Sodium

Hypernatremia:

• Diabetes Insipidus
• dehydration
• diuresis

Hyponatremia
- Hydration status

Dehydrated
- urine Na >20mmol/L:

• addison's disease
• iatrogenia (diruetics)

- urine Na <20mmol/L:

• GI tract, fistula

Euvolemic
- concentrated urine Osmol > 500mmol/L:

• SIADH

- dilute urine Osmol <500mmol/L:

• water overload
• hypothyroid
• glucocorticoid insufficiency

Hypervolemia (oedematous)

• Renal failure / nephrotic syndrome
• cardiac failure