Symptomatic Hyponatremia as the Initial Presentation of Small Cell Lung Carcinoma: A Case Report of Delayed Diagnosis

Lung cancer remains the leading cause of cancer related death in America. The national prevalence of lung cancer is 59.1 per 100,000; however, the state of West Virginia has a higher reported prevalence of 79.1 per 100,000. Small cell lung carcinoma (SCLC) accounts for 10-15% of total lung carcinomas. The syndrome of inappropriate antidiuretic hormone (SIADH) is a well-documented paraneoplastic syndrome associated with SCLC. We present a case of a 60-year-old female with greater than a 90 pack-year smoking history who presented with symptomatic hyponatremia. Throughout her multiple hospital admissions, she received numerous chest x rays, all of which initially revealed no lung pathology. This ultimately delayed her cancer diagnosis until a more thorough workup of her SIADH etiology was performed.