Hyponatremia

Case presentation

A 67-year-old male is currently hospitalized on the internal medicine ward. You are consulted for an endocrinology opinion due to newly identified hyponatremia. The primary team reports that the patient presented to the emergency department three hours ago with an acute onset of nausea and progressively worsening confusion over the preceding two days. The patient's past medical history is significant for chronic obstructive pulmonary disease (COPD), diagnosed ten years ago, for which he uses daily inhaler therapy. He has also been treated for major depressive episodes for the past year.

Laboratory Findings

Serum Sodium: 119 mmol/L

Potassium: 4.1 mmol/L

Serum Creatinine: Within normal limits

Blood Urea Nitrogen (BUN): Within normal limits

Referral &

Emergency

Evaluation

History

Exam

Diagnosis

Management

After two additional days, the patient's serum sodium levels have normalized. Given the stable correction and absence of further risk factors, fluid restriction has been appropriately discontinued.The patient is discharged with appropriate follow-up measures in place. A psychiatric consultation is scheduled for the following day to consider alternative psychotropic medications with a lower risk of inducing SIAD. Additionally, a serum sodium follow-up with the family physician is planned in seven days to ensure continued stability. The patient is also advised to avoid excessive fluid intake, with a target of 1.5–2 liters per day, to reduce the risk of recurrent hyponatremia. Although SIAD is most likely related to SSRI use, a low-dose chest CT scan is performed, which shows no evidence of pulmonary carcinoma.

Take Home Messages

References

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