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Transient posterior encephalopathy induced by chemotherapy in children
R Sánchez-Carpintero1, J Narbona, R López de Mesa
1Pediatric Neurology Unit, Department of Pediatrics, University Clinic of Navarra and School of Medicine, University of Navarra, Pamplona, Spain.
Insights
Three children experienced temporary neurological issues, including vision loss and confusion, during chemotherapy for osteosarcoma. These episodes, termed occipital-parietal encephalopathy, were linked to hypomagnesemia and resolved within weeks.
Area of Science:
- Pediatric Oncology
- Neuro-oncology
- Toxicology
Background:
- Osteosarcoma treatment often involves high-dose chemotherapy.
- Chemotherapy agents like methotrexate, cyclophosphamide, and dactinomycin can have significant side effects.
- Neurological complications, though rare, are a concern in pediatric cancer patients.
Observation:
- Three pediatric patients developed sudden confusional states and cortical blindness during chemotherapy.
- Transient neuropsychological deficits, including hemispatial neglect and apraxia, were observed post-treatment.
- All patients experienced arterial hypertension and hypomagnesemia during the acute phase.
Findings:
- Neuroimaging revealed parieto-occipital T2 signal abnormalities and hypoperfusion in affected patients.
- These neuroimaging findings correlated with the onset and resolution of clinical symptoms.
- The syndrome was named occipital-parietal encephalopathy, suggesting a transient, localized brain dysfunction.
Implications:
- Hypomagnesemia induced by chemotherapy may trigger a migrainelike mechanism causing these neurological deficits.
- Understanding this mechanism can aid in early diagnosis and management of chemotherapy-related neurological toxicities.
- Further research is needed to elucidate the precise pathophysiology and develop targeted interventions.
Abstract:
The cases of three children, 16, 12, and 12 years of age, who suffered sudden confusional state and cortical blindness lasting 12 to 30 minutes while under treatment with high-dose methotrexate, cyclophosphamide, and dactinomycin for a lower limb osteosarcoma are reported. Transient neuropsychologic deficits arose after the acute phase of treatment: left hemispatial neglect and constructive apraxia (Patient 1); constructive apraxia (Patient 2); and constructive apraxia and alexia without aphasia (Patient 3). The three patients recovered completely from all their deficits within the time frame of 3 hours to 2 weeks. Arterial hypertension and hypomagnesemia were found during the acute phase in all patients. In Patients 2 and 3, magnetic resonance imaging revealed increased parieto-occipital T(2) signal involving gray and white matter. In Patients 1 and 2, HmPAO-SPECT revealed parieto-occipital hypoperfusion that resolved a few days later. The alterations detected by neuroimaging were concurrent with the appearance and disappearance of the clinical symptoms. Such transient acute episodes have been named occipital-parietal encephalopathy. On the basis of our clinical, laboratory, and neuroimaging findings, an explanation for the origin of this syndrome, a migrainelike mechanism, triggered by chemotherapy-induced hypomagnesemia, is proposed.