Case Presentation: A 75 year old male was transferred into the ICU, already intubated, requiring antibiotics and pressors. He was hypotensive, tachypnic with respiratory distress, had severe oliguric AKI with serum creatinine of 6.0, and anemia with hemoglobin below 7.0. His initial CXR and CT showed scattered bilateral pulmonary opacities. After he did not improve with standard therapies, a BAL was pursued. It did not have a progressive RBC count and hemosiderin index was less than 20%, however he was started on PLEX while his immune titers were pending. A renal biopsy was pursued after his MPO titer and ANCA returned positive, demonstrating p-ANCA vasculitis (1:640). The biopsy diagnosed necrotizing crescentic glomerulonephritis. Finally to confirm DAH, he underwent a second BAL which showed hemosiderin indices of 54%, 62%, and 71% respectively. He was diagnosed with Microscopic Polyangiitis and finished 5 PLEX treatments, rituximab, steroids, and eventually transitioned to dialysis and out of the ICU.
Discussion: We present a patient with hypotension, acute kidney injury (AKI), hypoxic respiratory failure, and anemia. While suspicion for diffuse alveolar hemorrhage (DAH) was high, his initial bronchoalveolar lavage (BAL) was not diagnostic. However his immunohistochemical panel supported a small vessel vasculitis raising our suspicion. The important part to this case is the interplay between the yields of testing including BAL, laboratory evaluation, and kidney biopsy and how these all play a role into the decision of pursuing plasma exchange (PLEX).
Conclusions: His first BAL was inconsistent with DAH, despite presenting with hemoptysis, anemia, diffuse radiographic pulmonary infiltrates, and hypoxemic respiratory failure. Diagnosis often requires BAL as symptoms are nonspecific: hemoptysis is absent in up to one-third of patients, and radiographic imaging is also nonspecific. Two BALs were performed and only the second one was increasingly hemorrhagic with greater than 20% hemosiderin laden macrophages. 20% or greater is highly specific and sensitive for alveolar hemorrhage. Estimations for kidney biopsy yields are quoted as high as 96% with very limited data, however the yield from BAL tends be lower, with reliance on a rising RBC count in sequential BAL aliquots not sufficient to rule DAH in or out. The hemosiderin index is more diagnostic according to ATS guidelines, but can be artificially low if collected before 72 hours or after 12 days. Steroids and PLEX were potentially curative with manageable side effects and PLEX by CHEST Guidelines it is a Grade 1B recommendation for DAH in cases of severe AKI (creatinine above 5.7) or severe hemorrhage. This patient’s case was severe enough that while his workup was pending, PLEX was pursued. Studies have shown a mortality benefit and reduction in persistent need for hemodialysis at 3 months, but no benefit at 1 year. While the guidelines are only 1B, not all of the patient’s included in the study for PLEX and DAH fit into the severe category. Further research into the diagnostic yield for testing for DAH and PLEX’s benefits for severe patients is needed given the mortality remains high at 1 year and 5 year intervals, 82% and 62% respectively.