From renal salt wasting to SIADH.

Area of Science:

• Neurology
• Nephrology
• Endocrinology

Background:

• Hyponatraemia (low serum sodium) is a frequent complication after severe head injury, linked to poor outcomes.
• Management is challenging due to confounding factors and potential for worsening sodium levels.

Observation:

• A young male with head trauma and skull base fracture developed severe hyponatraemia.
• Initial treatments including fluid restriction and isotonic saline worsened his condition.
• Diagnostic indicators suggested renal salt wasting, complicating the clinical picture.

Findings:

• The patient was diagnosed with suspected syndrome of inappropriate antidiuretic hormone (SIADH).
• Treatment with hypertonic (3%) saline infusion successfully corrected serum sodium levels.
• Neurological status improved concurrently with sodium level normalization.

Implications:

• This case underscores the difficulties in diagnosing and managing hyponatraemia post-head injury.
• It highlights the importance of considering differential diagnoses and adapting treatment strategies.
• Clinical decision-making requires careful evaluation of individual patient factors and response to therapy.