water electrolytes part clinical biochemistry

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  • 8/15/2019 Water Electrolytes Part Clinical Biochemistry

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    Faculty of Health Sciences

    Universiti Kebangsaan Malaysia

    Puan Farah Wahida Binti Ibrahim

    Programme of Biomedical Science

    School Of Diagnostic & Applied Health Sciences

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    ……the solvent for biochemical reactions

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      roperties of Water

    • Solvent of life

    • Dipolar molecule

    • Unique properties

    • Hydrogen bonding potential

    •   olar nature

    • Biomedical importance of water;

    • Temperature regulation

    •us!ioning and lubricating

    • "eactant

    • Solvent

    • Transport

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    Water ontent

    Neonate 1 year 10-50 years >50 years

    79% 65% 60% (male)

    50% (female)

    60-52% (male)

    50-46% (female)

    • Water content of t!e !uman body in relation to age and se#

    $figures represent percentages of body weig!t%

    • H&' ( depends on body mass) lean muscle mass $contain

    *+() fat tissues contain &,(%

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    Water Distribution-ompartments

    Distribution Body water

    (ml/kg)

    Body weight

    (%)

    Body water

    (%)

    Total body water

    600 60.0 100.0

    Intracellular 330 33.0 55.0

    Extracellular 270 27.0 45.0

    Intravascular

    (plasma volume)

    45 4.5 7.5

    Interstitial

    lymph

    a)

    120 12.0 20.0

    Connective tissue

    Cartilageb)45 4.5 7.5

    Bonesb) 45 4.5 7.5

    Transcellularc) 15 1.5 2.5

     65% 60% (male)

    50%(female)

    60-52% (male)

    50-46% (female)a) Including 25% rapid distribution compartment of denser connective tissue.

    b) About 75% of connective tissue and bone is not measured by indicator substances (e.g.

    saccharose).

    c) Measured by active transport of substances by body cells.

    Mean values for total body water and distribution in young healthy adults

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    • Water losses come from t!e water contained in urine and

    stools and from insensible losses $loss of water via t!e s=in

    and lungs%>• Under normal conditions water inta=e and water loss are in

    balance

    Table 4: Daily water balance in adults

    Water intake

    • water intake in form of fluids (volumes of drinks

    including soups)

    1000-1500 ml

    • water intake in form of semi-solid and solid foods 700 ml

    • water from oxidation 300 ml

    Total daily water intake 2000-2500 ml

    Water output

    • water loss in urine 1000-1500 ml

    water loss through skin 500 ml• water loss through lungs 400 ml

    • water loss in stools 100 ml

    Total daily output 2000-2500 ml

    Water Homeostasis

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    Substrate

    oxidation Amount

    Water

    produced

    Lipids 100 g 107 ml

    Carbohydrates 100 g 55 ml

    Proteins 100 g 41 ml

    • T!e inta=e of water may come in t!e form of solid food or

    liquids>•

    4 furt!er source is t!e water resulting from t!e o#idation offood substrates in t!e body

    Water Homeostasis

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    Table 5: Additions to minimum water requirement,

    depending on the clinical situation in adults

     Additional daily requirement for osmotically free water

    temperature elevation by 1° C 0.1 - 0.3 l• moderate sweating 0.5 l

    • marked sweating, high fever 1.0 - 1.5 l

    • hyperventilation 0.5 l

    hyperventilation in very dry surroundings 1.0 - 1.5 l• exposed wound surfaces and body cavities

    (operation lasting up to 5 hours)

    0.5 - 3.0 l

    • T!e minimum daily water loss in an adult is about 6@,, ml>• 'f t!is) 81, ml is insensible loss) 6,, ml is in faeces and

    @*, ml is in urine $A6& m'sm-day of substances eliminated in

    urine wit! a ma#imum ac!ievable urinary osmolality of 6&,,

    m'sm-l%>• T!ere may be furt!er requirements to be considered)

    depending on t!e clinical situation

    Water Homeostasis

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    Water "egulation

    Hormones

    6> 4ntidiuretic !ormone $4DH%

    • or vasopressin• Produced by t!e posterior !ypot!alamus to reduce

    diuresis and increase water retention if serum

    osmolality increases or blood volume decreases

    &> "enin0angiotensin0aldosterone system

    • if blood flow decreases) t!e 9u#taglomerular cells in

    t!e =idneys secrete renin  production of

    angiotensin .. $vasoconstrictor%  stimulates

    aldosterone production  regulates reabsorption ofsodium and water in t!e nep!ron

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    /> 4trial natriuretic peptide $4

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    :luid S!ift-Water 3ovement

    • :actors controlling fluid e#c!anges

    • Diffusion 7 passive transport; movement of water) small

    molecules and ions from area wit! !ig! concentration to

    areas of lower concentration across semipermeablemembrane resulting in equal distribution of solutes

    • 4ctive transport 7 uses 4TP to move solutes from an area

    of low C ) egE

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    :luid S!ift-Water 3ovement

    •s!ifting is due to disease or in9ury

    •accumulation of fluids in tissue or in body cavity $t!ird space

    compartments% 7 egE liver disease

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    De!ydration

    F / 3a9or TypesF .sotonic

    F Hypotonic

    F Hypertonic

    Disorders of Water Balance

    'ver!ydration

    •/ 3a9or Types•

    .sotonic 0 e#pansion of t!e 5: only

    •Hypotonic 0 e#pansion of bot! t!e 5: and t!e .:

    compartments

    •Hypertonic 0 e#pansion of t!e 5: and contraction

    of t!e .:

    • T!ere are two fundamentally different disorders of water

    balance E de!ydration and over!ydration>

    • Depending on t!e e#tracellular

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    Disturbances of Water Balance

    Water and Solute Water OnlyGain Hypervolemia

    •Too much of water and solute

    intake

    •ECF vol ↑

    •Osmolarity constant

    •Eg : isotonic iv infusion

    Overhydration

    •Too much water intake

    •ECF vol ↑

    •Osmolarity ↓

    •Eg : drinking too much

    waterLoss Hypovolemia

    •Water and solute loss at the same

    time

    •Plasma vol ↓•Osmolarity normal, although vol is

    •Eg : blood loss

    Dehydration

    •Water is loss

    •Plasma vol ↓

    •Osmolarity ↑ because nosolute is loss

    •Eg : sweating

    • Gain or loss of ECF• Gain or loss of solute

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    .sotonic Status

    Overhydration Dehydration

    H2O Excess Deficient

    Na+ Excess Deficient

    SerumOsmolarity

    Normal Normal

    ECF vol Elevated Reduced

    ICF vol Normal Normal

    ClinicalSymtoms

    Oedema! effusions! hyertensiondysnoea"

    #hirst! tiredness! faintin$! collase!vomitin$! hyotonia! muscle crams!raid ulse

    Causes E$ % Excessive administration ofisotonic infusion solutions inoli$uric or anuric states! cardiacfailure! nehrotic syndrome!chronic uraemia! acute$lomerulonehritis! liver cirrhosis!rotein&losin$ enteroathy"

    E$ % 'lood loss! vomitin$! diarrhoea!fistulae! diuretics! draina$e ofascites! (ith eritonitis! 'urns!sedative and car'on monoxideintoxication! sunstro)e

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    Hypotonic Status

    Overhydration Dehydration

    H2O excess *more than Na+ deficient,loss

    Na+ excess deficient *Na+ loss more thanH2O

    SerumOsmolarity

    reduced lo(

    ECF vol elevated *fluid overload reduced *fluid shifted to ICF

    ICF vol elevated *diffusion from ECF elevated *diffusion from ECF

    ClinicalSymtoms

    -ea)ness! nausea! vomitin$!dysnoea! confusion! loss ofconsciousness"

    #iredness! faintin$! hyotonia!vomitin$! collase! fever! musclecrams! raid ulse! deressedconsciousness level

    Causes E$ % Excessive administration of

    salt&free solutions! $astric lava$e(ith (ater! increased .DH activity!liver failure

    E$ % Inade/uate sodium inta)e after

    vomitin$! diarrhoea! s(eatin$"Increased sodium losses due toadrenal failure! adrenalectomy!chronic diuretic theray *thia0ides!diarrhoea! fistula losses

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    Hypertonic Status

    Overhydration Dehydration

    H2O Excess Deficient *H2O loss $reater than Na+

    Na+ Excess *more than H2O Deficient

    SerumOsmolarity

    Increased Increased

    ECF vol Elevated Reduced

    ICF vol Reduced *osmolarityincreased  Due to diffusion

    Reduced *osmolarity increased  Due to diffusion

    ClinicalSymtoms

    1omitin$! diarrhoea! ulmonaryoedema! restlessness! chan$esin central venous ressure"

    #hirst! fever! dryness! restlessness!delirium! coma"

    Causes E$ % Excessive administration

    of NaCl! drin)in$ of sea (ater!Conns syndrome! Cushin$ssyndrome! administration ofsteroids"

    E$ % Inade/uate (ater inta)e! or

    increased (ater losses due to s(eatin$!osmotic diuretics! hyerventilation!chronic nehroathy! olyuric hase ofacute renal failure! dia'etes insiidus"

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    .3P'"T4 Severe de!ydration

    can lead to !ypovolaemic s!oc=) organ failure and deat!

    •T!e t!ree elements to assessing fluid balance and !ydration

    status areE clinical assessment) body weig!t and urine output;

    review of fluid balance c!arts; and review of blood c!emistry

    •:luid balance recording is often inadequate or inaccurate often

    because of staff s!ortages) lac= of training or lac= of time

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    IMPORTANT KEYPOINTS• Understand the concept behind the keywords : eg. hypo-, hyper-, iso-,

    euvolemia

    • Understand the physiology of fluid and electrolytes balance in order

    to understand the disturbance/disequilibrium (keypoints in

    diagnosis)•

    the distribution of electrolytes (intra or extra) shifting isconsidered as disturbance

    • the physiological function, eg : electrolytes important for

    neurological function, disturbances to the equilibrium causes

    neurological symptoms

    • Electrolyte disturbances are essentially always secondary processes.

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    • Understand the management and treatment (depends on aetiology

    and severity)

    • Effective management requires identification and treatment of the

    underlying primary disorder.

    • Since neurological symptoms of electrolyte disorders are generallyfunctional rather than structural, the neurologic manifestations of

    electrolyte disturbances are typically reversible

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    TASKS• Divide into three groups, presentation is on 19 Oct 2015 (20 mins/group)

    • One group/topic :• Water/Fluid• Sodium, Calcium, Phosphate,• Kalium, Magnesium, Chloride

    Content :• Physiological Function• Distribution• Disturbances

    • Causes• Who are at risks? (inlcuding who is at higher risk of getting

    fluid/electrolyte imbalance)• Signs/symptoms• Diagnosis (sample to use and why, tests)• Management and treatment

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    GOOD LUCK!!!!!