C41-22 An Unusual Cause of Diffuse Alveolar Hemorrhage in the Setting of Acquired Factor X Deficiency

Abstract Introduction We present the case of a 55-year-old male with acquired factor X deficiency causing massive hemoptysis and diffuse alveolar hemorrhage (DAH). Amyloidosis is the most common cause of acquired factor X deficiency in which factor X is sequestered by misfolded fibrils, leading to disruption of the coagulation cascade (Gertz & Dispenzieri, 2020). This case features a manifestation of acquired factor X deficiency in the presumed setting of amyloidosis. Case Presentation and Hospital Course A 55-year-old with asthma presented to the emergency department with 24 hours of hemoptysis. Upon arrival, hemoglobin was 9.6 g/dL, PTT 67.7 seconds, PT 78 seconds, INR 6.84. Fibrinogen was 587 mg/dL. Liver function was normal. Computed tomography angiography (CTA) showed bilateral ground-glass opacities. Bronchoscopy confirmed DAH. Workup showed factor X deficiency and a Beta-2-microglobulin (B2M) of 3.2 mg/L. Aspergillus antigen was detected in the bronchoalveolar lavage (BAL) fluid, however PCR was negative. Discussion Factor X deficiency can manifest in several disease etiologies which include amyloidosis, plasma cell dyscrasias, and infections (Ichinose et al., 2021). There have been documented cases of factor X deficiencies manifesting as pulmonary hemorrhages after acute upper respiratory infections (Mulhare et al., 1991). Acquired factor X deficiency is almost exclusively linked to amyloidosis, with rare exceptions caused by infections. Diagnosis of amyloidosis requires tissue sampling. Our patient expired prior to tissue sampling. Beta-2-microglobulin is a non-specific marker seen on immunologic cells that can be found in numerous nephrological, rheumatological, hematological diseases, including amyloidosis. (Prizment et al., 2019). Elevation is non-specific and cannot be used to diagnose amyloidosis Conclusion The patient had a new onset of factor X deficiency leading to diffuse alveolar hemorrhage. His rheumatologic workup was unremarkable, ruling out autoimmune induced factor X deficiency. The patient had a positive aspergillus antigen test with a negative PCR. Imaging was also negative for cavitary lesions, making infection an unlikely cause. In our literature reviews, we unable to locate any direct links between aspergillus and factor X deficiency. Although we could not confirm amyloidosis, the patient’s isolated acquired factor X deficiency and elevated B2M in the absence of rheumatologic, nephrogenic, or hematologic causes make amyloidosis a reasonable cause of this patient’s factor X deficiency. To the best of our knowledge and literature review, there have been no recorded cases of factor X deficiency causing DAH. This abstract is funded by: None