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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

Types of Body Fluid Disorder

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Pla

s ma

ISF ICFP

lasm

aISF ICF

Pla

sma

ISF ICF

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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ISF ICF

Pla

sm

a

2. The changes of Body Fluid Volume in Edema

Extracellular Intracellular

3. Classification of edema

a) According to edema area:

Local edema

Systemic edema (anasarca)

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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

Something tragic

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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① Cardiac edema :

Left heart failure – edema in the lungs (dyspnea).

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Hepatic Edema

Acute glomerulonephritis Chronic glomerulo-nephritis

Renal Edema

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Nutritional Edema

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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Assistant therapy of lymphatic edema

34Lymphapress

Before therapy After therapy

Assistant therapy of lymphatic

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