Specimen Name Result Units Range
Plasma Sodium 113 mmol/L (135-145)
Potassium 3.4 mmol/L (3.5-5.5)
Chloride 81 mmol/L (100-109)
Bicarbonate 24 mmol/L (22-32)
Glucose 8.0 mmol/L (3.8-5.5)
Urea 3.0 mmol/L (2.7-7.2)
Creatinine 90 μmol/L (60-110)
Osmolality 245 mmol/kg (275-295)
Urine Sodium 34 mmol/L (> 20)
Osmolality 570 mmol/kg

32yo female with poorly controlled epilepsy.

Presented to ED post-ictal.

Current Rx = Carbamazepine
Drug-induced "SIADH"
  • chlopropamide, carbamazepine, clofibrate
  • cyclophosphamide, vincristine, vinblastine
  • GA's, opioids
  • TCA's
  • oxytocics

 

Criteria for SIADH

  • Hypo-osmolar Hyponatraemia
  • Urinary [Na+] > 20 mmol/L
  • Urine hypertonic c.f. plasma
  • Normal renal, adrenal, cardiac and hepatic function
  • Absence of drugs causing "SIADH"
    i.e. drug-induced SIADH ≠ true SIADH
  • Corrected by water restriction alone.