Defined as serum Na concentration of less than 135 mmol/L

Common (up to 35% hospital inpatients)

Acute <48 hours

Chronic >48 hours

PC

• Often asymptomatic

May show signs of:

• high fluid intake
• nausea and vomitting
• convulsions
• headaches
• lethargy
• cramps
• weakness
• drowsiness

Investigations

• BP - fluid status