[An old lady with hyponatremia and recurrent falls]

Area of Science:

• Nephrology
• Endocrinology
• Internal Medicine

Background:

• Hyponatremia is a common electrolyte disorder in hospitalized patients.
• Differentiating causes like syndrome of inappropriate ADH secretion (SIADH) and cerebral salt wasting (CSW) can be challenging.
• CSW is a form of salt-wasting nephropathy.

Observation:

• A 79-year-old female presented with severe hyponatremia and hypochloremia after a fall.
• Clinical signs indicated volume depletion, with persistent high urinary sodium excretion despite hyponatremia.
• Initial response to normal saline infusion was transient, suggesting a diagnosis beyond SIADH.

Findings:

• The patient was diagnosed with cerebral salt wasting (CSW) due to persistent natriuresis.
• Fludrocortisone therapy led to sodium stabilization and symptom resolution.
• CSW involves inappropriately high urinary sodium excretion in hypovolemic patients.

Implications:

• Recognizing CSW is crucial for managing hyponatremia in hypovolemic individuals.
• Response to saline challenges can aid in distinguishing CSW from SIADH.
• Further research into CSW pathophysiology is warranted, with mineralocorticoid therapy showing promise.