A47-24 Lowering the Dose: Treating a Loculated Pleural Effusion in the Setting of Thrombocytopenia

Abstract Introduction Complicated pleural effusions commonly occur in the hospital and can be treated with intrapleural thrombolytics. In patients with concomitant thrombocytopenia, administering thrombolytics is a complex decision. Case Presentation A 55-year-old man with a recent history of right foot osteomyelitis presented with shortness of breath and fevers. He was tachycardic and hypoxic with a purulent right foot wound. Labs revealed leukocytosis and blood cultures were positive for methicillin resistant staphylococcus aureus. CT chest showed multiple cavitating alveolar opacities concerning for septic emboli. TTE revealed a 2.9x3.0 cm tricuspid vegetation. Below the knee amputation and debulking procedure of the tricuspid valve were completed. Post-operatively, the patient developed progressive thrombocytopenia (28x109/L). His course was further complicated by the development of a large loculated right effusion. Given his thrombocytopenia, he was deemed to be a poor candidate for a VATS decortication. He had an elevated risk of hemorrhage due to thrombocytopenia, so the decision was made to instill intrapleural alteplase (tPA) and dornase at a reduced dose after extensive discussion with the patient. He received 2.5 mg tPA and 2.5 mg dornase once with 2.8L output in 24hrs and dramatic improvement in symptoms. Discussion tPA is associated with bleeding risk and there have been reports of intrapleural tPA (10 mg) causing pleural hemorrhage at rates between 1.8 - 12%.1 Multiple studies have been conducted on low dose tPA aiming to assess effectiveness and reduce bleeding risk. The ADAPT trials examined the combination of 5 mg dornase with tPA dosing of 2.5 mg (ADAPT 2) and 5 mg (ADAPT 1) with positive findings.1,2 For patients with coagulopathies or malignancy that can increase bleeding risk, even lower dose tPA could provide benefit and prevent unnecessary procedures. Further research is needed for low dose tPA in patients with higher bleeding risk. References: 1.Popowicz N, Bintcliffe O, De Fonseka D, Blyth KG, Smith NA, Piccolo F, Martin G, Wong D, Edey A, Maskell N, Lee YCG. Dose de-escalation of intrapleural tissue plasminogen activator therapy for pleural infection: The Alteplase Dose Assessment for Pleural Infection Therapy project. Ann Am Thorac Soc 2017;14(6):929-936. 2.Popowicz N, Ip H, Lau EPM, Piccolo F, Dootson K, Yeoh C, Phu WY, Brown R, West A, Ahmed L, Lee YCG. Alteplase Dose Assessment for Pleural infection Therapy (ADAPT) Study-2: Use of 2.5 mg alteplase as a starting intrapleural dose. Respirology 2022;27(7):510-516. This abstract is funded by: None