Hyponatraemia Flashcards
What is hyponatraemia?
Sodium concentration of less than 135mmol/L in the blood
What does the severity of the signs and symptoms of hyponatraemia depend on?
How low the sodium concentration in the blood is
How fast the sodium concentration in the blood decreased
What are the signs and symptoms of mild hyponatraemia?
Headache
Nausea and vomiting
Fatigue
What are the signs and symptoms of severe hyponatraemia?
Confusion
Seizures
Coma
What causes neurological symptoms with hyponatraemia?
Water enters brain cells by osmosis
brain cells swell up
raised intracranial pressure
brain becomes compressed
What are the types of hyponatraemia?
High volume
Normal volume
Low volume
What is high volume hyponatraemia?
Both sodium ions and water in the blood increase
but water increases more than sodium ions
giving hyponatraemia
What are the causes of high volume hyponatraemia?
Heart failure
What is normal volume hyponatraemia?
Water in the blood stays approximately the same
but sodium ions are lost in urine
giving hyponatraemia
What are the causes of normal volume hyponatraemia?
SIADH
What is low volume hyponatraemia?
Both sodium ions and water in the blood decrease
but sodium ions decrease more
giving hyponatraemia
What are the causes of low volume hyponatraemia?
Vomiting, diarrhoea
Excessive sweating
Burns
Diuretics
How is hyponatraemia treated?
Fluid restriction
Give hypertonic saline
