Reversible Splenial Lesion Research Articles

Mild Encephalopathy With Splenial Lesion and Parainfluenza Virus Infection

Mild encephalopathy with reversible splenial lesions has mainly been associated with influenza A and B virus infection. Patients present with neurologic symptoms 1 to 3 days after a prodromal illness and recover completely within a few days. Magnetic resonance imaging typically shows reversible lesions with reduced diffusion in the corpus callosum, predominantly in the splenium. We report on a 5-year old Caucasian boy who was referred with recurrent seizures and decreased level of consciousness after a 2-day prodromal fever and cough. Magnetic resonance imaging showed cytotoxic edema of the entire corpus callosum and the adjacent periventricular white matter with diffusion restriction and faint T(2)-hyperintensity. Parainfluenza virus type 1-3 infection was documented by direct immunofluorescence in the initial nasopharyngeal swab, but polymerase chain reaction for parainfluenza virus type 1-4 in the cerebrospinal fluid remained negative. This is-to our knowledge-the first description of mild encephalopathy with reversible splenial lesions in association with parainfluenza virus infection. The pathogenesis of mild encephalopathy with reversible splenial lesions, however, still remains unclear, and further studies investigating detailed mechanisms that lead to the typical brain lesions are warranted.

Expanding the Spectrum of MERS Type 2 Lesions, a Particular Form of Encephalitis

We report on a 13-year-old boy who presented with signs suggestive of encephalitis and in whom magnetic resonance imaging revealed lesions in the genu and splenium of the corpus callosum and symmetrical lesions bilaterally in the center semiovale. This clinical-radiologic entity was previously reported in the literature and was given the acronym MERS type 2 (mild encephalitis with reversible splenial) lesion. The clinical, radiologic, and biochemical characteristics of the patient with MERS type 2 lesions presented in this article show some differences with those in previously reported patients. His clinical recovery was particularly slow, cerebrospinal fluid was abnormal, and on magnetic resonance imaging the typical time course of MERS type 2 lesions resolving through a phase of solitary lesions in the splenium of the corpus callosum, the so-called type 1 lesions, was not seen. He is also the first patient in whom mycoplasma pneumoniae was found to be associated with MERS type 2 lesions. These findings further expand the spectrum of MERS type 2 lesions. The question raises whether the MERS type 2 lesion represents a new type of encephalitis or a particular radiologically recognizable subtype of postinfectious encephalitis. In the article, previously reported patients with MERS type 2 lesions are reviewed.

A Case of Mild Encephalopathy with a Reversible Splenial Lesion Associated with G5P[6]Rotavirus Infection

We report a case of mild encephalopathy with a reversible splenial lesion (MERS) associated with acute gastroenteritis caused by rotavirus (RV) infection. The patient (male, 4 years and 3 months old) was admitted to our hospital for diarrhea and afebrile seizures. Head MRI revealed a hyperintense signal in the splenium of the corpus callosum on DWI and a hypointense signal on the ADC-map. After awakening from sedation, the patient's disturbance of consciousness improved. On day 5 after admission of the illness, the patient was discharged from the hospital in a good condition. Electroencephalography on day 2 after admission was normal. On day 8 of admission, head MRI revealed that the splenial lesion had disappeared. RV antigen-positive stools suggested that RV had caused MERS. This RV genotype was considered to be G5P[6]; it may have spread to humans as a strain reassortment through substitution of porcine RV into human RV gene segments. This extremely rare genotype was detected first in Japan and is not covered by existing vaccines; this is the first sample isolated from encephalopathy patients. Few reports have investigated RV genotypes in encephalopathy; we believe that this case is valuable for studying the relationship between genotypes and clinical symptoms.

A Child with Three Episodes of Reversible Splenial Lesion

In this study, we report the case of an 8-year-old girl who had three episodes of reversible splenial lesion of the corpus callosum (SCC) in 2 years. Vomiting, hypoglycemia, and fever were followed by altered consciousness and diminished muscle tone. In each episode, the clinical manifestations and abnormalities detected during magnetic resonance imaging resolved in 2 weeks. Transient alteration of vision and spike discharges revealed by interictal electroencephalogram implied the SCC lesions were related to epileptic activities. At follow-up, the patient had not presented with SCC lesions or altered consciousness for more than 4 years after undergoing carbamazepine treatment. Our case is the first report of a patient who presented with three episodes of reversible splenial lesion.

Mild Encephalopathy with Reversible Splenial Lesion in Children

Mild encephalopathy with reversible splenial lesion (MERS) is a recently described clinico-radiological syndrome. It is characterised by acute mild encephalopathy and changes in the splenium of the corpus callosum on brain magnetic resonance imaging (MRI). MERS has been described mainly in East Asian populations. Infection, particularly influenza, is the most common association. The prognosis is generally favourable with spontaneous resolution of clinical and radiological abnormalities. We report two cases of non-influenza MERS in children, one associated with varicella, and discuss their differing clinical presentations.

Transient Subcortical High-Signal Lesions in Kawasaki Syndrome

Kawasaki syndrome is an acute systemic vasculitis in children. The pathophysiology of Kawasaki syndrome presumably involves vascular inflammation, causing plasma leakage from systemic microvessels. From 1-30% of patients with Kawasaki syndrome exhibit central nervous system involvement, e.g., aseptic meningitis, epileptic seizures, transient hemiplegia, facial palsy, ataxia, chorea, ischemia, hearing loss, abnormal vision, disturbed consciousness, and behavioral changes. Neuroradiologically, Kawasaki syndrome demonstrates subdural effusion, infarction, atrophy, and reversible splenial lesions on magnetic resonance imaging. A 25-month-old boy developed transient hypertension with generalized seizure in the subacute phase of Kawasaki syndrome. Fluid-attenuated inversion recovery imaging, performed 5 hours and 2 days postseizure, indicated subtle, subcortical, high-signal-intensity lesions. Acute transient hypertension in this patient may have triggered the onset of lesions because of the increased permeability of brain microvessels, attributable to systemic vasculitis in Kawasaki syndrome. To our knowledge, subcortical lesions in Kawasaki syndrome were not previously reported.

Reversible Splenial Lesion Syndrome in Pediatric Systemic Lupus Erythematosus: Figure 1.

Transient lesions involving the splenium of the corpus callosum — reversible splenial lesion syndrome (RESLES) or mild encephalitis/encephalopathy with a reversible isolated splenium of the corpus callosum lesion (MERS) — have been described in patients with encephalopathy of various etiologies but rarely in systemic lupus erythematosus (SLE), limited to a case series of 3 patients1,2,3 …

High production of interleukin‐10 and interferon‐γ in influenza‐associated MERS in the early phase

Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) occurs in various diseases and pathologies, and the clinical symptoms are not consistent with the impaired region. The mechanism of the region specificity is unclear. We investigated the cytokine profiling in cerebrospinal fluid (CSF) and serum obtained from a child with MERS during influenza infection, and compared them with those of serious another serious type of influenza-associated encephalopathy. There was no elevation of Interleukin (IL)-1β, which induces convulsion. The inhibitory cytokines of IL-10 and IFN-γ were elevated in the early phase in CSF. Comparing them with other patients, the elevation of the cytokine levels were generally mild. Considering that the prognosis of this MERS case was favorable and high levels of inhibitory cytokines including IL-10 and IFN-γ might work to localize the lesion and to prevent sequelae.

National survey of pandemic influenza A (H1N1) 2009‐associated encephalopathy in Japanese children

The novel pandemic (pdm) influenza A (H1N1) 2009 virus caused an epidemic of critical illness, with some patients developing severe acute respiratory distress syndrome. Pdm H1N1 2009 infection has been reported to cause fatal encephalopathy and myocarditis as well as pneumonia. To investigate the actual characteristics of the encephalopathy associated with pdm H1N1 2009 infection in Japan, questionnaires were distributed and information collected on 207 cases of encephalopathy during one season. The results of the survey showed that encephalopathy was reported predominantly in males. The outcome was recorded in 188 of the 207 cases; 16 of 188 patients (8.5%) died, while 23 (12.2%) had sequelae. Serious cases were distributed across all age groups. Febrile convulsion was noted at a higher rate in medical past-history in cases without sequelae (40 of the 149 cases; 27%) than in serious cases. In contrast, pre-existing epilepsy and mental retardation were observed more frequently in serious cases. Twelve cases exhibited biphasic seizures; one-half of these had sequelae, but none was fatal. Ten cases were accompanied by high cytokine levels, and three of these children died. Among the 149 cases with good outcomes, 29 of 116 cases (25%) showed abnormalities on MRI, and 14 of these demonstrated reversible splenial lesions. Abnormal behaviors, especially delirium and visual hallucinations, were observed more frequently in cases without sequelae. In conclusion, pdm H1N1 2009 infection-associated encephalopathy was a critical disease in children, with rapidly progressive characteristics similar to those of seasonal influenza-associated encephalopathy.

A 4-year-old girl with clinically mild encephalopathy with a reversible splenial lesion associated with rotavirus infection

Rotavirus is a common cause of severe gastroenteritis in children. It is known that rotavirus gastroenteritis may be accompanied by neurological manifestations, including encephalitis/encephalopathy and seizures. We report a case of a 4-year-old girl with clinically mild encephalopathy with a reversible splenial lesion associated with rotavirus infection. She was admitted to our hospital because of reduced level of consciousness, seizures, diarrhea, and vomiting. Fecal rotavirus antigen testing was positive. Cell counts in the cerebrospinal fluid (CSF) were normal. She had a normal serum sodium level on admission. Brain computed tomography showed no cerebral edema. However, electroencephalography showed generalized high-voltage slow waves, and diffusion-weighted magnetic resonance imaging demonstrated a transient abnormality in the splenium of the corpus callosum. We diagnosed clinically mild encephalopathy with a reversible splenial lesion associated with rotavirus infection. She recovered well and exhibited no neurological sequelae. Rotavirus RNA and antigen were not detected in the CSF, suggesting that the reversible splenial change was caused by indirect effects on the central nervous system subsequent to viral infection. Her normal serum sodium level indicates that this change can occur without hyponatremia.

Gastroenteritis associated encephalopathy with reversible splenial lesion: three cases

Aims: Encephalopathy with or without seizures is a complication of gastroenteritis seen mainly in rotavirus infection. In some rare cases of rotavirus or adenovirus infection associated encephalopathy a reversible splenial lesion is described. This combination is called MERS (mild encephalitis/encephalopathy with reversible splenial lesion) and has a favourable outcome.

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.

A Case of Reversible Splenial Lesions in Late Postpartum Preeclampsia

There have been reports of various etiologies associated with reversible splenial lesions manifested as obviously restricted diffusion. We describe for a 27-year-old woman suffering from late postpartum preeclampsia associated with reversible splenial lesions. This association has not been reported to date. Awareness that profound late postpartum preeclampsia can rarely result in abnormalities of the splenium of the corpus callosum (SCC) may help clinicians avoid unnecessary diagnostic procedures and therapeutic interventions. Moreover, it must be stated that prediction of the clinical course based on DWI and ADC values should be used with caution.

Clinically Mild Encephalitis/Encephalopathy with a Reversible Splenial Lesion due to <i>Mycoplasma pneumoniae</i> Infection

Clinically Mild Encephalitis/Encephalopathy with a Reversible Splenial Lesion due to <i>Mycoplasma pneumoniae</i> Infection

Reversible Splenial Lesion Associated with Acute HIV Infection

Reversible Splenial Lesion Associated with Acute HIV Infection

Mumps-virus-associated Clinically Mild Encephalopathy With a Reversible Splenial Lesion

Mumps virus infection primarily involves the parotid glands and most frequently affects young children during the winter and spring months. It is known that mumps virus infection may be accompanied by neurological manifestations, including meningitis and encephalitis. However, few cases of acute encephalopathy have been reported to date. We report a case of a 4-year-old girl with clinically mild encephalopathy with a reversible splenial lesion associated with mumps virus infection. She had swelling of the bilateral parotid glands. She was admitted to our hospital because of reduced level of consciousness, seizures, and vomiting. Cell counts in the cerebrospinal fluid (CSF) were normal. She had a low serum sodium level on admission. Brain computed tomography showed mild cerebral edema. Electroencephalography showed partial high-voltage slow waves at the occipital lesion, and diffusion-weighted magnetic resonance imaging demonstrated a transient abnormality in the splenium of the corpus callosum. We diagnosed clinically mild encephalopathy with a reversible splenial lesion associated with mumps virus infection. She recovered well, and exhibited no neurological sequelae. Mumps virus RNA was not detected in the CSF, suggesting that the reversible splenial change was caused by indirect effects on the central nervous system subsequent to viral infection. Her low serum sodium level also indicates that this change can occur with hyponatremia. doi: http://dx.doi.org/10.4021/ijcp51w

Apparent diffusion coefficient restriction in the white matter: going beyond acute brain territorial ischemia

BackgroundReduction of apparent diffusion coefficient (ADC) values in white matter is not always ischaemic in nature.MethodsWe retrospectively analysed our MRI records featuring reduced ADC values in the centrum semiovale without grey matter involvement or significant vasogenic oedema.ResultsSeveral conditions showed the aforementioned MR findings: moose-horn lesions on coronal images in X-linked Charcot-Marie-Tooth disease; small fronto-parietal lesions in Menkes disease; marked signal abnormalities in the myelinised regions in the acute neonatal form of maple syrup urine disease; strip-like involvement of the corpus callosum in glutaric aciduria type 1; persistent periventricular parieto-occipital abnormalities in phenylketonuria; diffuse signal abnormalities with necrotic evolution in global cerebral anoxia or after heroin vapour inhalation; almost completely reversible symmetric fronto-parietal lesions in methotrexate neurotoxicity; chain-like lesions in watershed ischaemia; splenium involvement that normalises in reversible splenial lesions or leads to gliosis in diffuse axonal injury.ConclusionNeuroradiologists must be familiar with these features, thereby preventing misdiagnosis and inappropriate management.

Kawasaki disease complicated by mild encephalopathy with a reversible splenial lesion (MERS)

We reported four patients (2 to 10years) with Kawasaki disease complicated by clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS). All were treated with γ-globulin (2 to 6g/kg) after the diagnosis of Kawasaki disease, the fever being alleviated between day 6 and 25. One of two patients exhibiting a poor response to γ-globulin had a cardiac aneurysm as a sequela. Their neurological manifestations (delirious behavior and drowsiness), laboratorial hyponatremia, and radiological abnormalities completely disappeared. It is important for pediatricians to acknowledge that MERS can be observed in patients with Kawasaki disease, especially in older children, and that they might be at high risk for cardiac abnormalities.

Kawasaki disease-associated MERS: Pathological insights from SPECT findings

We report for the first time the single photon emission computed tomography (SPECT) findings of a patient with clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) associated with Kawasaki disease, which showed hypoperfusion of the bilateral cingulate gyri, thalamus, basal ganglia, brainstem, and cortex of the frontal lobes. These findings indicate that the pathogenesis of MERS is based on cerebral hypoperfusion due to vasculitis or cerebrovascular dehydration.

Epidemiology of acute encephalopathy in Japan, with emphasis on the association of viruses and syndromes

A research committee supported by the Japanese government conducted a nationwide survey on the epidemiology of acute encephalopathy in Japan using a questionnaire. A total of 983 cases reportedly had acute encephalopathy during the past 3years, 2007–2010. Among the pathogens of the preceding infection, influenza virus was the most common, followed by human herpesvirus-6 (HHV-6) and rotavirus. Among syndromes of acute encephalopathy, acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) was the most frequent, followed by clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS), acute necrotizing encephalopathy (ANE) and hemorrhagic shock and encephalopathy syndrome (HSES). Influenza virus was strongly associated with ANE and MERS, HHV-6 with AESD, and rotavirus with MERS. Mortality was high in ANE and HSES, but was low in AESD, MERS and HHV-6-associated encephalopathy. Neurologic sequelae were common in AESD and ANE, but were absent in MERS.