Download - 02 water electrolytes_ptii
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Water and Electrolytes Water and Electrolytes Balance and ImbalanceBalance and ImbalanceWater and Electrolytes Water and Electrolytes Balance and ImbalanceBalance and Imbalance
Physiological Basis of Water and Physiological Basis of Water and Sodium MetabolismSodium Metabolism
Disorder of Other ElectrolytesDisorder of Other Electrolytes
Regulation of Water and Sodium BalanceRegulation of Water and Sodium Balance
Disorder of Water and Sodium MetabolismDisorder of Water and Sodium Metabolism
ECF↓
Hypovolemic
ECF ↑
Hypervolemic
ECF N
Serum Na+ ↓
Hyponatremia
Hypovolemichyponatremia(Hypotonic)
Hypervolemic hyponatremia
(Water intoxication)
Normovolemic hyponatremia
Serum Na+ ↑
Hypernatremia
Hypovolemic hypernatremia(Hypertonic)
Hypervolemic hypernatremia
(Salt intoxication)
Normovolemic hypernatremia
Serum Na+ N Hypovolemia(Isotonic)
Hypervolemia(Edema)
Classification of Water and Sodium Metabolic Disorders
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Edema (Hypervolemia)1. What is edema?
Edema refers to the presence of excess fluid in the body tissue (or body cavity - Hydrops).
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b) Based on causative diseases:
Cardiac edema
Hepatic edema
Renal edema
Nutritional edema
Lymphatic edema
Inflammatory edema
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4. Pathogenesis of Edema
I. Fluid interchange across the
blood vessel
- Abnormal distribution
- Total amount of body fluid: N
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Two types of balances disrupted
II. Fluid interchange across the
body
- ↑ Retention of water and sodium
- Total amount of body fluid: ↑
① Capillary hydrostatic pressure (17 mmHg)
② Interstitial hydrostatic pressure (-6.5 mmHg)
③ Plasma colloidal osmotic pressure (28 mmHg)
④ Interstitial colloidal osmotic pressure (5 mmHg)
The normal interchange of body fluid between plasma and interstitial fluid
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(17 - (-6.5)) - (28 - 5) = 0.5 mmHg
①②
③④
① Increased capillary hydrostatic pressure
② Increased capillary permeability
③ Reduced plasma colloid osmotic pressure
④ Obstruction of lymph return
1) Imbalance of fluid interchange across the blood vessel
Four Mechanisms:
① Increased capillary hydrostatic pressure
Venous pressure ↑
Congestive heart failure
Venous obstruction (thrombus, tumor)
Artery congestion
Inflammation
② Increased capillary permeability
Inflammation: Infectious:
Bacteria
Virus Non-infectious:
Allergy
Toxins
Burns, etc Prolonged ischemia, hypoxia,
acidosis, and so on
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Proteins entering intersitium →↓ Plasma colloidal OP →↑ Interstitial colloidal OP
③ Reduced plasma colloid osmotic pressure
Protein Loss or Consumption ↑
Nephrotic syndrome (- loss through urine)
- caused by an increase in permeability of the capillary walls of the glomerulus.
Burns and wounds (- loss through injured skin)
Chronic inflammation
Protein Intake↓
Malnutrition
Protein Production ↓
Liver disease (cirrhosis)
④ Obstruction of lymph return
Interstitial fluid (and protein) return to blood obstructed
(e.g., tumor, parasites).
Lymphedema
① ↓glomerular filtration rate (GFR)
② ↑ filtration fraction (FF)
③ ↑ release of ADH and ADS
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Renal
2). Increased Retention of Water and Sodium
GFR
The flow rate (volume/min) of filtered fluid through the kidney.
N: 120 ml/min
2). Increased Retention of Water and Sodium
① Decreased glomerular filtration rate (GFR)
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Glomerulo-tubular Balance
2). Increased Retention of Water and Sodium
GFR120ml/min
Reabsorption 99% ~ 99.5%
Excretion1% ~ 0.5%
Glomerulo-tubular Imbalance
GFR↓
Reabsorption ↑
Excretion↓
② Increased filtration fraction (FF)
FFThe ratio of GFR versus renal plasma flow volume.N: 20%
GRF FF =
Plasma flow volume
Parameter Value
Renal plasma flow RPF=600 ml/min
Glomerular filtration rate GFR=120 ml/min
Filtration fraction FF=20%
① Decreased glomerular filtration rate (GFR)
Glomerular abnormalities: Nephrotic syndrome Chronic Kidney Disease (Glomerulonephritis)
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Decrease of effective circulating blood volume:
→ GFR↓
e.g., Congestive heart failure
Filtration fraction↑
Blood concentration in EGA
Oncotic pressure in capillary bed ↑
Reabsorption of fluid ↑
Urine ↓
Retention of sodium and water
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② Increased filtration fraction (FF)
↓ Effective circulating volume → Vasoconstriction (Efferent > Afferent) →↑ FF
e.g. Renal artery stenosis
③ Increased release of ADH and ADS
Hypovolemia or decreased effective circulating volume:
HemorrhageDehydrationCongestive heart failureetc.
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Circulating Volume
Sympathetic N↑
Renin ↑
Na+
Agt ↑
ADS↑
Circulating Volume↓
ADH↑
Macula densa
① ↓glomerular filtration rate (GFR)
② ↑ filtration fraction (FF)
③ ↑ release of ADH and ADS
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Renal
↑ intake of sodium and water
- Infusion too much
- Drinking too much
Extrarenal
2). Increased Retention of Water and Sodium
4. The most frequent clinical edema
① Cardiac edema:
Right heart failure.
This kind of edema usually shows up first in the legs and ankles.
Why? Because good old gravity is pulling all that "loose" fluid straight down.
So we call it “dependent edema”.
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5. Alternations of metabolism and function
Beneficial roles:
(1) Diluting and neutralizing toxin(s)
(2) Carrying antibodies and complements to edema region
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Harmful roles:
(1) Resulting in insufficient nutritional supply
(2) Inducing dysfunctions of affected organs
(3) May lead to death (edema of vital organs)
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6. Principles of prevention and treatment
Eliminate the causative disease(s)
Diuresis (excrete excessive Na+ and H2O)
Restrict the intake of Na+ and H2O
Promote body fluid back to blood vessels
1) Infuse plasma albumin
2) Apply assistant equipment, such as “lymphapress”
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