A case of clinically mild encephalitis with a reversible splenial lesion (MERS) after mumps vaccination

We describe for the first time an 8-year-old male patient who demonstrated clinically mild encephalitis with a reversible splenial lesion after mumps vaccination. He suffered from transient hallucinations, nuchal rigidity, and inappropriate antidiuretic hormone secretion syndrome. On the 5th day of admission, his head MRI showed symmetrical high-signal-intensity lesions on T2, FLAIR, and diffusion-weighted images in the splenium of the corpus callosum and in the periventricular white matter, while an apparent diffusion coefficient map showed reduced diffusion. The images were not enhanced by gadolinium. Follow-up MRI on the 16th day of admission revealed none of these abnormalities. His serum IgM and IgG antibodies against the mumps virus were positive according to an enzyme immunoassay. Mumps Torii vaccine strain was isolated from the patient’s cerebrospinal fluid. Previous reports demonstrated that transient delirious behavior, the syndrome of inappropriate antidiuretic hormone secretion, and good prognosis were the main clinical features of mild encephalitis with a reversible splenial lesion. This case shows that mild encephalitis with a reversible splenial lesion could occur after mumps vaccination.     

Reversible splenial lesion syndrome associated with SARS-CoV-2 infection in two children

BackgroundReversible splenial lesion syndrome (RESLES) is characterized by a temporary lesion in the splenium of the corpus callosum, emerging related to encephalitis, seizures, antiepileptic drug withdrawal, or metabolic disturbances. Among RESLES, mild encephalitis/encephalopathy with reversible splenial lesion (MERS) has been defined as a distinct clinicoradiologic syndrome associated with viral infections.Case presentationWe report two children with multisystem inflammatory syndrome-children related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) who developed RESLES during the disease course. Encephalopathy was the main central nervous system symptom. Both of the children showed a rapid recovery, and brain magnetic resonance imaging revealed complete resolution of the splenial lesion within 1 week.ConclusionThe complete resolution of the splenial lesion and rapid recovery from encephalopathy in RESLES associated with SARS CoV-2 were similar to observed in MERS.     

Focal lesions in the splenium of the corpus callosum in patients with epilepsy

Purpose:   A focal lesion in the splenium of the corpus callosum is a rare finding in patients with epilepsy. Intoxication with antiepileptic drugs, edema after generalized seizures, or a rapid change of antiepileptic drug levels have been proposed as possible mechanisms. The aim of the present study was to analyze the relationship between this lesion and possible etiologic factors.
Patients and methods:   We analyzed the magnetic resonance imaging (MRI) scans of 1,050 patients undergoing prolonged video-EEG (electroencephalography) monitoring and identified 24 patients with a focal lesion in the splenium of the corpus callosum. Twenty-four age- and gender-matched temporal lobe epilepsy patients without such a lesion served as a control group. We evaluated the following parameters for their possible etiologic significance: epilepsy syndrome, seizure types in medical history, seizure frequency during the past year prior to admission for prolonged video-EEG monitoring, localization of interictal spikes and ictal EEG patterns in patients with focal epilepsies as documented during prolonged video-EEG-monitoring, seizure types and seizure frequency during prolonged video-EEG monitoring, past as well as current antiepileptic medication, withdrawal of antiepileptic drugs during monitoring including duration of medication withdrawal, and finally drug levels above the therapeutic range.
Results :  The parameters analyzed showed no significant difference between the group of patients with focal lesions in the splenium of the corpus callosum and the control group.
Conclusion:   We could not identify a single etiologic factor responsible for the lesion in the splenium of the corpus callosum.     

Left hemispatial neglect with a splenial lesion

ABSTRACT

With injury of the anterior two-thirds of the corpus callosum, each hemisphere’s attentional bias to contralateral hemispace becomes manifest with each hand deviating ipsilaterally during line bisection tasks. Patients with infarctions in the right posterior cerebral artery distribution with occipital and splenial damage can also exhibit spatial neglect. The goal of this report is to learn the role of the splenium of the corpus callosum in mediating visuospatial attention. A right-handed woman with Marchiafava-Bignami disease and damage to the splenium of her corpus callosum without evidence of a mesial frontal, parietal, or occipital injury was assessed for spatial neglect with line bisections. When bisecting lines in her left hemispace with her right hand, she deviated to the right, but revealed no major deviations when the line was place in the midline, in right hemispace, or when bisecting lines with her left hand. This patient provides evidence that damage to the splenium can induce a special form of asymmetrical spatial neglect. This asymmetry might be related to the disconnected right hemisphere’s ability to allocate attention to both right and left hemispaces with the disconnected left hemisphere’s ability to allocate attention to the right but not left hemispace.     

Boomerang sign: Clinical significance of transient lesion in splenium of corpus callosum

Transient signal abnormality in the splenium of corpus callosum on magnetic resonance imaging (MRI) is occasionally encountered in clinical practice. It has been reported in various clinical conditions apart from patients with epilepsy. We describe 4 patients with different etiologies presenting with signal changes in the splenium of corpus callosum. They were diagnosed as having progressive myoclonic epilepsy (case 1), localization-related epilepsy (case 2), hemicrania continua (case 3), and postinfectious parkinsonism (case 4). While three patients had complete involvement of the splenium on diffusion-weighted image (“boomerang sign”), the patient having hemicrania continua showed semilunar involvement (“mini-boomerang”) on T2-weighted and FLAIR image. All the cases had noncontiguous involvement of the splenium. We herein, discuss these cases with transient splenial involvement and stress that such patients do not need aggressive diagnostic and therapeutic interventions. An attempt has been made to review the literature regarding the pathophysiology, etiology, and outcome of such lesions.     

The first pediatric case of mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) associated with Neisseria meningitidis

BackgroundMild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is a clinic-radiological syndrome characterized by neurological deficiencies and reversible magnetic resonance imaging findings in the splenium of the corpus callosum. Usually, it has a good prognosis, and patients recover without any sequelae. A viral infection has caused most MERS cases, and bacterial agents have rarely been reported as a cause of MERS.Case reportA 5-month-old male was admitted to the hospital with fever, poor feeding, decreased activity and groaning. He had focal seizures and required mechanical ventilation. A lumbar puncture was performed, and nucleic acid amplification tests (NAATs) of cerebral spinal fluid was positive for non-typeable serogroup of Neisseria meningitidis. Cranial magnetic resonance imaging (MRI) performed on day 3 of admission showed T2 hyperintensity and diffusion restriction at the splenium of corpus callosum (SCC). Diffusion restriction in the occipital horn of the left ventricular compatible with empyema was also obvious. According to the findings on cranial MRI, this clinical course was diagnosed as MERS associated with meningitis. His fever resolved in one week, cefotaxime was discontinued after 14 days, and the patient completely recovered. A follow-up MRI performed after three weeks of admission showed complete resolution of the signal intensity changes in the SCC and the occipital horn of the left lateral ventricle.ConclusionTo the best of our knowledge, this is the first report of MERS associated with Neisseria meningitidis in children. Bacterial agents as a cause of MERS should be kept in mind, and we should avoid unnecessary treatment strategies due to the good prognosis of MERS in children.     

Isolated reversible splenial lesion in tick-borne encephalitis: a case report and literature review

Here, we demonstrate a first case of tick-borne encephalitis (TBE) associated with an isolated reversible splenial corpus callosum lesion (IRSL) and highlight the wide range of different clinical entities in which such alterations have been observed. A 42-year-old man showed fever, cephalgia and mild disturbance of coordination and gait. Diagnosis was ascertained by slight CSF-pleiocytosis and positive TBE-IgG as well as by positive intrathekal specific antibody index on follow-up. MRI demonstrated a single ovoid hyperintensity in T2 and DWI with reduction in ADC in the splenium of corpus callosum which was abrogated in follow-up after 6 weeks. Most entities of IRSL presented with excellent prognosis, including our novel case of TBE. We discuss different possible pathomechanisms and the so far unexplained propensity of the splenium for such alterations. Clinicians should be familiar with this phenomenon to avoid unnecessary diagnostic or therapeutic efforts.     

Callosal disconnection syndrome due to acute disseminated enchephalomyelitis]

We have reported a very rare case of a patient with callosal disconnection syndrome due to acute disseminated enchephalomyelitis (ADEM). A 54-year-old right-handed woman developed sudden consciousness disturbance and fever after 2 weeks when she had common cold. She did not have a history of stuttering. On admission, the neurological finding showed consciousness disturbance, and exaggerated muscle stretch reflex in four extremities without meningeal irritation. The cerebrospinal fluid examination revealed the cell counts of 273/mm3, the protein of 348 mg/dl and the myelin basic protein 18.3 pg/ml. The brain MRI demonstrated a focal high signal intensity in the right cerebellar peduncle, right temporal lobe, left occipital lobe and corpus callosum on the T2-weighted and FLAIR images. The lesion of corpus callosum was the trunk and splenium, sparing the dorsal side of splenium. Her diagnosis was ADEM. The steroid pulse therapy (metylpredinisolone 1 g/day for 3 days) improved the consciousness disturbance. After 6 weeks from the onset, the neuropsycological examination was performed. The remarkable findings included pure alexia without color naming defects, the acquired stuttering and one-way disturbance of somesthetic transfer from the left hand to the right. This patient may contribute to the study of functional localization of the corpus callosum.     

伴有胼胝体压部可逆性病灶的临床症状轻微的脑炎/脑病1例报道并文献复习

目的探讨伴有胼胝体压部可逆性病灶的临床症状轻微的脑炎/脑病的临床特点、治疗及预后、发病机制。方法报道1例伴有胼胝体压部可逆性病灶的临床症状轻微的脑炎患者的诊治过程,总结其临床特征并复习相关文献。结果患者表现为发热、头痛、呕吐等非特异性脑膜炎症状,合并出现抗利尿激素分泌不当导致的低钠血症,头颅MRI检查发现胼胝体压部有可逆性的DWI高信号的孤立病灶,经抗病毒及对症治疗,临床痊愈。结论伴有胼胝体压部可逆性病灶的临床症状轻微的脑炎/脑病以头颅MRI上发现胼胝体压部可逆性病灶为特点,临床症状轻微,容易合并低钠血症,预后良好,病因及发病机制尚不清楚。     

Secondary white matter degeneration of the corpus callosum in patients with intractable temporal lobe epilepsy: a diffusion tensor imaging study

Imaging changes in patients with focal epilepsy are not only seen in areas where seizures arise but often also in remote locations. The mechanism for such changes is unknown. We aimed to investigate whether patients with temporal lobe epilepsy (TLE) have microstructural changes involving the posterior portion of the corpus callosum (CC), where it links the temporal lobes, using presurgical diffusion tensor imaging (DTI) sequences. Ten patients with medically intractable TLE (two mesial TLE, eight neocortical TLE) who had seizure-free surgical outcomes were compared with 10 healthy controls. The regions of interest were outlined at each Witelson region (WR). Fractional anisotropy (FA), apparent diffusion coefficient (ADC) and three principal diffusivity values (lambda1, lambda2, lambda3) were determined in each WR. We performed tractography originating at each WR. In the TLE patients, the FA values were lower at the splenium of the corpus callosum (WR 7) compared to controls (p<0.05). Analysis of Eigen values in that location revealed that lambda1 values were decreased while lambda2 and lambda3 values were increased (p<0.05). Tractography revealed the connection between both temporal lobes via WR 7. In conclusion, decreased FA values with decreased lambda1 and increased lambda2 and lambda3 at the splenium of CC suggest that the pathologic changes, Wallerian degeneration, extend to the corpus callosum in TLE patients. Seizure-induced damage may cause secondary white matter degeneration along the tapetum and through the splenium of the corpus callosum, a potential pathway of spread in temporal lobe seizures.     

Simultaneous diffusion-weighted magnetic resonance images and brain blood perfusion scintigraphy for a transient lesion in the splenium of the corpus callosum

A transient lesion in the splenium of the corpus callosum is a rare disease and its pathogenesis is unclear. We performed simultaneous diffusion-weighted magnetic resonance images and brain blood perfusion scintigraphy for a transient lesion in the splenium of the corpus callosum. This transient lesion showed hyperintensity on the diffusion-weighted images and hypointensity on the apparent diffusion coefficient map. However, normal blood perfusion was observed on brain blood perfusion scintigraphy. Transient axonal or intramyelinic edema might be a cause of the transient lesion in the splenium of the corpus callosum.     

Recurrence of transient splenial lesions in a child with "benign convulsions with gastroenteritis"

We report a 2-year-old girl who demonstrated "benign convulsions with gastroenteritis (CwG)" with transient splenial lesions twice during the winter. The first episode was associated with noro-virus and the second with rota-virus. During each episode, seizures occurred in clusters without clinical signs of dehydration, hypoglycemia, electrolyte derangement or cerebrospinal fluid abnormalities, and her consciousness was clear during the interictal period. Those findings were consistent with CwG. As transient splenial lesions were not accompanied by any neurological abnormalities other than seizures, she was not diagnosed as having encephalopathy, but as having CwG. Diffusion-weighted magnetic resonance imaging of the brain demonstrated hyperintense lesions in the splenium of the corpus callosum, which disappeared within a week. We speculate that CwG is likely to lead to transient splenial lesions.     

Reversible Corpus Callosum Splenial Lesion Due to Steroid Therapy

Reversible corpus callosum splenial (CCS) lesions are rare findings and usually detected incidentally. We presented a case of 15‐year‐old boy with a diagnoses of nephrotic syndrome. He was referred for neuropsychiatric symptoms following dose reduction on steroid treatment. Brain magnetic resonance imaging (MRI) revealed a focal lesion in the CCS, hyperintense on T2 and FLAIR and hypointense on T1 images with diffusion restriction on apparent diffusion coefficient map. Follow‐up MRI 3 weeks later showed complete resolution of the lesion. It was probably result of focal intramyelinic edema due to excytotoxic mechanisms and/or arginine‐vasopressin release.     

Bright splenium of a psychotic mind

A twenty-one-year old primigravida presented two weeks postpartum with new onset of behavioral alteration and irrelevant talking without fever, headache, or seizures. Magnetic resonance imaging (MRI) of brain showed a lesion with diffusion restriction in splenium of corpus callosum. A possibility of postpartum psychosis was considered after ruling out various etiologies for splenium hyperintense lesion. Near complete resolution of symptoms was noted after initiation of antipsychotic medications. Literature has described multiple etiologies for lesions involving splenium of corpus callosum on brain imaging. We present this case as a unique clinical presentation of splenial pathology in the form of postpartum psychosis.     

Transient lesion in the splenium of the corpus callosum due to carbamazepine

Keeping in mind that lesions located in the splenium of the corpus callosum can sometimes be temporary may help us avoid invasive diagnostic and therapeutic methods. Transient lesion in the splenium of the corpus related to using or withdrawal of antiepileptic drugs are rarely encountered. In this article, we present a non-epileptic patient found to have a centrally located isolated lesion in the splenium of the corpus callosum on the tenth day following the sudden withdrawal of carbamazepine after two weeks of use. The lesion was observed to disappear two months later and the carbamazepine treatment or sudden withdrawal of the drug was thought to be responsible for this reversible splenial lesion.     

Splenial corpus callosum lesion and hemifield visual color anomia associated with intracranial hypertension

Lesions in the splenium of the corpus callosum are a rare complication of a variety of clinical conditions including ischemia, trauma, acute disseminated encephalomyelitis, infection, electrolyte imbalances, seizures, and antiepileptic drugs. This report describes a child presenting with hemifield visual color anomia, headache, and papilledema, who was found to have a midline splenial lesion on diffusion-weighted magnetic resonance imaging (MRI). Lumbar puncture revealed elevated intracranial pressure. His symptoms and MRI findings resolved quickly following treatment of his increased intracranial pressure. This is the first report describing an association between intracranial hypertension and a lesion in the splenium of the corpus callosum.     

Lesions in the Splenium of the Corpus Callosum on MRI in Children: A Review

A wide variety of conditions may involve the splenium of the corpus callosum on magnetic resonance imaging in children. A single cause may present with different patterns of splenial involvement, and multiple diseases may have similar imaging findings. Keeping this limitation in mind, the goal of this text is to assist in the diagnostic process of pediatric neurological diseases that are characterized by prominent involvement of the splenium of the corpus callosum on imaging. The various pathologies will be reviewed and categorized based on etiology, reversibility, and pattern of additional or associated findings. Transient splenial lesions in children are an uncommon radiologic finding of unknown etiology in a long list of conditions that may present with altered consciousness, and it usually carries a favorable prognosis. The discussion continues with the presentation of diseases inflicting irreversible damage on the splenium. Familiarity with the various causes implicated in splenial injury may assist in the formulation of differential diagnosis in the appropriate clinical setting using an easily recognizable imaging finding.     

Agraphia with reversible splenial corpus callosum lesion caused by hypoglycemia

Background

Neurological manifestations caused by hypoglycemia range from reversible focal deficits and transient encephalopathy to irreversible coma or death. Recently, high signal intensity lesions in the splenium of the corpus callosum on diffusion-weighted magnetic resonance imaging were reported in adults experiencing hypoglycemia. However, patients presenting with agraphia are rare.

Reversible splenial lesion in the corpus callosum following rapid withdrawal of carbamazepine after neurosurgical decompression for trigeminal neuralgia

Reversible splenial lesions (RSL) of the corpus callosum have been described in various clinical conditions, and some are attributed to the action of antiepileptic drugs (AED). Abrupt withdrawal of an AED in preparation for surgical treatment can result in RSL of the corpus callosum in patients with trigeminal neuralgia who do not have epilepsy. We report two patients who developed RSL following surgical treatment of trigeminal neuralgia. Since our two patients did not have epilepsy, it is strongly suggested that the AED, rather than convulsive status epilepticus, could be a contributing factor in RSL. The pathogenesis of AED-associated RSL is not clear. Similar RSL can appear under various circumstances, implying that factors other than AED can influence a common end-point mechanism that results in RSL. Nevertheless, delirium after surgery may be a cue for inquiring about RSL. This condition is transient and represents a clinicoradiological syndrome with an excellent prognosis. We should consider this phenomenon in the perioperative period after surgery for trigeminal neuralgia to avoid invasive diagnostic and therapeutic procedures.