FLUID AND ELECTROLYTE BALANCE WATER

FLUID AND ELECTROLYTE BALANCE WATER

Water is the solvent of life.

It is more important than any other single compound to life.

Water is comprised of two atoms of hydrogen and one atom of oxygen.

H₂O

DISTRIBUTION OF WATER

Water is a major body constituent.

An adult human contains about 70% of water.

This water is distributed in

 Intracellular space (inside the cells).

Extracellular space (outside the cells)

Fluid present in the intracellular space is known as intracellular fluid (ICF).

Fluid present outside the cells is known as extracellular fluid (ECF).

ECF is further divided into :

Interstitial fluid, and

plasma.

Distribution of water in an adult man

FUNCTIONS OF WATER

It provides the aqueous medium to the organisms which is essential for the various biochemical reactions to occur.

It serves as a vehicle for transport of solutes.

Helps in regulation of body temperature.

WATER AND FLUID BALANCE

Water and fluid balance is achieved in a health individual by balancing the daily water intake and water output.

WATER METABOLISM

INTAKE

Water is ingested in the form of drinking water, drinks and beverages, water content of solid foods (fruits, vegetables, etc.)

Sources of water

Exogenous water: It includes ingested water and beverages and water content of solid foods.

Water intake is highly variable which may range from 0.5 to 5 liters.

Ingestion of water is mainly controlled by a thirst centre located in the hypothalamus.

2. Endogenous water: it is the metabolic water produced within the body.

This water (300 – 350 ml/day) is derived from the oxidation of foodstuffs.

On an average about 125 ml of water is generated for 1,000 calories consumed by the body.

It is estimated that :

1 gm of carbohydrate produces 0.6ml of water

1 gm of protein produces 0.4 ml of water

Fat produces 1.1 ml of water.

ABSORPTION:

Water is absorbed in the upper small intestine and distributed by way of blood and lymph into various cells and tissues of the body.

The half life of water in human beings is about 9 days.

EXCRETION:

Water is excreted by all the four routes of excretion---

Skin

Lungs

Kidneys

Intestines

It is excreted in the form of urine, sweat and intestinal secretions.

Urine :

Major route of water loss.

Normal urine output is 1 – 2 liter per day.

2.  Skin :

Loss of water (450 ml/day) occurs through the body surface by perspiration.

Highly depends on the atmospheric temperature and humidity.

3. Lungs:

Loss of water is about 400 ml / day.

Lost through expiration.

Water loss by perspiration via skin and lungs is collectively referred as insensible water loss.

4. Feces :

Water loss is about 150 ml / day.

Tremendously increased in diarrhea.

ELECTROLYTES

The minerals in our blood and other body fluids that carry an electric charge.

These are the compounds which are readily dissolved in water.

They may be positively or negatively charged.

                       E.g.  Na^+,  Cl^-  .

These are required for normal cellular functions and survival.

The concentration of electrolytes are expressed as mill equivalents per liter (mEq/l).

FUNCTIONS

Electrolytes play a critical role in almost every metabolic reaction in the body. For example, they:

Help control water balance and fluid distribution in the body.

Create an electrical gradient across cell membranes that is necessary for muscle contraction and nerve transmission

Regulate the acidity (pH) of the blood

Help regulate the level of oxygen in the blood

Are involved in moving nutrients into cells and waste products out of cells

ELECTROLYTES DISTRIBUTION IN BODY

Electrolytes are well distributed in the body fluids in order to maintain 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.

There is a marked difference in the concentration of  electrolytes (cations and anions) between ECF and ICF.

This difference in the concentration is essential for the cell survival.

Mechanism controlling fluid and electrolyte movement

Diffusion

 Facilitated diffusion

 Active transport

 Osmosis

 Hydrostatic pressure

 Oncotic pressure

Diffusion

Movement of molecules from an area of high concentration to low concentration.

Occurs in liquids, solids, and gases.

Membrane separating two areas must be permeable to substance for diffusion to occur

Facilitated Diffusion

 Very similar to diffusion

 Specific carrier molecules involved to accelerate diffusion

Active transport

Process in which molecules move against concentration gradient

Example: sodium-potassium pump

Osmosis

Movement of water between two compartments by a membrane permeable to water but not to a solute

 Water moves from area of low solute concentration to area of high solute concentration

 Requires no energy

Hydrostatic Pressure

Amount of pressure required to stop osmotic flow of water

 Water will move from less concentrated to more concentrated side

 Determined by concentration of solutes in solution

Oncotic Pressure

Force within a fluid compartment

 Major force that pushes water out of vascular system at capillary level

Regulation of Water Balance

 Hypothalamic regulation

 Pituitary regulation

 Adrenal cortical regulation

 Renal regulation

 Cardiac regulation

 Gastrointestinal regulation

 Insensible water loss

Electrolyte imbalance

Sodium (Na+) (135-145 mmol/liter)
 

Sodium is the major positive ion (cation) in fluid outside of cells (ECF).

 The chemical notation for sodium is Na+.

Excess sodium (such as that obtained from dietary sources) is excreted in the urine.

Sodium regulates the total amount of water in the body and the transmission of sodium into and out of individual cells also plays a role in critical body functions.

 Many processes in the body, especially in the brain, nervous system, and muscles, require electrical signals for communication.

The movement of sodium is critical in generation of these electrical signals.

Too much or too little sodium therefore can cause cells to malfunction, and extremes in the blood sodium levels (too much or too little) can be fatal.

 Hypernatremia

excess sodium in relation to water.

Serum sodium level > 145 mmol/L.

There are numerous causes of hypernatremia; these may include kidney disease, too little water intake.

Manifestations:

Convulsions,

pulmonary edema,

 tachycardia.

Elevated hematocrit and serum sodium level

• Hyponatremia

Serum sodium level <135 mmol/L

Causes includes: vomiting, sweating, burns, etc.

Clinical manifestations

Abnormal mental status

Confusion

Decreased consciousness

Hallucinations

Possible coma

Convulsions

Fatigue

Headache

Irritability

Loss of appetite

Muscle spasms or cramps

Muscle weakness

Nausea

Restlessness

Vomiting

Potassium (K+) ( 3.5 - 5.0  mEq/L )

Potassium is the major positive ion (cation) found inside of cells (ICF).

The chemical notation for potassium is K+.

 The proper level of potassium is essential for normal cell function.

 Among the many functions of potassium in the body are regulation of the heartbeat and the function of the muscles.

A seriously abnormal increase in potassium (hyperkalemia) or decrease in potassium (hypokalemia) can profoundly affect the nervous system and increases the chance of irregular heartbeats (arrhythmias), which, when extreme, can be fatal.

HYPERKALEMIA

Increased potassium is known as hyperkalemia (>5.0 mEq/l).

 Potassium is normally excreted by the kidneys, so disorders that decrease the function of the kidneys can result in hyperkalemia.

 Certain medications may also predispose an individual to hyperkalemia.

Clinical manifestations

Nausea

Slow, weak, or irregular pulse

Sudden collapse, when the heartbeat gets too slow or even stops

Hypokalemia

Hypokalemia refers to  decreased potassium level (< 3.5mEq/l).

Can arise due to kidney diseases; excessive loss due to heavy sweating, vomiting, or diarrhea, eating disorders, certain medications, or other causes.

Clinical manifestations

Abnormal heart rhythms (dysrhythmias), especially in people with heart disease

Constipation

Fatigue

Muscle damage (rhabdomyolysis)

Muscle weakness or spasms

Paralysis

Chloride (98 - 108 mmol/L)

Chloride is the major anion (negatively charged ion) found in the fluid outside of cells and in the blood.

Chloride also plays a role in helping the body maintain a normal balance of fluids.

HYPERCHLOREMIA

It refers to Increased chloride level              (>108 mmol/L)

 Elevations in chloride may be seen in certain kidney diseases. 

HYPOCHLOREMIA

It refers to decreased chloride (<98 mmol/L).

 Chloride is normally lost in the urine, sweat, and stomach secretions.

Excessive loss can occur from heavy sweating, vomiting, and adrenal gland and kidney disease.

CALCIUM (8.5 – 10.5 mg/dl) 

Calcium is a mineral found mostly in  bones, where it builds and maintains bone strength.

 A small amount of calcium is also found in muscle and blood cells.

Important roles: 

helps muscles contract

helps nerves and the brain work properly

helps regulate (control) your heart rhythm and blood pressure

Hypercalcemia

Increased serum level of calcium (>10.5 mg/dl).

Causes

Hyperparathyroidism ( one or more of the parathyroid glands produces too much Pth. This, in turn, causes the bones to release too much calcium into the blood.

Kidney disease

Clinical manifestations

Stones (renal or biliary)

Bones (bone pain)

Groans (abdominal pain, nausea and vomiting)

 polyuria

Psychiatric overtones (Depression 30-40%, anxiety, insomnia, coma)

Hypocalcaemia

Presence of low serum calcium levels in the blood, usually taken as less than 2.1 mmol/L or 8.5 mg/dl.

Causes

Eating disorders

Exposure to mercury

Excessive dietary magnesium, as with supplementation.

Prolonged use of medications/laxatives containing magnesium

Absent parathyroid hormone (PTH)

Magnesium 1.5 – 2.5 mg/dl
(0.7mol/lit)

It helps maintain normal muscle and nerve function, keeps heart rhythm steady, supports a healthy immune system, and keeps bones strong. Magnesium also helps regulate blood sugar levels, promotes normal blood pressure, and is known to be involved in energy metabolism and protein synthesis

Hypermagnesemia is an electrolyte disturbance in which there is an abnormally elevated level of magnesium in the blood.^[1] Usually this results in excess of magnesium in the body.

Weakness, nausea and vomiting

Impaired breathing

Decreased respirations

Hypotension

Hypercalcemia

Arrhythmia and Asystole

Decreased or absent deep tendon reflexes

Bradycardia

an abnormally low level of magnesium in the blood

Deficiency of magnesium causes weakness, muscle cramps, cardiac arrhythmia, increased irritability of the nervous system with tremors, athetosis, jerking, nystagmus and an extensor plantar reflex. In addition, there may be confusion, disorientation, hallucinations, depression, epileptic fits, hypertension, tachycardia and tetany.

[edit]Causes

causes

 not enough magnesium in the diet, the intestines are not absorbing enough magnesium, or the kidneys are excreting too much magnesium.

DEHYDRATION

A Condition characterized by water depletion in the body.

It’s causes are:

Insufficient intake of water

Excessive loss of water.

Like in case of diarrhea, vomiting, excessive sweating, fluid loss in burns, kidney disease, etc.

Types of dehydration

It is classified into two types:

Diarrhea with loss of water alone

Diarrhea with deprivation of water and electrolytes.

Symptoms

Mild to moderate dehydration is likely to cause:

Dry, sticky mouth

Sleepiness or tiredness

Thirst

Decreased urine output

Few or no tears when crying

Dry skin

Headache

Constipation

Dizziness or lightheadedness

Severe dehydration, a medical emergency, can cause

Extreme thirst

irritability and confusion

Very dry mouth, skin and mucous membranes

Lack of sweating

Little or no urination — any urine that is produced will be dark yellow or amber

Sunken eyes

dry skin that lacks elasticity and doesn't "bounce back" when pinched into a fold

Low blood pressure

Rapid heartbeat

Rapid breathing

Fever

In the most serious cases, delirium or unconsciousness

Treatments

The only effective treatment for dehydration is to replace lost fluids and lost electrolytes. The best approach to dehydration treatment depends on age, the severity of dehydration and its cause.