From Brew to Bronchoscopy: A Case of Hyponatremia That Was Anything but Basic

TL;DR

A patient with severe low sodium levels was found to have lung cancer, showing the need to thoroughly investigate underlying causes in similar cases.

Contribution

Highlights the importance of considering cancer in the differential diagnosis of hyponatremia.

Findings

Severe hyponatremia was initially attributed to alcohol use and dehydration.

Further testing revealed mediastinal lymphadenopathy and small cell lung cancer.

The case underscores the need for comprehensive evaluation in patients with hyponatremia.

Abstract

We present the case of a 53-year-old female with a history of chronic alcohol use, hypertension, chronic obstructive pulmonary disease (COPD), and significant smoking history, who presented with severe hyponatremia. Initial laboratory studies revealed a sodium level of 115 mEq/L. The patient reported chronic vomiting, poor oral intake, and heavy alcohol consumption. Her hyponatremia was initially attributed to multiple factors, including alcohol-related dehydration, beer potomania, and potential medication-induced syndrome of inappropriate antidiuretic hormone (SIADH) secretion. However, further evaluation with chest computed tomography (CT) revealed extensive mediastinal lymphadenopathy. Bronchoscopy with fine-needle aspiration confirmed a diagnosis of small cell lung cancer (SCLC). This case highlights the importance of a comprehensive evaluation for hyponatremia, particularly in patients with malignancy risk factors, to avoid overlooking severe underlying conditions such as cancer.

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