A 16-year-old girl is brought to the office after a day of fever, malaise, shortness of breath, chest tightness, and nonproductive cough. Her symptoms started after visiting a farm during summer camp. The patient says she was feeding hay to cattle and milking a cow to get farm experience. Her mother recalls that she "got sick" when visiting another farm several years ago, and it took her several days to recover after returning home. The patient has a history of eczema, and her brother has asthma. Temperature is 38 C (100.4 F), blood pressure is 120/70 mm Hg, pulse is 88/min and regular, and respirations are 22/min. Pulse oximetry shows 92% when breathing room air. Lung auscultation reveals bilateral fine crackles but no wheezing. Office spirometry shows decreased forced vital capacity. Which of the following are the most likely chest x-ray findings in this patient?

Question

A 16-year-old girl is brought to the office after a day of fever, malaise, shortness of breath, chest tightness, and nonproductive cough.  Her symptoms started after visiting a farm during summer camp.  The patient says she was feeding hay to cattle and milking a cow to get farm experience.  Her mother recalls that she "got sick" when visiting another farm several years ago, and it took her several days to recover after returning home.  The patient has a history of eczema, and her brother has asthma.  Temperature is 38 C (100.4 F), blood pressure is 120/70 mm Hg, pulse is 88/min and regular, and respirations are 22/min.  Pulse oximetry shows 92% when breathing room air.  Lung auscultation reveals bilateral fine crackles but no wheezing.  Office spirometry shows decreased forced vital capacity.  Which of the following are the most likely chest x-ray findings in this patient?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d4b3_c21e_bc81_d73574f76c02_MD0003_00 This patient's presentation with fever, malaise, nonproductive cough, and dyspnea after visiting a farm is consistent with hypersensitivity pneumonitis (HP). HP is an exaggerated immunologic response to an inhaled antigen; molds, animal proteins, and certain bacteria are common precipitating agents. Patients with a history of atopy (eg, asthma, eczema) are more likely to develop HP, and smoking decreases the risk of developing HP, possibly due to blunting of the pulmonary immunologic response. precipitating agents HP can have variable presentation depending on the dose and chronicity of antigen exposure. Acute HP (present in this patient) likely results from relatively high-dose acute exposure and presents with abrupt-onset (eg, within 6 hr) symptoms (eg, fever, malaise, cough, dyspnea). Hypoxemia is common and crackles are often present on lung auscultation. Chest x-ray is normal in some cases but usually shows scattered micronodular interstitial opacities representing patchy interstitial inflammation. The symptoms are self-limiting and resolve after several days with removal of antigen exposure. With long-term, low-to-moderate-dose antigen exposure, patients can develop chronic HP. Chest x-ray reveals diffuse reticular interstitial opacities, which represent an extensive network of interstitial inflammation and fibrosis. Chronic disease is often irreversible. Pulmonary function testing in both acute and chronic HP shows a restrictive pattern; chronic disease also demonstrates reduced diffusion capacity. (Choice B) Bilateral pleural effusions are often seen with volume overload (eg, decompensated heart failure, renal failure) or conditions with widespread and intense pulmonary inflammation (eg, multifocal bacterial pneumonia). However, pleural effusions are rarely present with HP. Bilateral pleural effusions (Choice C) An enlarged heart contour is seen with pericardial effusion or decompensated heart failure. The pericardium and heart are not significantly affected with HP. enlarged heart contour (Choice D) Hyperinflated lung fields are seen with the air trapping that occurs with chronic obstructive pulmonary disease or asthma exacerbation. HP is associated with a restrictive (rather than obstructive) pattern; therefore, air trapping does not occur. Hyperinflated lung fields (Choice E) Upper lobe infiltrates with cavitation can be seen with reactivation tuberculosis. Alveolar infiltrates (caused by the alveoli filling with fluid) are not typical of HP and cavitation does not occur. cavitation Educational objective: Hypersensitivity pneumonitis is an exaggerated immunologic response that some individuals develop to an inhaled antigen. Chest x-ray in acute disease usually reveals scattered micronodular interstitial opacities due to patchy interstitial inflammation. Chronic disease shows diffuse reticular interstitial opacities, representing an extensive network of interstitial inflammation and fibrosis. References: Imaging of hypersensitivity pneumonitis. (http://www.ncbi.nlm.nih.gov/pubmed/27719974)

A 16-Year-Old Girl Is Brought to the Office After a Day