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Abstract(s)
A nefropatia por Imunoglobulina A constitui a glomerulonefrite primária mais comum a nível mundial. Esta é principalmente diagnosticada no início da vida adulta ou na infância e parece ser uma doença com alguma predileção pelo sexo masculino.
Quanto à fisiopatologia, esta ainda não está completamente estabelecida, no entanto sabe-se que é o resultado de um fenómeno de “multi-hit”. O aumento da produção de IgA com défice de galactose constitui o primeiro hit, seguindo-se o reconhecimento destas moléculas por anticorpos antiglicanos. Do reconhecimento surge a formação de complexos imunes circulantes. O depósito destes complexos inicia uma reação mesangial que resulta em excessiva proliferação celular, excesso de matriz extracelular e mesmo de produção de citocinas.
No que concerne à apresentação clínica e curso da doença, a principal marca desta doença é a heterogeneidade. A apresentação mais frequente é caracterizada por um episódio de hematúria macroscópica durante uma infeção do trato respiratório ou gastrointestinal, que ocorre tradicionalmente em doente jovem.
O diagnóstico definitivo desta doença continua dependente da análise histológica de material obtido por biópsia renal, nomeadamente a deteção de depósitos mesangiais de IgA. Contudo muitos outros testes podem ser utilizados como auxiliares de diagnóstico.
A avaliação do prognóstico é também um passo importante na avaliação da nefropatia por IgA e existem preditores clínicos e histológicos, sendo que o grau de proteinúria é um dos fatores de prognóstico mais fiável.
Relativamente à abordagem terapêutica, não existem ainda tratamentos específicos para esta patologia. As guidelines propõem opções terapêuticas que em alguns pontos são contraditórias. As estratégias terapêuticas mais utilizadas prendem-se com o uso de bloqueadores do eixo renina-angiotensina-aldosterona, de óleo de peixe, de antiagregantes plaquetários, de corticosteroides e de diversos imunossupressores. Opções cirúrgicas como a realização de amigdalectomia ou transplantação renal foram também propostas. E mesmo intervenções ao nível do estilo de vida parecem ser efetivas. Contudo, é importante ressalvar, que a maior parte destas opções terapêuticas não são aceites de forma consensual.
IgA nephropathy is the most common primary glomerulonephritis worldwide. This is primarily diagnosed in the beginning of the adult life or during the childhood and it seems to be more commonly associated to the male gender. With regards to pathophysiology, it is found not to be completely established, even though it is known that it is the result of a “multi-hit” phenomenon. The increase of IgA production with a deficit of galactose composes the first hit. It is followed by these molecules recognition by anti-glycan antibodies. From the recognition arise the formation of immune complexes. And the deposit of these complexes begins a mesangial reaction that results in an excess of cell proliferation, excess of extracellular matrix and even the production of cytokine. Regarding the clinical presentation and disease course, the principal marking relates to heterogeneity. Its most common manifestation is characterized by a visible hematuria episode during a respiratory tract or gastrointestinal infection, generally in a young patient. The definitive diagnosis is still dependent on the histologic analysis of material obtained through a kidney biopsy, namely the IgA mesangial deposit detection. However, a significant amount of other testing can be used as diagnostic aids. The prognosis evaluation is also an important step in the IgA nephropathy evaluation and there are clinical and histologic predictors, being the proteinuria extent one of the most reliable diagnostic factors. As for the therapeutic approach, there are not yet specific treatments for this pathology. And even the guidelines propose therapeutical options that are contradictory. The treatment strategies more commonly used attach themselves to the use of renin-angiotensin-axis blockers, fish oil, antiplatelets, corticosteroids and other immunosuppressants. Surgical options such as tonsillectomy or renal transplantation were also proposed. And even the lifestyle interventions seem to be effective. Nevertheless, it is important to emphasize that most of these therapeutical options are not consensual.
IgA nephropathy is the most common primary glomerulonephritis worldwide. This is primarily diagnosed in the beginning of the adult life or during the childhood and it seems to be more commonly associated to the male gender. With regards to pathophysiology, it is found not to be completely established, even though it is known that it is the result of a “multi-hit” phenomenon. The increase of IgA production with a deficit of galactose composes the first hit. It is followed by these molecules recognition by anti-glycan antibodies. From the recognition arise the formation of immune complexes. And the deposit of these complexes begins a mesangial reaction that results in an excess of cell proliferation, excess of extracellular matrix and even the production of cytokine. Regarding the clinical presentation and disease course, the principal marking relates to heterogeneity. Its most common manifestation is characterized by a visible hematuria episode during a respiratory tract or gastrointestinal infection, generally in a young patient. The definitive diagnosis is still dependent on the histologic analysis of material obtained through a kidney biopsy, namely the IgA mesangial deposit detection. However, a significant amount of other testing can be used as diagnostic aids. The prognosis evaluation is also an important step in the IgA nephropathy evaluation and there are clinical and histologic predictors, being the proteinuria extent one of the most reliable diagnostic factors. As for the therapeutic approach, there are not yet specific treatments for this pathology. And even the guidelines propose therapeutical options that are contradictory. The treatment strategies more commonly used attach themselves to the use of renin-angiotensin-axis blockers, fish oil, antiplatelets, corticosteroids and other immunosuppressants. Surgical options such as tonsillectomy or renal transplantation were also proposed. And even the lifestyle interventions seem to be effective. Nevertheless, it is important to emphasize that most of these therapeutical options are not consensual.
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Keywords
Glomerulonefrite Imunoglobulina A Nefropatia Por Iga