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From renal salt wasting to SIADH
  1. Tzy Harn Chua1,
  2. Matin Ly1,
  3. Senthil Thillainadesan2,
  4. Katie Wynne1,2
  1. 1Department of Medicine, School of Medicine and Public Health, University of Newcastle, Newcastle, New South Wales, Australia
  2. 2Department of Diabetes and Endocrinology, John Hunter Hospital, Newcastle, New South Wales, Australia
  1. Correspondence to Dr Katie Wynne, Katie-Jane.Wynne{at}


Hyponatraemia is common following major head injury and is associated with significant morbidity and mortality. A 20-year-old man presented with reduced consciousness after head trauma and was found to have a fractured skull base with bilateral frontal contusions. On day 3 of his admission, he developed hyponatraemia with raised urine sodium and osmolality, despite receiving dexamethasone and intravenous fluid therapy. His hyponatraemia worsened after the treatment with fluid restriction and oral salt. He was in negative fluid balance suggesting possible renal salt wasting. A trial of isotonic normal saline resulted in a further fall in serum sodium level. He was subsequently treated for suspected syndrome of inappropriate ADH with a hypertonic (3%) saline infusion. His sodium level and neurological status improved. This case report illustrates the confounding factors that commonly affect clinical decision-making when treating patients with hyponatraemia following head injury. The guidelines for diagnosis and management are discussed.

  • neurological injury
  • fluid electrolyte and acid-base disturbances
  • medical management
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  • Contributors KW managed the patient. THC, ML, ST and KW gathered data, prepared the manuscript for publication and approved the final version.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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