Hyponatremia and hypernatremia

Question 1

Hypernatramia

Answer 1

Hypernatremia is a common electrolyte problem and is defined as a rise in serum sodium concentration to a value exceeding 145 mmol/L

Question 2

Symptoms and signs of hypernatraemia

Answer 2

• lethargy
• thirst
• wekaness
• iriitability
• confusion
• coma
• fits

Question 3

Laboratory features of hypernatraemia

Answer 3

• increased sodium
• increased albmin
• increased urea

Question 4

Causes of hypernatraemia

Answer 4

Usually due to water loss in excess of sodium

• fluid loss without water replacmeent (diarrhoea, vomitting, burns)
• diabetes inspidious
• osmotic diuresis
• primary aldosteronism
• iatrogenic - incorrect IV fluid replacement

Question 5

Managment of hypernatraemia

Answer 5

• give water orally if possible
• if not give IV glucose 5% IV slowly guided by urine output and plasma Na+

Question 6

Hyponatraemia

Answer 6

Hyponatremia is defined as a serum sodium level of less than 135 mEq/L and is considered severe when the serum level is below 125 mEq/L.

Question 7

Symptoms and signs of hyponatraemia

Answer 7

• anorexia, nausea and amalise initially
• followed by headache, irritability, confusion, weakness, decreased GCS and seizures

Question 8

Causes of hyponatraemia

Answer 8

if the urinary sodium is >20mmol/l - then sodium an H20 are lost via the kidneys: Addisons, renal failure, diuretic excess, osmolar diuresis

Question 9

management of hyponatraemia

Answer 9

• correct the underlying causes: neve base treatment on Na+ concentratio alon
• replace Na and water at the same rate they were lost
• asymptomatic - fluid restriction, although decmeclocycline ADH antagonist
• acute or symptomatic or dehydraed - cautious rejudration with 0.9% saline may be given, but do not correct changes rapidly
• Vaptans - vasopressor rector antagonist