Acute fibrinous organising pneumonia: a manifestation of trimethoprim-sulfamethoxazole pulmonary toxicity

Abstract

A 50-year-old man was treated with trimethoprim-sulfamethoxazole (TMP-SMX) for acute arthritis of his right big toe. Within a few days, he developed dyspnoea, hypoxaemia and diffuse pulmonary infiltrates. Symptoms improved with discontinuation of the antibiotic but worsened again with its reintroduction. An open lung biopsy was performed. We describe the workup performed and the factors that pointed to a final diagnosis of TMP-SMX-related pulmonary toxicity in the form of acute fibrinous organising pneumonia.

Rare idiopathic interstitial pneumonias: LIP and PPFE and rare histologic patterns of interstitial pneumonias: AFOP and BPIP

“…However, in some cases, focal or diffuse organizing pneumonia predominates, in keeping with the outcome dichotomy described above. Traction bronchiectasis and fibrosis can also develop . AFOP manifesting as a solitary mass has been reported .…”

“…Corticosteroid therapy and other immunosuppressive regimens have been tried in AFOP including cyclophosphamide, mycophenolate mofetil and azathioprine with variable responses …”

“…Other clinical associations with AFOP include the severe acute respiratory syndrome (SARS), autoimmune disorders (juvenile dermatomyositis, inflammatory myopathy, primary biliary cirrhosis, lupus, ankylosing spondylitis, undifferentiated connective tissue disease), drug reactions (trimethoprimsulfamethoxazole, abacavir), lung transplantation, environmental exposures (construction work, coal mining, zoological work) and infections such as Haemophilus influenza and Mycoplasma pneumoniae. [57][58][59][60][61][62][63][64][65][66][67][68] A case of AFOP has been reported in a patient with chronic renal failure on haemodialysis. 69 HRCT appearances of diffuse ground glass opacities and bilateral basal consolidation, described only in case reports, are most often closest to those of DAD with or without organizing pneumonia.…”

“…Corticosteroid therapy and other immunosuppressive regimens have been tried in AFOP including cyclophosphamide, mycophenolate mofetil and azathioprine with variable responses. 55,56,[58][59][60][61][62][63][64][65][66]71,72 In summary, AFOP is a histologic pattern of lung injury, which lies between DAD and organizing pneumonia and is not associated with a stereotyped natural history or treated course. In some cases, based on outcome, AFOP can be conceptualized as a fibrinous variant of DAD, but in other cases, imaging features and outcome resemble those in COP.…”

COVID‐19 related lung pathology: old patterns in new clothing?

“…21 First reported by Beasley et al in 2002, 22 it is an accepted histological pattern of interstitial pneumonia, but is viewed neither as an idiopathic clinicopathological entity nor a disease-specific histological pattern, as there are a variety of causes (drug, infections) and associations (connective tissue disorders, post-transplantation). [22][23][24][25][26][27][28][29][30][31][32][33] It is also not infrequent to see areas of OP, AFOP and DAD in the same autopsy from a patient dying of acute lung injury, and computerised tomography data describe some patients with COVID-19 who have disproportionate consolidation prior to, or alongside, classic DAD, 34,35 which may reflect a cohort with OP/AFOP as a sequelae of immune dysregulation, as seen in anti-synthetase syndrome. 36 Therefore, the presence of AFOP may reflect the final common pathway of DAD, systemic virally induced immune dysregulation, 37 secondary infection or any combination (Figure 1).…”