Brief presentation on water and electrolyte imbalance

1. WATER AND ELECTROLYTE
IMBALANCE

2. COMPOSITION OF BODY FLUIDS
• Water makes 50% of body weight of women and
60% of that of men
• Two major compartments
• Intracellular fluid 55-75%
• Extracellular fluid 25-45%
• Major ECF particle – sodium, chloride and
bicarbonate ions
• ICF particle – potassium and organic phosphate
esters

8. • OSMOLALITY AND OSMOLARITY
Osmolal concentration of a solution is
called osmolality when the concentration is
expressed as osmoles per kilogram of water,
it is called osmolarity when it is expressed as
osmoles per litre of solution.

9. BLOOD VOLUME
• Blood contains both extracellular fluid (the fluid
in plasma) and intracellular fluid (the fluid in
the red blood cells).
• However, blood is considered to be a separate
fluid compartment because it is contained in a
chamber of its own, the circulatory system.
• About 60 percent of the blood is plasma and 40
percent is red blood cells, but these percentages
can vary considerably

10. HEMATOCRIT ( PACKED CELL VOLUME )
• Hematocrit is the fraction of the blood
composed of red blood cells, as determined by
centrifuging blood in a hematocrit tube until the
cells become tightly packed in the bottom of the
tube.
• Men – 0.40
• Women – 0.36

11. EQUILIBRIUM BETWEEN INTRACELLULAR AND
EXTRACELLULAR FLUID
• The distribution of fluid between
intracellular and extracellular
compartments, in contrast, is determined
mainly by the osmotic effect of the
smaller solutes—especially sodium,
chloride, and other electrolytes—acting
across the cell membrane. The reason for
this is that the cell membranes are highly
permeable to water but relatively
impermeable to even small ions such as
sodium and chloride. Therefore, water
moves across the cell membrane rapidly
and the intracellular fluid remains
isotonic with the extracellular fluid.

12. OSMOSIS AND OSMOTIC PRESSURE
• When there is concentration difference for water
net movement of water does occur across the cell
membrane, causing the cell either to swell or
shrink, depending on the direction of the water
movement. This process of net movement of
water caused by a concentration difference of
water is called osmosis.
• The exact amount of pressure required to stop
osmosis is called the osmotic pressure of the
sodium chloride solution.

14. OSMOLARITY OF BODY FLUIDS
• about 80 percent of the total osmolarity of the interstitial
fluid and plasma is due to sodium and chloride ions,
whereas for intracellular fluid, almost half the osmolarity
is due to potassium ions and the remainder is divided
among many other intracellular substances. the total
osmolarity of each
• of the three compartments is about 300mOsm/L, with
the plasma being about 1mOsm/L greater than that of
the interstitial and intracellular fluids. The slight
difference between plasma and interstitial fluid is caused
by the osmotic effects of the plasma proteins, which
maintain about 20mm Hg greater pressure in the
capillaries than in the surrounding interstitial spaces

15. FLUID SHIFTS AND OSMOLARITIES AFTER INFUSION
OF HYPERTONIC SALINE

16. HYPOVOLEMIA
Combined sodium and water loss
• Renal causes – increased urinary sodium and
water loss
exogenous mannitol and pharmacologic
diuretics
• Extrarenal causes – GIT, skin and respiratory
system
third spacing in sepsis, burns, peritonitis,
pancreatitis

21. HYPONATREMIA
• It results from loss of sodium containing fluids
with a shift of water into the cells
• Sodium concentration < 135 mM
• Causes : GI loss – diarrhea, vomiting
Renal loss – diuretics, adrenal
insufficiency
Skin loss – burns, wound drainage

22. MANAGEMENT OF HYPONATREMIA
• Sodium replacement via orals
• Lactate ringers solution
• 0.9% sodium chloride
• Serum sodium must not increase more than 12
meq/L in 24 hrs

23. HYPERNATREMIA
• Higher than normal sodium level > 145 meq/L
• CAUSES : gain of sodium in excess of water
inadequate water intake
increased serum sodium concentration
• MANAGEMENT : hypotonic electrolyte infusion
0.3% sodium chloride
diuretics

25. HYPOKALEMIA
• Plasma potassium concentration < 3.5mM
• CAUSES : Decreased intake
renal loss
GI loss
magnesium deficiency
• TREATMENT : oral replacement
IV potassium chloride

26. HYPERKALEMIA
• Plasma potassium level of 5.5mM
• CAUSES : pseudohyperkalemia
excess intake or tissue necrosis
hypoaldosteronism
renal disease
drugs

27. MANAGEMENT OF HYPERKALEMIA
• Intravenous calcium gluconate
• Insulin infusion
• Removal of potassium by diuretics or dialysis
• Sodium polysterone sulphate
• Novel potassium binder - patiromer

28. HYPERCALCEMIA
• Causes – excess PTH production
hypercalcemia of malignancy
excess calcium intake
endocrine disorders
increase in bone resorption
management – hydration
bisphosphonates
denosumab [ RANKL antibody ]

29. HYPOCALCEMIA
• Causes – Vit D deficiency
parathyroid agenesis/destruction
pancreatitis,rhabdomyolysis
PTH resistance syndromes
drugs
Clinical features
chovstek’s sign
trousseau’s sign

30. MANAGEMENT OF HYPOCALCEMIA
• Intravenous calcium gluconate
• Elemental calcium
• Vitamin D
• PTH ( 1-84) Natpara

31. GIBBS DONNAN EQUILIBRIUM
• If diffusible solutes are
separated by a
membrane that is freely
permeable to water and
electrolytes but totally
impermeable to one
species of ions, the
diffusible ions become
unequally distributed
between the two
compartments

32. GOLDMAN HODGKIN KATZ EQUATION
• To determine the reverse potential across a cell
membrane

33. NERNST EQUATION
• Relates the membrane potential to the
distribution of an ion at equilibrium
• Ecell = E0 – (RT/nF) lnQ

35. THANK YOU