Khan, Ayesha

Abstract Introduction:AFOP is a pattern of lung injury with intra-alveolar fibrin balls and organizing pneumonia. In 2013, the ATS/ERS revised their classification of idiopathic-interstitial-pneumonia to include acute-fibrinous-organizing-pneumonia(AFOP) in their rare histologic patterns. Methods: MEDLINE(PubMed), EMBASE, and Cochrane were searched for AFOP-related case reports/case series. Mesh terms used included (“acute fibrinous and organizing pneumonia” OR AFOP OR “acute fibrinous organizing pneumonia” OR (“acute fibrinous” AND “organizing pneumonia”) OR (“acute fibrinous” AND “organizing pneumonia”). A total of 177 patients were synthesized in these 169 articles, 9 of which were case series and the rest individual case reports. A quality review and data extraction was done on Covidence using a JBI checklist.Results:Mean age of 52.2 +/- 17.4 years with 55% of them were males. The associations were; malignancy (16%), smoking (14%), organ transplant (13%), Hypertension (10%), and use of immunosuppressive agents (6%) were frequent risk factors. Cough (73%), shortness of breath (71%), and fever (61%) were found highly frequent symptoms. Predominant radiological findings were multifocal infiltrates/consolidation (50%) and ground glass appearance (39%). Leukocytosis and inflammatory markers were elevated in most cases. Transbronchial/EBUS (32%), open surgical (29%), imaging-guided (22%), and VATS (14%) were common modes of lung biopsy. Treatment is usually steroids (88%) and antibiotics (69%). Death occurred in 23% of the cases, clinical or radiological improvement was achieved in 69%, while only three recurrences were reported. Most cases are either idiopathic or associated with myelodysplastic syndrome as causative factors reported by authors. DiscussionAFOP presents non-specific symptoms and a community-acquired pneumonia-like clinical picture. Treatment included antibiotics, corticosteroids, and other immunosuppressants with variable outcomes. Discontinuation of suspected drug was the sole treatment strategy reported in some cases. Partial lobectomy/lesion resection was a successful treatment in some instances with localized disease.The survival in AFOP was significantly worse than obliterative bronchiolitis (median time to death 101 vs. 294 days; P = 0.02). A statistically non-significant trend towards higher mortality associated with higher body mass index (BMI) and a long interval between symptom onset and diagnosis of AFOP was reported by Kim et al. in a cohort from South Korea. Conclusion:AFOP being a rare histological pattern of acute lung injury, is a relatively new entity that requires a better clinical and radiologic understanding for the clinical challenge it poses. This systematic review will be able to provide answers to clinicians to think in that direction and manage acute lung injury accordingly.