Hyper and hyponatraemia

Question 1

Hypernatraemia

Answer 1

> 145mmol/L

Question 2

Causes of hypovolaemic hypernatremia

Answer 2

Diuretics - loop diuretics

Dehydration / fluid restriction

• diarrhoea, vomiting, burns, or excessive sweating

Acute tubular necrosis

HHS

Question 3

Euvolemic Hypernatremia

Answer 3

Diabetes insipidus (DI)

Question 4

Hypervolaemic Hypernatremia

Answer 4

Excessive hypertonic saline administration

Steroid excess - Conn’s syndrome or Cushing’s syndrome

Question 5

Clinical featured of hypernatremia

Answer 5

Excess thirst

Weakness
Lethargy
Irritability
Confusion
Coma and seizures

Question 6

Investigations

Answer 6

Metabolic panel of bloods:
- including serum glucose, K+, Cl- , urea, and creatinine

VBG

Urine osmolality

May need:

• ADH levels
• CT head

Question 7

Mx of hypernatremia

Answer 7

Replacement of fluids - 5% dextrose

Question 8

Complications of rapid correction of hyponatraemia

Answer 8

Central Pontine Myelinolysis

Question 9

Hyponatraemia

Answer 9

serum sodium <135mmol

Question 10

Causes of hypo-osmotic hyponatraemia

Answer 10

Hypovalaemic:

• Vomiting or Diarrhoea
• Diuretics

Euvolaemic:
- Acute fluid overload
- SIADH

Hypervolaemic:
- Congestive Cardiac Failure or Liver Cirrhosis
- Acute Tubular Necrosis

Question 11

Post-Operative Hyponatraemia

Answer 11

Fluid retention - stress response causes increased ADH release and cortisol release

Question 12

Mx of hyponatraemia

Answer 12

Intravenous fluids (such as 0.9% sodium chloride) slowly