Toxic-Metabolic Neurologic Disorders in Children: A Neuroimaging Review

Imaging Findings in Children Presenting with CNS Nelarabine Toxicity

Nelarabine is a nucleoside analog critical for the treatment of patients with T-cell acute lymphoblastic leukemia/lymphoma. However, clinical peripheral and central neurologic adverse events associated with nelarabine administration have been reported. Neuroimaging of brain neurotoxicity has only been described in very few reports in pediatric patients so far. Six children with diagnosed T-cell acute lymphoblastic leukemia who clinically experienced possible, probable, or definite nelarabine-induced toxicity and underwent spine and/or brain MR imaging were reviewed. Neuroimaging findings showed a mixture of patterns including features of acute toxic leukoencephalopathy (seen in 6 cases), posterior reversible encephalopathy syndrome (2 cases), involvement of deep gray structures (1 case) and brainstem (2 cases), cranial and spinal neuropathy (2 cases each), and myelopathy (2 cases). Even though neuroimaging findings are nonspecific, the goal of this article was to alert the pediatric neuroradiologists, radiologists, and clinicians about the possibility of nelarabine-induced neurotoxicity and its broad neuroimaging spectrum.

Imaging of Inherited Metabolic and Endocrine Disorders

"Inherited metabolic disorders represent a large group of disorders of which approximately 25% present in neonatal period with acute metabolic decompensation, rapid clinical deterioration, and often nonspecific imaging findings. Neonatal onset signifies the profound severity of the metabolic abnormality compared with cases with later presentation and necessitates rapid diagnosis and urgent therapeutic measures in an attempt to decrease the extent of brain injury and prevent grave neurologic sequela or death. Here, the authors discuss classification and clinical and imaging findings in a spectrum of metabolic and endocrine disorders with neonatal presentation."

Frequency, shape, and estimated volume of intracranial physiologic calcification in different age groups investigated by brain computed tomography scan: a retrospective study

Intracranial calcification is referred to calcification of parenchyma and vascular structures in brain which can be physiologic or pathologic. This study was conducted with the purpose of investigating the frequency, location, pattern, dimensions and estimated volume of intracranial physiologic calcification (IPC) by computer tomography in different age groups. In this cross-sectional retrospective study, brain computed tomography scans of 216 patients were analyzed in 9 age groups each containing 24 patients from 2 to 89 years old. Data were analyzed by SPSS software using one way analysis of variance (ANOVA, post hoc Tukey), chi square, and linear regression tests (P≤0.05 was considered significant). Rate of calcification in different areas were as follows: pineal gland (75.0%), habenula (36.4%), pineohabenula (15.0%), right lateral ventricle choroid plexus (RCP) (67.7%), left lateral ventricle choroid plexus (LCP) (62.7%), falx cerebri (26.8%), petroclinoid ligament (13.2%), tentorium cerebelli (6.8%), third ventricle choroid plexus (0.9%), fourth ventricle choroid plexus (2.7%), basal ganglia (0.9%). A significant correlation exists between the presence of calcification in pineal, habenula, RCP, and LCP (P≤0.001). Nodular shape of calcification was dominant (47.9%). Estimated volume of pineal calcification showed increased levels in group 8 (70–79 years old) compared to group 2 (10–19 years old) (P≤0.05). Since the accurate description of radiologic appearance of IPCs (location, shape, and size) accompanied with age and clinical manifestation is of great importance in diagnosis and distinguishing from pathologic calcification—for example in patients with melatonin dysregulation or schizophrenic patients—this study was required.

Chemotherapy-related neurotoxicity in pediatric cancer patients: magnetic resonance imaging and clinical correlation

Background

Cancer is the second most common cause of death among children aged 1–14 years in the USA. Pediatric malignancies have elevated morbidity and mortality in the absence of proper treatment. Intensive treatment regimens have resulted in a significant increase in the number of survivors but also have been associated with the risk of developing neurotoxicity. The purpose of this study is to emphasize the role of advanced MRI techniques in the early detection of different chemotherapy neurotoxicities and make radiologists aware of them providing early management to prevent permanent damage.

Results

We evaluated 63 patients (43 males and 20 females), and their ages ranged from (2 to 17 years) with suspected chemotherapy-related neurotoxicity. MR examinations were performed with 1.5-T Philips systems. Clinical data were correlated with magnetic resonance imaging (MRI), and different treatment complications were diagnosed. All of our 63 patients were receiving chemotherapy treatment, and they developed different neurological symptoms. Patients diagnosed as posterior reversible encephalopathy syndrome were 41 with 8 patients had typical and 33 had atypical criteria, 16 patients diagnosed as cerebral venous sinus thrombosis with magnetic resonance venography (MRV) are the most important sequence that successfully diagnosed them, and finally, 6 patients diagnosed as methotrexate neurotoxicity with diffusion-weighted images (DWI) are the most important sequence for early diagnosis.

Conclusion

Chemotherapy is associated with certain neurotoxicities, conventional MRI can detect them, but by the use of advanced MRI techniques including MRV and DWI early detection of these neurotoxicities can occur. Therefore, the combination of conventional MRI together with advanced techniques improves the diagnostic efficacy of MRI in the early diagnosis of neurotoxicity.

Posterior Reversible Encephalopathy Syndrome in Childhood Hematological/Oncological Diseases: Multicenter Results

The aim of the study was to analyze the characteristics of posterior reversible encephalopathy syndrome (PRES) cases treated at 10 different institutions in our country. Fifty-eight patients diagnosed with PRES were included in this study. The data of PRES cases from 10 departments of pediatric hematology/oncology were analyzed. The mean age of the patients at the time of diagnosis of PRES was 8.95±3.66 years. Most patients (80.4%) had a primary diagnosis of acute leukemia. Patients received chemotherapy (71.4%) and/or used steroids within 14 days before the diagnosis of PRES (85.7%). Hypertension was found in 83.9% of the patients. Twenty-six patients had infections and 22 of them had febrile neutropenia. The most common electrolyte disorders were hypocalcemia, hypomagnesemia, and hypopotassemia. Six patients had tumor lysis syndrome and 4 had inappropriate antidiuretic hormone syndrome. Magnetic resonance imaging was used for diagnosis in all patients. The most commonly involved regions by magnetic resonance imaging were occipital (58%), parietal (51%), and frontal lobes (45%), respectively. Twenty-five patients required intensive care and 7 patients were intubated. In conclusion, PRES may develop during the follow-up and treatment of hematological diseases. In addition to steroid and intense combined chemotherapies, immunosuppressive agents and hypertension are also factors that may be responsible for PRES.

Acute Cerebellitis and Atypical Posterior Reversible Encephalopathy Syndrome Associated with Methadone Intoxication

We report a case of a 9-year-old boy who presented with altered mental status and ataxia following 3 days of vomiting. Shortly after arrival to our emergency department, he declined and required intubation. The following day, he recovered and was successfully extubated. He was found to be positive for methadone on his urine drug screen. Brain imaging demonstrated a pattern of acute cerebellitis. Following extubation, the patient returned to his normal mental status; however, he began to have consistently elevated blood pressure and bradycardia and subsequent brain imaging showed supratentorial changes that were related to atypical posterior reversible encephalopathy syndrome. Through medical management including high-dose steroids and antihypertensive medications, the patient's blood pressure normalized, and he was eventually discharged home without further complications.

Pediatric Acute Toxic Leukoencephalopathy: Prediction of the Clinical Outcome by FLAIR and DWI for Various Etiologies

BACKGROUND AND PURPOSE

Pediatric acute toxic leukoencephalopathy is a clinicoradiologic entity comprising various etiologies. This study aimed to identify the MR imaging appearance of pediatric acute toxic leukoencephalopathy from various etiologies and determine whether the etiology correlates with clinical outcome.

MATERIALS AND METHODS

We retrospectively reviewed the electronic records of patients with pediatric acute toxic leukoencephalopathy younger than 19 years of age who had MR imaging within <2 weeks of presentation, including DWI and FLAIR sequences. Two neuroradiologists scored the DWI and FLAIR severity and measured the percentage ADC reduction within the visibly affected regions and normal-appearing WM. The percentage ADC reduction and DWI and FLAIR severity were correlated with clinical outcome using the Spearman correlation.

RESULTS

Of 22 children, 3 were excluded due to a nontoxic cause or incomplete examination. Regarding the included 19 children (mean age, 13 years), the etiologies of pediatric acute toxic leukoencephalopathy were the following: methotrexate (n = 6), bone marrow transplantation (n = 4), fludarabine (n = 3), cytarabine (n = 1), carboplatin (n = 1), vincristine (n = 1), cyclosporine (n = 1), uremia (n = 1), and bevacizumab (n = 1). Three subgroups were analyzed (chemotherapy, n = 12; immunosuppression, n = 5; others, n = 2). There was a strong correlation of FLAIR (r  = 0.773, P < .001) and DWI (r = 0.851, P < .001) severity with clinical outcome, and patients treated with fludarabine had the worst outcomes. High percentage ADC reduction values were associated with adverse outcomes, and lower percentage ADC reduction values were associated with favorable outcomes (r = 0.570, P = .011).

CONCLUSIONS

The DWI and FLAIR severity scores appear highly prognostic, whereas percentage ADC reduction is moderately prognostic for clinical outcomes in pediatric acute toxic leukoencephalopathy. Immunosuppressive pediatric acute toxic leukoencephalopathy tends toward favorable outcomes, and fludarabine tends toward worse outcomes.

Intracranial calcifications on CT: an updated review

Intracranial calcifications are frequently encountered in non-contrast computed tomography scan in both adult and pediatric age groups. They refer to calcifications within the brain parenchyma or vasculature and can be classified into several major categories: physiologic/age-related, dystrophic, congenital disorders/phakomatoses, infectious, vascular, neoplastic, metabolic/endocrine, inflammatory and toxic diseases. In this updated review, we present a wide spectrum of intracranial calcifications from both pediatric and adult populations focusing on their pattern, size and location.