This document provides an overview of fluid and electrolyte balance in the human body. It discusses water intake and output, the distribution and regulation of body water, and hormonal control of fluid balance. Electrolyte composition, distribution, and regulation are described. Common electrolyte imbalances like hyponatremia, hypernatremia, hypokalemia, and their symptoms and treatments are summarized. The document emphasizes the importance of fluid and electrolyte homeostasis for normal physiological functioning.

1. GOOD MORNING

2. FLUID AND ELECTROLYTE BALANCE
Guided by: Dr SHOBHA K.S
Presented by : Dr UDAYKIRAN

3.  contents
o Introduction
o fluid balance
o Functions of water
o Distribution of body water
o Water turnover and balance
o Water intake
o Water output
o Hormonal regulation of urine production
o Dehydration
o Overhydration

4. o Electrolyte balance
o Electrolyte composition of body fluids
o Osmolarity and osmolality of body fluids
o Regulation of electrolyte balance
o Metabolism of electrolytes
o Acid-base balance
o Maintenance of blood pH
o Disorders of acid-base balance

5.  The organism possesses tremendous capacity to survive against odds maintaining
homeostasis
 This is particularly true with regards to water , electrolytes and acid base status of
the body
 Water is the most abundant substance in living systems , making up 70% or more
of the weight of most organisms

6. Fluid balance

7. What is a fluid ?
A substance that has no fixed shape and yields easily to external
pressure ;
fluid can be either a gas or a liquid
(or)
A fluid is a substance that has the capacity to flow and assume the
form of the container into which it has been poured

9. Distribution of body water
 Total body water in an adult of 70kg varies from 60-70%(36-49 litres)of total
body weight
 The body water can be visualized to be distributed mainly into two
compartments:
 Intracellular fluid(ICF)
 Extracellular fluid(ECF)

10. Total body water(60-70%)
(36-49L)
ICF(50%)
35 L
ECF(20%)
14 L
Interstitial tissue fluid(ITF)
15% - 11 L
Plasma intravascular fluid(IVF)
5% - 3 L

11.  The extracellular compartment must be recognized as more heterogenous
and should be subdivided into four more subdivisions:
I. Plasma
II. Interstitial and lymph fluid
III. Fluid of dense connective tissue , cartilage and bone
IV. Transcellular fluid

14. Water turnover and balance
 The body possesses tremendous capacity to regulate its water content in a healthy
individual.
 This is achieved by balancing the daily water intake and water output
 Water intake :
water is supplied to the body by:
A. Exogenous sources
B. Endogenous sources

15. EXOGENOUS WATER
 Ingested water and beverages , water content of solid foods constitute the
exogenous sources of water
 Ingestion of water is mainly controlled by a thirst center located in hypothalamus
 Increase in osmolality of plasma causes increased water intake by stimulating
thirst center

16. ENDOGENOUS WATER
 The metabolic water produced within the body is endogenous water
 300-350 ml/day is derived from oxidation of food stuff
 It is estimated that 1g of carbohydrates , proteins, fats respectively , yield 0.6
ml,0.4 ml and 1.1ml of water
 On an average , about 125ml of water is generated for 1000 calories consumed by
the body

17. Water output
 Four distinct routes for elimination of water from body:
1. Urine
2. Skin
3. Lungs
4. feces

18. Urine
 It is the major route for water loss from the body
 The urine output is about 1-2 l/day
 Water loss through kidneys although highly variable ,is well regulated to meet the
body demand to get rid of water or to retain
 About 500ml/day of water is essential as the medium to eliminate the waste
products from the body
KIDNEYS

19. Hormonal regulation of urine production
 About 180L of water is filtered by glomeruli into the renal tubules everyday
 Most of them is reabsorbed and only 1-2 L is excreted as urine
 Water excreted by kidney is tightly controlled by vasopressin also known as anti
diuretic hormone (ADH) of posterior pituitary gland
 The secretion of ADH is regulated by osmotic pressure of plasma

21. Skin
 Loss of water (450 ml/day)occurs through the body surface by
perspiration
 This mostly depends on atmospheric temperature and humidity
Lungs
During respiration , some amount of water (about 400ml/day)is lost
through the expired air

22. The lost water by perspiration (via skin) and respiration (via lungs) is collectively
referred to as “INSENSIBLE WATER LOSS”
FECES
 About 150ml/day is lost through feces in a healthy individual
 Fecal loss of water is tremendously increased in diarrhea

23. What is fluid balance?
 Fluid balance is a term used to describe the balance of the input
and output of fluids in the body to allow metabolic processes to
function correctly (Welch, 2010).
 Around 52% of total body weight in women and 60% in men
is fluid.

24. Goals of maintenance of fluids
 Prevent dehydration
 Prevent electrolyte disturbance
 Prevent ketoacidosis
 Prevent protein degradation

25. Factors affecting fluid balance
LIFESTYLE FACTORS:
o Exercise
o Stress
o nutrition
DEVELOPMENTAL FACTORS:
o Infants and children
o Adolescents and middle aged adults
o Older adults
PHYSIOLOGICAL
FACTORS:
o Cardiovascular
o Respiratory
o Gastrointestinal
o Renal
o Integumentary
CLINICAL FACTORS:
o Surgery
o Chemotherapy
o Medications
o Gastrointestinal intubation
o Intravenous therapy
Hormones responsible for regulation of fluid and electrolyte balance are:
-Antidiuretic hormone released by posterior pituitary
-Aldosterone secreted by adrenal cortex
-Atrial natriuretic peptide , produced by the heart

26. Abnormalities associated with water balance
-Dehydration
-Overhydration

27. Dehydration
 Dehydration is a condition characterized by “water depletion in the body”. It may
be due to insufficient intake or excessive water loss or both
 Dehydration is generally classified into two types:
1) due to loss of water alone
2) due to deprivation of water and electrolytes

28.  Hypovolemia , also known as water depletion or volume contraction , is
a state of abnormally low extracellular fluid in body
 Hypovolemia is due to either loss of both salt and water or decrease in
blood volume
 Common causes are:
-blood loss
-vomiting
-diarrhea
-burns

29. Causes of Dehydration
 Diarrhea
 Vomiting
 Excessive sweating
 Fluid loss in burns
 Adrenocortical dysfunction
 Kidney diseases
 Deficiency of ADH(diabetes insipidus)

31. Characteristics of Dehydration
There are three degrees of dehydration:
 Mild
-occurs when fluid loss or diminished fluid intake leads to decrease
in total body water content
-it is said that individuals can become dehydrated if they loss just
2% of their total body weight due to water depletion

32.  Moderate
-occurs with fluid deficit of 5-10% in infants and 3-6% in children
-the fluid deficit should be replaced within 4 hours
 Severe
-it is a medical emergency and an advanced state of dehydration
 causes of severe dehydration:
-heat
-illness
-not drinking enough water
-medications such as diuretics used for high BP

33. Thirst mechanism
DECREASED
VOLUME OF ECF
STIMULATES
OSMORECEPTORS IN
HYPOTHALAMIC
THIRST CENTER
INCREASED
OSMOLALITY OF ECF DECREASED
SALIVA
SECRETION
DRY
MOUTH
SENSATION OF
THIRST;PERSON SEEKS
A DRINK
INCREASED
VOLUME OF
ECF
DECREASED
OSMOLALITY
OF ECF
WATER ABSORBED
FROM
GASTROINTESTINAL
TRACT
DRINKS
WATER
= STIMULATION
= INHIBITION

34. Treatment
 Intake of plenty of water
 In subjects who cannot take orally water should administrated IV in an
isotonic solution(usually 5%glucose)
 If dehydration is accompanied by loss of electrolytes, the same should
be administrated by oral or IV route
 This has to be done by carefully monitoring the water and electrolyte
status of the body

35. Overhydration
 Overhydration or water intoxication is caused by excessive retention of
water in the body
 This may occur due to excessive intake of large volumes of salt free
fluids, renal failure, overproduction of ADH
 Overhydration is observed after major trauma or operation , lung
infection
 Water intoxication is associated with dilution of ECF and ICF with
decrease in osmolality

36. Clinical symptoms
 Headache
 Lethargy
 Convulsions
Treatment
 Stoppage of excess water intake
 Administration of hypertonic saline

37. Water tank model

38. Electrolyte balance

39. Electrolyte balance
 Electrolytes are the compounds which readily dissociate in solution and exists as
ions i.e. positively and negatively charged particles
 concentration of electrolytes are expressed as milliequivalents (mEq/L) rather
than milligrams
 The following formula is used to convert the concentration from mg/l to mEq/L
mEq/L= mg per litre valency
atomic weight

40. Electrolyte composition of body fluids
 Electrolytes are well distributed in the body fluids in order to maintain the
osmotic equilibrium and water balance
 The total concentration of cations and anions in each body compartment(ECF and
ICF)is equal to maintain electrical neutrality
K+ HPO4
-
Cl-
HCO3
-
Na+
PROTEINS

42. Osmolality of plasma
 Osmolality is a measure of solute particles present in the fluid medium
 Na+ and its associated anions make largest contribution (90%) to the plasma osmolality
 Osmolality is generally measured by “OSMOMETER”

43. Osmolality of ECF and ICF
 Movement of water across the biological membranes is dependent on the osmotic
pressure difference between the ICF and ECF
 In healthy state the osmotic pressure of ECF which is mainly due to Na+ ions is
equal to the osmotic pressure of ICF , which is predominantly due to K+ ions
 There is no passage of water molecules in or out of the cells, due to this osmotic
equilibrium

44. Normal ranges ,their roles and
disturbances in common electrolytes

45. IONS RANGE FUNCTION DISTURBANCES
134-145mEq/L Helps maintain fluid balance
Needed for muscle
contractions
Helps with nerve signalling
Magnesium 0.75-0.95 mmol/L  Needed for muscle contractions
 Proper heart rhythms
 Nerve functioning
 Bone building and strength
 Reducing anxiety
 Digestion
 Keeping a stable protein-fluid
balance
Phosphorus 0.8 -1.3 mmol/L Formation of bones and teeth
It is also needed for the body to make
proteins for growth , maintenance and
repair of cells and tissues
Hypernatremia
Hyponatremia
Hypermagnesemia
Hypomagnesemia
Hyperphosphatemia
Hypophosphatemia
Sodium

46. IONS RANGE FUNCTION DISTURBANCES
3.5-5.0 mmol/L Keeps blood pressure levels
stable
Regulates heart contractions
Helps with muscle functions
2.20-2.55 mmol/L Helps with muscle contractions
Nerve signalling
Blood clotting
Cell division
Forming/maintaining bones and
teeth
Hyperkalemia
Hypokalemia
Hypercalcemia
Hypocalcemia
Calcium
potassium

47. Regulation of electrolyte balance

48.  Aldosterone-is a mineralocorticoid produced by adrenal cortex
Antidiuretic hormone
 An increase in the plasma osmolality (mostly due to Na+) stimulates hypothalamus to
release ADH
 It effectively increases water reabsorption by renal tubules
Renin-angiotensin: aldosterone secretion is controlled by renin angiotensin system
Aldosterone and ADH coordinate with each other to maintain the normal fluid and
electrolyte balance

49. Electrolyte imbalance

50. Signs of an electrolyte imbalance
 Changes in heartbeat
 Anxiety and trouble in sleeping
 Muscle spasms
 Digestive issues
 Fatigue
 Confusion , dizziness and irritability

51. HYPONATREMIA:
 An imbalance between the total body water accumulation and the
body’s accumulation of electrolytes
 It is defined as concentration of less than 135mEq/l as a result of an
accumulation of total body water greater than the body’s accumulation
of electrolytes (sodium + potassium)

52. Symptoms of hyponatremia
• Nausea and vomiting
• Headache
• Convulsion
• Restlessness and irritability
• Muscle weakness , spasms and cramps
• Seizures
• Loss of energy , drowsiness and fatigue
• coma

53. Treatment of hyponatremia
 Hyponatremia treatment is aimed at addressing the underlying cause, if possible.
 If you have moderate, chronic hyponatremia due to your diet, diuretics or drinking too
much water, recommend temporarily cutting back on fluids. Also suggest adjusting your
diuretic use to increase the level of sodium in your blood.
 If you have severe, acute hyponatremia, you'll need more-aggressive treatment. Options
include:
• Intravenous fluids. Your doctor may recommend IV sodium solution to slowly raise the
sodium levels in your blood. This requires a stay in the hospital for frequent monitoring
of sodium levels as too rapid of a correction is dangerous.
• Medications. You may take medications to manage the signs and symptoms of
hyponatremia, such as headaches, nausea and seizures.

54. HYPERNATREMIA:
 Plasma Na+ >145 mEq/l
 Due to increased sodium and decreased water
Caused due to:
 Excessive intake of sodium
 Excessive sodium retention
 Insufficient intake of water
 Loss of pure water
-long term sweating with chronic fever
-polyuria

55. Symptoms of hypernatremia
• Hypernatremia typically causes thirst
• Serious symptoms include: brain dysfunction
• Severe hypernatremia leads to:
-Convulsion
-Muscle twitching
-Seizures
-Coma
-May cause death

56. Treatment of hypernatremia
 Hypernatremia can occur rapidly (within 24 hours) or develop more slowly over time
(more than 24 to 48 hours).
 All treatment is based on correcting the fluid and sodium balance in your body.
 For mild cases, you may be able to treat the condition by increasing your fluid intake.
 For more severe cases, you’ll likely be connected to an IV drip. That’s used to
intravenously supply fluid to your blood.
 Also monitor you to see if your sodium levels are improving, and adjust your fluid
concentration accordingly.

57. Hypokalemia
 Hypokalemia is when blood's potassium levels are too low.
 Potassium is an important electrolyte for nerve and muscle cell functioning, especially
for muscle cells in the heart.
 kidneys control your body's potassium levels, allowing for excess potassium to leave the
body through urine or sweat.

58. Symptoms of hypokalemia
 Elevation of bp
 Abnormal heart rhythm
 Muscle weakness
 Myalgia
 Tremors
 Muscle cramps
 Constipation
 Flaccid paralysis
 hyporeflexia
Mild hypokalemia
Severe hypokalemia
More severe hypokalemia

59. TREATMENT OF HYPOKALEMIA
 In treating hypokalemia , the first step is to identify and stop ongoing losses of potassium
 Discontinue diuretics/laxatives
 Use potassium sparing diuretics if diuretic therapy is required (eg , severe heart failure)
 Treat diarrhea or vomiting

60. Hyperkalemia
 It is defined as a serum potassium concentration greater than 5.5mEq/L
 The normal serum concentration range of potassium is 3.5-5mEq/L
It is classified into:
 Mild-5.5-6mEq/L
 Moderate-6.1-6.9mEq/L
 Severe->7mEq/L

61. Symptoms of hyperkalemia
 Nausea
 Fatigue
 Muscle weakness or
 Tingling sensation
Serious symptoms include:
 Slow heartbeat
 Weak pulse

62. Treatment of hyperkalemia
 Diet low in potassium(for mild cases)
 Discontinue medication that increase blood potassium levels
 IV glucose and insulin
 IV calcium
 Sodium bicarbonate administration
 Diuretics administration
 Medication such as albuterol , epinephrine that stimulates beta 2 adrenergic receptors
 Dialysis if other measures have failed or if renal failure is present

63. HYPERCALCEMIA
 Hypercalcemia is a condition in which the calcium level in your blood is
above normal
 Hypercalcemia is usually a result of overactive parathyroid glands
 Besides building strong bones and teeth, calcium helps muscles contract
and nerves transmit signals.
 Normally, if there isn't enough calcium in your blood, your parathyroid
glands secrete a hormone that triggers:
• Bones to release calcium into your blood
• Digestive tract to absorb more calcium
• Kidneys to excrete less calcium and activate more vitamin D, which plays a
vital role in calcium absorption

64. SYMPTOMS
 You might not have signs or symptoms if your hypercalcemia is mild.
 More-severe cases produce signs and symptoms related to the parts
of your body affected by the high calcium levels in your blood.
 Examples include:
• Kidneys
• Digestive system
• Bones and muscles
• Brain
• Heart

65. Hypercalcemia is caused by
• Overactive parathyroid glands (hyperparathyroidism)
• Cancer
• Hereditary factors
• Immobility
• Severe dehydration
• Medications
• Supplements

66. TREATMENT OF HYPERCALCEMIA
 If hypercalcemia is mild, we might choose to watch and wait,
monitoring bones and kidneys over time to be sure they remain healthy.
 For more severe hypercalcemia, we might recommend medications or
treatment of the underlying diseases
 In some cases, medication recommend are:
• Calcitonin (Miacalcin)
• Calcimimetics
• Bisphosphonates
• Prednisone
• IV fluids and diuretics

67. HYPOCALCEMIA
 This deficiency may be due to a variety of factors, including:
• poor calcium intake over a long period of time, especially in
childhood
• medications that may decrease calcium absorption
• dietary intolerance to foods rich in calcium
• hormonal changes, especially in women
• certain genetic factors
• Other causes of hypocalcemia
include malnutrition and malabsorption.

68. SYMPTOMS
 Severe symptoms of hypocalcemia include:
• confusion or memory loss
• muscle spasm
• numbness and tingling in the hands, feet, and face
• depression
• hallucinations
• muscle cramps
• weak and brittle nails
• easy fracturing of the bones

69. TREATMENT OF HYPOCALCEMIA
 Commonly recommended calcium supplements include:
• calcium carbonate- which is the least expensive and has the most
elemental calcium
• calcium citrate- which is the most easily absorbed
• calcium phosphate-which is also easily absorbed and doesn’t cause
constipation
 Calcium supplements are available in liquid, tablet, and chewable
forms.

70. HYPERPHOSPHATEMIA:
 High level of phosphate or phosphorous in blood is known as
hyperphosphatemia
 A high phosphate level is often a sign of kidney damage
Symptoms:
• People with high phosphate levels don’t have symptoms
• In some people with chronic kidney disease , high phosphate levels
cause calcium levels in the blood to drop
• Symptoms of low calcium include:
-muscle cramps
-bone and joint pain
-weak bones
-rash
-itchy skin

71. Causes:
 High vitamin D levels
 Damage to cells
 Serious body wide infections
 Diabetic ketoacidosis
Treatment:
-Reduce the amount of phosphate in diet
-Remove extra phosphate with dialysis
-Limit foods that are high in phosphorous such as:
• Milk
• Red meat
• Breads
• Additives and preservatives

72. HYPOPHOSPHATEMIA:
 Low levels of phosphate in the blood
 There are two types of hypophosphatemia:
-Acute hypophosphatemia
-Chronic hypophosphatemia
-familial hypophosphatemia , is rare
Symptoms:
• Muscle weakness
• Bone pain
• Bone fractures
• Irritability
• Appetite loss
• Confusion
• Tooth decay or late baby teeth

73. Causes:
Certain medical conditions can cause hypophosphatemia by:
-Decreasing the amount of phosphate absorption in intestine
-Increasing the amount of phosphate removal through kidneys
-Moving phosphate from inside the cells to the area outside the
cells
Other causes includes:
-Severe malnutrition , such as anorexia or starvation
-Alcoholism
-Severe burns
-Chronic diarrhea
-Vitamin D deficiency

74. Long term or excess use of certain drugs , such as:
-Diuretics
-Antacids
-Theophylline , Bronchodilators
-Corticosteroids
-Mannitol
-Bisphosphonates
Treatment:
• If a medication caused this condition , stop taking the drug
• Taking more phosphate in diet
• Intake of vitamin D supplements

75. Acid base balance

76. Acid base balance
 Acid base balance means regulation of [H+] in the body fluid
 Even slight changes in H+ value from normal can cause marked
alteration in the rate of chemical reaction in the cells
 For this reason the regulation of H+ is the most important aspect of
homeostasis

77.  Normal pH of blood is maintained in narrow range of 7.35-7.45 i.e.
slightly alkaline
 The pH of ICF is rather variable
 The pH of erythrocytes is 7.2
 While in skeletal muscles it may be as low as 6.0

78. Production of acids by body
 The metabolism in the body is accompanied by an overall production of acids
 Like the volatile acids such as carbonic acids ( predominantly about 20,000mEq/day)
 Or non volatile acids (about 80mEq/day) such as lactic acid, sulfuric acid , phosphoric
acid etc.
 All these acids add up H+ ions to the blood

79. Production of bases by body
 The formation of basic compounds in the body in the normal
circumstances is negligible
 Some amount of bicarbonates are generated from the organic acids such
as lactate and citrate
 Ammonia produced in the amino acid metabolism is converted to urea ,
hence its contribution as a base in the body is insignificant

80. Maintenance of blood pH
 The body has developed three lines of defense mechanism to regulate
the bodies acid-base balance and maintain the blood pH
I. Blood buffer system
II. Respiratory mechanism
III. Renal mechanism

81. Blood buffer
 Buffer may be defined as a solution of a weak acid (HA) and its salts
(BA) with a strong base.
 The buffer resists the change in pH by addition of acid or alkali and
 the buffering capacity is dependent on the absolute concentration of
salts and acids
 Blood contains three buffer systems:
1. Bicarbonate buffer
2. Phosphate buffer
3. Protein buffer

82. Bicarbonate buffer system
 Sodium bicarbonate and carbonic acid (NaHCO3-H2CO3) is the most predominant buffer
system of ECF , particularly the plasma
 Carbonic acid dissociates into hydrogen and bicarbonate ions
Henderson- hasselbalch equation:
pH = pKa + log
It is evident from this equation that the pH is dependent on ratio of the concentration
of base to acid
[Base]
[Acid]

83. Blood pH and the ratio of HCO3
- and H2CO3
 The plasma bicarbonate (HCO3
-) Concentration is around 24
mmol/L(range 22-26 mmol/L)
 Carbonic acid is a solution of Co2 in water
 In normal circumstances the concentration of bicarbonates and carbonic
acid determines the pH of blood
 Further , the bicarbonate buffer system serves as an index to understand
the disturbances in acid-base balance in the body

84. Phosphate buffer system
 Sodium dihydrogen phosphate and disodium hydrogen phosphate
(NaH2Po4-Na2HPo4) constitute the phosphate buffer
 Its mostly an intracellular buffer and is of less importance in plasma
due to its low concentration
 Its is established that the ratio of base to acid for phosphate buffer is 4
compared to 20 for bicarbonate buffer

85. Protein buffer system
 The plasma proteins and hemoglobin together constitute the protein buffer system of
blood
 Imindazole group of histidine (pH=6.7) is the most effective contributor of protein buffer
 The plasma protein account for about 2% of the total buffering capacity of plasma
 Hemoglobin of RBC is also an important buffer it mainly buffers the fixed acids ,
besides being involved in the transport of gases (CO2 and O2)

86. Respiratory mechanism for pH regulation
 Respiratory system provides a rapid mechanism for maintenance of
acid-base balance
 This is achieved by regulating the concentration of carbonic acid
(H2Co3) in the blood
 The large volumes of CO2 produced by the cellular metabolic activity
endanger the acid base equilibrium of the body
 In normal circumstances all the CO2 is eliminated from the body in
expired air via the lungs
H2Co3 CO2 +H2O
Carbonic anhydrase

87.  The rate of respiration is controlled by a respiratory center ,located in the medulla of the
brain
 The center is highly sensitive to change in pH of blood
 Any decrease in the blood pH causes hyperventilation to blow off CO2 thereby reduces
the H2Co3 concentration simultaneously ,the H+ ions are eliminated as H2O
 Respiratory control of blood pH is rapid but only a short term regulatory process , since
hyperventilation cannot proceed for long

88. Hemoglobin as a buffer
 Hemoglobin of erythrocytes is also important in the respiratory regulation of pH
 At tissue level, hemoglobin binds to H+ ions and helps transport CO2 and HCo3
- with a
minimum change in pH (referred to as isohydric transport)
 In lungs , as hemoglobin combines with O2 ,H+ ions are removed which combine with
HCo3
- to form H2Co3 the latter dissociates to release CO2 to be exhaled

89. Generation of HCO3
- by RBC
 Due to lack of aerobic metabolic pathways , RBC produce very little
CO2
 The plasma CO2 diffuses into the RBC along the concentration gradient
 where it combines with water to form H2Co3.this reaction is catalyzed
by carbonic anhydrase (also called as carbonate dehydratase)
 In RBC, H2Co3 dissociates to produce H+ and HCO3
-

90.  H+ are trapped and buffered by hemoglobin as concentration gradient of HCO3
- increases
in RBC
 It diffuses into plasma along with concentration gradient ,in exchange for Cl- ions , to
maintain electrical neutrality
 This phenomenon , is referred to as chloride shift, helps to generate HCO3
-
Erythrocyte
CO2 + H2O
CA
H2Co3
HCo3
- + H
HCo3
-
Cl-
Cl-
CO2
HHb
HB
plasma

91. Renal mechanism for pH regulation
 The kidneys regulate the blood pH by maintaining the alkali reserve , besides
excreting or reabsorbing the acidic or basic substances
 Urine pH is normally lower than blood pH – approximately 6.0

92. CARBONIC ANHYDRASE AND RENAL REGULATION
 The enzyme carbonic anhydrase is of central importance in the renal
regulation of pH which occurs by the following mechanisms:
I. Excretion of H+ ions
II. Reabsorption of bicarbonate
III. Excretion of titratable acid
IV. Excretion of ammonium ions

93. EXCRETION OF H+ IONS

94. REABSORPTION OF BICARBONATE

95. EXCRETION OF TITRATABLE ACIDS

96. EXCRETION OF AMMONIUM IONS

97. DISORDERS OF ACID-BASE BALANCE
 The body has developed an efficient system for maintenance of acid base equilibrium
with a result that the pH of blood is almost constant
 The blood pH compatible to life is 6.8-7.8 , beyond that life cannot exist
 Acid base disorders are mainly classified as:
a) ACIDOSIS - a decline in blood pH
b) ALKALOSIS – a rise in blood pH
Metabolic acidosis
Respiratory acidosis
Metabolic alkalosis
Respiratory alkalosis

98.  The four acid-base disorders are primarily due to alterations in either
bicarbonate or carbonic acid
 The metabolic acid-base balance disorder are caused by a direct alteration in
bicarbonate concentration while the respiratory disturbances are due to a
change in carbonic acid level(i.e. CO2)

100. Metabolic acidosis Respiratory acidosis
CAUSES: CAUSES:
-Diabetes mellitus
(ketoacidosis)
-Renal failure
-Lactic acidosis
-Severe diarrhea
-Renal tubular acidosis
-Severe asthma
-Pneumonia
-Cardiac arrest
-Obstruction in airways
-Chest deformities
-Depression of respiratory
center(by drugs e.g. opiates)
SYMPTOMS: SYMPTOMS:
TREATMENT: TREATMENT:
-Rapid and shallow breathing
-confusion
-fatigue
-headache
-sleepiness
Increased heart rate
-head ache
-drowsiness
-confusion
Signs include:
-tremors
-myoclonic jerks
-Bronchodilator medicines and corticosteroids
-Non invasive positive pressure ventilation
-Oxygen if blood oxygen is low
-Treatment to stop smoking
Treatment works in three main ways:
-excreting or getting rid of excess
acids
-buffering acids with a base to
balance blood acidity

101. Metabolic alkalosis Respiratory alkalosis
CAUSES: CAUSES:
-Severe vomiting
-Hypokalemia
-Intravenous
administration of
bicarbonate
-Hyperventilation
-Anemia
-High altitude
-Salicylate poisoning
SYMPTOMS: SYMPTOMS:
TREATMENT: TREATMENT:
-confusion
-head tremor
-lightheadedness
-muscle twitching
-nausea , vomiting
-prolonged muscle spasms
-dizziness
-bloating
-feeling lightheaded
-Discomfort in chest area
-dry mouth
-tingling in the arms
-confusion
This cane be prevented by restricting
oxygen intake into the lungs
e.g. breathing in a paper bag
It is treated by replacing water and
electrolytes(sodium and potassium) while
treating the cause

102. Conclusion:
 Water is the solvent of life.
 Undoubtedly water is more important than any other single compound
in our life
 Fluid movements in the body and fluid electrolyte balance are the
inevitable process for normal body function
 Assessment of body fluids is important to determine causes of
imbalance
 Standard assessment methods include physical examination , serum
electrolytes , and accurate body weight and fluid intake and output
measurements

103. References:
 A MATHER , L BURNETT , DR SULLIVAN , P STEWART . CLINICAL BIOCHEMISTRY
AND METABOLIC MEDICINE.IN:DAVIDSONS PRINCIPLES AND PRACTICE OF
MEDICINE 23RD EDITION PG NO.345-369
 LONGO , FAUCI , KASPER , HAUSER , JAMESON , LOSCALZO .
ELECTROLYTE/ACID BASE BALANCE.IN:HARRISONS MANUAL OF MEDICINE 18TH
EDITION PG NO.3-25
 GUYTON AND HALL . THE BODY FLUIDS COMPARTMENTS:EXTRACELLULAR
FLUIDS;INTERTITIAL FLUIDS AND EDEMA.IN:TEXTBOOK OF MEDICAL
PHYSIOLOGY.INTERNATIONAL EDITION 13TH PG NO.303-321
 LONGO , FAUCI , KASPER , HAUSER , JAMESON , LOSCALZO . HYPERCALCEMIA
AND HYPOCALCEMIA.ENDOCRINOLOGY AND METABOLISM.IN:HARRISONS
MANUAL OF MEDICINE 18TH EDITION PG NO.1159-1167
 MICHEAL M.COX , DAVID L.NESON . WATER .IN:LEHNINGER PRINCIPLES OF
BIOCHEMISTRY 5TH EDITION PG NO.43-63