Abstracts

Rationale: Posterior reversible encephalopathy syndrome(PRES) is a clinico-radiologic disorder characterized by clinical manifestations of seizures, headache, altered mental status, visual disturbances, and transient vasogenic edema, predominantly on the posterior cerebrum in cranial magnetic resonance images. Clinical and radiographic abnormalities of PRES usually involve a transient course with favorable outcomes. However, the clinical course of PRES varies, depending on the underlying disease, especifically, in hematology-oncology patients. This study was designed to investigate clinical manifestations, radiographic features, predisposing factors, and long-term neurologic and radiologic outcomes of PRES as a complication during the treatment of acute childhood leukemia. Methods: 648 patients aged less than 18 years were treated for acute leukemia at the Department of Pediatrics of Seoul St. Mary s Hospital between January 2003 and May 2011. Among these patients, PRES was evident in 19 (12 males and 7 females) who were monitored for an average of 40.3 months after developing the complication of PRES. A retrospective chart review was performed on these patients to evaluate demographic data, primary diagnoses, treatment protocols, clinical manifestations, types of acute therapy, cranial magnetic resonance imaging and electroencephalogram findings, and neurologic and seizure outcomes. Results: The mean ages at time of diagnosis of PRES and primary leukemia were 6.7 years and 5.4 years, respectively. Seizures comprised the most common clinical sign (18 cases), followed by headache, confusion, or visual disturbance. Hypertension was observed before the onset of PRES in six patients. Among 18 patients who manifested seizures, nine required long-term anticonvulsant therapy because of continued epileptiform discharges in the electroencephalogram or repeated seizure episodes. Three patients manifested recurrent seizures although they were receiving more than three kinds of antiepileptic drugs. Among eight patients who developed PRES after HSCT, six required long-term antiepileptic drugs. On the other hand, among 11 patients who demonstrated PRES without HSCT, only three required long-term antiepileptic drugs (P= 0.070). High signal intensities were observed at the posterior parietal lobe (16 cases) or occipital lobe (19 cases) in brain MRI. Lesions were also observed in the temporal lobe, frontal lobe, thalamus, cerebellum, and external capsule. Overall, atypical PRES lesions were evident in eight out of 19 patients. Hippocampal sclerosis, temporal lobe atrophy, and ischemia also developed. Conclusions: The main predisposing factors for PRES during induction chemotherapy seemed to include ALL chemotherapy regimens. In addition, hypertension and immunosuppressive agents seemed to comprise the main predisposing factors for PRES after HSCT. When PRES develops as a complication of acute childhood leukemia, long-term anticonvulsant therapy is frequently required, and intractable seizures may develop. Additional long-term structural sequelae on cranial magnetic resonance imaging commonly occur.