Hyponatraemia Flashcards Preview

Hugh's MD3 Paediatrics > Hyponatraemia > Flashcards

Flashcards in Hyponatraemia Deck (6):

What are some causes of hyponatraemia?

Most common
- Administration of hypotonic fluids (eg 0.18% Na)
- Conditions with impaired free water secretion and high ADH levels eg sepsis, meningitis, surgery
- Relative fluid intake excess in patients taking exogenous ADH
- GI loss

Less Common
- Adrenal insufficiency
- Defect in renal tubular absorption
- Psychogenic polydipsia


What is the definition of hyponatraemia?

Serum Na less than 135mmol/L


When do symptoms occur usually? What are some?

When Na is less than 125mmol/L

- Headache
- Lethargy, irritibility
- Nausea, vomiting
- Hyporeflexia
- Seizures
- Reduced conscious state


How else do you assess hyponatraemia?

Assess volume state on examination

Other investigations:
Serum creatinine, K, glucose, urea, chloride
Urine osmolarity and Na


How do you manage hyponatraemia

If symptomatic - Seizures and CNS depression
- ICU referral, 4ml/kg 3% Na solution until Na is 125 and above
- Intravenous anti-convulsants as clinically indicated

If not symptomatic
- Depending on fluid status either restrict water intake (if euvolaemic) or use normal maintenance fluids (if dehydrated)


What is the maximum rate of correction of hyponatraemia? Why?

8mmol/L over 24hours
Risk of cerebral pontine demyelination