Hyponatremia

Question 1

Presentation

Answer 1

Neuro - gait instability
Cognitive - poor concentration,headache, reduced consciousness, seizures (cerebral edema)
GI - N+V
CV - cardiorespiratory arrest

Question 2

Classification

• mild
• moderate
• severe

Answer 2

Mild 130-135
Moderate 125-129
Severe U125

Question 3

Possible underlying causes

-low urine osmolality

Answer 3

Primary polydipsia
Inappropriate IV fluid
Low Na intake

Question 4

Possible underlying causes

• high urine osmolality (100+)
• low urine Na

Answer 4

HF
PHTN
Nephrotic syndrome, hypoalbuminemia
GI loss 
Past diuretic use

Question 5

Possible underlying causes

• high urine osmolality
• high urinary Na

Answer 5

SIADH
AVP like drugs
Salt wasting 
Vomiting
Hypoadrenalism, Addisons

Question 6

Management

• acute severe
• symptomatic

Answer 6

150ml 3% hypertonic saline over 20min
Monitor
Repeat and monitor until 5mmol/L increase

Treat underlying cause

Limit rise in Na to U10 in first 24hours
Limit rise in Na to U8 every 24hs afterwards until Na = 130

Question 7

Management

• asymptomatic
• mild symptoms

Answer 7

If not hypovolemic
-stop uneccasery parenteral fluids and contributing meds
Treat underlying cause

If hypervolemic, SIADH
-fluid restriction

If hypovolemic
-restore ECV with saline