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

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. Aim The prevalence and predictors of cerebral lesions appearing during the acute phase of iTTP and Shiga toxin-producing Escherichia coli -HUS or atypical HUS were evaluated in a prospective multicenter study. 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. Results Among 73 TMA cases (mean age 46.9 ± 16 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, three 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. Conclusion At the acute phase of iTTP or HUS, both symptomatic and covert ischemic lesions are detected in one third of cases on MRI. Diagnosis of iTTP and the presence of old infarcts on MRI are associated with the occurrence of such acute lesions as well as increased blood pulse pressure, that may represent a potential target to further improve the therapeutic management of these conditions.