Dr. Njoki assignment
ELECTROLYTE IMBALANCES
MBCHB YEAR 4 GROUP 1
1. Grace Yula
2. Mercy Chepkemoi
3. Zachary Abere
4. Polycarp Okoth
5. William Misera
6. Edwin Nganga
7. Martin Ndiema
8. Kevin Rutto
1.Define hypernatremia
Plasma Sodium concentration that is above the upper limit of reference range (135-145 mmol/l).
2.sodium changes in the body often follow changes in the total body water
a) define hypovolemic hypernatremia
Sodium concentration above 145 mmol/occurring in a state of excessive water loss compared to
electrolytes.
I.
Give three examples that causes above
Decreased water intake example in the elderly
Gastrointestinal losses eg diarrhea and fistulas
Osmotic and loop diuretics
b) define euvolemic hypernatremia
Sodium concentration above 145 mmol/l occurring in a state of equal sodium and water loss.
II.
Give three examples of causes of above
Diabetic insipidus ,nephrogenic ,andcentral
Insensible losses respiratory and dermal.
C)define hypervolemia hypernatremia
Hypernatremia occurring in presence of increased blood volume, due to net increased sodium
either intake or reduced renal excretion.
III.
Give three examples of causes of above
Primary hyperaldosteronism
Hypertonic dialysis
Sodium chloride tablets
Cushing syndrome
3) Acute hypernatremia is often more symptomatic than chronic hypernatremia
a) Define acute hypernatremia
Hypernatremia occurring in a documented period of less than 24hours
b)define chronic hypernatremia
Hypernatremia occurring in a documented period of more than 48 hours.
c)explain the pathophysiology leading to the difference in symptomatology
In acute hypernatremia there is a rapid shift of fluid from the intracellular compartment to the
extracellular compartment due to the high osmolality of ECF this cause shrinkage of the brain
cell and can result in subarachnoid subdural hematomas.
However in chronic state the brain cell can accommodate by activating membrane transporters
that mediate influx and intracellular accumulation of organic osmolytes eg glutamate,
myoinositol resulting in an increase in ICF water and normalization of brain parenchyma.
In summary in chronic hypernatremia the brain is given time to adjust to the state in acute
hypernatremia the brain does not have time to adapt.
4)outline 5 major neurological symptoms of acute hypernatremia
Altered mental status
Weakness
Neuromuscular irritability
Seizures
coma
5) outline 3 laboratory test that can be used to investigate hypernatremia
Serum sodium concentration
Urine sodium concentration
Urine osmolality
6) rehydration is the mainstay of management of hypernatremia
a) outline 4 crystalloids that can be used to manage hypernatremia
5%dextrose in water
Ringer lactate
0.45 normal saline
0.9 normal saline in water
b) what is the formula use to estimate the total amount of water needed to correct
hypernatremia
Calculating free water deficit
{([NA]-140)/140}*(TBW)
c) Explain how acute hypernatremia should be treated
goal of treatment is to bring sodium to 145meq/l. water deficit should be reduced
gradually to roughly 10-12 meq/l about 1mmol/l/hour .rapid correction improves
prognosis.
replace half water deficit over next 24 hours
replace reaming over next 24 hours
measure serum and urine electrolytes every 1-2 hours .
d) Explain how chronic hypernatremia should be treated
Risk of treatment related complication is increased due to cerebral adaptation to the
hyperosmolar state .Hence plasma sodium should be lowered at more moderate rate (5-8
meq/l/day) about 0.5meq/l/h .
If volume deficit is present, restore with isotonic sodium chloride prior to freee sodium
administration.
