Predictors of acute ischemic cerebral lesions in immune-mediated thrombotic thrombocytopenic purpura and hemolytic uremic syndrome

Abstract

Background: The immune form of thrombotic thrombocytopenic purpura (iTTP) and the hemolytic and uremic syndrome (HUS) are two major forms of thrombotic microangiopathy (TMA). Their treatment has been recently greatly improved. In this new era, both the prevalence and predictors of cerebral lesions occurring during the acute phase of these severe conditions remain poorly known. <break><break>Aim: The prevalence and predictors of cerebral lesions appearing during the acute phase of iTTP and shigatoxin-producing Escherichia coli-HUS or atypical HUS were evaluated in a prospective multicenter study. <break><break>Methods: Univariate analysis was performed to report the main differences between patients with iTTP and those with HUS or between patients with acute cerebral lesions and the others. Multivariable logistic regression analysis was used to identify the potential predictors of these lesions. <break><break>Results: Among 73 TMA cases (mean age 46.89 15.99 years (range: 21-87 years) with iTTP (n = 57) or HUS (n= 16), one third presented with acute ischemic cerebral lesions on magnetic resonance imagery (MRI); two individuals also had hemorrhagic lesions. One in ten patients had acute ischemic lesions without any neurological symptom. The neurological manifestations did not differ between iTTP and HUS. In multivariable analysis, 3 factors predicted the occurrence of acute ischemic lesions on cerebral MRI: 1) the presence of old infarcts on cerebral MRI, 2) the level of blood pulse pressure, 3) the diagnosis of iTTP. <break><break>Conclusion: Cerebral MRI is crucial to detect both symptomatic and covert ischemic lesions at the acute phase of iTTP and HUS and helps identify patients with old infarcts, at the highest risk of neurological worsening. The diagnosis of iTTP further increases the risk of ischemic lesions but also an increased level of blood pressure that may represent a potential target to further improve the therapeutic management of these conditions.