A splenial lesion with transiently reduced diffusion in clinically mild encephalitis is not always reversible: A case report

Cytotoxic lesion of the corpus callosum in pediatrics: A case report

Cytotoxic lesions of the corpus callosum are considered a clinical-radiological syndrome that generates transitory damage to the corpus callosum; especially in the splenium, with a multicausal origin such as drugs, malignant neoplasms, infections, subarachnoid hemorrhage, metabolic disorders, and traumas. The clinical presentation varies in severity. Some patients have complete recovery in a few days, while others present a more serious clinical, requiring admission to pediatric intensive care. We present a case of a pediatric patient with cytotoxic lesions of the corpus callosum (CLOCCs) confirmed by brain magnetic resonance imaging (MRI). The patient was admitted due to gastrointestinal symptoms, progressing to altered consciousness, postural instability, dysarthria, and paroxysmal events. A literature search of all reported cases of compromises of CLOCCs was carried out to identify the different terms used to describe this syndrome and consolidated a report of utility in the clinic of this pathology.

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.

Shigella-associated mild encephalitis with reversible splenial lesion in Hospital Center Delafontaine, Saint-Denis, France: a case report

BACKGROUND

Mild encephalitis with reversible splenial lesion of the corpus callosum (MERS) is a clinical/radiological syndrome characterized by hyperintense signal changes in the splenium of the corpus callosum visible on diffusion weighted imaging (DWI) in the brain Magnetic Resonance Imaging (MRI) associated with various neurological symptoms. Progression is usually favorable with disappearance of the MRI brain lesion and regression of clinical symptoms over a few days to a few weeks. The exact pathophysiology remains unclear. MERS can be associated with various pathogens.

CASE PRESENTATION

We report here a paediatric case of MERS associated with Shigella flexneri infection. A five-year-old boy with no relevant past medical history presented with symptoms such as headache, fever, profuse diarrhea and hallucinations. A brain Magnetic Resonance Imaging performed on Day 2 of the symptoms revealed hyperintense signal changes of the splenium of the corpus callosum in T2 FLAIR sequence. This infection had a favorable outcome after antibiotic therapy. No further recurrence of symptoms was observed and a follow-up clinical examination eight weeks later was normal. A follow-up brain Magnetic Resonance Imaging three months after discharge was also normal and the hyperintense signal changes of the splenium of the corpus callosum had disappeared completely.

CONCLUSIONS

MERS is a clinical/radiological syndrome with a generally good prognosis. We believe that this is the first description of a case of Shigella-associated MERS. It is useful to know about this condition to help distinguish it from acute disseminated encephalomyelitis.

Mild encephalitis/encephalopathy with a reversible splenial lesion in children

PURPOSE

We aimed to present clinical and radiologic characteristics of mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) in children.

METHODS

Eight children (5 boys and 3 girls; median age, 5.9 years; age range, 8 months to 14.1 years) diagnosed with MERS between September 2015 and June 2017 were included in the study. We reviewed the patient's data, including demographic characteristics, prodromal and neurologic symptoms, neurologic examination, magnetic resonance imaging and electroencephalography findings, laboratory findings, treatment, and prognosis.

RESULTS

Prodromal symptoms were nausea and vomiting (n=6), diarrhea (n=6), and fever (n=3). Initial neurologic symptoms were seizures (n=4), delirious behavior (n=1), drowsiness (n=1), ataxia (n=1), transient blindness (n=2), abnormal speech (n=2), and headache (n=1). Two patients had a suspected infective agent: urinary tract infection caused by Escherichia coli and gastroenteritis caused by rotavirus. Seven patients had type I lesions, comprising characteristic symmetric ovoid (n=6) and band-shaped (n=1) T2-weighted hyperintense lesions at the spenium of corpus callosum, and one patient had type II lesion with additional symmetric posterior periventricular lesions. The lesions were isointense to mildly hypointense on T1-weighted imaging and did not show enhancement. All lesions displayed restricted diffusion. In all patients, neurologic symptoms completely normalized < 48 hours from the onset of symptoms without any sequelae.

CONCLUSION

MERS has characteristic imaging features and favorable outcome.

Reversible lesions of the corpus callosum with initially restricted diffusion in a series of Caucasian children

BACKGROUND

Reversible lesions of the corpus callosum with initial restricted diffusion on diffusion-weighted imaging (DWI) are rare and mainly described in the south Asiatic population.

OBJECTIVE

The purpose of this study was to describe the clinical presentation, imaging findings, prognosis and etiology of transient restricted diffusion lesions of the corpus callosum in a series of Caucasian children.

MATERIALS AND METHODS

Seven children presenting with a transient restricted DWI lesion of the corpus callosum were included. Their clinical presentations and paraclinical examinations were investigated in addition to their MRI findings during the acute phase and at follow-up.

RESULTS

Five patients initially presenting with prodromal flu-like symptoms were diagnosed with mild encephalopathy with reversible corpus callosum lesions, three of which were due to the influenza virus. For two patients (twins) with a stroke-like presentation and without febrile illness, a central nervous system manifestation of X-linked Charcot-Marie-Tooth disease with connexin 32 mutation was diagnosed. All patients had a good clinical prognosis without clinical sequelae or residual MRI lesion for all patients at follow-up.

CONCLUSION

A transient lesion of the corpus callosum with restricted diffusion should prompt the radiologist to suggest an infectious trigger in children. The prognosis of these patients was good with normalization of clinical symptoms and MRI without any specific treatment.

Mild encephalopathy/encephalitis with a reversible splenial lesion (MERS): A report of five neonatal cases

Mild encephalopathy/encephalitis with a reversible splenial (MERS) lesion is a clinic-radiological entity. The clinical features of MERS in neonates are still not systemically reported. This paper presents five cases of MERS, and the up-to-date reviews of previously reported cases were collected and analyzed in the literature. Here we describe five cases clinically diagnosed with MERS. All of them were neonates and the average age was about 4 days. They were admitted for the common neurological symptoms such as hyperspasmia, poor reactivity and delirium. Auxiliary examinations during hospitalization also exhibited features in common. In this report, we reached following conclusions. Firstly, magnetic resonance imaging revealed solitary or comprehensive lesions in the splenium of corpus callosum, some of them extending to almost the whole corpus callosum. The lesions showed low intensity signal on T1-weighted images, homogeneously hyperintense signal on T2-weighted images, fluid-attenuated inversion recovery and diffusion-weighted images, and exhibited an obvious reduced diffusion on apparent diffusion coefficient map. Moreover, the lesions in the magnetic resonance imaging disappeared very quickly even prior to the clinical recovery. Secondly, all the cases depicted here suffered electrolyte disturbances especially hyponatremia which could be easily corrected. Lastly, all of the cases recovered quickly over one week to one month and majority of them exhibited signs of infections and normal electroencephalography.

Mild Encephalopathy with Reversible Lesions in the Splenium of Corpus Callosum and Bilateral Cerebral Deep White Matter in Identical Twins

Identical twin brothers developed mild encephalopathy at the age of 7.0 and 9.7 years (Patient 1) and 10.7 years (Patient 2). Patient 1 had influenza A at the time of his second episode, but triggering agents were not evident at the first episode. The triggering agents in Patient 2 were unclear. The neurological features of both patients included transient facial numbness, left arm paresis, dysarthria, and gait disturbance. Diffusion-weighted images from magnetic resonance imaging showed high signal levels at the splenium of corpus callosum and in the bilateral cerebral deep white matter. These results are characteristic of mild encephalitis/encephalopathy with a reversible isolated splenium of corpus callosum lesion. All three episodes were treated with a methylprednisolone pulse. Acyclovir was also administered to Patient 2 and to Patient 1 during his first episode. Patient 1 received an anti-influenza agent and intravenous immunoglobulin during his second episode. Both patients recovered completely without sequelae. Genetic factors, which may predispose identical twins to develop encephalopathy, are discussed.

Transient Splenial Lesion of the Corpus Callosum Related to Migraine with Aura in a Pediatric Patient

BACKGROUND

Transient splenial lesions of the corpus callosum are rare radiological findings first described in association with epilepsy, antiepileptic drugs and viral encephalitis. However, subsequently more cases were described associated with diverse clinical conditions.

CASE REPORT

We describe a 13-year-old girl suffering from migraine with aura presenting with headache, right-sided hemiparesis and encephalopathy. Brain magnetic resonance imaging revealed an ovoid lesion in the splenium of the corpus callosum. The patient's neurological symptoms resolved within 3 days without therapy and the lesion disappeared in follow up magnetic resonance images obtained 3 weeks after the onset of the symptoms.

RESULTS

Migraine with aura was considered to be the cause of the lesion. To our knowledge the present case is the first report of a pediatric patient with a diagnosis of migraine with aura presenting with hemiparesis and encephalopathy.

CONCLUSIONS

A diagnosis of transient lesion of the corpus callosum should be suspected in patients with migraine with aura presenting with hemiparesis and encephalopathy. A mild course and a good prognosis might be expected in the presence of a splenial lesion of the corpus callosum.

Reversible splenial lesion syndrome associated with encephalitis/encephalopathy presenting with great clinical heterogeneity

BACKGROUND

Reversible splenial lesion syndrome (RESLES) is a disorder radiologically characterized by reversible lesion in the splenium of the corpus callosum (SCC). Most of patients with RESLES associated with encephalitis/encephalopathy were identified in Japanese population, but almost no Chinese patients were diagnosed as RESLES associated with encephalitis/encephalopathy.

METHODS

Possible patients with reversible isolated SCC lesions were retrieved from January 2012 to July 2015 using keyword "restricted diffusion and isolated SCC lesion" in MRI report system from a large academic center. The clinical, laboratory and radiological data were summarized.

RESULTS

A total of 15 encephalitis/encephalopathy patients (9 males and 6 females) were identified with a reversible isolated SCC lesion. Except for 13 patients with fever symptom, 8 patients also had cold symptoms before the onset of neurological symptoms. The neurological symptoms included headache, vertigo, seizure, disturbance of consciousness, and delirious behavior. Thirteen patients completely recovered within 1 month, but 2 patients who were subjected to mechanical ventilation had persistent neurological deficits. The initial MRI features showed isolated ovoid or extending SCC lesions with homogeneous hyperintense on diffusion weighted imaging (DWI) and decreased apparent diffusion coefficient (ADC) values. The follow-up MRI revealed that isolated SCC lesions with diffuse restriction disappeared at 10 to 32 days after the initial MRI study. Fractional anisotropy map revealed the decreased value of SCC lesion in a severe case with poor prognosis.

CONCLUSIONS

RESLES associated with encephalitis/encephalopathy is a reversible syndrome with an excellent prognosis in most patients, while a few patients required ventilator supporting at the early stage might have severe neurological sequelae. Reversible signal changes on DWI and ADC are identified in all patients, but fractional anisotropy values can be decreased in severe patient with neurological sequelae.

Mild encephalopathy with reversible splenial lesion: an important differential of encephalitis

Mild encephalopathy with a reversible splenial lesion (MERS) is a clinico-radiological syndrome characterized by a transient mild encephalopathy and a reversible lesion in the splenium of the corpus callosum on MRI. This syndrome has almost universally been described in children from Japan and East Asia. Here we describe seven cases of MERS occurring in Caucasian Australian children from one centre seen over a 3 year period. All patients had a fever-associated encephalopathy (n = 7), which presented with confusion (n = 4), irritability (n = 3), lethargy (n = 3), slurred speech (n = 3), drowsiness (n = 2) and hallucinations (n = 2). Other neurological symptoms included ataxia (n = 5) and seizures (n = 1). These symptoms resolved rapidly over 4-6 days followed by complete neurological recovery. In all patients, MRI performed within 1-3 days of onset of encephalopathy demonstrated a symmetrical diffusion-restricted lesion in the splenium of the corpus callosum. Three patients had additional lesions involving other parts of the corpus callosum and adjacent periventricular white matter. These same three patients had mild persisting white matter changes evident at followup MRI, while the other patients had complete resolution of radiological changes. A potential trigger was present in five of the seven cases: Kawasaki disease, Salmonella, cytomegalovirus, influenza B and adenovirus (all n = 1). Elevated white cell count (n = 4), elevated C reactive protein (n = 5) and hyponatremia (n = 6) were commonly observed. CSF was performed in four patients, which showed no pleocytosis. This case series of MERS demonstrates this condition occurs outside of East Asia and is an important differential to consider in children presenting with acute encephalopathy.

Clinical and Neuroimaging Profile of Children with Lesions in the Corpus Callosum

PURPOSE

T2-hyperintense signal changes in corpus callosum (CC) have been described in epilepsy and encephalitis/encephalopathy. Little is known about their pathophysiology. The aim of this study was to examine the clinical presentation and evolution of CC lesions and relationship to seizures.

METHODS

We identified 12 children among 29,634 patients from Radiology Database. We evaluated following characteristics: seizures and accompanying medical history, antiepileptic drug usage, presenting symptoms, and radiological evolution of lesions.

RESULTS

CC lesions were seen in patients with prior diagnosis of epilepsy (n = 5) or in those with new onset seizures (n = 3), or with encephalitis/encephalopathy without history of seizures (n = 4). Seizure clustering or disturbances of consciousness were the main presenting symptoms. No relationship was observed between CC lesion and AEDs. On imaging, ovoid lesions at presentation resolved on follow up imaging and linear lesions persisted. DTI showed that the fibers passing through splenial lesions originated from the posterior parietal cortex and occipital cortex bilaterally.

CONCLUSION

In patients with seizures, no clear relationship was demonstrated between seizure characteristics or AED use with CC lesions. Ovoid lesions resolved and may have different pathophysiologic mechanism when compared to linear lesions that persisted.

Toxic leukoencephalopathies, including drug, medication, environmental, and radiation-induced encephalopathic syndromes

Toxic leukoencephalopathies can be secondary to the exposure to a wide variety of exogenous agents, including cranial irradiation, chemotherapy, antiepileptic agents, drugs of abuse, and environmental toxins. There is no typical clinical picture, and patients can present with a wide array of signs and symptoms. Involvement of white matter is a key finding in this scenario, although in some circumstances other high metabolic areas of the central nervous system can also be affected. Magnetic resonance (MR) imaging usually discloses bilateral and symmetric white matter areas of hyperintense signal on T2-weighted and fluid-attenuated inversion recovery images, and signs of restricted diffusion are associated in the acute stage. In most cases, the changes are reversible, especially with prompt recognition of the disease and discontinuation of the noxious agent. Either the MR or clinical features may be similar to several nontoxic entities, such as demyelinating diseases, leukodystrophies, hepatic encephalopathy, vascular disease, hypoxic-ischemic states, and others. A high index of suspicion should be maintained whenever a patient presents recent onset of neurologic deficit, searching the risk of exposure to a neurotoxic agent. Getting to know the most frequent MR appearances and mechanisms of action of causative agents may help to make an early diagnosis and begin therapy, improving outcome. In this review, some of the most important causes of leukoencephalopathies are presented; as well as other 2 related conditions: strokelike migraine attacks after radiation therapy syndrome and reversible splenial lesions.

Clinico-radiological spectrum of reversible splenial lesions in children

Recently, many cases of children presenting reversible splenial lesions during febrile illness (RESLEF) have been reported; however, their overall clinico-radiological features are unclear. To describe the clinico-radiological features, we retrospectively reviewed the etiology (pathogen), clinical course, laboratory data, magnetic resonance imaging and electroencephalography (EEG) findings, therapy, and prognosis of 23 episodes in 22 children (1 child recurred) who presented neurological symptoms, with RESLEF. The etiologies (pathogens) varied. Seizure occurred in 7 episodes, disturbance of consciousness (DC) in 13, and delirious behavior in 18. Serum sodium levels <136 mEq/L were observed in 18 episodes. Lesions outside the splenium were found in 4 cases. Slow waves were observed on EEG in 10 episodes. Methylprednisolone pulse therapy was given in 7 cases. No case resulted in neurological sequelae. Among 23 episodes, clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) was diagnosed in 6 episodes, whereas non-MERS was observed in 17 episodes. No difference was observed in almost all the clinico-radiological features' data between the 2 groups. The largest differences were observed in the rate of purposeless movement, DC, extension of the abnormal lesions outside the splenium, and marked slowing of background activity on EEG. RESLEF exhibit a spectrum of clinico-radiological features. These results suggest that non-MERS and MERS both are a part of a larger pathological condition, which we have termed as RESLEF spectrum syndrome. Given the view that such a syndrome exists, the clinical characteristics and position of non-MERS and MERS become clear.

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.

Acute brain MRI findings in 120 Malawian children with cerebral malaria: new insights into an ancient disease

BACKGROUND AND PURPOSE

There have been few neuroimaging studies of pediatric CM, a common often fatal tropical condition. We undertook a prospective study of pediatric CM to better characterize the MRI features of this syndrome, comparing findings in children meeting a stringent definition of CM with those in a control group who were infected with malaria but who were likely to have a nonmalarial cause of coma.

MATERIALS AND METHODS

Consecutive children admitted with traditionally defined CM (parasitemia, coma, and no other coma etiology evident) were eligible for this study. The presence or absence of malaria retinopathy was determined. MRI findings in children with ret+ CM (patients) were compared with those with ret- CM (controls). Two radiologists blinded to retinopathy status jointly developed a scoring procedure for image interpretation and provided independent reviews. MRI findings were compared between patients with and without retinopathy, to assess the specificity of changes for patients with very strictly defined CM.

RESULTS

Of 152 children with clinically defined CM, 120 were ret+, and 32 were ret-. Abnormalities much more common in the patients with ret+ CM were markedly increased brain volume; abnormal T2 signal intensity; and DWI abnormalities in the cortical, deep gray, and white matter structures. Focal abnormalities rarely respected arterial vascular distributions. Most of the findings in the more clinically heterogeneous ret- group were normal, and none of the abnormalities noted were more prevalent in controls.

CONCLUSIONS

Distinctive MRI findings present in patients meeting a stringent definition of CM may offer insights into disease pathogenesis and treatment.

Mild encephalitis/encephalopathy with a reversible splenial lesion: evaluation by diffusion tensor imaging. Two case reports

Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is a clinico-radiological syndrome with a very particular clinical course. Three patients with MERS were evaluated by various sequences of magnetic resonance imaging with diffusion tensor imaging. Initial diffusion-weighted imaging showed reduction in the apparent diffusion coefficient values in the lesions, which completely resolved with the elimination of symptoms. However, diffusion anisotropy of the lesions showed no remarkable abnormalities in the early or delayed phases. These results may indicate that white matter architecture is preserved in both early and delayed phases in MERS.

Restricted diffusion in the corpus callosum in hypoxic-ischemic encephalopathy

Restricted diffusion within the splenium of the corpus callosum was described in various conditions, but is not a prominent finding in magnetic resonance imaging after neonatal hypoxic-ischemic encephalopathy. Perinatal characteristics were reviewed in 42 term neonates with hypoxic-ischemic encephalopathy treated with selective head cooling. Neonatal images of 34 infants were reviewed. Ten of 34 (29%) infants demonstrated restricted diffusion changes within the splenium of the corpus callosum, with a significantly higher incidence of death or severe developmental delay, compared with infants without changes in the splenium of the corpus callosum (n = 24) (P = 0.002). The positive predictive value of changes in the splenium of the corpus callosum regarding poor outcomes or death was 90%. Changes in the splenium of the corpus callosum were also associated with lower birth weights, larger base deficits in cord arterial gas, and more severe encephalopathy during enrollment in selective head cooling. Restricted diffusion within the splenium of the corpus callosum of term infants with hypoxic-ischemic encephalopathy is often associated with extensive brain injury, and in these circumstances appears to be an early neuroradiologic marker of adverse neurologic outcomes.