Point-of-care lung ultrasound for diagnosis of Pneumocystis jirovecii pneumonia: notes from the field

BACKGROUND: Thoracic ultrasound is helpful to evaluate lung pathology in patients with acute dyspnea. Several studies have demonstrated the efficacy of point-of-care ultrasound in patients with extrapulmonary TB and HIV co-infection. This retrospective, open-label case-control study explores the role of lung ultrasound in the diagnosis of Pneumocystis jirovecii pneumonia (PJP) in HIV-positive patients. In particular, it highlights the potential role of specific sonographic features that may be unique to this population. METHODS: The record of all HIV-positive patients admitted from 1.1.2013 to 31.6.2017 to the Department of Infectious Diseases and Tropical Medicine of san Bortolo Hospital, Vicenza, Italy, with a discharge diagnosis of acute lung injury (ALI) and who received point-of-care ultrasound of the chest for clinical purposes was included in the analysis. The patients were scanned according with the evidence-based recommendation. RESULTS: Of 273 HIV-positive patients whose records were reviewed, 81 (29.6%) were diagnosed with ALI. Complete documentation was available for 24 patients, of which 14 (58.3%) had microbiologically confirmed PJP (PJP+) and 10 (41.7%) had other conditions (PJP-). B-lines, subpleural consolidations, and cystic changes were significantly more frequent in patients with PJP (14/14 vs. 6/10, p = 0.0198; 14/14 vs. 4/10, p = 0.0016; 8/14 vs. 0/10, p = 0.0019, respectively). In particular, B-lines and subpleural consolidations were present in all PJP+ patients in our cohort giving a sensitivity of 100%, but their specificity was low (45 and 60%, respectively). On the contrary, the presence of consolidations with cystic changes had a very high specificity for PJP (100%), but low sensitivity (57%). Pleural effusions and consolidations with linear air bronchograms were not observed in PJP+ patients. CONCLUSIONS: B-lines, subpleural consolidations, and cystic changes are suggestive of PJP. Lung consolidation with air bronchograms and pleural effusion should prompt suspicion of other etiologies. These findings have the potential to be useful in the daily management of HIV-positive patients in resource-limited settings where other diagnostic tools are rarely available.