Abstract Introduction Microscopic polyangiitis (MPA) is vasculitis characterized by the presence of Antineutrophil Cytoplasmic Antibodies (ANCA), prototypically p-ANCA in MPA. The most common organ system involvement is renal, with 80-90% of all cases showing involvement of the kidneys. This involvement ranges from microscopic hematuria/proteinuria to fulminant renal failure due to RPGN. The second most common system involved in MPA is the pulmonary system ranging from 25-90% of cases. Typically, MPA-related pulmonary disease presents as a diffuse and often life-threatening alveolar hemorrhage, although approximately 10-15% present as chronic interstitial fibrosis with a usual interstitial pneumonia pattern. Case Presentation This is a 70-year old gentleman with a past medical history of treated tuberculosis and pre-diabetes who initially presented 4 months prior with unilateral right sided chest pain. His social history is relevant for remote mild asbestos exposure through working in demolition and minimal smoking history, noted to have 50 pounds of weight loss over the past year. He was found to have right-sided pneumothorax treated with endobronchial valve placement and interstitial lung disease initially attributed to asbestos exposure with usual interstitial pneumonia pattern. He re-presented 4 months status-post EBV removal with recurrent right pneumothorax. The patient was hemodynamically stable and saturated well on 2LNC after pigtail catheter placement. Non-contrast chest CT showed interval increase in severity of his ILD with apical right pneumothorax. Admission labs showed AKI with creatinine of 1.63. He endorsed difficulty ambulating and 8 months of burning pain in the right ulnar nerve distribution and bilateral feet. We found severe left foot drop and polyneuropathy with MRI brain showing acute/subacute strokes of the hippocampus, Sylvian fissures, and left external capsule. Urinalysis showed 6 RBCs/HPF. 24 hour urine collection showed nephritic range proteinuria and urine creatinine clearance of 31. With AKI/CKD, microscopic hematuria, lung disease, and peripheral neuropathy, vasculitis rose in our differential. P-ANCA serologies were over 7x the upper limit of normal highly suggestive of MPA. Renal biopsy confirmed the diagnosis of MPA. He had hypocomplimentemia, atypical for ANCA vasculitides but associated with worse prognosis. We initiated pulse dose steroids and rituximab therapy to good effect and resolution of pneumothorax through talc pleurodesis. Discussion MPA is an ANCA associated vasculitis that typically presents with kidney and pulmonary involvement. Typical presentation of pulmonary involvement is through diffuse alveolar hemorrhage. We describe a rare presentation of MPA with ILD, recurrent pneumothorax, hypocomplimentemia, and small vessel stroke. This abstract is funded by: None
Goldberg et al. (Fri,) studied this question.