Syndrome of inappropriate antidiuretic hormone

Case history

A 76-year-old homeless man presents to the emergency department after police find him disoriented on the streets in late August. The patient gives little history, but admits to ongoing cough with productive sputum, night sweats/chills, and mild dyspnea. He proceeds to suffer from a seizure. Vital signs demonstrate an elevated temperature at 101.7°F (38.7°C), a respiration rate of 26 breaths per minute, 94% oxygen saturation (on 3 L of O2), and pulse 87 bpm, with no evidence of orthostatic hypotension. Physical exam demonstrates a malnourished and disheveled man in a postictal state. There is no sign of injury to the body. Crackles can be heard at the right lung base. Lab work demonstrates serum sodium of 120 mEq/L, serum creatinine of 1.0 mg/dL, and negative alcohol and toxicology screens. Chest x-ray demonstrates a large infiltrate in the right lower lung, consistent with pulmonary infection or abscess.