Clinico-radiological spectrum of reversible splenial lesions in children

Recently, many cases of children presenting reversible splenial lesions during febrile illness (RESLEF) have been reported; however, their overall clinico-radiological features are unclear.     

Increased cytokines/chemokines and hyponatremia as a possible cause of clinically mild encephalitis/encephalopathy with a reversible splenial lesion associated with acute focal bacterial nephritis

ObjectiveClinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS), the second most common encephalopathy syndrome in Japan, is most often associated with viral infection. Bacterial MERS has been rarely reported but is mostly associated with acute focal bacterial nephritis (AFBN) for an unknown reason. We examined cytokines and chemokines in four MERS patients with AFBN to determine if they play an important role in the pathogenesis.MethodsWe examined the clinical charts and MRI results in four MERS patients with AFBN, and measured 10 cytokines and chemokines in serum and cerebrospinal fluid in the acute phase. These were analyzed using the Mann-Whitney U test, compared with the control group (cases with a non-inflammatory neurological disease). Longitudinal changes in the serum cytokine and chemokine levels were evaluated in two patients.ResultsHyponatremia was observed in all four patients with MERS associated with AFBN (128–134 mEq/L). CSF analysis revealed increased cytokines/chemokines associated with Th1 (CXCL10, TNF-α, IFN-γ), T reg (IL-10), Th17 (IL-6), and neutrophil (IL-8 and CXCL1). In serum, upregulation was observed in those associated with Th1 (CXCL10, TNF-α, IFN-γ), Th17 (IL-6), and inflammasome (IL-1ß). The increased serum cytokines/chemokines in the acute stage normalized within 2 weeks in patients 1 and 2, so examined, in accordance with their clinical improvement.ConclusionIncreased cytokines/chemokines and hyponatremia may be factors that explain why AFBN is likely to cause MERS.     

Cytotoxic lesions of the corpus callosum in children: Etiology,clinical and radiological features,and prognosis

ObjectivesCytotoxic lesions of the corpus callosum (CLOCCs) are secondary lesions associated with entities like infection manifested by restricted diffusion on diffusion-weighted cranial magnetic resonance imaging. Our objectives are to evaluate the clinic-radiological spectrum of pediatric patients with cytotoxic lesions of the corpus callosum (CC).MethodsChildren (0–18 years) admitted between February 2017 and May 2020 with splenial lesions showing diffusion restriction on MRI, either isolated or within involvement of other parts of the brain, were included retrospectively. The primary lesions of the CC (e.g. acute disseminated encephalomyelitis, acute ischemic infarction, and glioblastoma multiforme) were excluded. CLOCCs were divided into infection-associated, metabolic disorder–associated, and trauma-associated lesions, as well as CLOCCs involving other entities. Data were collected from the medical databases.ResultsForty-one patients were determined to have CLOCCs. Twenty-five (61%) were infection-associated, nine (22%) were trauma-associated, and three (7%) were metabolic disorder–associated cases, including 2 inherited disorders of metabolism. There were four (10%) patients with other entities, three with epilepsy, and one had an apparent life-threatening event. Six patients had a known etiology among the infection-associated group; one had multisystem inflammatory syndrome caused by COVID-19 and one had been infected by COVID-19 without any complications. All the infection-associated patients with isolated splenial lesions recovered totally, although six patients required intensive care hospitalization. Four trauma-associated patients had sequela lesions.ConclusionsCLOCCs are associated with a spectrum of diseases, including the new coronavirus, COVID-19 infection. Infection-associated CLOCCs has the best prognosis, although severe cases may occur. Sequelae are possible based on the etiology.     

Usefulness of arterial spin labeling imaging,which contributed to the early detection of cerebellitis complicated by clinically mild encephalitis/encephalopathy with a reversible splenial lesion: Lessons from three cases

BackgroundCerebellitis is a rare complication of clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS); however, MERS with cerebellitis is associated with a higher risk of neurological sequelae in comparison to MERS alone. Although the disease is difficult to diagnose by conventional MRI in the early disease phase, arterial spin labeling (ASL), a noninvasive MRI perfusion technique using magnetically-labeled arterial blood water protons, is considered promising.Case reportWe experienced three cases of MERS with cerebellitis. Diffusion-weighted imaging showed a high-intensity lesion at the splenium of the corpus callosum. ASL showed increased blood flow in the cerebellum in all three cases, despite cerebellar symptoms being inapparent or difficult to notice in the early phase of disease in all cases. Patients received methylprednisolone pulse therapy and intravenous immunoglobulin from the early phase of the disease and recovered without neurological sequelae.DiscussionASL magnetic response imaging simultaneously showed an area of hyperperfusion in the cerebellum. At the same time, the apparent diffusion coefficient of the splenial lesion was decreased in all three cases. The successful diagnosis of cerebellitis in the acute phase led to early therapeutic intervention, which may be important for this condition. We report the usefulness of ASL and review the relevant literature on MERS with cerebellitis.