EXPLORING KIDNEY INVOLVEMENT IN MULTIPLE MYELOMA:FIRST DESCRIPTIVE COHORT IN SOUTHERN MOROCCO

Introduction: Multiple Myeloma (MM) is a malignant and a clonal proliferation of plasma cells that secrete a monoclonal immunoglobulin or its fragment. Renal involvement is common in MM, secondary to the production of monoclonal immunoglobulins (IgM) with intrarenal deposition of light chains. This renal involvement can exacerbate the already poor prognosis due to tumor progression. The aim of our study is to describe the epidemiological, clinical, biological, therapeutic, and evolutionary aspects of renal involvement in MM. Patients and Methods: We conducted a prospective descriptive study based on the analysis of 22 cases of MM treated at the Nephrology Department of University Hospital Center of Agadir over a period of 4 years (April 2020 - March 2024). The study included all patients meeting the International Myeloma Working Group (IMWG) 2014 classification criteria. Results: The average age of our patients was 59.4 years, with a male-to-female ratio of 1.44. The average consultation delay was 2 months. Clinical manifestations were predominantly general deterioration, osteoarticular symptoms, and mucocutaneous pallor, present in the majority of our patients. Biological assessments revealed anemia in all cases, severe in half of them. Hypercalcemia was present in the majority of cases (72.7%). Hyperproteinemia was noted in 45% of patients, being significant (>100 g/L) in half of them. Hypoalbuminemia was observed in more than three-quarters of the patients. Severe renal failure was present in 77.2% of patients, with an average serum creatinine level of 66 mg/L. Infectious syndromes were found in half of the patients at admission, primarily urinary (60%) or pulmonary (40%) infections. A monoclonal peak was observed in 77.3% of patients, mainly in the gamma-globulin zone. The myelogram was significant in all cases. Immunofixation revealed a predominance of kappa light chains (62%).. Radiological osteolytic lesions were found in 77.3% of cases. All patients had high tumor mass myeloma. Kidney biopsies were not systematically performed, being done in only 2 patients. Therapeutically, chemotherapy was initiated in most patients. Dialysis was indicated in 8 cases (36.3%), and was successful in 6 out of 8 patients. Renal response was complete in 9 cases (40.9%), partial in 3 cases (13.6%), and minor in 6 cases (27.3%). Worsening renal function was observed in 4 patients (18.2%), with 2 patients progressing to chronic dialysis. Infectious complications were noted in 14 patients during their follow-up (63.6%). Hematological toxicity from chemotherapy was observed in 9 patients (40%). with a follow-up period of 22 months, 9 patients are in complete remission, 7 patients have died, and 6 patients were lost to follow-up. Discussion and Conclusion: Multiple Myeloma remains an incurable disease. However, the advent of new therapies has significantly improved its prognosis. Early diagnosis and management is essential for rapidly restoring renal function and preventing serious complications.