water and electrolyte homeostasis for vet. students
TRANSCRIPT
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Examination of Body FluidsWater and Electrolytes
byDr. Ali H. Sadiek
Prof. of Internal Veterinary Medicine and Clinical Laboratory Diagnosis
Faculty of Veterinary Medicine, Assiut UniversityE-mail: [email protected]
Course Objectives1. 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.
INTRACELLULAR
VASCULARE
XT
RA
CE
LL
UL
AR
1/3 2/3
INTERST IT IAL
Fluid Compartments
K+
Mg2+
PhosphatesProteins
Na+
Cl-
HCO3-
Fluid Compartments
Extracellular Intracellular
Ca 2+
mmol cations = mmol anions
•H2O freely permeable
Water Balance
65 %
32 %
3 %
60 %
25 %
13 % 2 %
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:
1. Dehydration: Water loss > water gain.
2. 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. Diarrhea: Acute, continuous in neonates
2. Vomiting for long periods
3. Fever: continuous fever
4. Sweating: severe in race horse, accompany colic.
5. Severe burns and severe hemorrhage.
6. Polyuria and renal failure.
7. Ruminal impaction, obstructed bowel and Schok
8. Water deprivation
9. Fasting for a long period.
Dehydration and water balance
oligouria
Clinical Evaluation of Dehydration
1. Character of feces: Very loose or runny feces are at a high risk
of being dehydrated.
2. 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
3. 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. Increased RBCs count.
2. Increased PCV.
3. Increased Hb.
4. Increased plasma proteins.
5. Increase urea in blood.
6. Increased Sp. Gravity of urine
Clinical and lab. Assessment of dehydration
Fluids required
Ml/kg
Total solids
(g/l)
PCV %
Sunken eye
Skin tinting check
%Water loss
20-25 70-80 40-45 + -4-6
30-50 80-90 50 ++2-4 6-8
50-80 90-100 55 +++6-10 8-10
80-120 120 60 +++20-45 10-12
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 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 edema1. Hyponutritional edema.2. Decreased serum albumin assoc. renal, hepatic,
parasitic infections.3. Long lasting protein loss (Johnes, fasciola,
hemonchus) .4. Renal edema: Loss of albumin
Breaskt edema Right sided heart failure
Distended Jugular veinRight 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
+Na 15 147 142
+K 155 4 5
+Ca 2 2.5 -
Cations
Mg+ 27 1 2
HCO3- 10 30 27
Cl- 1 114 103
PO4- 100 2 2
SO4- 20 1 1
Anions
Organic acids 1 7.5 -
proteins 62 - 16
AnionGap: It is about 8-12 mmol/L AG= ( [Na+]+[K+] ) - ( [Cl-]+[HCO3-] ) AG= ( [Na+] ) - ( [Cl-]+[HCO3-
Electrolyte of Body Fluids (mmol/l)
Fluids Na+ Cl- K+ HCO3- H+ Ca2+
Serum 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 40 30 20 0 0
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 Priorities1. Conserve sodium
2. Excrete free water
3. Conserve free water
Sodium Homeostasis
Extracellular Intracellular
freeH2O
↑freeH2O
Na+
Hyponatremia: Na+ < 135 mmol/L
Hypernatremia Na+ >145 mmol/L
More prevalent than hypernatremia, It Associate:1.Acute hypertonic diarrhea and vomiting2.Surgery and accidents.3.Diuretic therapy4.Tubular nephritis.5.Bacterial and viral infection6.Heart failure.7.Hyperglycemia
Rarely occurred and associate:1.Excess dietary Na.2.Water deprivation.3.Hypotonic diarrhea4.Chronic renal failure.5.Severe burns and fever.6.Hyperaldosteronism
�ٍSigns of Hyponatremia: Na+ < 135 mmol/L
Signs of Hypernatremia Na+ >145 mmol/L
Signs vary acording to degree and acuteness of change
Severe (< 120 meq/L): neuropsychiatric
Anorexia, Nausea and vomiting Lethargy and Fatigue Restlessness and
irritability Muscle weakness,
spasms or cramps Seizures Decreased
consciousness or coma
Symptoms dependent on rate of change, level and volume status
Neuropsychiatric Restlessness
Hyperreflexia Weakness Delirium
Chloride HomeostaisNormal 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 > 110 mmol/l)
1. Associate hyponatremia in most cases.
2. Hypochloremia without hypnatremia are seen in
Vomition, Sequestration of
abomasal secretions in abomasal torsion displacement and impaction
Metabolic and Endocrine 1. Hyperparathyrodism2. Rebal tubular acidosis3. Metabolic Acidosis4. Hypernatremia
Gastrointestinal 1. Dehydration 2. Prolonged diarrhea3. Loss of pancreatic
secretion
Potassium Homeostasis: 3.5-4.5 mmol/L
K+
4200 meq Intracellular
20 meq intravascular
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 loss1.Diuresis
2.Tubular renal failure3.Gastrointestinal loss
Intracellular displacement (Alkalosis)
Inadequate intakeHyperaldosteronism
• Poor renal excretion1. K+-sparing diuretics2. Renal failure with
acidosis• Cell death
• Burns, Crush injury/tissue necrosis
• 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 symptomatic2. Nausea3. Fatigue,4. Muscle weakness,5. Slow heartbeat and
weak pulse. 6. Severe hyperkalemia
can result in fatal cardiac arrest
Hyperkalemia ECG: shortened PR interval , prominent U waves , inverted T waves , increased R wave amplitude , increase QRS duration
Hypokalemic ECG: P waves become peaked and PR interval increased. depression of ST segment, T waves flattened and U wave more prominent.
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