Severe infections such as pneumonia can cause hyponatremia. This phenomenon is widely attributed to the syndrome of inappropriate antidiuretic hormone secretion (SIADH), although the mechanism is not fully understood. Healthcare providers must identify and treat the cause of low sodium correctly to prevent elevated morbidity and mortality. This report describes an uncommon case of severe hyponatremia in a 26-year-old male with no known medical history and no risk factors for immunosuppression. He presented with worsening body pain and shortness of breath, and he noted an ulcerated lesion on his lower back that had drained purulent fluid in the past week. Laboratory studies revealed severe hyponatremia, with a sodium level of 117 mEq/L, and chest X-ray depicted bilateral interstitial opacities concerning for pneumonia. The patient was started on normal saline, empiric antibiotics, and bilevel positive airway pressure in the emergency department. He was admitted to the intensive care unit (ICU) and subsequently required intubation. After a prolonged ICU course, the patient eventually made a full recovery with no residual deficits. Our report demonstrates an uncommon case of severe hyponatremia in a young, previously healthy patient. He presented with alarmingly low sodium levels, likely secondary to SIADH in the setting of sepsis due to skin abscess and pneumonia. The severity of the patient's hyponatremia was a fundamental factor in identifying the critical nature of his disease and the need for expeditious treatment. Familiarity with appropriate management of hyponatremia is crucial for emergency physicians.