Transcript Fluid and Electrolyte Imbalance Lecture 2

Fluid and Electrolyte Imbalance
Lecture 2
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Sodium Imbalance
• Normal value ( 135-145mEq/L)
• Sodium is a primary determinant of serum
osmolarity. Increase in sodium lead to increase
osmolarity
• Sodium also has a major role in water
distribution. Sodium and water usually are lost
and gained together
• Sodium is important in creation and
transmission of nerve impulse and muscle
contraction
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• Sodium deficit ( Hyponatremia): defined as
sodium level below 135mEq/L
Can happened in 2 cases :
• Loss of sodium from blood in a proportion that
is higher than loss of water
• Significant increase in water with no change in
sodium content ( dilution hyponatremia)
• Hyponatremia can happened in both
hypervolemia and hypovolemia
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Causes of hyponatremia
• Vomiting, sweating, diarrhea, fistula, use of
diuretics if combined with loss sodium intake
• Deficiency of aldosterone
• ( up normal) Increase anti diuretic hormone(
ADH) such as in syndrome of inappropriate
antidiuritic hormone ( SIADH).
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Clinical manifestations of
hyponatremia
• With minor change Poor skin turgor, headache,
dry mucosa, orthostatic hypotension
• With a level of less than 115mEq/L neurologic
changes such as alteration in mental status,
increase intracranial pressure seizure and coma.
• Hyponatremia results in accumulation of water in
brain tissue ( cerebral edema) due to osmotic
gradient.
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Diagnostic findings in hyponatremia
• Decrease serum sodium ( less than
135mEq/L)
• Decrease urine sodium to less than 20mEq/L
as the kidney try to conserve sodium
• Low urine specific gravity (1.002-1.004)
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Management of hyponatremia
• Sodium replacement : increase oral intake
• Normal saline 0.9% or Ringer Lactate IV
• Sodium should not be increased in a rate
higher than 12mEq/L
• Water restriction less than 800ml/24hrs in
case of fluid excess such as (SIADH)
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Sodium excess (Hypernatremia )
• High serum sodium more than 145mEq/L
• Cause by increase is sodium in different
proportion than water
• Can happened in both hypervolemia and
hypovolemia
Causes
Decrease fluid intake ( especially in unconscious
patient).
Administration of hypertonic saline solution
Drowning in sea water
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Clinical manifestation of
hypernatremia
• Neurologic manifestation as a result of increase
plasma osmolarity and movement of water out
of the cells.
• Restlessness, weakness, delusion hallucination
• Thirst
Assessment and diagnostic findings
Increase sodium higher than 145mEq/L and
serum osmolarity higher than 300mOsm/kg
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Medical management of
hypernatremia
• Administer hypotonic saline solution such as
NS 0.45%
• Sodium level is reduced in a rate no faster
than 0.5 to 1 mEq/L/ hr
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Potassium Imbalance
• Normal value in serum is 3.5-5mEq/L
• Potassium is a major intracellular electrolyte
• Influence both cardiac and skeletal muscle
activity
• Potassium is very sensitive to change in serum
level
• Kidney is the primary regulator of serum
potassium with 80% excretion through kidney
while the other 20% is excreted via bowle and
sweat
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Potassium Deficit (Hypokalemia)
• Decrease in serum potassium less than
3.5mEq/L
• Causes include diuretics, Gastrointestinal loss
as in vomiting and diarrhea, illeostomy.
• Increase aldosteron secretion
• Diuretics ( lasix)
• Increase insulin secretion as in diabetes I
insulin increase entry of insulin into skeletal
muscle and hepatic mucles
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Clinical manifestations of hypokalemia
• Fatigue, anorexia, nausea
• Muscle weakness, paresthesia, decrease bowel
motility
• Inability of kidney to excrete urine
• Increase sensitivity to digitalis( digoxin)
• Electrocardiogram (ECG) changes flat T wave,
inverted T wave, depressed ST segment
elevated U wave
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Medical management of hypokalemia
• Potassium supplement: usually 40-80mEq/L
• High potassium diet as most fruits, legume,
whole grain, milk, meat.
• Potassium chloride is a routine supplement
and usually the concentration is 20mEq40mEq/ for each liter
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Potassium Excess (Hyperkalemia)
• Potassium decrease less than 3.5mEq/L
Causes
• mainly is decrease renal excretion ( renal
failure).
• Decrease aldosteron secretion.
• Side effect of medications such as heparin,
ACE inhibitor (captopril), NSAID, potassium
sparing diuretic such as spironalacton(
aldacton)
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Clinical manifestations of
hyperkalemia
• The most common is cardiac when the level is
higher than 7mEq/L and early changes can be
noted at a value 6mEq/L such as:
• Peaked narrow T wave
• St segment depression
• Shortened QT interval
• PR interval prolonged followed by disappearance
of P wave.
• Prolongation of QRS complex that entails cardiac
arrhythmia and cardiac arrest
• Muscle weakness may be paralysis related to
depolarization block ( speech muscle and
respiratory muscle
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Medical management of hyperkalemia
• Restriction of potassium
• Cation exchange resin ( Kayexalate): bind with
potassium in the intestine and removed through
stool.
• Administration of calcium gluconate ( to protect
the heart but has no effect on the potassium
level)
• Administration of sodium bicarbonate
• Administration of hypertonic dextrose solution
with insulin: insulin bind potassium and sugare
and move it to the cells
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Calcium Imbalance
• 99% of the total body calcium in the skeletal
system
• Normal serum value for the total calcium is
8.6-10.2mg/dl ( 2.2-2.6mmol/L) .
• The ionized calcium 4.5- 5.1mg/dl) ( the lap
give readings for both ionized and total)
• Calcium is absorbed in the food in the
presence of gastric acidity and vitamin D
• Excretion mainly via feces with the reminder
through urine
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Calcium deficit ( Hypocalcemia)
• Lower than 4.5- 5.1mg/dl for the ionized or
lower than 8.6mg/dl for the total
• Causes include hypoparathyroidism ( decrease
parathormon cause less release of calcium
from the bone)
• Inflammation of pancreas( pancreatitis)
• Renal failure ( because of increase in
phosphate cause decrease in calcium)
• Inadequate vitamin D consumption
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Clinical manifestations of
hypocalcemia
• Increase neuronal excitability resulting in Tetany:
increase both sensory and motor peripheral nerve
discharge . Symptoms of tetany include general
tingling in fingers and feet, face, and around
mouth
• Trousseau’s sign
• Chvostek’s sign
• Mental changes then Seizure
• ECG changes such as prolonged QT interval,
prolonged St SEGMENT
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• Diagnostic findings of hypocalcemia
• Serum calcium level and serum albumin level
(because significant amount of calcium in blood
is bonded to albumin)
• Medical management
• Increase dietary intake( milk, green leafy
vegetables, canned salmon, sardines, and
oyster
• IV supplement as calcium gluconate, or calcium
chloride
• Vitamin D therapy ( increase absorption from
the GIT
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Calcium Excess ( Hypercalcemia)
• Increase total calcium higher than 10.2mg/dl or ionized
calcium higher than 5.1 mg/dl.
• Causes include malignancy and hyperparathyroidism (
increase parathormone)
• Clinical Manifestations
• Increase calcium lead to suppress neuronal activity at
the neuromuscular junction which cause muscle
weakness, incoordination, anorexia, and constipation.
• Increase urine output due to disturbed renal function
• Cardiac standstill in sever case when calcium is higher
than 18mg/dl
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Medical management of
hypercalcemia
• Administer high volume of NS0.9% to dilute
the serum and increase urine output
• Phosphate may be given as it increase calcium
excretion
• Lazix rarely given as it increase excretion
• Also rarely Calcitonin may be given as it move
calcium from the blood to the bone.
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