Water And Electrolyte Homeostasis For Vet. Students

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Examination of Body Fluids Water and Electrolytes by

Dr. Ali H. Sadiek

Prof. of Internal Veterinary Medicine and Clinical Laboratory Diagnosis

Faculty of Veterinary Medicine, Assiut University E-mail: [email protected]

Course Objectives 1. What are the body fluid compartments and distribution? 2. Causes, signs, and management of disorders in : • • •

Body fluid Concentration, Electrolyte composition Acid-base balance

What are the Body fluids ? • Intracellular Fluid (ICF): 65-75 % of B. Fluids and 35-45 % of B. weight. • Higher % of P, K and lowered % of Na, Cl.

• Extra cellular fluids (ECF): 25 % of B. Fluids and 15 % of body weight. • In plasma, lymph, interstitial tissue, intercellular, CSF, Synovial, GIT. • Higher % of Na, Cl and lowered % of P, K. • Electrolytes moves freely bet. ICF and ECF according its homeostasis.

Fluid Compartments

EXTRACELLULAR

1/3

V A S C U L A R

2/3 I N T E R S T I T I A L

INTRACELLULAR

Fluid Compartments Extracellular

Intracellular

K+

Na+ ClHCO3-

Mg2+ Ca 2+ Phosphates Proteins

•H2O freely permeable mmol cations = mmol anions

Water Balance 2% 13 %

3%

32 %

65 %

25 %

60 %

Water and electrolyte balance • It is correlated with levels of fluid and electrolytes (Na, K, Cl) in plasma • Loss of Na followed by loss of water. • Kidney compensate imbalance by:  Decreased urine secretion in dehydration and vice versa in edema under control of Levels of electrolytes and ADH.

Water and Electrolyte Imbalance I- Water Imbalance. • It occurs when water gain exceed water loss or vice versa • Signs of water Imbalance: • Dehydration: Water loss > water gain. • Edema: Water gain > water loss

1- Dehydration • Dehydration occurs when water loss exceed water gain without compensation. • Rare in adult animals, common in neonates. • Kidney is very sensitive to the level of body water, so it reduce water loss according to the body needs (ADH).

Cause of dehydration 1. 2. 3. 4. 5. 6. 7. 8. 9.

Diarrhea: Acute, continuous in neonates Vomiting for long periods Fever: continuous fever Sweating: severe in race horse, accompany colic. Severe burns and severe hemorrhage. Polyuria and renal failure. Ruminal impaction, obstructed bowel and Schok Water deprivation Fasting for a long period.

Dehydration and water balance

oligouria

Clinical Evaluation of Dehydration • Character of feces:  Very loose or runny feces are at a high risk of being dehydrated. 3. Classic signs of dehydration:  Sunken eyes,  Dry mouth and nose,  Fast or very slow pulse, polypnea  Cold extremities (ears /or legs)  Oliguria and constipation.  Weight loss, emaciation and recumbency

Clinical Evaluation of Dehydration 1. Skin tenting check or skin elasticity test. • Firmly pinch the loose folds of skin on the neck of the calf and check to see how long the skin remains tented. • If it remains tented for 2 to 6 seconds, the calf is moderately dehydrated and • Longer than 6 seconds indicates that the calf is severely dehydrated.

Signs of Dehydtaion in calves and adult cattle

Laboratory assessment of Dehydtaion

1. 2. 3. 4. 5. 6.

Increased RBCs count. Increased PCV. Increased Hb. Increased plasma proteins. Increase urea in blood. Increased Sp. Gravity of urine

Clinical and lab. Assessment of dehydration Water loss %

Skin tinting check

Sunken eye

6-4

-

+

8-6

4-2

10-8 12-10

PCV %

Total solids

Fluids required

(g/l)

Ml/kg

45-40

80-70

25-20

++

50

90-80

50-30

10-6

+++

55

100-90

80-50

45-20

+++

60

120

120-80

Treatment of dehydration • Fluid and electrolyte therapy: should be formulated on the basis of % of bwt loss, PCV, Hb, protein, blood pH. • It should contain all of the following ingredients:  Glucose for energy;  An alkalinizing agent to treat acidosis, such as bicarbonate, acetate, citrate or lactate;  Na, K, and Cl- to replenish lost electrolytes. • It may include other ingredients such as glutamine, glycine and gelling agents.

Oral Rehydration Therapy

Oral Rehydration Solution Ingredient

M/W

Mmol/l

g/l

Glucose

180

<200

<36

Na

23

<145

<3.3

Glycine

75

<145

<10.9

Na HCO3- 84

50-80

4.2-6.7

Na citrate

294

50-80

14.7-23.5

Na acetate 136

50-80

6.8-10.9

K

39

50-100

0.8-1.2

Cl-

35

50-100

1.8-3.2

2- Increased Total Body Water (Edema) • • •

Increased body stores of water It may be local, general Inflammatory or none.

Causes of edema 5. Hyponutritional edema. 6. Decreased serum albumin assoc. renal, hepatic, parasitic infections. 7. Long lasting protein loss (Johnes, fasciola, hemonchus) . 8. Renal edema: Loss of albumin

Breaskt edema Right sided heart failure

Distended Jugular vein Right sided heart failure

3-Hepatic edema: - Decreased alb. Synthesis

4- Cardiac: - Right sided heart failure (Generalized edema) - Left sided heart failure (pulm. Edema)

5- Obstructive: - Lymph vessel obst. (pregnancy and filariasis)

Pregnancy (obstructive edema)

Bottle jaw in hypoalbuminic cow

Bottle jaw in hypoalbuminic sheep

Water intoxication • Consumption of excess water specially after long period of deprivation. • Administration of excess hypotonic fluid via stomach tube, IV Infusion • It is ch, by swelling and rupture of RBCs, hb uria, anemia

Electrolyte of Body Fluids (mmol/l) Electrolytes

ICF

ECF

Interstitial

15

147

142

K

155

4

5

Ca

2

2.5

-

Mg+

27

1

2

HCO3-

10

30

27

Cl-

1

114

103

PO4-

100

2

2

SO4-

20

1

1

Organic acids

1

7.5

-

proteins

62

-

16

+

Na

+

Cations

Anions

+

AnionGap: It is about 8-12 mmol/L AG= ( [Na+]+[K+] ) - ( [Cl-]+[HCO3-] ) AG= ( [Na+] ) - ( [Cl-]+[HCO3-

Electrolyte of Body Fluids (mmol/l) K+

HCO3-

H+

Ca2+

140 105

4

25

0

9

Gastric

60

90

10

0

90

0

Pancreas

140

70

5

90

0

0

Ileum

130 110

10

30

0

0

Colon

50

30

20

0

0

Fluids

Na+

Serum

Cl-

40

AnionGap: It is about 8-12 mmol/L AG= ( [Na+]+[K+] ) - ( [Cl-]+[HCO3-] ) AG= ( [Na+] ) - ( [Cl-] +[HCO3-]

Sodium Homeostasis: 135-145 mmol/L The Kidney’s Priorities 2. Conserve sodium 3. Excrete free water 4. Conserve free water

Sodium Homeostasis Extracellular Intracellular

Na+

↑free H2O

free H2O

Hyponatremia: Na+ < 135 mmol/L More prevalent than hypernatremia, It Associate: 2.Acute hypertonic diarrhea and vomiting 3.Surgery and accidents. 4.Diuretic therapy 5.Tubular nephritis. 6.Bacterial and viral infection 7.Heart failure. 8.Hyperglycemia

Hypernatremia Na+ >145 mmol/L Rarely occurred and associate: 2.Excess dietary Na. 3.Water deprivation. 4.Hypotonic diarrhea 5.Chronic renal failure. 6.Severe burns and fever. 7.Hyperaldosteronism

Signs of Hyponatremia:ٍ Na+ < 135 mmol/L Signs vary acording to degree and acuteness of change Severe (< 120 meq/L): neuropsychiatric

Signs of Hypernatremia Na+ >145 mmol/L Symptoms dependent on rate of change, level and volume status Neuropsychiatric

 Anorexia, Nausea and vomiting  Restlessness  Lethargy and Fatigue  Hyperreflexia  Restlessness and irritability  Weakness  Muscle weakness, spasms  Delirium or cramps  Seizures  Decreased consciousness or coma

Chloride Homeostais Normal range: 95-110 mmol/L • Maintains tonicity • Promotes renal reabsorption of Na+ • Helps regulation of acid via reciprocal relationship with HCO3• Renal acid excretion depends bicarbonate reabsorption with chloride excretion

Causes of Hypochloremia (Cl < 95 mmol/l)

Causes of Hyperchloremia ( (Cl > 110mmol/l

• Associate hyponatremia in most cases. • Hypochloremia without hypnatremia are seen in  Vomition,  Sequestration of abomasal secretions in abomasal torsion displacement and impaction

Metabolic and Endocrine 2. Hyperparathyrodism 3. Rebal tubular acidosis 4. Metabolic Acidosis 5. Hypernatremia Gastrointestinal 8. Dehydration 9. Prolonged diarrhea 10.Loss of pancreatic secretion

Potassium Homeostasis: 3.5-4.5 mmol/L

20 meq intravascular

K

+

4200 meq Intracellular

Function of Potassium (K) • It plays an important role in controlling activity of smooth muscle (such as the muscle found in the digestive tract) and skeletal muscle as well as the muscles of the heart. • Both hypokalemia and hyperkalemia can lead to abnormal heart rythm. • It is also important for normal transmission of electrical signals throughout the nervous system within the body.

Causes of Hypokalemia (K< 3.5 mmol/l)

Causes of Hyperkalemia ( (K > 6.5 mmol/l

Potassium loss • Poor renal excretion • K+-sparing diuretics 2.Diuresis • Renal failure with 3.Tubular renal failure 4.Gastrointestinal loss acidosis Intracellular displacement • Cell death • Burns, Crush (Alkalosis) Inadequate intake injury/tissue necrosis Hyperaldosteronism • IV K infusion • Hypoaldosteronism • Dehydration and hemolysis

Signs of Hypokalemia (K< 3.5 mmol/l)

Signs of Hyperkalemia ( (K > 6.5 mmol/l

1. Irregular heartbeat, 2. Extreme thirst; 3. Frequent urination; and confusion. 4. Muscle weakness, cramping, or flaccid paralysis; 5. Severe cases can result in cardiac arrest and paralysis of the lungs.

1. It may be a symptomatic 2. Nausea 3. Fatigue, 4. Muscle weakness, 5. Slow heartbeat and weak pulse. 6. Severe hyperkalemia can result in fatal cardiac arrest

Hypokalemic ECG: P waves become peaked and PR interval increased. depression of ST segment, T waves flattened and U wave more prominent.

Hyperkalemia ECG: shortened PR interval , prominent U waves , inverted T waves , increased R wave amplitude , increase QRS duration

Tissues and cellular osmolality • Osmolality is a count of the number of particles in a fluid sample intra and extracellular • It is affected by the levels of electrolyte, fine particles e.g glucose, urea, plasma proteins. • In ECF it is about 300 mosmol (Isoosmolality) • More than 300 mosmol ( Hyeprosmolality) • Less than 300 mosmol ( Hypoosmolality) • Water moves towerd hyperosmolalit

Tissues and cellular osmolality Serum Osmolality: • It is measured via levels of NA, K, Urea, sugar as follow: • mOsm/kg= 2 (Na + K mmol/l) in normal blood sugar and urea levels • mOsm/kg= 2 {Na + K mmol/l)} + {glucose (mg/dl) / 18} + BUN (mg/dl) / 28. in increased blood sugar and urea levels

Hyperosmolality • It occurs when levels of Na, glucose, urea, ketones increased in blood. • Hyperosmolaity (Counted osmolitity increased by > 30 mosmol • It indicated the presence of fine toxic molecules in blood (ethyl glycol, ethyl propylene) that results in moving fluids into extracellular fluids and shrinkage of cells and hiding of dehydration

Hypo-osmolality • It associate hyponatremia • Hypo-osmolality leads to moving fluids from extracellular to intracellular space resulting in swelling and rupture of cells • Swelling of RBCs lead to its hemolysis, nervous signs, Hburia • Hypo-osmolality with dehydration worsen the condition because of fluid retention intracellular that may lead to Circulatory collapse.

Fluid Movements