RESUMO
BACKGROUND: Monoclonal gammopathy of renal significance (MGRS) encompasses a heterogeneous group of kidney diseases in which a monoclonal immunoglobulin secreted by a clone of B cells or plasma cells causes kidney damage without meeting the hematological criteria for malignancy. Among the various forms of involvement, MGRS can manifest as a proximal tubule disorder, such as Fanconi syndrome (FS), characterized by urinary loss of phosphate, glucose, amino acids, uric acid and bicarbonate. Few cases of MGRS have been described in the literature, manifesting as FS and monoclonal production of lambda light chains, almost all of which are secondary to the production of kappa light chains. CASE PRESENTATION: Here we report a clinical case of a 45-year-old Brazilian male, African descent, with proximal weakness of the lower limbs, whose initial assessment showed a urine summary with the presence of proteinuria and glycosuria without hyperglycemia, associated with mild worsening of renal function, hypouricemia, hypocalcemia and phosphaturia. Evolution was characterized by a MGRS manifesting as FS and osteomalacia. CONCLUSION: The diagnosis of MGRS is not always easy, it requires knowledge of the clinical characteristics, diagnostic criteria and prognosis of each case. Therefore, all possible efforts should be made for multidisciplinary diagnosis.
Assuntos
Síndrome de Fanconi , Nefropatias , Gamopatia Monoclonal de Significância Indeterminada , Osteomalacia , Paraproteinemias , Síndrome de Fanconi/complicações , Síndrome de Fanconi/diagnóstico , Humanos , Cadeias lambda de Imunoglobulina , Rim/patologia , Rim/fisiologia , Nefropatias/patologia , Masculino , Pessoa de Meia-Idade , Gamopatia Monoclonal de Significância Indeterminada/complicações , Osteomalacia/complicações , Osteomalacia/etiologia , Paraproteinemias/complicações , Paraproteinemias/diagnóstico , Paraproteinemias/patologiaRESUMO
Abstract Proliferative glomerulonephritis with monoclonal immunoglobulin deposits is defined as membranoproliferative glomerulonephritis like injury with monotypic Ig deposits restricted to a single light chain isotype.Here we present a patient who presented with hypocomplementemia and nephrotic syndrome, who was initially diagnosed with proliferative glomerulonephritis with monoclonal immunoglobulin deposits. He developed disseminated tuberculosis after a brief course of immunosuppression. Successful treatment of tuberculosis resulted in the complete remission of glomerular disease and the disappearance of monoclonal protein. Hence, we believe he had Tuberculosis-related proliferative glomerulonephritis with monoclonal immunoglobulin deposits. Treatment strategies have not been structured due to the rarity of the condition and lack of randomized trials. However, expert opinion suggests clone-based therapy. proliferative glomerulonephritis with monoclonal immunoglobulin deposits with a benign course without clone-based therapy has been reported. Patients seldom respond to classic immunosuppressants. Even some cases experience slowly progressive disease under angiotensin converting enzyme inhibition alone. There are also cases secondary to viral infections. Our case and the particular "benign" cases lead us to an intriguing proposition that proliferative glomerulonephritis with monoclonal immunoglobulin deposits might not be a single disease. A subset of patients may be experiencing infection-related or post-infectious glomerulonephritis presenting as proliferative glomerulonephritis with monoclonal immunoglobulin deposits.
Resumen La lesión similar a la glomerulonefritis membranoproliferativa con depósitos de Ig monotípicos restringidos a un isotipo de cadena ligera única se conoce actualmente como glomerulonefritis proliferativa con depósitos de inmunoglobulina monoclonal. A continuación presentamos a un paciente que presentó hipocomplementemia y síndrome nefrótico, al que inicialmente se le diagnosticó glomerulonefritis proliferativa con depósitos de inmunoglobulina monoclonal. Desarrolló tuberculosis diseminada después de un breve curso de inmunosupresión. El tratamiento exitoso de la tuberculosis dio como resultado la remisión completa de la enfermedad glomerular y la desaparición de la proteína monoclonal. Por lo tanto, creemos que tenía glomerulonefritis proliferativa con depósitos de inmunoglobulina monoclonal relacionada con tuberculosis diseminada. Las estrategias de tratamiento no se han estructurado debido a la rareza de la afección y la falta de ensayos aleatorios. Sin embargo, la opinión de los expertos sugiere una terapia basada en clones. Se ha informado de glomerulonefritis proliferativa con depósitos de inmunoglobulina monoclonal con un curso benigno sin terapia basada en clones. Los pacientes rara vez responden a los inmunosupresores clásicos. Incluso algunos casos experimentan una enfermedad de progresión lenta solo con la inhibición de la enzima convertidora de angiotensina. También hay casos secundarios a infecciones virales. Nuestro caso y los casos "benignos" particulares nos llevan a la propuesta intrigante de que la glomerulonefritis proliferativa con depósitos de inmunoglobulina monoclonal podría no ser una sola enfermedad. Un subgrupo de pacientes puede estar experimentando glomerulonefritis postinfecciosa o relacionada con una infección que se presenta como glomerulonefritis proliferativa con depósitos de inmunoglobulina monoclonal.
RESUMO
Monoclonal gammopathy of renal significance (MGRS) can present with different morphologic features and lead to kidney failure. The Henoch-Schönlein purpura nephritis (HSPN) that cannot be relieved by treatment with glucocorticoid and immunosuppressive agents suggests the presence of monoclonal gammopathy in adult patients. The present study reports on a single case of HSPN associated with IgA-κMGRS. The patient who suffered from recurrent skin purpura for 6 months and nephrotic syndrome for 2 months was admitted to our hospital. Bone marrow biopsy showed monoclonal gammopathy of undetermined significance. Kidney biopsy indicated a Henoch-Schönlein purpura nephritis (HSPN, ISKDC classified as type III) with positive staining with κ-light chain in the glomeruli and renal tubular epithelial cells. Furthermore, skin biopsy showed leukocytoclastic vasculitis and negative staining for Congo red and light chain. Given both the renal and cutaneous involvement, the patient was considered to have HSPN associated with IgA-κMGRS. The patient experienced an exacerbation in his purpura-like lesions and clinical status after treatment with glucocorticoid and immunosuppressive agents. Consequently, the patient was put on a regimen that included dexamethasone (20 mg on the 1st, 4th, 8th, and 11th days of each month, iv) and bortezomib (2.4 mg on the 1st, 4th, 8th, and 11th days of each month, iv). Eight weeks after treatment, he had complete resolution of his cutaneous purpura and his biochemical parameters improved. The latent presence of MGRS in cases of HSPN should be considered in adult patients. Increased cognizance and correct treatment options could improve patient outcomes.