A 64-year-old man comes to the office for evaluation of persistent cough and worsening dyspnea over the last 6 months. The cough is dry, nagging, and present throughout the day. He reports mild dyspnea with exertion, which has become increasingly bothersome. The patient has no chest pain, syncope, orthopnea, or paroxysmal nocturnal dyspnea. He had an inferior wall myocardial infarction due to right coronary artery occlusion 5 years ago and was treated with a drug-eluting stent. The patient's other medical concerns include a hiatal hernia and hypertension. Medications include aspirin, losartan, atorvastatin, and ranitidine. Temperature is 36.8 C (98.2 F), blood pressure is 130/78 mm Hg, pulse is 82/min, and respirations are 15/min. Pulse oximetry is 97% on room air. Head and neck examination is normal. Jugular venous pressure is normal. There are no murmurs, extra sounds, or gallops. Fine, dry inspiratory crackles are heard in the lower lung zones. Diaphragm excursion is normal and symmetric. There is no peripheral edema. Chest x-ray is normal. What is the most appropriate next step in immediate management?

Question

A 64-year-old man comes to the office for evaluation of persistent cough and worsening dyspnea over the last 6 months.  The cough is dry, nagging, and present throughout the day.  He reports mild dyspnea with exertion, which has become increasingly bothersome.  The patient has no chest pain, syncope, orthopnea, or paroxysmal nocturnal dyspnea.  He had an inferior wall myocardial infarction due to right coronary artery occlusion 5 years ago and was treated with a drug-eluting stent.  The patient's other medical concerns include a hiatal hernia and hypertension.  Medications include aspirin, losartan, atorvastatin, and ranitidine.  Temperature is 36.8 C (98.2 F), blood pressure is 130/78 mm Hg, pulse is 82/min, and respirations are 15/min.  Pulse oximetry is 97% on room air.  Head and neck examination is normal.  Jugular venous pressure is normal.  There are no murmurs, extra sounds, or gallops.  Fine, dry inspiratory crackles are heard in the lower lung zones.  Diaphragm excursion is normal and symmetric.  There is no peripheral edema.  Chest x-ray is normal.  What is the most appropriate next step in immediate management?

Quizplus · Accepted Answer

This patient with ischemic heart disease has dry cough, exertional dyspnea, and inspiratory crackles. Given the lack of clinical evidence for heart failure (eg, normal jugular venous pressure, no peripheral edema), he should be evaluated for early interstitial lung disease (ILD). Inspiratory "Velcro" (eg, fine, dry) crackles are sensitive for interstitial fibrosis, which is present in many forms of ILD. They are typically audible long before abnormalities on chest x-ray (CXR) or pulmonary function testing emerge, underscoring the value of careful auscultation. Early into disease progression, interstitial lung abnormalities may not be seen on CXR. Therefore, patients with suspected ILD should undergo high-resolution computed tomography (HRCT), a thin-slice (usually 1 mm) CT scan protocol developed to visualize subtle interstitial lung features (eg, reticulation, honeycombing). Compared to conventional CT, HRCT provides sharper images because slices are taken in a "step-and-shoot" format (as opposed to helical continuous scanning). A prone sequence is often acquired to remove compressive atelectasis, allowing better visualization of subtle reticulation or honeycombing in the dorsal dependent lung. The crisp detail offered by HRCT allows for specific classification of ILD (eg, usual interstitial pneumonia, cryptogenic organizing pneumonia). In addition to HRCT, workup of suspected ILD involves full pulmonary function testing (eg, lung volumes, diffusing capacity). (Choices A and E) Barium esophagography and a proton pump inhibitor (PPI) are useful in evaluation and management of patients with gastroesophageal reflux (which can cause cough) or certain forms of dysphagia (associated with aspiration and cough). Reflux-induced lung microinjury can promote pulmonary fibrosis (eg, idiopathic pulmonary fibrosis [IPF], a form of ILD). However, simple reflux would not explain dyspnea or Velcro crackles. Although PPIs are often recommended for reflux-driven IPF, HRCT should be obtained to establish the diagnosis first. (Choice C) Patients with known coronary atherosclerotic disease are at risk for cardiac ischemia and/or congestive heart failure (CHF). Stress imaging is often complementary to pulmonary workup. However, although ischemia can cause dyspnea (angina equivalent), it does not explain dry cough and fine crackles. Although ischemic left-sided CHF can cause dyspnea, it is classically associated with wet (vs dry) crackles, frothy sputum, and orthopnea; in addition, an inferior wall myocardial infarction is most likely to cause right-sided (eg, peripheral edema), rather than left-sided, symptoms. (Choice D) P2Y₁₂inhibitors (eg, clopidogrel) are occasionally substituted for aspirin in patients with aspirin-exacerbated respiratory disease (AERD). AERD presents with asthma (episodic wheezing, rather than crackles and progressive dyspnea), recurrent nasal polyps, and hypersensitivity to nonsteroidal anti-inflammatory drugs. ₁₂ Educational objective: In patients with suspected early interstitial lung disease, initial workup includes high-resolution computed tomography scanning and full pulmonary function testing. References: High-resolution CT of interstitial lung disease: a continuous evolution (http://www.ncbi.nlm.nih.gov/pubmed/24481766) Role of imaging in progressive-fibrosing interstitial lung diseases (http://www.ncbi.nlm.nih.gov/pubmed/30578332)

A 64-Year-Old Man Comes to the Office for Evaluation of Persistent