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PATIENT
Mr. P is a 32-year-old man with 4 weeks of cough and progressive shortness of breath. He complains of a persistent cough productive of purulent sputum and low-grade fever. His past medical history is unremarkable.
On physical exam, Mr. P appears mildly short of breath. Vital signs are pulse, 95 bpm; temperature, 37.9°C; RR, 20 breaths per minute; BP, 140/90 mm Hg. He has temporal wasting. Lung exam reveals diffuse fine crackles bilaterally. Cardiac exam is normal.
At this point, what is the leading hypothesis, what are the active alternatives, and is there a must not miss diagnosis? Given this differential diagnosis, what tests should be ordered?
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RANKING THE DIFFERENTIAL DIAGNOSIS
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The first pivotal decision in patients with an acute cough identifies signs or symptoms that suggest pneumonia to distinguish common upper respiratory infection, acute bronchitis, and influenza from various pneumonias (see Figure 10-1). Mr. P has several concerning signs and symptoms that suggest pneumonia (rather than an upper respiratory infection or acute bronchitis) including his dyspnea and crackles. Clearly a chest radiograph is indicated.
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PATIENT
His chest radiograph demonstrates bilateral diffuse infiltrates (Figure 10-5). No cardiomegaly is seen. A CBC is normal. SaO2 is 85%.
At this point, what is the leading hypothesis, what are the active alternatives, and is there a must not miss diagnosis? Given this differential diagnosis, what tests should be ordered?
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The cough, fever, and radiograph are diagnostic of pneumonia. Although CAP is the most common type of pneumonia in patients presenting from the community, the next pivotal step reviews the clinical history and radiograph searching for clues that might suggest other types of pneumonia including TB, aspiration pneumonia, and Pneumocystis pneumonia (see Figure 10-2).
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PATIENT
Mr. P has no known exposures to TB and was born in the United States. He admits to drinking heavily, often a pint of gin per day, and occasionally losing consciousness. He does not remember any episodes of vomiting and aspirating. He denies injection drug use and reports that he has not been sexually active in several years. He denies having sex with men.
At this point, what is the leading hypothesis, what are the active alternatives, and is there a must not miss diagnosis? Given this differential diagnosis, what tests should be ordered?
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Although CAP is most common, Mr. P has several clinical features that increase the likelihood of other types of pneumonia. His alcohol use clearly increases the likelihood of aspiration pneumonia (even in the absence of known frank aspiration). Alcoholism, substance abuse, and neurologic disorders are leading risk factors for ...