality (becomes hypoosmotic), water shifts from the ECF to the ICF, increasing cell volume hypotonic solution (0.45 % saline)  cell swelling i.v. administration of isotonic saline  no change in the ICF volume or osmolality

31 Movement of Water Between the ECF and the ICF - 4 Cell in hypotonic solution –water shifts from the ECF to the ICF –increasing cell volume (cell swelling) –active decreasing of intracellular osmotic pressure and water shifts from the ICF to the ECF –decreasing of intracellular volume (general increasing)

32 Changes of red blood cells volume due to plasma osmolality disturbances

33 TBF 40 l IVF (3 l) volume of erythrocytes (2 l) ECF (15 l) ICF (25 l) blood volume (5 l)

34 Plasma osmotic activity = 2x [Na + ] + urea + glucose = 2x [Na + + K + ] + 5

35 Example: –Chronic renal insufficiency patient: plasma Na + level 125 mmol/l plasma glucose level 5 mmol/l plasma urea level 50 mmol/l Approximate osmolarity: 2 x = 305 mmol/l

36 Regulation of volume and osmolarity - 1 GIT Kidney – main regulatory system via releasing water and electrolytes Circulatory system –perfusion –distribution of water and electrolytes in body compartments (Starling forces) –renal perfusion  releasing of water and electrolytes

37 Regulation of volume and osmolarity - 2 Signals for GIT – thirst Circulatory system – nervous system (sympathetic/ parasympathetic) Kidneys – nervous system + 3 hormonal regulatory systems: –Antidiuretic hormon (ADH) –Atrial natriuretic factor (ANF) –Renin – angiotenzin – aldosteron (R-A-A)

38 Regulation of volume and osmolarity - 3 –Antidiuretic hormon (ADH) Stimulus for releasing –  plasma osmolarity –  effective circulatory volume  secretion –Hypervolemia –Hypoosmolarity –Feed-back – ADH plasma level Target - distal tubulus and collecting duct –  water permeability –  urea permeability Effect –up to min

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40 Regulation of volume and osmolarity - 4 –Renin – angiotensin – aldosteron (R-A-A) –Activation of renin secretion:  kidney perfusion (  afferentation from vas afferens receptors;  CO – baroreceptors – SNS activation  NaCl in macula densa region –Angiotensin I –Angiotensin II –Aldosteron

41 Main cells of distal tubules have intracelullar receptors for aldosterón. Receptors after hormon-binding act as transcript factors and they induce intracellular proteins which increased reabsorption of Na + from tubules and K + secretion into the urine. Intercallar cells – regulation of ABB..

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44 Regulation of volume and osmolarity - 5 –Atrial natriuretic factor (ANF) Secretion timulus : –  atrial filling Effects: –Vessels – vasodilation of vas afferens –Endocrine system –  secretion of ADH, renin and aldosteron –Kidneys –Glomerular hyperperfusion (via vasodilatation of vas afferens)   GFR –  Na + reabsorption   Na + releasing

45 Heart failure  CO  EABV Activation R – A - A  Water retention (kidney)  Venous return  Diastolic filling  ANF   ANF feed-back

46 VOLUME IMBALANCES Extracellular Fluid (ECF) Volume Deficit = hypovolemia = the isotonic loss of body fluids, with relatively equal losses of sodium and water. - primarily affect ECF - relatively equal losses or gains of sodium and water  ECF volume deficit or excess - fluid will not be transferred from ICF to ECF (osmolality remains the same)

47 Volume imbalances - affect ECF - involve relatively equal losses or gains of Na+ and water leading to an ECF volume deficit or excess - fluid will not be transferred from the ICF to the ECF as long as the osmolality in the two compartments remains the same

48 OSMOTIC IMBALANCES - primarily affect ICF - relatively unequal losses or gains of sodium and water - hypoosmolality  cell swelling

49 Osmotic imbalances - affect ICF - involve relatively unequal losses or gains of Na + and water -  concentration of Na + in the ECF  water moves from the ECF to the ICF (cell swelling) -  concentration of Na + in ECF should  water moves from the ICF to ECF (cell shrinkage)

50 ECF volume deficit (hypovolemia) Isotonic loss of body fluids; equal losses of sodium and water Causes: Blood or plasma loss sequestration of fluid in soft tissue injuries (third spacing): burns, peritonitis

51 ICV ECV IVVISV H2OH2O NaCl ECF volume deficit - hypovolemia

52 ICV ECV IVVISV H2OH2O NaCl ECF volume deficit - hypovolemia

53 ECF volume deficit (hypovolemia) Consequences:  EABV (  venous return   cardiac output  hypotension) Hemodynamic changes –Tachycardia –Peripheral vasoconstriction  Ht ADH, R-A-A activation Clinical features: - circulatory collapse and shock - hematocrit and serum protein levels are elevated - normal natremia

54 Hyperosmolal hypohydratation - dehydration Cause: increase loss of water than sodium (loss of hypoosmotic fluid) A. Loss of hypoosmolatic fluid –Vomiting –Diarrhea –Sweating –Disturbances of urine creation Polyuria in acute renal failure Osmotic diuresis Central or peripheral diabetes insipidus B. Decrease waterr intake –Coma patients –Patient unable to communicate (babies) –  feeling of thirst (old people, „after surgery people“)

55 ICV ECV IVVISV H2OH2O NaCl Hyperosmolal imbalance - dehydration

56 ICV ECV IVVISV H2OH2O Hyperosmolal imbalance - dehydration NaCl

57 ICV ECV IVVISV H2OH2O Hyperosmolal imbalance - dehydration NaCl

58 Hyperosmolal hypohydratation - dehydration Consequences: –  ECF osmolaity – cell shrinkage (CNS) - neurological manifestation: agitation, coma, seizures - thirst - dry mucosa, tongue - oliguria

59 ECF volume excess Cause: isoosmolar fluid retention Accumulation of ECF Pathogenesis - alteration in Starling forces - congestive heart failure, nephrotic syndrome, cirrhosis of the liver -  cardiac output   effective circulating volume  renal sodium retention  Ht (or normal)

60 Starling forces ICF ISF IVF KfKf Lymph capillary cell Pc cc PiPi ii Jr = Kf [(Pc – Pi) – (  c -  i)]

61 Heart failureHepatic cirrhosisNephrotic syndrome  CO  Pc Ascites  plasma albumin IVF  interstitial space  EABV  SNS,  R-A-A  Na+ and water reabsorption Edema (hyperhydratation)

62 ICV ECV IVVISV H2OH2O NaCl ECF volume excess – generalised edema

63 ICV ECV IVVISV H2OH2O NaCl ECF volume excess – generalised edema

64 Hypoosmolar imbalance – water intoxication Cause:  water intake or retention than sodium  water intake  ADH –Endogennous origin – hypothalamus –Ectopic creation ADH – bronchogenic CA, lymphomas,... Disturbances of kidneys –Oligoanuric phase of acute renal failure

65 ICV ECV IVVISV H2OH2O NaCl Hypoosmolar imbalance – water intoxication

66 ICV ECV IVVISV H2OH2O NaCl Hypoosmolar imbalance – water intoxication

67 ICV ECV IVVISV H2OH2O NaCl Hypoosmolal imbalance – water intoxication


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