Case Presentation:

This is a 39‐year‐old farmer admitted with dyspnea and productive cough with dark sputum. The patient stepped into a closed silo 3 days prior to admission. Approximately 8 hours later, he developed significant dyspnea, productive cough with dark sputum, fever, and malaise. The cough became dry subsequently. In the emergency department he was found to have a temperature of 39°C, tachycardia, and a white blood cell count of 20,000; the chest roentgenogram was normal. He received a dose of ceftriaxone and azithromycin and was transferred to our hospital. History was significant for well‐controlled gout on allopurinol, morbid obesity, and impaired fasting glucose; the patient recalled that along with his father, he experienced a brief episode of shortness of breath the first time he went into the silo a year before. An arterial blood gas showed methemoglobin of 2.1%. A computed tomography of the chest was normal. He was started on intravenous methylprednisolone 0.5 mg/kg intravenously every 6 hours; oxygen was administered via nasal cannula at 2 L/min, resulting in an oxygen saturation of 98%–100% with no distress. He was able to be weaned to room air within 24 hours. A formal prophylactic recommendation was given to the patient for the next silo filling: to start daily prednisone 40 mg by mouth 2 days before silo filling, on the day of silo filling, and 2 days after.


Silo filler's disease is a preventable occupational disease that causes acute lung injury secondary to inhalation of nitrogen dioxide gases in an agricultural silo. These gases form rapidly in farm silos that are filled with fresh organic material (e.g., grains, hay). Toxic and lethal levels of nitrogen dioxide accumulate on top of the silage; the clinical presentation is related to the duration of exposure and the concentration of this gas. The exposure period starts from the day of silo filling and up to 10 days. As in our case, most symptomatic exposures are mild and self‐limited; however, the clinical presentation can be dramatic, causing acute respiratory distress syndrome, bronchiolitis obliterans, and even death from asphyxiation. The new generation of farmers may be unaware of the potential risks involved with this preventable but potentially fatal disorder. In the lung, nitrogen dioxide hydrolyzes to nitrous and nitric acid, causing profound chemical pneumonitis, pulmonary edema, and methemoglobinemia. This results in a leftward shift of the hemoglobin dissociation curve with impaired oxygen delivery and compounds the already‐present hypoxia. This is prevented by venting the silos, avoiding immediate exposure when opening the hatches, using special respirators, and taking prophylactic steroids prior to exposure. The treatment is supportive, including oxygen supplementation, mechanical ventilation, and steroids.


The hospitalist, especially in rural areas, shall be aware of silo filler's disease, its broad clinical spectrum, and its prophylaxis and treatment.


M. Auron ‐ none; M. Y. Duran‐Castillo ‐ none; J. Parambil ‐ none; M. C. Alraies ‐ none