Pulmonary Edema Occurring after Nitric Acid Exposure

Abstract

Nitric acid (HNO₃) is a strong acid and oxidizing agent used for various applications including production of ammonium nitrate in the fertilizer industry. Nitrogen oxides formed when nitric acid interacts with the environment have been implicated in inhalation injuries. This describes a case of a 49-year-old male who presented to the emergency department complaining of an acute onset of shortness of breath approximately 12 hours after being exposed to nitric acid fumes. He presented with a room air oxygen saturation of 80 percent with moderate to severe respiratory distress. His plain film chest radiograph showed bilateral pulmonary infiltrates and pulmonary edema. Over a seven-day hospital course, he had an improvement in his clinical status and chest X-ray with normal pulmonary function tests one month after discharge. Although exposure to the fumes of nitric acid is known to cause delayed pulmonary edema, it is rarely reported in the medical literature. This case serves as a reminder to consider exposure to fumes of nitric acid in a patient presenting with pulmonary edema and highlights the importance of obtaining a work history.

Figure 1

Initial chest X-ray.

Figure 2

Chest X-ray seven days after admission.