Clinically mild encephalitis/encephalopathy with a reversible splenial lesion

Meningitis Retention Syndrome With Mild Encephalopathy With a Reversible Splenial Lesion in a 30-Year-Old Woman: A Case Report

We describe a 30-year-old woman who had meningitis retention syndrome (MRS) with mild encephalitis/encephalopathy with a reversible splenial lesion (MERS), which occurred with fever, urinary retention, and weakness in both legs. A case of MRS with MERS is rare among adults, and its clinical course and treatment planning remain unknown. In the present, we highlighted the change in magnetic resonance imaging, blood tests, and cerebrospinal tests along with the treatment. A multidisciplinary approach by a radiologist and neurologist led to the diagnosis and appropriate treatment.

International consensus definitions for infection-triggered encephalopathy syndromes

AIM

To develop standardized diagnostic criteria for 'infection-triggered encephalopathy syndrome (ITES)' and five specific clinical syndromes of ITES.

METHOD

The draft definitions were based on existing criteria, standardized, and discussed by a panel of international experts using nominal group technique over 18 months to achieve consensus. All criteria use the same format: (1) presence of infection/fever; (2) clinical features including encephalopathy; (3) neuroradiological features on magnetic resonance imaging; (4) exclusion of other causes.

RESULTS

We first highlighted differences between ITES and infectious and autoimmune encephalitis, which is the most important differential diagnosis. Consensus was achieved to define five specific ITESs: acute encephalopathy with biphasic seizures and late reduced diffusion; acute necrotizing encephalopathy; mild encephalopathy with a reversible splenial lesion; acute fulminant cerebral oedema; and acute shock with encephalopathy and multiorgan failure. Two further conditions that are currently classified as epilepsy syndromes but have similar features to ITES, namely febrile infection-related epilepsy syndrome and hemiconvulsion-hemiplegia-epilepsy syndrome, are also discussed.

INTERPRETATION

The consensus definition is expected to improve awareness of this disease concept, provide diagnostic framework, and facilitate future international research and clinical trials.

Case report: Reversible splenial lesion syndrome preceding the onset of multiple sclerosis

Background

The reversible splenial lesion syndrome is frequently associated with systemic and central nervous system infections. Whether an infection associated with the occurrence of the reversible splenial lesion syndrome could play a role in the later development of multiple sclerosis is unknown.

Methods

Case Report.

Results

A 27-year-old woman developed an infection-related reversible splenial lesion syndrome. Diagnostic findings did not establish a specific type of infection, but revealed evidence for a potential disposition towards autoimmunity. 32 months after the initial presentation, new clinical and radiological manifestations developed that led to a diagnosis of multiple sclerosis.

Conclusions

In susceptible individuals, infectious disease processes involving the central nervous system, such as described in this case, might be a factor in the pathogenesis of multiple sclerosis. More research on the prodromal stage of multiple sclerosis is needed to better understand the relationship between infections and autoimmunity.

[An adult case of adenovirus type 3 infection presenting as clinically mild encephalitis/encephalopathy with a reversible splenial lesion and increased IL-6 levels in the cerebrospinal fluid]

A 42-year-old Japanese man with a history hepatitis C who had undergone bone marrow transplantation for Burkitt lymphoma. He visited our hospital after developing a fever and sore throat. A computed tomography scan of the chest revealed pneumonia, and the patient was admitted to our hospital. After admission, he experienced a transient alteration of consciousness. Increased IL-6 levels in the cerebrospinal fluid and brain magnetic resonance imaging revealed clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS). He received steroid pulse therapy and was discharged on the 14th hospital day. A neutralization test of paired serum revealed more than 4-fold increase in the adenovirus type 3 antibody titer, and a diagnosis of adenovirus-induced pneumonia was made. MERS was suspected to be involved in the pathology of encephalitis or encephalopathy following the adenovirus type 3 infection.

Adult-onset of mild encephalitis/encephalopathy with reversible splenial lesion (MERS): case report and systematic review

BACKGROUND

Mild encephalitis/encephalopathy with reversible splenial lesion (MERS) is a clinical-radiological syndrome characterized by transient central nervous system symptoms and a reversible lesion in the splenium of the corpus callosum (SCC) on magnetic resonance (MR). We reported a case of adult-onset MERS with uncommon presentation and reviewed the existing literature.

METHODS

We described a case of adult-onset MERS with uncommon symptoms and signs and performed a systematic review of case series including more than four patients of adult-onset (> 14 years old) MERS, from January 2000 to December 2022. We summarized the clinical, laboratory, imaging and therapy data.

RESULTS

We included seven eligible studies for a total of 51 adult-onset MERS patients. Neurological manifestations were preceded by prodromal symptoms in most of the patients (88%), mainly with fever (78%). Headache was the most common symptom (50%), followed by seizures (22%) and disturbance of consciousness (22%). Inflammatory changes on cerebrospinal fluid were present in a half of patient, so defining encephalitis cases. Clinal recovery, was achieved in all patients but two with severe disturbance of consciousness who required ventilator support in the acute phase. MR showed isolated lesion in the SCC in 92% of patients, while 8% of patients showed also extracallosal lesions, all the lesions resolved or improved on follow-up imaging.

CONCLUSIONS

MERS is a form of encephalitis/encephalopathy with a broad range of central nervous system manifestation, often with mild symptoms, such as headache alone, that can lead to overlooked some cases, with an excellent prognosis in most patient.

Mild encephalitis/encephalopathy with reversible splenial lesion (MERS) associated with respiratory syncytial virus and Pseudomonas putida infection: A case report

Background

Clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is a mild encephalopathy, which may be associated with various pathogens, including virus and bacteria. However, there have been no reports on MERS associated with co-infection by respiratory syncytial virus (RSV) or Pseudomonas putida in adults.

Case presentation

We reported a 29-year-old Chinese woman with MERS associated with RSV and Pseudomonas putida. This woman presented with fever, sore throat, cough, and altered mental states. The results of RSV-RNA in the specimens from throat and sputum culture of Pseudomonas putida were positive. The initial head CT scan on the day of admission revealed abnormal hypodense lesions in the suprasellar cistern (SCC). Subsequent brain magnetic resonance imaging (MRI) also demonstrated abnormal hypersignals in the same region. The patient's altered mental status improved on day after ceftriaxone and low-dose corticosteroid therapy. The SCC hypersignal on MRI completely resolved after three weeks, and no recurrence of symptoms occurred during the two-month follow-up period.

Conclusions

It is the first reported case of MERS associated with RSV and Pseudomonas putida in the adult, which broadens the spectrum of potential etiologies in MERS. When a patient with a respiratory tract infection presents with neurological symptoms, the possibility of MERS should be considered.

Febrile neutropenia induced by adjuvant radiotherapy for a patient with breast cancer accompanied with reversible splenial lesion syndrome (RESLES, TypeI): a case report

BACKGROUND

Reversible splenial lesion syndrome (RESLES) is known as a neuro-imaging syndrome with recurrent but reversible lesion of the corpus callosum, characterized by nonspecific but usually mild encephalopathies and specific imaging manifestations.There are few published reports in the field of oncology.

CASE PRESENTATION

A 33-year-old female with right breast cancer and with no particular family history was admitted to hospital with high fever and severe headache, after receiving adjuvant radiotherapy. Blood routine test upon admission suggested neutropenia, considering myelosuppression associated with radiotherapy. There were no definite findings of common pathogenic microorganism, and no imaging indication of certain infectious sites other than a likely reversible corpus callosum syndrome suggested by brain MRI, which was relieved after systemic antibiotic therapy and granulocyte colony-stimulating factor injection.

CONCLUSIONS

Reversible splenial lesion syndrome is a kind of clinical-imaging syndrome with multiple clinical manifestations and etiologies. This breast cancer patient after postoperative adjuvant radiotherapy develops a complication of RESLES that rings an alarm bell to the oncologists not to easily recognize the corpus callosum lesion as infarction or metastasis. Meanwhile, the potential pathogenic mechanisms need to be explored further.

Cytotoxic Lesions of the Corpus Callosum (CLOCCs) Related to Hypoglycemia: Clinical Insights and Pathogenesis

We describe the case of an 88-year-old man with cytotoxic lesions of the corpus callosum (CLOCCs) related to hypoglycemia. The patient developed a disturbance of consciousness following excessive alcohol consumption and anorexia. In the emergency room, his blood sugar level was 9 mg/dL, and he was immediately treated with a rapid infusion of glucose. Brain magnetic resonance imaging (MRI) revealed hyperintensity in the corpus callosum and bilateral deep white matter on diffusion-weighted imaging, along with decreased apparent diffusion coefficient values. The following day, these findings were attenuated, and he was diagnosed with CLOCCs. In this report, we discuss clinical insights and the possible pathogenesis of the development of CLOCCs due to hypoglycemia, considering the previous literature.

Clinical and Etiological Profile of Children With Acute Viral Encephalitis in a Tertiary Care Hospital: A Cross-Sectional Study

BACKGROUND

 Acute encephalitis refers to the clinical diagnosis of children who have a sudden onset of symptoms and show evidence of inflammatory lesions in the brain. Timely diagnosis is crucial for both lifesaving measures and the preservation of brain functions.

OBJECTIVE

 The objective of the study was to determine the clinical and etiological profile of acute viral encephalitis in children within a tertiary care hospital.

METHODS

 This hospital-based cross-sectional study was conducted in the Pediatric Intensive Care Unit (PICU) at Dr. D. Y. Patil Medical College, Hospital, and Research Centre in Pune. The study included children aged one month to 12 years diagnosed with suspected viral encephalitis. Over 22 months, from August 2022 to June 2024, 35 children who met the inclusion criteria were enrolled. Data collection involved clinical examinations, laboratory investigations, and imaging studies, following informed consent from the parents or guardians.

RESULTS

The study examined 35 patients with suspected acute encephalitis syndrome (AES) and found a male-to-female ratio of 3.4:1. Among the patients, 22 (62.85%) had a confirmed viral etiology, while 13 (37.17%) had an unknown etiology. The most common virus isolated was mumps, with school-age children most affected. The cases were concentrated in the Chikhali, Bhosari, Nigdi, and Chinchwad regions. Symptoms included fever, seizures, vomiting, and altered mental status. Low vaccination rates were observed, and the Glasgow Coma Scale (GCS) scores, shock incidence, and ventilation showed an association with mortality. Most patients required intensive care, antiedema measures, antibiotics, and antivirals. The mortality rate was 11.4%, with 17% of patients discharged with neurological sequelae.

CONCLUSION

Causative agents such as mumps, herpes simplex virus (HSV), dengue, and many other viruses are now more prevalent than the Japanese encephalitis (JE) virus. Bad clinical course and fatal outcomes are observed in patients affected with rabies, HSV, and H1N1 influenza virus. Factors such as GCS scores, shock, and need for ventilation play a significant role in determining patient prognosis. Early detection and prompt treatment may aid in better outcomes for patients.

Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS)

Background

Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is increasingly recognized as a clinicoradiological syndrome. Its etiology is diverse, encompassing a variety of triggers, including infections and metabolic abnormalities. Uniquely, MERS may present with psychiatric symptoms, such as delirium, visual hallucinations, and catatonia, posing diagnostic challenges. The variability of these neuropsychiatric symptoms necessitates early diagnosis through magnetic resonance imaging (MRI) to avoid prolonged antipsychotic treatment.

Case Presentation

This report details a case of MERS in a 39-year-old male. The patient initially presented with headache, sore throat, and abnormal laboratory results: leukocytosis, neutrophilia with a left shift, elevated C-reactive protein (CRP) levels, and hyponatremia. On the fourth day of admission, he developed severe anxiety and restlessness, exhibited thoughts of death, and reported experiencing vivid hallucinations upon closing his eyes. MRI revealed a hyperintense lesion in the corpus callosum. A lumbar puncture showed no increase in cell count or protein. The patient showed a positive response to treatment with antibiotics and olanzapine, demonstrating rapid symptomatic improvement. A follow-up MRI on the 11th day showed complete resolution of the brain lesions. Six months later, no neurological or psychiatric sequelae were noted. The patient's clinical progression and imaging findings led to a definitive diagnosis of MERS.

Conclusion

The early presentation of symptoms such as restlessness, hallucinations, and death ideation played a critical role in diagnosing MERS, with early MRI examination being instrumental in both diagnosis and preventing prolonged antipsychotic medication use.

Coexisting Sacrococcygeal Teratoma With Mild Encephalitis/Encephalopathy With a Reversible Splenial Lesion: A Case Report

Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is a rare disease characterized by a reversible lesion in the splenium of the corpus callosum (SCC) observed on MRI. The exact etiology of MERS is unknown, although infections and antiepileptic drugs have been reported as potential causes. Herein, we present the case of a 56-year-old male patient who experienced fever and headache for 3 days. He was referred to our hospital after symptomatic treatment by his primary care physician failed to improve his symptoms. The patient had no psychiatric symptoms or significant neurological findings. Head MRI revealed a high signal on SCC on diffusion-weighted imaging, raising the suspicion of MERS. All examinations to determine the cause of MERS were negative. The patient's symptoms improved with antibiotics and B complex vitamins. Upon admission, abdominal CT incidentally revealed a well-defined mass on the dorsal surface of the rectum suspected to be a tailgut cyst, warranting surgical resection. The cranial margin of the tumor was caudal to the third sacrum, and a trans-sacral approach was used for resection. The fifth sacrum and the coccyx were resected, and the tumor was resected without damaging the rectum. A histopathological examination revealed a mature teratoma without any malignancy. A follow-up CT at four months postoperatively showed no evidence of clinical recurrence of MERS. Adult-onset MERS is relatively rare, and no association with tumors has been reported. The association between encephalitis and teratomas includes ovarian teratomas, which cause anti-N-methyl-D-aspartate receptor encephalitis and paraneoplastic limbic encephalitis. Although the cause of MERS was unknown in this case, we report the coexistence of a sacral teratoma and MERS to contribute to the knowledge of the association between them.

Mild Encephalopathy/Encephalitis With Reversible Splenial Lesion Associated With Meningitis Related to Mumps Disease: An Unusual Presentation in a Male Adult

Mild encephalitis/encephalopathy with reversible splenial lesion (MERS) is characterized by mild neurological manifestations associated with spontaneously reversible lesions of the splenium of the corpus callosum. While various conditions and diseases can trigger MERS, infectious causes predominate, with mumps being notably linked to MERS in the pediatric population. Although rare in adults, there are sporadic case reports associating mumps with MERS. Here we report a 23-year-old male patient with a typical presentation of mumps who presented with meningeal syndrome, dizziness, seizures, and right orchitis. Brain MRI showed classic findings of MERS syndrome while cerebrospinal fluid analysis demonstrated lymphocytic pleocytosis. Our patient had a confirmed diagnosis of mumps disease with multiple complications, including MERS, meningitis, and orchitis, and was managed with symptomatic medications and antiviral therapy. Subsequently, there was a gradual resolution of these manifestations and the outcome was favorable, with no residual sequelae.

Central Pontine Myelinolysis: A Rare and Life-Threatening Adverse Effect of Clobazam and Quetiapine

Central pontine myelinolysis (CPM) is a rare neurological disorder characterized by demyelination within the central portion of the pons. While hyponatremia is a well-known precipitating factor, other etiologies, including medication use, have been reported. We present a case of a 69-year-old male with a history of obsessive-compulsive disorder, stroke, and type 2 diabetes mellitus who developed confusion, altered sensorium, and weakness in all four limbs. An MRI brain imaging revealed characteristic findings suggestive of CPM. Despite normal serum sodium levels, discontinuation of clobazam and quetiapine, medications taken by the patient, led to clinical improvement. This case underscores the importance of considering medication-induced CPM in the differential diagnosis of patients presenting with neurological symptoms, even in the absence of electrolyte abnormalities.

Viral entry and translation in brain endothelia provoke influenza-associated encephalopathy

Influenza-associated encephalopathy (IAE) is extremely acute in onset, with high lethality and morbidity within a few days, while the direct pathogenesis by influenza virus in this acute phase in the brain is largely unknown. Here we show that influenza virus enters into the cerebral endothelium and thereby induces IAE. Three-weeks-old young mice were inoculated with influenza A virus (IAV). Physical and neurological scores were recorded and temporal-spatial analyses of histopathology and viral studies were performed up to 72 h post inoculation. Histopathological examinations were also performed using IAE human autopsy brains. Viral infection, proliferation and pathogenesis were analyzed in cell lines of endothelium and astrocyte. The effects of anti-influenza viral drugs were tested in the cell lines and animal models. Upon intravenous inoculation of IAV in mice, the mice developed encephalopathy with brain edema and pathological lesions represented by micro bleeding and injured astrocytic process (clasmatodendrosis) within 72 h. Histologically, massive deposits of viral nucleoprotein were observed as early as 24 h post infection in the brain endothelial cells of mouse models and the IAE patients. IAV inoculated endothelial cell lines showed deposition of viral proteins and provoked cell death, while IAV scarcely amplified. Inhibition of viral transcription and translation suppressed the endothelial cell death and the lethality of mouse models. These data suggest that the onset of encephalopathy should be induced by cerebral endothelial infection with IAV. Thus, IAV entry into the endothelium, and transcription and/or translation of viral RNA, but not viral proliferation, should be the key pathogenesis of IAE.

Clinical characteristics of SARS-CoV-2-associated encephalopathy in children: Nationwide epidemiological study

OBJECTIVE

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sometimes triggers acute encephalopathy as a serious neurological complication in children. We previously reported the clinico-radiological findings of SARS-CoV-2-associated encephalopathy. The advent of the SARS-CoV-2 omicron variant led to a marked increase in pediatric patients with coronavirus disease 2019 (COVID-19); however, epidemiological changes with acute encephalopathy according to the emergence of SARS-CoV-2 have not yet been documented. Therefore, the present study investigated epidemiological differences in SARS-CoV-2-associated encephalopathy during the BA.1/BA.2 and BA.5 predominant periods and also between SARS-CoV-2-associated and non-SARS-CoV-2-associated encephalopathy.

METHODS

We conducted a nationwide survey of SARS-CoV-2-associated encephalopathy in Japanese children between June and November 2022. We compared the present results during the BA.5 predominant period and previous findings during the BA.1/BA.2 predominant period. We also compared the clinico-radiological syndromes of encephalopathy between SARS-CoV-2-associated and non-SARS-CoV-2-associated encephalopathy.

RESULTS

Although many patients with SARS-CoV-2-associated encephalopathy in the BA.5 predominant period had seizures as their initial symptoms, no significant differences were observed in the clinical features. Patients with SARS-CoV-2-associated encephalopathy had worse outcomes than those with non-SARS-CoV-2-associated encephalopathy (p-value = 0.003). Among 103 patients with SARS-CoV-2-associated encephalopathy, 14 (13.6%) had severe types of acute encephalopathy, namely, encephalopathy with acute fulminant cerebral edema (AFCE) and hemorrhagic shock and encephalopathy syndrome (HSES). Also, 28 (27.2%) patients with SARS-CoV-2-associated encephalopathy had poor outcome: severe neurological sequelae or death. Ninety-five patients (92.2%) were not vaccinated against SARS-CoV-2.

CONCLUSIONS

In SARS-CoV-2-associated encephalopathy, high percentages of AFCE and HSES can result in poor outcomes.

Transient blindness due to mild reversible encephalopathy in a 7-year-old boy

Mild encephalopathy with a reversible splenial lesion (MERS) is a rare phenomenon, which shows transient lesion in corpus callosum and causes temporary encephalopathy features. A disturbance of consciousness and abnormal and delirious behavior are the most significant neurological symptoms. A seven-year-old child with a history of fever and cough was admitted to our hospital due to sudden bilateral blindness. His physical examination showed confusion, fever, and delirious behavior. No sign of meningeal irritation or focal neurological deficit was observed. The electroencephalogram showed diffuse slow waves representing mild encephalopathy. Brain MRI showed a signal alteration in the splenium of the corpus callosum, and magnetic resonance angiography (MRA) was normal. This finding was suggestive of a reversible cytotoxic lesion. Treatment with empiric antivirals was initiated, and the symptoms were completely resolved. In a few children, sudden blindness has been reported to be an initial symptom of MERS. There is currently no evidence of efficient treatment methods. However, to convince patients and their families about the good outcome of the disease, the diagnosis of MERS provides pediatricians with useful prognostic information.

Case report: Clinically mild encephalitis/encephalopathy with a reversible splenial lesion: an autopsy case

Clinically mild encephalitis/encephalopathy with a reversible splenial lesion is a clinicoradiological syndrome characterized by transient neuropsychiatric symptoms and hyperintensity of the splenium of the corpus callosum on diffusion-weighted MRI. Although intramyelinic edema and inflammatory cell infiltration can be predicted by MRI, the pathology of the splenium of the corpus callosum remains unknown. We encountered a case of clinically mild encephalitis/encephalopathy with a reversible splenial lesion and hypoglycemia in a patient who died of sepsis, and an autopsy was performed. The postmortem pathological findings included intramyelinic edema, myelin pallor, loss of fibrous astrocytes, microglial reactions, and minimal lymphocytic infiltration in the parenchyma. Based on these findings, transient demyelination following cytotoxic edema in the splenium of corpus callosum was strongly considered a pathogenesis of "clinically mild encephalitis/encephalopathy with a reversible splenial lesion" associated with hypoglycemia, and it could be generalized for the disease associated with the other causes. As cytotoxic edema could be the central pathology of the disease, the recently proposed term cytotoxic lesions of the corpus callosum may be applicable to this syndrome.

A nationwide survey of adenovirus-associated encephalitis/encephalopathy in Japan

BACKGROUND

Adenovirus is a major pathogen causing febrile illness among children. It may also cause acute encephalitis/encephalopathy. This study aimed to elucidate the clinical features of adenovirus-associated encephalitis/encephalopathy (AdVE) among children in Japan.

METHODS

A nationwide survey of children with AdVE was conducted. An initial survey was distributed among pediatricians to obtain information about children with AdVE treated between January 2014 and March 2019. A second survey was used to obtain the clinical information of children with AdVE from hospitals that responded to the initial survey and those identified from a literature search of the reported cases. We collected demographic data and information about symptoms of infection, neurological symptoms, laboratory parameters, treatment, and outcomes. Outcomes were determined using the Pediatric Cerebral Performance Category Score.

RESULTS

Clinical information was available for 23 children with a median age of 39 months. Two had preexisting neurological disorders and six had a history of febrile seizures. The outcome was good in 15 patients and poor in eight patients. Serum lactate dehydrogenase, glucose, and ammonia levels were higher among children with a poor outcome compared to those with a good outcome. Clinically mild encephalitis/encephalopathy with a reversible splenial lesion was the most common type (n = 8), followed by acute encephalopathy with biphasic seizures and late reduced diffusion (n = 7).

CONCLUSION

A prior history of febrile seizures was frequent in children with AdVE. Several different subtypes of acute encephalopathy were seen in children with AdVE, and the outcome was poor in those with acute encephalopathy with biphasic seizures and late reduced diffusion and hemorrhagic shock and encephalopathy syndrome. Elevated lactate dehydrogenase, glucose, and ammonia levels on admission were found to correlate with a poor outcome.

Mild Encephalopathy With Reversible Splenial Lesion (MERS) in a Child With Influenza

Mild encephalopathy with reversible splenial lesion (MERS) is a rare clinical-radiological syndrome with a favorable prognosis that typically presents with central nervous system symptoms such as altered mental status, delirious behavior, seizures, muscle weakness, ophthalmoplegia, and headache. The diagnosis of MERS is based on a constellation of central nervous system symptoms within one week of fever, a lesion in the splenium of the corpus callosum, and complete resolution without sequelae. Both clinical and imaging findings generally resolve within a few months. Treatment is largely supportive care and/or treatment of the primary cause.

Two Cases of Acute Focal Bacterial Nephritis With Central Nervous System Manifestations in Children and Literature Review

Acute focal bacterial nephritis (AFBN) is a kidney disease characterized by a localized bacterial infection that manifests as an inflammatory mass. Most children with AFBN have nonspecific symptoms including fever, vomiting, and abdominal discomfort, and some develop neurological symptoms such as meningeal irritation, unconsciousness, and seizures as their condition worsens. This was 2 cases of AFBN with central nervous system manifestations in children, and we analyzed its possible mechanisms of the clinical and radiographic features. We experience 2 very unusual cases of AFBN which were linked to central nervous system abnormalities. A 6-year-old boy with AFBN and clinically moderate ncephalitis/encephalopathy with a reversible splenial lesion (MERS) presented with neurological symptoms, including unconsciousness and convulsions. The second case involved an 8-year-old child with AFBN-associated acute encephalopathy who exhibited neurological symptoms, including unconsciousness. According to previous research, AFBN is linked to central nervous system impairment. As a result, when a clinician meets a patient with an inexplicable fever caused by a neurological condition, he should pay attention to this diagnosis of AFBN and follow it in the abdominal graph.

Diffusion-Restricted Lesions of the Splenium: Clinical Presentation, Radiographic Patterns, and Patient Outcomes

Background and Objectives

Diffusion-restricted (DR) lesions of the splenium are encountered in a wide variety of pathologies, and their significance is often unclear. We sought to report the spectrum of clinical presentations, neuroimaging patterns, and the predictors of radiographic and clinical outcomes from DR splenial lesions.

Methods

This was a single-center, retrospective cohort study from January 1, 2009, to August 1, 2020. A consecutive sample of 3,490 individuals who underwent brain MRI with reported corpus callosum lesions during the study period were evaluated for DR lesions in the corpus callosum. DR lesions were defined as increased signal intensity on diffusion-weighted imaging sequences with decreased signal intensity on apparent diffusion coefficient. Patients with prior neurosurgical procedures, hemorrhage-associated DR, anoxic brain injury, and chronic or previously known or characterized disease processes in the corpus callosum were excluded. Clinical and radiologic outcomes were ascertained, including readmissions within 1 year, in-hospital mortality rates, and resolution of DR at first follow-up imaging. Outcomes were defined a priori.

Results

Two hundred patients met criteria for inclusion. The average age was 57 years (standard deviation 19 years). Near half of the patients were women (47%). Encephalopathy (55%), focal weakness (46.5%), and cortical signs (44%) were the most common presenting clinical features. Thirty-five cases (17.5%) had features consistent with cytotoxic lesions of the corpus callosum (CLOCCs). Vascular causes were most frequent (61%), followed by malignancy-related (15%) and trauma (8%). In-hospital mortality occurred in 8.5% of cases, 46.5% were readmitted to the hospital within 1 year, and 49.1% of patients had resolution of the splenial DR at the next scan. Backward stepwise regression models showed that mass effect was negatively associated with splenial DR resolution (odds ratio [OR]: 0.12, confidence interval [CI] 0.03-0.46, p = 0.002). Encephalopathy was significantly associated with in-hospital mortality (OR: 4.50, CI 1.48-17.95, p = 0.007). Patients with a CLOCC had less frequent readmissions at 1-year compared with patients without a CLOCC, p = 0.015.

Discussion

Vascular DR lesions of the splenium were more common than CLOCCs and other etiologies in this cohort. While splenial DR lesions can present a clinical challenge, their associated clinical and radiographic characteristics may predict outcome and guide prognosis.

Reversible splenial lesion syndrome in children: a retrospective study of 130 cases

Background

Reversible splenial lesion syndrome (RESLES) is a new clinico-radiological syndrome. We retrospectively analyzed the clinical features of 130 children with RESLES in China, which is the largest case series available in the literature.

Methods

The clinical data of children diagnosed as RESLES in Jiangxi Provincial Children's Hospital between 2017 and 2023 were retrospectively analyzed. The 130 cases were divided into two groups: ≤ 3 years old group (group A) (n = 83) and > 3 years old group (group B) (n = 47). The chi-squared test or Fisher's test was used to evaluate the data.

Results

The vast majority of patients (127/130 cases, 97.7%) had prodromal symptoms of infection. Preceding infections of the gastrointestinal tract were statistically more significant in group A (60/83, 72.3%) than in group B (11/47, 23.4%) (P < 0.05). Preceding infections of the respiratory tract were statistically more significant in group B (33/47, 70.2%) than in group A (17/83, 20.5%) (P < 0.05). Seizures were statistically more significant in group A (82/83, 98.8%) than in group B (24/47,51.1%) (P < 0.05). The disturbance of consciousness and headache/dizziness were statistically more significant in group B (27/47, 57.4%; 37/47, 78.7%) than in group A (3/83, 3.6%; 1/83, 1.2%), respectively (P < 0.05). Convulsions with mild gastroenteritis (CwG) were statistically more significant in group A (50/83, 60.2%) than in group B (8/47, 17.0%) (P < 0.05). However, encephalitis/encephalopathy was statistically more significant in group B (20/47, 42.6%) than in group A (10/83, 12.0%) (P < 0.05). MRI showed cytotoxic edema in typical locations (RESLES type-1 limited to the splenium of the corpus callosum and RESLES type-2 spread to the entire corpus callosum, adjacent white matter, or both). There was full recovery of the lesions of MRI in all cases from 3 days to 50 days after the initial examinations. All the children showed normal neurodevelopment.

Conclusion

Infection was the most common cause of RESLES. Infections of the gastrointestinal tract are common in ≤ 3 years old children, while infections of the respiratory tract are common in >3 years old children. Younger patients are more likely to develop convulsions, and older children were more likely to have symptoms with disturbance of consciousness and headache/dizziness. RESLES has characteristic MRI manifestations and a good prognosis.

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

BACKGROUND

Cerebellitis 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 REPORT

We 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.

DISCUSSION

ASL 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.

Anti-MDA5 antibody-positive dermatomyositis with mild encephalopathy with reversible splenial lesion: a possible rare association?

Central nervous system (CNS) involvement in dermatomyositis (DM) is seldom observed. However, there are very rare case reports of CNS involvement with juvenile dermatomyositis. Encephalopathy in DM may occur for a number of reasons, such as cerebral vasculitis and hypoperfusion/hypertensive encephalopathy, but mostly as a consequence of immunosuppressant treatment. We report here for the first time the case of a patient with two rare diseases, namely anti-MDA5 antibody-positive dermatomyositis and mild encephalopathy with reversible splenial lesion (MERS).

A case of mild encephalitis associated with COVID-19

We report a case of mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) in a 31-year-old man. He had been diagnosed with mild COVID-19 3 days earlier and presented to the emergency department with altered mental status. Brain magnetic resonance imaging (MRI) showed a high-intensity area confined to the splenium of the corpus callosum on diffusion-weighted imaging, which is consistent with MERS. MERS is characterized by a reversible change in the splenium of the corpus callosum. MERS secondary to COVID-19 has been reported recently. It is important to consider MERS in COVID-19 patients with impaired consciousness.

Neuroimaging in acute infection-triggered encephalopathy syndromes

Acute encephalopathy associated with infectious diseases occurs frequently in Japanese children (400-700 children/year) and is the most common in infants aged 0-3 years. Acute encephalopathy is classified into several clinicoradiological syndromes; acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is the most common subtype, followed by clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) and acute necrotizing encephalopathy (ANE). Neuroimaging, especially magnetic resonance imaging (MRI), is useful for the diagnosis, assessment of treatment efficacy, and evaluation of the pathophysiology of encephalopathy syndromes. MRI findings essential for diagnosis include delayed subcortical reduced diffusion (bright tree appearance) for AESD, reversible splenial lesions with homogeneously reduced diffusion for MERS, and symmetric hemorrhagic thalamic lesions for ANE. We reviewed several MRI techniques that have been applied in recent years, including diffusion-weighted imaging for the characterization of cerebral edema, arterial spin labeling for evaluating cerebral perfusion, and magnetic resonance spectroscopy for evaluating metabolic abnormality.

Reversible splenial lesion syndrome type II in youth mimicking acute ischemic stroke like onset: A case report

BACKGROUND

Reversible splenial lesion syndrome (RESLES) is a newly recognized syndrome. Its typical pathologic findings is a reversible progress correlated with transiently reduced diffusion lesion in the splenium of the corpus callosum. The common clinical symptoms include mildly altered states consciousness, delirium, and seizure.

METHODS

We presented a 21-year-old patient with signs of acute ischemic stroke (AIS), including symptoms of weakness on the right upper limb and aphasia, lasting 50 minutes until he was taken to the emergency. He just had a cough 20 days ago.

RESULTS

An elevated level of white blood cell count, neutrophil count, monocyte count, protein of cerebrospinal fluid was found in laboratory examinations. Magnetic resonance imaging revealed distinct lesions involving white matter in the splenium of the corpus callosum and frontal-parietal cortex on both cerebral hemispheres. Digital subtraction angiography examination was also unremarkable. The patient recovered to baseline within 4 days. We treated the patient with glucocorticoid, antiviral drugs, butylphthalide, and dehydrating drugs. In addition, the follow-up brain magnetic resonance imaging scan showed reduced lesions. AIS-like symptoms did not occur during a 30-day follow-up period.

CONCLUSION

This patient with reversible splenial lesion syndrome type II exhibited AIS-like symptoms, which was uncommon on clinical. This case extends the recognized clinical phenotypes for this disorder.

Concurrent bacterial liver abscess and mild encephalitis/encephalopathy with reversible splenial lesion in a patient with poorly controlled type 2 diabetes

A 34-year-old man with poorly controlled type 2 diabetes was admitted to our hospital because of fever, headache, vomiting, and impaired consciousness. His hemoglobin A1c level was as high as 11.0%. Abdominal computed tomography revealed a bacterial liver abscess, while head magnetic resonance imaging simultaneously showed a high-signal lesion on diffusion-weighted imaging and a low-signal lesion on the apparent diffusion coefficient map of the splenium of the corpus callosum. No significant findings were detected in the cerebrospinal fluid. The latter findings led to a diagnosis of mild encephalitis/encephalopathy with reversible splenial lesions. His impaired consciousness resolved on Day 5 after treatment with ceftriaxone and metronidazole infusion and intensive insulin therapy; magnetic resonance imaging on Day 20 showed that the lesion in the splenium of the corpus callosum had disappeared. We propose that when a person with poorly controlled diabetes develops a bacterial infection and presents with impaired consciousness and headache, clinicians should consider the complications of mild encephalitis/encephalopathy with reversible splenial lesion.

Autoimmune glial fibrillary acidic protein astrocytopathy coexistent with reversible splenial lesion syndrome: A case report and literature review

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a rare autoimmune disorder. Reversible splenial lesion syndrome (RESLES) is a transient clinical-imaging syndrome characterized by specific magnetic resonance imaging (MRI) pattern. A 58-year-old man was admitted with a fever, headache, and confusion for 1 week. Brain MRI showed abnormal leptomeningeal enhancement in the brainstem and high signal intensity on diffusion-weighted MRI of the corpus callosum. Anti-GFAP antibody was positive in the serum and cerebrospinal fluid analysis. This patient significantly improved and had no relapse after glucocorticoid and immune suppressant therapy. A repeated brain MRI revealed the lesion in the corpus callosum and abnormal leptomeningeal enhancement in the brainstem disappeared. Linear perivascular radial enhancement is the characteristic pattern of autoimmune GFAP astrocytopathy which is rarely coexistent with RESLES.

An elderly man with mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) without neuropsychiatric sequelae

Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is less common in the elderly, and most have some sequelae. However, even in the elderly, MERS may have a good prognosis, and a specific treatment is not always required.

A nationwide survey of human metapneumovirus-associated encephalitis/encephalopathy in Japan

BACKGROUND

As there have been no comprehensive reports of human metapneumovirus-associated encephalopathy (hMPVE), this study examined the clinical features of hMPVE in children in Japan.

METHOD

A nationwide survey of children with hMPVE was conducted using a structured research form. An initial survey asked pediatricians about children with hMPVE treated between 2014 and 2018. A second survey obtained patient information from hospitals that responded to the initial survey and those identified as having treated cases from a literature search. We collected demographic data, symptoms of hMPV infection, neurological symptoms, laboratory data, treatment, and outcomes. Outcomes were determined using the Pediatric Cerebral Performance Category Score.

RESULT

Clinical information was available for 16 children. Their median age was 37 months. Six had preexisting neurological disorders. The interval between the onsets of infection and hMPVE was 4 days. Outcomes were good in 11 patients and poor in 5. There were no significant differences in demographic data, neurological symptoms, or laboratory data between the patients with good and poor outcomes. The encephalopathy subtypes were acute encephalopathy with biphasic seizures and late reduced diffusion in 3, clinically mild encephalitis/encephalopathy with a reversible splenial lesion in 3, hemorrhagic shock and encephalopathy syndrome in 2, and others in 8.

CONCLUSION

The outcomes of children with hMPVE were not very different from those of acute encephalopathy due to other viruses. We found no factors associated with poor outcomes.

Neurological features related to influenza virus in the pediatric population: a 3-year monocentric retrospective study

Influenza virus is generally characterized by fever, myalgia, and respiratory symptoms. Neurological entities have already been described, such as acute necrotizing encephalitis (ANE). We aimed to highlight the non-exceptional nature and explore the clinical spectrum and evolution of neurological features related to influenza virus in children. This monocentric observational study included patients under 18 years old, positive for influenza virus, between January 2017 and April 2019 in a pediatric university hospital. Patients were classified into two groups: those with or without a previous significant neurological or metabolic disorder. Two hundred eighty-nine children were identified with influenza infection. Thirty seven had a neurological manifestation: 14 patients who had previous significant neurological or metabolic disorder and 23 patients with no medical history. We identified several clinical patterns: 22 patients had seizures, 7 behavior disorders, 5 disturbances of consciousness, and 3 motor deficits. Four were diagnosed with a known influenza-associated neurological syndrome: 1 ANE, 1 cytotoxic lesion of the corpus callosum, 1 hemiconvulsion-hemiplegia-epilepsia syndrome, and 1 recurrent encephalitis in the context of a RANBP2 mutation. The neurological outcome was favorable in most cases. None of the patients with previous significant disorder retained sequalae or had a recurrence. Two patients had a fatal outcome, and both had a predisposing disorder.

CONCLUSION

Various neurological manifestations can be associated with influenza virus. Certain entities led to a poor prognosis, but in most cases, symptoms improved within a few days. The severity of the neurological manifestations correlated with previous neurological or metabolic disorders.

WHAT IS KNOWN

• Influenza viruses are well known pathogens with a seasonal epidemic evolution, particularly affecting children. These viruses cause acute fever with respiratory symptoms, associated with myalgia and headaches. Neurological presentation in influenza-virus infection is a well-established possibility as influenza virus is considered to be responsible for 27 to 36% of childhood encephalitis. Some specific and severe entity as acute necrotizing encephalitis, cytotoxic lesion of the corpus callosum, or Hemiconvulsion-hemiplegia-epilepsy syndrome are well described.

WHAT IS NEW

• In a French monocentric cohort of 37 children with influenza-related neurologic manifestations, the majority of these manifestations, including seizure, drowsiness, motor deficiency, hallucination… are self limiting and do not lead to after-effects. In rare cases (4/37), they may reveal severe encephalitis requiring rapid and appropriate treatment. Otherwise, comparison of a group of 14 children with underlying neurological or metabolic disorder with a group of 23 children free of any significant disorder show that the severity of the neurological manifestations was largely related to previous neurological or metabolic disorders highlighting the importance of vaccination in this population.

Japanese Spotted Fever Associated with Mild Encephalitis/Encephalopathy with a Reversible Splenial Lesion

A 58-year-old woman had disseminated intravascular coagulation (DIC) and septic shock caused by Japanese spotted fever (JSF). Following treatment with minocycline, her general condition gradually improved; however, her disorientation persisted. Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) type II was diagnosed based on brain magnetic resonance imaging (MRI) showing a hyperintense area in the splenium of the corpus callosum and bilateral cerebral white matter on diffusion-weighted imaging. Thereafter, her consciousness gradually improved, but she continued to experience difficulty concentrating and attention deficits. MERS type II may take longer to improve than type I, and long-term follow-up is required.

Mild Encephalopathy With Partial Reversible Splenium Lesion Associated With SARS-CoV-2 Infection

Viral-associated encephalitis/encephalopathy includes a wide spectrum of syndromes reported often in children. A rare form presents with mild encephalitis/encephalopathy and reversible splenial lesion(s). This report describes a case of this rare presentation associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in a 68-year-old woman. The patient presented to the hospital with altered mental status. Examination revealed mild encephalopathy with disorientation to date and time. Initial laboratory workup was significant for mild hypernatremia and acute kidney injury, and a polymerase chain reaction (PCR) test for SARS-CoV-2 was positive. MRI of the brain revealed an area of hyperintensity and water restriction in the corpus callosum. The patient was treated with tocilizumab, dexamethasone, and remdesivir. MRI of the brain five weeks later revealed partial resolution of the hyperintensity, and complete resolution of the restricted diffusion previously seen in the corpus callosum, which confirmed the diagnosis of mild encephalitis/encephalopathy with a reversible splenial lesion. We highlight the importance of recognizing this phenomenon in association with SARS-CoV-2 infection.

Prediction and assessment of acute encephalopathy syndromes immediately after febrile status epilepticus

OBJECTIVE

This study aimed to predict occurrence of acute encephalopathy syndromes (AES) immediately after febrile status epilepticus in children and to explore the usefulness of electroencephalogram (EEG) in the early diagnosis of AES.

METHODS

We reviewed data from 120 children who had febrile status epilepticus lasting >30 min and were admitted to our hospital between 2012 and 2019. AES with reduced diffusion on brain magnetic resonance imaging was diagnosed in 11 of these patients. EEG and serum cytokines were analyzed in AES patients. Clinical symptoms and laboratory data were compared between AES and non-AES patients. Logistic regression analysis was used to identify early predictors of AES.

RESULTS

Multivariate logistic regression identified serum creatinine as a risk factor for developing AES. A scoring model to predict AES in the post-ictal phase that included serum creatinine, sodium, aspartate aminotransferase, and glucose was developed, and a score of 2 or more predicted AES with sensitivity of 90.9% and specificity of 71.6%. Post-ictus EEG revealed non-convulsive status epilepticus in four of the seven AES patients.

CONCLUSION

Children with febrile status epilepticus may be at risk of developing severe AES with reduced diffusion. Post-ictus EEG and laboratory data can predict the occurrence of severe AES.

Severe pediatric acute encephalopathy syndromes related to SARS-CoV-2

Background and objectives

To clarify whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection cause acute encephalopathy in children and which are the most common syndromes that cause them and what are the outcomes.

Methods

A nationwide web-based survey among all members of the Japanese Society of Child Neurology to identify pediatric patients aged < 18 years who developed acute encephalopathy in Japan between 1 January 2020 and 31 May 2022 associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection confirmed by polymerase chain reaction or antigen tests using pharyngeal swabs. Acute encephalopathy was defined as acute onset of impaired consciousness lasting > 24 h or an altered mental state; neurological symptoms arising within 2 weeks of onset of COVID-19 or multisystem inflammatory syndrome in children (MIS-C)/pediatric inflammatory multisystem syndrome (PIMS); evidence of SARS-CoV-2 infection; and reasonable exclusion of other diseases. Patients were divided into the known clinico-radiological acute encephalopathy syndrome group and unexplained or unclassifiable acute encephalopathy group. Outcomes were assessed by pediatric cerebral performance category (PCPC) score at hospital discharge.

Results

Of the 3,802 society members, 217 representing institutions responded, and 39 patients with suspected acute encephalopathy were reported, of which 31 met inclusion criteria. Of these patients, 14 were diagnosed with known clinico-radiological acute encephalopathy syndromes, with acute encephalopathy with biphasic seizures and late reduced diffusion (five patients) being the most common. Five developed acute encephalopathy associated with MIS-C/PIMS. Among 31 patients, 9 (29.0%) had severe sequelae or died (PCPC ≥ 4). Two of three patients with encephalopathy with acute fulminant cerebral edema and two with hemorrhagic shock and encephalopathy syndrome died. The PCPC scores were higher in the known clinico-radiological acute encephalopathy syndrome group than in the unexplained or unclassifiable acute encephalopathy group (P < 0.01).

Discussion

Acute encephalopathy related to SARS-CoV-2 infection was demonstrated to be more severe than that caused by other viruses in Japan. Acute encephalopathy syndromes characterized by specific neuroradiological findings was associated with poor clinical outcomes.

Cytotoxic Lesions beyond the Corpus Callosum Following Acute Meningoencephalitis and Mycoplasma Pneumoniae Infection: A Case Report and Literature Review

Cytotoxic lesions of the corpus callosum (CLOCCs) are secondary lesions associated with a variety of clinical causes. The presence of a small and reversible lesion in the splenium of corpus callosum with restricted diffusion on cranial magnetic resonance imaging is the defining feature. The clinical-radiological manifestations have been documented as mild and reversible. Severer presentations were scarcely reported. In this report, we described a 25-year-old man with preceding fever, worsening somnolence, and convulsions. He was diagnosed with acute meningoencephalitis and Mycoplasma pneumoniae infection after workups. After medical treatments, he had neurological deterioration and progressing CLOCCs from a small oval lesion in the center of splenium extending to the whole corpus callosum and bilaterally adjacent white matter. The patient received intravenous methylprednisolone and immunoglobulin successively, and his neurological conditions improved. The CLOCCs, not always mild and reversible, could present with severe clinicoradiological features.

Case of clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) due to Legionella pneumonia

Clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is a clinicoradiologic syndrome diagnosed by temporary hyperintense lesion in the area, including the splenium of the corpus callosum, on diffusion-weighted imaging and neuropsychiatric symptoms that recover without sequelae. MERS is rare in adults, especially elderly people. We herein report a man in his 60s diagnosed with MERS caused by Legionella pneumonia. He completely recovered with only the administration of levofloxacin and azithromycin despite the risk factors of an advanced age, medical history of untreated hypertension, bilateral spontaneous pneumothoraxes, smoking and drinking habits and pulmonary emphysema. To our knowledge, this is the oldest case of MERS due to Legionella pneumonia and extremely old among total MERS cases. Our research revealed that Legionella species are the most common pathogens of adult-onset MERS, while viruses are the main causative factors in children. This case helps clarify the features of MERS in high-risk adults.

"Reversible cytotoxic lesion of the corpus callosum following SARS-CoV-2 mRNA vaccine administration: a finding to be aware of"

Cytotoxic lesions of the corpus callosum (CLOCCs) are a clinical-radiological spectrum of disorders secondary to several etiopathogeneses. Cytotoxic lesions of the corpus callosum are typically associated with mild clinical symptoms including fever, headache, confusion, and altered mental status. We present a case of a 51-year-old Caucasian woman who developed a reversible lesion of the splenium of the corpus callosum associated with small round-shaped white matter hyperintensities after the first dose of SARS-CoV-2 mRNA vaccine. Magnetic resonance imaging is fundamental for diagnosis and no treatment is generally required.

Non-severe COVID-19 complicated by cytotoxic lesions of the corpus callosum (mild encephalitis/encephalopathy with a reversible splenial lesion): a case report and literature review

BACKGROUND

Coronavirus disease 2019- (COVID-19-) associated cytotoxic lesions of the corpus callosum (CLOCCs) have been reported as a rare neurological abnormality in severe cases. Here, a case of CLOCCs in the early stages of mild COVID-19 infection during the Omicron BA.1 epidemic is reported along with a literature review.

CASE REPORT

A Japanese woman with COVID-19 presented to the emergency department with altered consciousness and cerebellar symptoms a day after fever onset. Magnetic resonance imaging (MRI) revealed a lesion with restricted diffusion in the corpus callosum. She exhibited no complications of pneumonia, her neurological symptoms resolved after two days, and after 10 days, the brain lesion was not detected on MRI.

LITERATURE REVIEW

The PubMed database was searched for case reports that met the CLOCC definition proposed by Starkey et al. The search yielded 15 COVID-19-associated cases reported as CLOCCs and 13 cases described under former terms, including mild encephalitis/encephalopathy with a reversible splenial lesion. Adult cases with a documented course were accompanied by pneumonia or hypoxemia, whereas pediatric cases were mostly accompanied by a multisystem inflammatory syndrome.

CONCLUSION

COVID-19-associated CLOCCs can occur, even at an early, non-severe stage. Therefore, this condition may be underdiagnosed if MRI is not performed.

Case report: Reversible encephalopathy associated with liposomal amphotericin B in a patient with cryptococcal meningitis

Liposomal amphotericin B (L-AMB) is an anti-fungus medicine that has fewer side effects than traditional amphotericin B (AMB). Neurotoxicity of L-AMB has rarely been observed, and only one case of leukoencephalopathy during intravenous L-AMB has been reported. Herein, we described a patient with cryptococcal meningitis presenting with late-onset reversible encephalopathy associated with liposomal amphotericin B.

Update on benign convulsions with mild gastroenteritis

Benign convulsions with mild gastroenteritis (CwG) are characterized by afebrile convulsions associated with viral gastroenteritis in previously healthy infants and children. The main causative pathogens are rotavirus and norovirus. CwG occurs frequently in both East Asian and Western countries. The prevalence of CwG was reportedly not decreased by the introduction of rotavirus vaccines, and the prevalence of norovirus-associated CwG has been increasing annually. Convulsions in CwG are usually clustered, do not last longer than 5 minutes, and are mostly generalized. Laboratory diagnostics, electroencephalography (EEG), and imaging findings are usually normal. There is a probability of mild, transient abnormal findings on EEG or imaging limited to the acute disease phase. Although several reports have suggested that pathogens that affect the central nervous system through direct or indirect mechanisms could be related to the pathophysiology of CwG, its mechanism is not fully understood. Several antiepileptic drugs are effective during convulsions; however, long-term antiepileptic treatment is not required as CwG usually has a good prognosis.

Rotavirus infection-associated central nervous system complications: clinicoradiological features and potential mechanisms

Despite the introduction of vaccines in 2006, rotavirus remains one of the most common causes of pediatric gastroenteritis worldwide. While many studies have conclusively shown that rotavirus infection causes gastroenteritis and is associated with various extraintestinal manifestations including central nervous system (CNS) complications, extraintestinal manifestations due to rotavirus infection have been relatively overlooked. Rotavirus infection-associated CNS complications are common in children and present with diverse clinicoradiological features. Rotavirus infection-associated CNS complications can be classified based on clinical features and brain magnetic resonance imaging findings, particularly lesion location on diffusion-weighted imaging. Common clinicoradiological features of rotavirus infection-associated CNS complications include: (1) benign convulsions with mild gastroenteritis; (2) acute encephalopathies/encephalitis, such as mild encephalopathy with a reversible splenial lesion, acute encephalopathy with biphasic seizures and late reduced diffusion, and acute necrotizing encephalopathy; (3) acute cerebellitis; and (4) neonatal rotavirus-associated leukoencephalopathy. The precise mechanism underlying the development of these complications remains unknown despite a number of clinical and laboratory studies. Here we review the diverse clinicoradiological features of rotavirus infection-associated CNS complications and propose a hypothesis of their pathophysiology.

Atezolizumab-induced Encephalitis in a Patient with Hepatocellular Carcinoma: A Case Report and Literature Review

We herein report a case of encephalitis in a 42-year-old woman with hepatocellular carcinoma following atezolizumab plus bevacizumab therapy. After two weeks of treatment, she was admitted for a high fever, impaired consciousness, and convulsive seizure refractory to diazepam. Magnetic resonance imaging revealed a hyperintense splenial lesion. A cerebrospinal fluid test excluded malignancy and infection. These findings were highly suggestive of a diagnosis of encephalitis due to atezolizumab, an immune-related adverse event. Steroid pulse therapy improved the fever and seizure. However, her incomplete right-sided paralysis and aphasia persisted. This is the first case report of encephalitis caused by atezolizumab plus bevacizumab therapy for hepatocellular carcinoma.

Transient splenial lesions of the corpus callosum and infectious diseases

Transient splenial lesion of the corpus callosum can be observed in various diseases such as cancer, drug use, metabolic disorders, and cerebrovascular disorders, as well as in patients with infectious diseases. During the coronavirus disease 2019 (COVID-19) pandemic, there were increasing reports of these lesions being detected on brain imaging tests performed in patients with neurological symptoms. On brain magnetic resonance imaging, findings suggestive of cytotoxic edema are observed in the splenium; these are known to disappear with improvement of clinical symptoms. Cytokinopathy caused by infection increases the permeability of the blood–brain barrier and activates the glial cells of the brain to induce cytotoxic edema. Most patients have a good prognosis. The causes, mechanism, diagnosis, treatment and prognosis of transient splenial lesions of the corpus callosum will be summarized in this review.

[Kawasaki disease complicated with mild encephalitis/encephalopathy with a reversible splenial lesion: A case report and literature review]

We reported a pediatric case of Kawasaki disease complicated with mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) from Beijing Tsinghua Changgung Hospital. The clinical data were retrospectively analyzed and the related literature was reviewed. The clinical features, treatment and prognosis of the disease were summarized to improve recognition of Kawasaki disease complicated with MERS. A 7-year-old boy was diagnosed with Kawasaki disease due to continuous high fever for 6 d, accompanied by strawberry tongue, conjunctival congestion, erythema-like hyperemia rash, and cervical enlarged lymph nodes. And treatment was started with intravenous immunoglobulin (IVIG: 2 g/kg) and oral aspirin [40 mg/(kg·d)]. Twenty-four hours after the treatment of IVIG, the patient' s fever persisted and in addition he developed headache and drowsiness. His cranial magnetic resonance imaging (MRI) demonstrated a localized lesion in the splenium of the corpus callosum with high intensity signal on diffusion-weighted images (DWI) and T2-weighted, and low intensity signal on apparent diffusion coefficient (ADC) and T1-weighted. Based on these findings, he was diagnosed with MERS-complicated Kawasaki disease. Methylprednisolone [2 mg/(kg·d)] treatment was started intravenously, and within several hours he was afebrile and the neurological symptoms disappeared. A follow-up MRI was conducted after 1 week was normal. He was discharged without any neurological sequelae and coronary artery lesions. A total of 12 qualified foreign literature were retrieved, with no Chinese literature searched. Seventeen children were reported, the median age was 6.5 years (range: 1-14 years), among them 11 cases were children over 5 years old, and 4 cases were complicated with coronary artery lesions. All children had neurological symptoms, such as consciousness disorder, visual hallucination or convulsion. MRI conformed to MERS imaging changes. After active treatment, the neurological manifestations and radiological abnormalities completely disappeared, leaving no neurological sequelae. Kawasaki disease complicated with MERS had not been reported in China by now. Literature that identified Kawasaki disease complicated with MERS mostly occurred in children over 5 years old. Cranial MRI examination is helpful for early diagnosis. Timely treatment can reverse MERS in a short time, without neurological sequelae left.

Diagnosis of Transient Brain Lesion in the Corpus Callosum Splenium in Emergency Service and Elucidation of Accompanying Conditions

Corpus Callosum Cytotoxic Lesion (CLOCCs) once rarely seen in the literature has been more often diagnosed in emergency services nowadays with widespread use of cranial magnetic resonance imaging (MRI). CLOCCs is defined as a clinical and radiological spectrum disorder. Patient’s neurological symptoms usually improve completely within 1 month after the onset of the disease without any sequel. This is generally associated with cytotoxic edema of the splenium corpus callosum. It is important investigate the primary causes that lead to this condition and start the appropriate treatment according to the real diagnosis. We present a case diagnosed as CLOCCs secondary to pneumonia upon admission to our emergency service.