Brain Imaging Findings and Neurologic Complications after Allogenic Hematopoietic Stem Cell Transplantation in Children

Abstract

Hematopoietic stem cell transplantation (HSCT) is the only therapy for a subset of patients with malignant and nonmalignant diseases. Central nervous system (CNS) complications continue to be an important cause of morbidity and significantly contribute to mortality after HSCT. These complications include infections, cerebrovascular lesions, therapy-induced diseases, metabolic disturbances, and post-HSCT carcinogenesis. Following HSCT, three phases can be identified on the basis of the patient's immune status: the pre-engraftment period (<30 days after HSCT), the early postengraftment period (30-100 days after HSCT), and the late postengraftment period (>100 days after HSCT). There is a distinct relationship between the patient's degree of immunodeficiency after HSCT and the incidence of various complications that may occur. Early diagnosis of CNS complications is crucial for successful management and a good prognosis, and computed tomography and magnetic resonance imaging play an important role in achieving these goals. The global increase in the use of HSCT requires radiologists to be familiar with CNS complications, their relationship to the patient's immune status, and their imaging appearances. This article describes the clinical background of HSCT; reviews the incidence, causes, and timeline of brain complications in children who underwent allogenic HSCT; and identifies the characteristic imaging findings of these disorders. RSNA, 2018.

Epileptic Seizures After Allogeneic Hematopoietic Stem Cell Transplantation

“…According to changes in their immune status during transplant practice, three phases can be divided: the initial (<30 days after HSCT), intermediate (30-100 days after HSCT), and late (>100 days after HSCT) periods. Intracranial infection can occur at these three distinct time points and predominant microorganisms in each phase differ (64,66). What is more, it takes time for these immunocompromised patients to reconstitute a functioning immune system, making them more susceptible to opportunistic infection s (67).…”

“…In contrast to HLA-matched sibling transplantation, patients receiving umbilical cord blood transplantation are more likely to develop a CNS infection (1.7 vs. 8.2%; P < 0.001) (68), probably because of a delayed hematologic and immune recovery. The spectrum of major causative pathogenic agents is as follows: fungi such as Aspergillus and Candida, viruses like human herpesvirus-6 (HHV-6), cytomegalovirus, herpes simplex virus, protozoal infection particularly toxoplasma, and G+/G-bacteria (64,66,(68)(69)(70)(71). Convulsions are a common finding in neurologic infections manifesting as meningitis, encephalitis, or brain abscesses, but are of an extremely nonspecific nature.…”

Patterns of central nervous system complications of post-hematopoietic stem cell transplant in pediatric oncology patients: a single institute experience

“…Hematopoietic stem cell transplantation (HSCT) is a highly effective treatment for various benign and malignant diseases [1]. Few studies are available in the pediatric age group describing the incidence of posttransplant central nervous system complications (CNSC) and ranged from 8 to 65%, being the principal causes of death in 9 to 17% of the cases [2,3].…”

“…Post-transplant CNS complications are categorized into five major groups: cerebrovascular, metabolic, infectious, therapy-induced disorders, and post-HSCT carcinogenesis [3].…”

“…With the global increase in using HSCT, it requires a high level of diligence for radiologists to be familiar with CNS complications, their relationship to the patient's immune status, and their imaging appearances [3,7].…”