Rapidly Progressive Renal Failure in Young Adult: An Atypical Presentation of Multiple Myeloma - A Case Report

Patients frequently present with renal impairment that does not fit the criteria for acute kidney injury or chronic kidney disease. This condition, known as rapidly progressive renal failure (RPRF), encompasses a diverse range of clinical syndromes characterized by the progressive renal impairment over days to weeks. We present a case of a 37-year-old male with a short history of uremic symptoms and decreased urine output with no significant history or examination findings except pallor. The patient had a creatinine of 1.6 mg/dL in April 2022, rising to 4.4 mg/dL, then 11.6 mg/dL during May, 17.6 mg/dL in June, presented to us with a creatinine of 24.6 mg/dL, with normal kidney size and corticomedullary differentiation (CMD). Beta-2-microglobulin was elevated, and renal biopsy showed features suggestive of multiple myeloma (MM). Atypical appearing tubular casts showing 3+ patternless staining for kappa light chains and negativity for lambda light chains were observed. The patient was started on chemotherapy for MM, and renal function was gradually improving. Renal failure as the sole presentation of MM is rare, especially in young adults. This case emphasizes an atypical RPRF, particularly given the patient’s young age.