A 55 yo African American Male with DMII, HTN, CKD, Hyperlipidemia who initially presented with worsening right leg swelling and diagnosed with an unprovoked right femoral vein non-occlusive Deep Venous Thrombosis (DVT) and occlusive thrombus of the right popliteal vein. The patient underwent tissue plasminogen activator (TPA) administration and mechanical thrombectomy. He was discharged with a warfarin bridge with therapeutic lovenox. He subsequently presented 7 months later with worsening generalized swelling and shortness of breath. During the inpatient stay he was found to have nephrotic range proteinuria at 9 grams/day. Given worsening shortness of breath and fluid overload and transthoracic echocardiogram was performed which showed an LV appearance compatible with some infiltrative process therefore Cardiac MRI performed showing asymmetric concentric left ventricular hypertrophy with heterogeneous myocardial signal intensity and patchy enhancement, most likely representing cardiac amyloidosis. In coordination with nephrology there was a renal biopsy done showing membranous nephropathy(MN) with no evidence of amyloid or light chain deposition. Given the suggestion of amyloidosis on Cardiac MRI there remained a question of primary versus secondary membranous nephropathy. A serum Phospholipase A2 Receptor IgG was detected with a titer of 1:160 (reference <1:10), suggestive of a primary (idiopathic) membranous nephropathy. During the inpatient admission the patient was started on steroids with Solumedrol and transitioned to Prednisone and Cyclophosphamide 2.5 mg/kg daily. Upon discharge the patient had both Cardiology and Nephrology followup. Approximately 2 months after treatment with steroids and cyclophosphamide the proteinuria decreased from 9 grams/day to 5 grams/day.
Discussion: This case brought two different diagnosis together in an attempt to make a unifying diagnosis. Membranous Nephropathy can be divided between primary (idiopathic) or secondary. In our case renal biopsy was suggestive of primary MN and an Phospholipase A2 (PLA2) Receptor IgG was sent to help confirm primary MN. The PLA2 Receptor is a known antigen for primary MN. Given the suggestion of cardiac amyloidosis there continued to be a clinical suspicion for secondary MN even after the renal biopsy which is why the PLA2 Antibody was sent. As far as the cardiac amyloidosis the issues of distinguishing immuoglobulin light-chain (AL) from transthyretin-related cardiac amyloidosis (ATTR) remains. The gold standard of cardiac amyloid diagnosis is with an endomyocardial biopsy. In an attempt to avoid an invasive cardiac biopsy there was consideration given to a Pyrophosphate Scintigraphy for further evaluation to distinguish AL from ATTR cardiac amyloidosis.
Conclusions: We present a case of a patient who initially presented with a DVT and later presented with nephrotic range proteinuria found to have primary MN. In an attempt to keep a broad differential workup revealed a suggestion of cardiac amyloidosis. In the inpatient setting its important for Hospitalists to keep a broad differential which may help to elucidate other diagnosis as it did in our patient.
To cite this abstract:
Varughese, JI; Hussain, F . INPATIENT DIAGNOSIS OF PRIMARY MEMBRANOUS NEPHROPATHY AND CARDIAC AMYLOIDOSIS. Abstract published at Hospital Medicine 2017, May 1-4, 2017; Las Vegas, Nev.
Journal of Hospital Medicine.
2017; 12 (suppl 2).
https://www.shmabstracts.com/abstract/inpatient-diagnosis-of-primary-membranous-nephropathy-and-cardiac-amyloidosis/. Accessed March 31, 2020.
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