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!!!!!