CRESCENTIC GLOMERULONEPHRITIS WITH LIGHT CHAIN DEPOSITION DISEASE – AN ECCENTRIC PRESENTATION OF MULTIPLE MYELOMA.

Introduction:

Multiple myeloma is a plasma cell disorder characterised by clonal proliferation of malignant plasma cells producing monoclonal protein and causing organ damage. 50% of multiple myeloma patients present with renal involvement that can vary from mild reversible AKI to severe renal impairment requiring hemodialysis. The spectrum commonly includes light chain cast nephropathy (LCCN), Light chain deposition disease (LCDD) and AL amyloidosis. Here we present this rare case of crescentic glomerulonephritis with light chain deposition disease in a patient of multiple myeloma.

Methods:

Clinical vignette – A 49-year-old female, homemaker noticed swelling of the legs which progressively increased and to which are added complaints of dyspnea, reduced urine output and anorexia for last 2 months. There was no associated fever, hematuria, hemoptysis, arthralgia, photosensitivity or skin rash. She had no comorbidities, addiction or history of intake of native medication. Clinically she was oriented, pale and tachypneic. Pulse rate - 112 /minute. BP – 180/90 mm of Hg. Respiratory rate – 34/minute. Spo2  - 96% (in room air). Bilateral pedal edema and hepatosplenomegaly was present with no obvious lymphadenopathy. On auscultation, s3 gallop was present, with normal breath sounds.  

Results:

Initial evaluation suggested severe anemia (Hemoglobin – 4 g/dl, WBC – 5.7´ 109/l, Platelet – 190 ´ 109/l) with microcytic hypochromic RBCs with anisocytosis in the Peripheral smear. Serum creatinine was 2.49 mg/dl with eGFR of 23ml/min as per CKD-EPI creatinine equation (2021). Sub nephrotic proteinuria (24hour urine protein – 2.3 gm) with active urine sediment was evident in urine analysis. In addition, hyperuricemia (UA - 10.1 mg/dl), hypoalbuminemia (Alb- 2.1g/dl), altered A:G ratio(AGR – 0.5) and hypercalcemia (corrected Ca - 10.2mg/dl) was present. Renal biopsy was considered in view of normal kidney size and CMD with rapidly progressive glomerulonephritis presentation. Light microscopy revealed crescentic and nodular glomerulonephritis without evidence of cast nephropathy. Circumferential fibro cellular crescents with PAS +ve fuchsinophilic and argyrophilic nodules were present. IFTA was Nil. On Immunofluorescence, IgA was 1+ and lambda 3+ smudged deposits in the glomerular mesangium and the capillary walls along with tubular basement membrane and vessels with no other deposits. Congo stain was negative. SPEP/SFLC detected M band in the gamma region, Total IgA – 3595 mg/dl with IgM and IgG being normal , free kappa/lambda ratio – 0.02 (Involved/uninvolved FLC ratio >100) and b2 microglobulin - 14359 ng/ml. Rest immunology profile and viral serology were negative. There was evidence of marrow plasmacytosis in the bone marrow analysis with 65% plasma cells. Multiple myeloma was diagnosed based on 2019 IKMG consensus criteria.

Conclusions:

Light chain cast nephropathy is the most common renal pathology associated with multiple myeloma but rare presentations still exist. This patient had Crescentic Glomerulonephritis associated with Light chain deposition disease (LCDD) - an infrequent renal involvement with absent LCCN inspite of high tumor burden. Since Treatment outcome and prognosis also differ based on histopathological diagnosis, Renal biopsy may be considered for patients of renal dysfunction in multiple myeloma.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.