A 42-year-old male who works in a hog confinement area presents to your office complaining of cough, fever, wheeze, and dyspnea. He and some other workers were cleaning the confinement area with high-pressure hoses (which aerosolized hog waste), and they all developed the same symptoms, which started between 4 and 8 hours after work. On examination, he is febrile with a respiratory rate of 28. He is able to talk in complete sentences. There are slight crackles when you auscultate the lungs. His chest x-ray is normal.
Question 3.1.1 The most likely diagnosis is:
A) "Farmer's lung" (hypersensitivity pneumonitis).
B) Organic dust toxicity syndrome.
C) Reactive airway disease.
D) Hydrogen sulfide poisoning.
E) Bronchiolitis obliterans.
Answer 3.1.1 The correct answer is "B." Organic dust toxicity syndrome (ODTS) occurs when moldy or decomposed hay and other organic material (such as hog manure) is moved. Endotoxins are aerosolized and inhaled, leading to the symptoms. The tip off here is that everyone on the job site was affected. Since hypersensitivity pneumonitis ("A") is specific to the individual, generally only one worker at the site will have symptoms. Compared with ODTS, hypersensitivity pneumonitis may present with an abnormal chest x-ray with micronodular or reticular opacities. "C" is incorrect because everyone is involved and febrile, which is not consistent with reactive airway disease. "D" is not correct. Hydrogen sulfide poisoning presents as a toxic pneumonitis with pulmonary edema, dyspnea, hypoxia, and loss of consciousness. Hydrogen sulfide also acts as a direct cellular toxin that binds to cytochrome oxidase system, similar to cyanide. In addition, hydrogen sulfide exposure comes from cleaning manure pits (as anyone in Iowa would know). Finally, "E," bronchiolitis obliterans, is a chronic illness rather than an acute one. Of note, there is a strong association between ODTS and development of chronic bronchitis.
Question 3.1.2 Appropriate treatment for this patient includes:
B) Intubation and mechanical ventilation.
Answer 3.1.2 The correct answer is "C." Supportive care is the usual treatment of ODTS. Antibiotics are not needed because the syndrome is mediated by endotoxins rather than direct infection. "B" is incorrect because this patient is not in significant respiratory distress.
Remember that other work exposures can cause fever, including "metal fume fever" (febrile by the end of the week, resolves on the weekend only ...