{'fraction_non_alphanumeric': 0.016831108531630876, 'fraction_numerical': 0.00812536273940801, 'mean_word_length': 5.708171206225681, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Reversible Hypertensive Encephalopathy in Childhood

Reversible hypertensive encephalopathy (RHE) is clinically characterized by sudden onset of headache, visual changes, altered mental functioning and seizures. Typical MRI features include bilateral cerebral lesions depicted as hyperintense in T2 sequences and iso or hypointense in T1 images. These areas of vasogenic oedema are best visualized by diffusion-weighted imaging (DWI) sequences and apparent diffusion coefficient (ADC) maps. The neuroradiological changes usually resolve completely at follow-up. The pathogenesis of RHE is poorly understood. A number of factors have been implicated including an elevated systemic blood pressure breaking through the autoregulation capacity of the cerebral vascular system, but also immunosuppressant medication like ciclosporine A and tacrolimus as well as interferon alfa. A retrospective study of the five-year period 1999–2004 was undertaken on patients admitted to our Institution with clinical and neuroradiological features compatible with a diagnosis of RHE. Neuroradiological investigation disclosed hypodense areas on CT scan in four out of five cases and hyperintense images in T2 and FLAIR MRI sequences in eight out of eight patients, mainly affecting the unilateral or bilateral occipitoparietal regions. Clinical symptoms and MRI findings had normalized at follow-up in five cases between 2 and 11 weeks, whereas three patients died from complications of the underlying disease. RHE is not an uncommon complication arising in childhood cancer. MRI with DWI sequences is the gold standard for the detection and differential diagnosis of RHE-induced changes allowing adequate treatment and follow-up monitoring.