Abstracts

Rationale: Neurological complications are reported in 11 to 70% of recipients of hematopoietic stem cell transplantation (HSCT) in children, with seizures as the most common symptom. The authors here describe the clinical manifestations and risk factors for seizures occurring after HSCT in children, and compare the 3-year survival rates of those who experience such seizures and those who do not. Methods: A total of 197 pediatric patients (113 male, 84 female) received HSCT at the HSCT center, St. Mary's Hospital, the Catholic University of Korea, from August, 2001 to August, 2005. Of these patients, 28 patients (21 male, 7 female) experienced seizures after HSCT. Patient population was divided into 2 groups according to age at the time of HSCT : (1) < 5 years old, and (2) ? 5 years old. The time of seizure onset was divided into 3 periods: (1) less than 1 month after HSCT : the period of engraftment, and (2) between 1-3 months after HSCT : the period of acute graft versus host disease, (3) 3 months after HSCT : the period of chronic graft versus host disease. Patient variables such as, age, sex, method of HSCT, use of total body irradiation, use of busulfan, the stage of acute graft versus host disease (aGVHD), the malignant or non-malignant nature of the patient's underlying disease, were analyzed to decide upon risk factors for seizures after HSCT. The 3-year survival rate of patients experiencing seizures after HSCT was compared to that of patients who did not experience seizures. Results: The overall incidence of seizures developing after HSCT was 14.2%, with boys reporting a higher incidence than girls. No significant difference was found with regards to onset and type of seizure. Abnormal neuroimaging findings were noted in 20 patients (76.9%), with posterior reversible leukoencephalopathy syndrome being the most common finding. EEG abnormalities were noted in 21 patients (91.3%); cortical dysfunction was the most prevalent EEG finding. Amongst the possible risk factors for seizures, the age of the patient and the grade of aGVHD were statistically significant. Patients age of 5 years or older showed a 4.2 times greater incidence of seizures (P=0.025) than those younger. Also, patients with grade 2-4 acute GVHD showed a 2.77 times greater incidence of seizures (P=0.034) than those with grade 0-1 aGVHD. The 3-year survival rate of patients experiencing seizures was 37 9%, compared to 68 3% for those who did not experience seizures (P<0.001). Conclusions: (1) 14.2% of pediatric patients who received HSCT experienced seizures after transplantation. (2) Factors predicting seizures after HSCT: 1) Patient age : ? 5 years old, 2) GVHD of grade 2 or above (3) The 3-year survival of patients experiencing seizures after transplantation was significantly lower than patients who did not undergo seizures. (4) Early investigations and prompt treatments are required for pediatric patients experiencing seizures after HSCT as such seizures seem to have a direct linkage with the long term prognosis of the patient.