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

Underlying Disorders in Children With Infection-Related Acute Encephalopathy

BACKGROUND

Various factors contribute to the development of infection-related acute encephalopathy (AE) in children, such as infectious agents and chronic underlying disorders. We studied underlying disorders in children with AE to identify predisposing factors of AE.

METHODS

We investigated underlying disorders or past histories in patients with two types of AE from the database in the Tokai area of Japan between 2009 and 2022: 204 patients with AE with reduced subcortical diffusion (AED) and 137 with clinically mild encephalopathy with a reversible splenial lesion (MERS). We compared them with 89 patients with acute disseminated encephalomyelitis (ADEM) to clarify the specific disorders in the two AE types.

RESULTS

The prevalence of underlying disorders in AED (34%, 70 patients) was significantly higher than that in ADEM (12%, 11 patients) (P < 0.01). The prevalence of underlying disorders in MERS was 23% (32 patients). The underlying disorders included seizure disorders, premature birth, genetic/congenital disorders, and endocrine/renal diseases. In patients with seizure disorders in AED, five patients (18%) had Dravet syndrome and four (15%) had West syndrome, whereas none with MERS had these syndromes. Twenty-five (12%) of 204 patients with AED, three (2%) with MERS, and one (1%) with ADEM were preterm or low birth weight.

CONCLUSIONS

The high prevalence of seizure disorders suggests that seizure susceptibility is an important predisposing factor in AED. Premature birth also has an impact on the development of AED. Caution is required regarding the development of AE in patients with chronic seizure disorders or premature birth.

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.

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.

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.

A Fatal Case of Neuroblastoma Complicated by Posterior Reversible Encephalopathy with Rapidly Evolving Transplantation-Associated Thrombotic Microangiopathy

Background: Transplantation-associated thrombotic microangiopathy (TA-TMA) is a severe complication of hematopoietic stem cell transplantation and is sometimes fatal. Observations: A 4-year-old, male patient with stage M neuroblastoma (NBL) who had received an allogeneic bone marrow transplantation (BMT) from his sibling five months previously presented with rapidly progressive posterior reversible encephalopathy (PRES) complicated with TA-TMA. Although the patient was transferred to the pediatric intensive care unit, he died within one week after the onset of the latest symptoms. Conclusions: This is the first description of a fatal case of NBL complicated by PRES with rapidly evolving TA-TMA after an allogenic BMT.

Genetic and environmental risk factors of acute infection-triggered encephalopathy

Acute encephalopathy is a constellation of syndromes in which immune response, metabolism and neuronal excitation are affected in a variable fashion. Most of the syndromes are complex disorders, caused or aggravated by multiple, genetic and environmental risk factors. Environmental factors include pathogenic microorganisms of the antecedent infection such as influenza virus, human herpesvirus-6 and enterohemorrhagic Escherichia coli, and drugs such as non-steroidal anti-inflammatory drugs, valproate and theophylline. Genetic factors include mutations such as rare variants of the SCN1A and RANBP2 genes, and polymorphisms such as thermolabile CPT2 variants and HLA genotypes. By altering immune response, metabolism or neuronal excitation, these factors complicate the pathologic process. On the other hand, some of them could provide promising targets to prevent or treat acute encephalopathy.

Cytotoxic corpus callosum lesion and mild CSF pleocytosis during hantavirus infection: a case report

A middle-aged, previously healthy male patient presented with high fever, headache, and aching limbs for 3 days. Laboratory results showed signs of acute kidney injury, elevated procalcitonin, and mild thrombocytopenia. On neurological examination, he had no focal neurological deficits, especially no meningism or visual disturbances. Cerebrospinal fluid (CSF) examination showed mild lymphocytic pleocytosis, and magnetic resonance imaging (MRI) revealed a lesion of the splenium corporis callosum. The patient received anti-infective treatment with acyclovir and ceftriaxone until laboratory results returned positive hantavirus IgM and IgG antibodies in the serum indicating an active hantavirus infection. The renal retention parameters and thrombocytopenia receded following treatment with intravenous fluids, analgesic, and antipyretic agents. MRI follow-up 10 days later showed a residual small FLAIR-positive lesion without any persistent callosal diffusion abnormality. The patient was discharged symptom-free after 8 days and had recovered fully 2 months later. The source of infection in this patient remained unclear. Cytotoxic lesions of the corpus callosum (CLCC) are secondary lesions usually with a good prognosis but require further investigation regarding their underlying etiology and should not be confounded with primary callosal lesions, such as ischemia or lymphoma.

A pediatric case of autoimmune glial fibrillary acidic protein astrocytopathy with unique brain imaging patterns and increased cytokines/chemokines

BACKGROUND

Autoimmune anti-glial fibrillary acidic protein (GFAP) astrocytopathy represents a new spectrum of autoimmune inflammatory central nervous system disorders. In recent years, there have been an increasing number of reports on pediatric patients with this disease other than those in Japan.

CASE REPORT

A 6-year-old previously healthy boy presented with fever persisting for approximately 10 days, consciousness disturbance, anorexia, and hyponatremia (Na, 121 mEq/L). Even after appropriate correction of hyponatremia, consciousness disturbance was prolonged and was accompanied by gait disturbance, visual hallucinations, and autonomic dysfunction (bradycardia and urinary dysfunction). On a plain MRI, T2-weighted and fluid-attenuated inversion recovery images showed abnormal hyperintense lesions in the bilateral basal ganglia, thalamus, and periventricular white matter. The cerebrospinal fluid was positive for anti-GFAP antibody before treatment, and cytokines/chemokines were increased. He received three courses of intravenous methylprednisolone, followed by gradually tapered oral prednisolone for 6 months, without relapse after 1 year of observation.

CONCLUSION

In cases of autoimmune encephalitis with prolonged consciousness disturbance, hyponatremia, urinary dysfunction, and MRI findings with hyperintensities in the bilateral basal ganglia, thalamus, and periventricular white matter, anti-glial fibrillary acidic protein antibodies should be examined.

Fatal X-linked lymphoproliferative disease type 1-associated limbic encephalitis with positive anti-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antibody

BACKGROUND

X-linked lymphoproliferative disease type 1 (XLP1) is a rare monogenic immune dysregulation disorder caused by a deficiency of a signaling lymphocyte activation molecule-associated protein (SAP). While many patients with XLP1 present with fatal hemophagocytic lymphohistiocytosis upon Epstein Barr virus (EBV) infection, a small fraction present with limbic encephalitis in the absence of EBV infection. It is poorly understood why SAP deficiency may cause limbic encephalitis in XLP1.

CASE

A 12-year-old boy presented with seizures, changes in personality, memory loss, and cognitive deficits during treatment for interstitial pneumonia. A diagnosis of limbic encephalitis was made. Despite treatment against CD8+ T cell-mediated autoimmunity with intravenous methylprednisolone, dexamethasone, intravenous immunoglobulin, plasma exchange, cyclosporine, weekly etoposide, mycophenolate mofetil, and adalimumab, encephalitis progressed until the patient died after one month of treatment intitiation. Post-mortem genetic testing revealed a de novo SH2D1A truncating mutation. Tests for EBV infection were negative. Initial spinal fluid revealed markedly elevated protein levels, mild pleocytosis, and elevation of two chemokines (C-X-C motif chemokine ligand [CXCL] 10 and CXCL 13). Moreover, initial spinal fluid was tested positive for anti-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) autoantibody.

DISCUSSION

In XLP1-associated limbic encephalitis, anti-AMPAR autoantibody production by the dysregulated immune system due to SAP deficiency might be a pathogenic mechanism of central nervous system manifestations. In addition to the standard treatment for XLP1, targeted treatment against B-cell-mediated immunity might be indicated for patients with XLP1-associated limbic encephalitis.

Two Pediatric Cases of Multisystem Inflammatory Syndrome with Overlapping Neurological Involvement Following SARS-CoV-2 Vaccination and Unknown SARS-CoV2 Infection: The Importance of Pre-Vaccination History

The SARS-CoV-2 vaccine roll-out has been successful around the world. However, there are increasing concerns about adverse events. We report two pediatric cases of Multisystem-Inflammatory-Syndrome (MIS-C) with neurological involvement that occurred after SARS-CoV-2 vaccination and unknown recent SARS-CoV-2 infection. Brain magnetic resonance revealed mild-encephalopathy with reversible-splenial-lesion in both cases and complete resolution within 4 weeks. In conclusion, this report aims to describe rare emerging clinical entities that can help pediatricians to make an early diagnosis and to provide appropriate treatment. Multisystem-Inflammatory-Syndromes following COVID-19 vaccination remain rare events. When a history of a recent contact with SARS-CoV-2 is present, a careful evaluation by the clinicians in charge of immunization activities is suggested prior to proceeding with the vaccination.

Cytotoxic lesions of the corpus callosum after COVID-19 vaccination

A 23-year-old previously healthy man (Patient 1) and a 33-year-old woman with a past history of depression (Patient 2) developed neurological symptoms approximately 1 week after receipt of the first COVID-19 mRNA vaccination and deteriorated over the next week. Patient 1 reported nausea, headache, a high fever, and retrograde amnesia. Patient 2 reported visual disturbance, headache, dysarthria, a left forearm tremor, dysesthesia of the mouth and distal limbs, and visual agnosia. PCR test results for SARS-CoV-2 were negative. Complete blood cell count, biochemistry, and antibody test and cerebrospinal fluid test findings were unremarkable. Diffusion-weighted and fluid-attenuated inversion recovery MRI of the brain showed a high signal intensity lesion at the midline of the splenium of the corpus callosum compatible with cytotoxic lesions of the corpus callosum (CLOCCs). High-dose intravenous methylprednisolone improved their symptoms and imaging findings. CLOCCs should be considered in patients with neurological manifestation after COVID-19 vaccination.

Case report: Mild encephalitis with a reversible splenial lesion associated with SARS-CoV-2 infection in a patient with MYRF variant

We report a 14-year-old girl with a heterozygous p. Gln403Arg variant in the MYRF gene, who had five episodes of encephalopathy. She experienced reduced consciousness, numbness in the arm, and impaired verbal communication from day 4 of SARS-CoV-2 infection. Magnetic resonance imaging of her head showed reduced water diffusion in the corpus callosum and deep white matter. These features were similar to those seen in her previous episodes of encephalopathy. She was treated with methylprednisolone pulse therapy and recovered completely within a week.