Atypical uraemic haemolytic syndrome in pregnancy

Atypical haemolytic uraemic syndrome is one of the main variants of thrombotic microangiopathy, and is characterised by excessive complement activation in the microvasculature. It is also characterised by the clinical triad; non-immune haemolytic anaemia, thrombocytopenia, and acute renal failure. In addition, 60% of patients have mutations in the genes encoding complement regulators (factor H, factor I, membrane cofactor proteins, and thrombomodulin), activators (factor B and C3), as well as autoantibodies against factor H. Multiple factors are required for the disease to manifest itself, including a trigger and gene mutations with adequate penetration. Being one of the differential diagnoses of preeclampsia–eclampsia and HELLP syndrome means that the clinician must be familiar with the disease due to its high mortality, which can be modified with early diagnosis and comprehensive treatment.

ResumenEl síndrome hemolítico urémico atípico es una variante de la microangiopatía trombótica, caracterizado por una excesiva activación del complemento. Se caracteriza por presentar anaemia hemolítica no autoinmune, trombocitopenia y falla renal aguda. Se ha observado que el 60% de los pacientes presentan mutaciones en los genes que codifican al complemento, tanto reguladores (factor H, factor I, cofactor de proteínas de membrana y trombomodulina), activadores (factor B y C3) como autoanticuerpos contra el factor H. Se requiere la presencia de múltiples factores para su manifestación, estos incluyen: un disparador y mutaciones de genes con la penetrancia adecuada. Es necesario que el clínico esté familiarizado con la enfermedad, ya que presenta una elevada morbimortalidad que puede ser modificada si se identifica de manera temprana y se da un tratamiento oportuno.