Edema That Is More than Cardiac: Two Cases of Mixed Cryoglobulinemic Membranoproliferative Glomerulonephritis (MPGN) Mimicking Congestive Heart Failure (CHF)

Introduction: Mixed cryoglobulinemia can have life threatening manifestations like glomerulonephritis, gastrointestinal and pulmonary vasculitis, digital ischemia and stroke. It often presents with nonspecific symptoms like lethargy, lower extremity edema, arthralgias, hypertension with lab findings of hypoalbuminemia, elevated creatinine, proteinuria, hematuria. Clinical findings may overlap with CHF, leading to delayed diagnosis. Case Description: Case 1: 74 yo female with PMH of Rheumatoid Arthirits, was repeatedly being hospitalized for bilateral lower extremity edema, SOB and joint/muscle aches. Labs showed Hb 9 g/dl, BNP 7k pg/ml, creatinine 1.24 mg/dl, elevated CRP and Rheumatoid factor, hematuria, urine protein creatinine ratio (UPCR) 1.66g. ECHO showed normal ejection fraction. Autoimmune workup negative for ANA, ANCA, Anti-GBM, SSA, SSB, ds-DNA, and complements were low. Normal SPEP, negative Hep B, C, HIV serology. Cryoglobulin resulted positive, and renal biopsy showed MPGN with polytypic IgM deposits, immune thrombi, endarteritis, consistent with mixed type II/type III cryoglobulinemic glomerulonephritis. Bone marrow biopsy and flow cytometry confirmed CLL. She received corticosteroids and rituximab. Renal function stabilized, proteinuria resolved. Case 2: 38 yo female with PMH of diabetes, hypertension, was also being hospitalized repeatedly with bilateral leg swelling, dyspnea, mild chest pain, fever, cough. She was discharged with diuretics for CHF exacerbation and with antibiotics for pneumonia. Lab results showed creatinine 1.36mg/dl, BNP 5k pg/ml, UA with hematuria, UPCR 13g. Respiratory panel was positive for parainfluenza virus. Autoimmune workup and serology workup negative as in above case, including negative ASO, normal complement. However, had elevated cryoglobulins. Kidney biopsy showed mixed cryoglobulinemic glomerulonephritis secondary to viral pneumonia. Unfortunately, over a year developed ESRD, now on hemodialysis. Discussion: Maintaining broad differential with high suspicion is critical in early diagnosis as cases illustrate initial overlapping physical/lab findings between CHF and mixed cryoglobulinemia, masquerading diagnosis of cryoglobulinemia. Delayed diagnosis and treatment may lead to worse outcomes.