Diagnostic Error in Patients With Pulmonary Symptoms: More Challenging Cases

Alan Fein, MD; Joaquin E. Morante, MD; Aashir M. Shah, MBBS

Disclosures

December 19, 2017

No Improvement in Pneumonia Symptoms

A 67-year-old man with a history of hypertension, insulin-dependent diabetes, and hyperlipidemia presents with nonresolving pneumonia. He was first diagnosed with community-acquired pneumonia 3 months ago. At that time, a chest x-ray revealed a right lower-lobe infiltrate. His symptoms have persisted despite completing a course of azithromycin. He was told that he probably had bronchitis and was managed with antitussive medications, without improvement. Because of persistent symptoms, including cough, fever, anorexia, and weight loss, levofloxacin was prescribed. A repeat chest x-ray showed a persistent right lower-lobe lobar infiltrate. Despite a second course of antibiotics, the patient continued to have a productive cough and developed a fever (temperature of 101°F). Areas of thin-walled cavitation were noted on chest CT (Figure 8).

Figure 8. Chest CT showing lung cavitation.

The patient was next scheduled for bronchoscopy, and bronchoscopic alveolar lavage was positive for acid-fast bacilli on smear. He was started on appropriate four-drug therapy pending final culture and sensitivities. M tuberculosis grew on cultures obtained from sample.

What was the diagnostic error in this case?

Nonresolving Pneumonia

Nonresolving pneumonia can be described as a slow or incomplete resolution of pneumonia despite treatment. Potential causes of nonresolution include inadequate or inappropriate antibiotic therapy, antibiotic-resistant pathogens, infectious complications, or incorrect diagnosis. Clinical history, physical examination, and laboratory evaluation are important in assessing possible factors that impede the resolution of pneumonia symptoms.

In a case where resolution of symptoms is delayed, more aggressive diagnostic modalities can be used to investigate possible causes of treatment failure. Chest CT is a tool for evaluation of lung parenchyma. Bronchoscopy may be beneficial to obtain microbiological samples as well as tissue to rule out other possible diagnoses, such as cancer or interstitial pneumonias. In this case, TB should have been suspected in a diabetic with persistent lower-lobe cavitary infiltrate.

Risk factors should be assessed in all patients with delayed resolution of pneumonia. Advanced age, chronic obstructive pulmonary disease (COPD), chronic kidney disease, cardiovascular disease, liver dysfunction, and immunosuppression all may contribute to a delayed response to treatment. Lung cancer should also be suspected in patients with COPD and a significant smoking history.

Because interstitial lung disease may present with symptoms that mimic an infectious respiratory disease, this algorithm may be useful in evaluating patients with nonresolving pneumonia (Figure 9).

Figure 9. Algorithm for the evaluation and management of nonresolving pneumonia. From Finich S et al[6]

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