Hyponatremia secondary to multiple etiologies: a case report

Area of Science:

• Nephrology
• Endocrinology
• Internal Medicine

Background:

• Hyponatremia management can be complex, especially with co-existing conditions.
• Burn injuries can significantly impact fluid and electrolyte balance.
• Distinguishing causes of hyponatremia requires careful clinical and biochemical evaluation.

Observation:

• A 68-year-old male with a thermal burn presented with dehydration and hyponatremia (serum Na 123 mmol/L).
• The patient exhibited high urinary sodium excretion, elevated plasma AVP, and low renin/aldosterone levels.
• Despite treatment for hypothyroidism, hyponatremia persisted, later responding to DMC and then fludrocortisone.

Findings:

• The patient was diagnosed with hypothyroidism, SIADH (Syndrome of Inappropriate Antidiuretic Hormone secretion), and ultimately CSWS (Cerebral Salt Wasting Syndrome).
• Hyponatremia was exacerbated by the burn injury and SIADH, but primarily attributed to CSWS.
• Clinical signs of dehydration and edema were present, complicating laboratory interpretation.

Implications:

• This case highlights the diagnostic challenges in patients with multiple co-existing disorders affecting sodium balance.
• Understanding the interplay between burn injury, endocrine disorders, and neurological conditions is crucial for effective hyponatremia management.
• The case underscores the importance of considering CSWS in complex hyponatremia presentations.