Abstract: SA-PO216
C3 Glomerulonephritis, a Rare Etiology of the Pulmonary Renal Syndrome
Session Information
- Trainee Case Reports - V
October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Reports
- 1203 Glomerular Diseases: Clinical, Outcomes, and Trials
Authors
- Bobart, Shane A., Mayo Clinic, Rochester, Minnesota, United States
- Sethi, Sanjeev, Mayo Clinic, Rochester, Minnesota, United States
- Fervenza, Fernando C., Mayo Clinic, Rochester, Minnesota, United States
Introduction
C3 Glomerulopathy (C3GN) is a rare disease due to complement factor deposition in the glomerulus as a result of dysregulation of the alternative complement pathway. We present a rare case of C3GN presenting with diffuse alveolar hemorrhage (DAH) as a pulmonary-renal syndrome.
Case Description
A 20 year old female presented to the emergency department with flank pain and hematuria. Approximately 8 weeks prior, she had polyarthralgia, purpuric rash over the abdomen, buttocks and lower extremities with associated edema. She was treated for post-streptoccocal infection in the setting of high ASO titer (1490 IU/mL). On examination, she demonstrated persistent petechial rash and new right sided CVA tenderness. Blood pressure was 126/70 mmHg. On investigation, she was anemic with hemoglobin 8.1, had an acute kidney injury with creatinine 1.6 mg/dL and urinalysis showed 3.5 grams predicted 24 hour proteinuria, dysmorphic hematuria, >100 RBCs per high power field. Serology tests were notable for negative ANA, PR3-ANCA, MPO-ANCA, anti-GBM, Cryoglobulin, Hepatitis, HIV serology and paraproteinemia studies.
Kidney biopsy showed focal endocapillary proliferative, crescentic, and necrotizing glomerulonephritis with bright glomerular C3 staining. On electron microscopy there was mesangial, intramembranous and sub-endothelial deposits with absence of sub-epithelial humps. She was initiated on pulse dose steroids and subsequently developed spontaneous hemoptysis requiring emergent intubation. Bronchoscopy confirmed DAH with cytopathology showing 0% hemosiderin-laden macrophages. Further work up revealed low complement (C3 40, C4 6 mg/dL) with decreased function of the alternate complement pathway at 55% (75-170% normal range). A diagnosis of C3GN with associated pulmonary hemorrhage was made. She required plasmapheresis and transitioned to prednisone and mycophenolate mofetil. As an outpatient, genetic testing showed 3 copies of C3GN risk alleles, but with negative mutations for complement factor H and factor I, negative factor H autoantibody or C3 nephritic factor. Renal function deteriorated despite aggressive immunosuppression and eculizumab therapy and she required hemodialysis.
Discussion
C3GN should also be considered part of the differential diagnosis in the setting of ANCA negative pulmonary renal syndrome.