Correct!
4. Bronchoscopy
Bronchoscopy would be the best choice for further assessment to this patient. Surgical lung biopsy certainly could provide a diagnosis, and could subsequently play a role for the evaluation of this patient, but is premature at this point. 133 Xe-Ventilation – 99m Tc-perfusion scintigraphy could provide some information regarding abnormal ventilation and differential pulmonary perfusion in the areas of infiltrative lung abnormalities, but it is unlikely that this procedure would contribute any useful information regarding the etiology of the lung opacities. 67Ga-citrate scanning is now seldom used, only occasionally playing a role for the assessment of diffuse lung disease, which could be of some relevance to this patient, but, generally, the appearance of increased pulmonary tracer uptake at 67Ga-citrate is non-specific. 18FDG-PET scanning is primarily employed for the assessment and staging of primary intrathoracic malignancy and metastatic disease as well as the evaluation of an indeterminate solitary pulmonary nodule, but increased tracer utilization in the lung parenchyma at 18FDG-PET in patients with diffuse opacities is also a relatively non-specific finding that does not reliably differentiate malignancy from benign etiologies, nor does it narrow the differential diagnostic considerations for these opacities.
The patient underwent bronchoscopy, carried out to the first subsegmental level, which showed normal anatomy on normal tracheobronchial mucosa. No secretions were seen. A few flecks of blood were detected at the orifice of the right upper lobe following bronchoalveolar lavage and few mucous plugs were found in the cloudy lavage fluid. A few bacteria were noted upon examination of the lavage fluid, for which the patient was started on broad-spectrum antibiotics.
Several days later the bacteria seen at bronchoalveolar lavage were identified as normal flora. Examination of the lavage fluid showed 10% neutrophils, 8% eosinophils, 2% lymphocytes, and 80% macrophages. Additional laboratory testing showed no elevated systemic inflammatory markers and renal and hepatic laboratory data were within normal limits. Equivocal elevation of the PR3-ANCA antibody (0.6; normal ˂0.4, equivocal, 0.4-0.9) and MPO-ANCA antibody (0.6; normal ˂0.4, equivocal, 0.4-0.9) were noted, but C- and P-ANCA antibodies were negative. The patient’s anti-nuclear antibody level was weakly positive at 1.2 (normal, ≤1). Serum protein electrophoresis was normal, as was urinalysis.
Which of the following disorders is the least likely etiology for the diagnosis for this patient? (Click on the correct answer to proceed to the fifth of nine pages)