Reversible focal splenial lesions

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.

Acute alcohol intoxication presenting acquired lesion of the corpus callosum in a young healthy woman: A case of possible Marchiafava-Bignami disease

Background

Marchiafava-Bignami disease is a rare neurological disease characterized by acquired lesions of the corpus callosum. Although the major causative etiology is chronic alcoholism, a case caused by acute alcohol intoxication has not yet been reported.

Case Presentation

A 19-year-old female with no known medical history or a history of chronic alcohol consumption was brought to the emergency department in a coma after binge alcohol consumption. Even after an overnight observation, she remained comatose. After a thorough examination including magnetic resonance imaging, which showed lesions of the corpus callosum, she was treated with thiamine for Marchiafava-Bignami disease. She recovered completely and at the follow-up, the callosum lesion had resolved.

Conclusion

This is a rare case within the spectrum of Marchiafava-Bignami disease caused by acute consumption of alcohol. Clinicians should be aware of this potentially devastating critical condition among patients with severe alcohol intoxication, which might have been overlooked.

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.

Clinical Features of Cytotoxic Lesions of the Corpus Callosum Associated with Aneurysmal Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Patients with SAH due to a ruptured intracranial aneurysm occasionally show reversible high-signal lesions in the splenium of the corpus callosum on DWI. These lesions are called cytotoxic lesions of the corpus callosum. This study retrospectively reviewed cases of aneurysmal SAH and investigated clinical features of cytotoxic lesions of the corpus callosum associated with SAH.

MATERIALS AND METHODS

Participants comprised 259 patients with aneurysmal SAH who had undergone curative treatment at our hospital. We examined the following items related to cytotoxic lesions of the corpus callosum: occurrence rate, timing of appearance and disappearance of the lesions, lesion size, aneurysm location, severity of SAH, treatment method, clinical course, and outcome.

RESULTS

Among the 259 cases, DWI detected cytotoxic lesions of the corpus callosum in 33 patients (12.7%). The mean periods from the onset of SAH to detection and disappearance of cytotoxic lesions of the corpus callosum were 6.3 days (range, 0-25 days) and 35.7 days (range, 9-78 days), respectively. Cytotoxic lesions of the corpus callosum were classified into 2 types: a small type localized in the splenium in 26 cases (78.9%) and a large type spread along the ventricle in 7 cases (21.2%). The severity of SAH, coiling, hydrocephalus, and poor mRS score at discharge were significantly higher in the group with cytotoxic lesions of the corpus callosum. However, multivariate analysis did not identify cytotoxic lesions of the corpus callosum as a risk factor for poor outcome.

CONCLUSIONS

Cytotoxic lesions of the corpus callosum appear at a frequency of 12.7% in patients with aneurysmal SAH. Cytotoxic lesions of the corpus callosum associated with SAH take several days to appear and subsequently resolve within about a month. Cytotoxic lesions of the corpus callosum were likely to occur in patients with high-grade SAH but did not represent a predictor of poor outcome.

Clinical and imaging features of reversible splenial lesion syndrome with language disorder

Reversible splenial lesion syndrome (RESLES) is a single-stage non-specific syndrome with unclear pathogenesis. There has been no report on answer delay in patients with RESLES. We report a female patient who was admitted to our department for mixed aphasia accompanied by cognitive impairment. During the rapid improvement of aphasia, there was a clear phase of language output response delay accompanied by resolution of imaging lesions. We analyzed the course and the examination results of the patient and speculated the cause and pathogenesis. RESLES-relevant knowledge was systematically reviewed, which will help doctors in the classification of cerebral function and the diagnosis of RESLES. The specific language and cognitive impairment may be associated with the damage of contact fibers in the bilateral primary and secondary sensory and motor cortices.

Does restricted diffusion in the splenium indicate an acute infarct?

OBJECTIVE

Although splenial lesions are rare, they are frequently associated with ischemic infarcts, antiepileptic drug toxicity or abrupt discontinuation, viral encephalitis, and metabolic disturbances. In this study, we evaluated clinical and imaging findings and aetiology in 16 patients with splenium lesions.

METHODS

Between 2013 and 2017, patients with splenium lesions were examined. Magnetic resonance imaging (MRI) was performed using a 1.5-T unit with fluid attenuation inversion recovery sequences. Additionally, diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps were examined.

RESULTS

The patients were 11 males and 5 females; the mean age was 52.3 ± 20.3 (22-87) years. The patients were admitted with the following conditions: consciousness disorder (n = 7, 43.7%), headache (n = 3, 18.7%), seizure (n = 3, 18.7%), ataxia (n = 3, 18.7%), hemiparesis (n = 4, 25%), meaningless speech (n = 2, 12.5%), fever (n = 3, 18.7%), perioral numbness (n = 1, 6.2%), and diplopia (n = 1, 6.2%). Hyperintensity in the splenium was observed in DWI sequences in all patients on MRI. Fourteen patients (87.5%) showed hypointensity in the same region on ADC. In patients with ischemic infarcts, the splenium lesions were most commonly observed in the area of the posterior cerebral artery (n = 4, 25%). MRI showed splenial signal changes in DWI sequences in all patients. Hyperintensity in the splenium was observed in DWI sequences in all patients on MRI. Fourteen patients (87.5%) showed hypointensity in the same region on ADC. The aetiologies were defined as multiple sclerosis (n = 1, 6.2%), ischemic infarction (n = 4, 25%), tuberculous meningitis (n = 3, 18.7%), viral encephalitis (n = 2, 12.5%), hypernatremia (n = 1, 6.2%), brain tumour (n = 1, 6.2%), Marchiafava-Bignami syndrome (n = 1, 6.2%), head trauma (n = 1, 6.2%), substance use (n = 1, 6.2%), and epilepsy (n = 1, 6.2%).

CONCLUSION

Not every diffuse restriction observed on MRI indicates an ischemic stroke. Although radiologic images of the splenium may suggest acute ischemic infarction, the actual cause may be another pathology. Therefore, the symptoms and aetiologies of patients with splenium lesions should be considered and investigated from a wide range of perspectives.

[MERS type II mimicking leukoencephalopathy was suspected to be associated with mycoplasma pneumonia infection]

A 16-year-old male with language disorders, such as motor aphasia or mutism, was hospitalized on day 4 after the onset of fever. Magnetic resonance imaging (MRI) on admission revealed lesions of the corpus callosum and brain white matter. Brain single photon emission computed tomography (99mTc-ethyl cysteinate dimer) on day 7 shows hypoperfusion (with right dominance) of bilateral upper parietal region. His condition improved gradually with symptomatic treatments alone, and he was discharged on day 13. The lesions on the MRI disappeared by day 15. Although this case might have suffered from leukoencephalopathy, clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) type II was suspected from the reversible splenial lesion. Except for the elevation (640 times) of mycoplasma pneumonia antibody titer (particle agglutination) in the serum, the blood tests and cerebrospinal fluid findings showed no significant abnormalities. We then considered this encephalopathy was related to mycoplasma pneumonia infection. Since no symptoms of mycoplasma infection except for neurologic symptoms were observed, indirect mechanism, such as immune-mediated reactions, is suggested to cause encephalopathy in this case.

Treatment-related transient splenial lesion of the Corpus Callosum in patients with neuropsychiatric disorders: a literature overview with a case report

Introduction: Transient-localized lesions of the splenium of the corpus callosum (SCC) have been described in various clinical conditions, some of them being attributed to the withdrawal of psychotropic drugs. The pathophysiology of the lesion reflects cytotoxic edema and reversible demyelination.Areas covered: The present article aimed at reviewing cases of transient SCC lesion exclusively related to changes in pharmacotherapy. It also reports the original case of a patient receiving a complex psychopharmacological therapy who developed a transient SCC lesion investigated by magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and pharmacogenetic profiling.Expert opinion: To date, only one review on the subject has been published, analyzing 22 cases of transient SCC lesion arising in epileptic patients on antiepileptic therapy. It hypothesized that the nature of the lesion is a cytotoxic edema and the cases described in the subsequent 14 years seem to support this hypothesis. The authors reported the case of an Italian-Egyptian patient who developed a transient SCC lesion after the rapid withdrawal of Carbamazepine and Lurasidone. The lesion completely disappeared from the MRI performed after 1 month. Patient's ethnic group and its pharmacogenetic profile were considered as possible causes of altered drug metabolism and, likely, of the SCC lesion.

The splenium of the corpus callosum: embryology, anatomy, function and imaging with pathophysiological hypothesis

BACKGROUND AND PURPOSE

The splenium of the corpus callosum is the most posterior part of the corpus callosum. Its embryological development, anatomy, vascularization, function, imaging of pathology, possible pathophysiological mechanisms by which pathology may develop and the clinical consequences are discussed.

METHODS

A literature-based description is provided on development, anatomy and function. MR and CT images are used to demonstrate pathology. The majority of pathology, known to affect the splenium, and the clinical effects are described in three subsections: (A) limited to the splenium, with elaboration on pathophysiology of reversible splenial lesions, (B) pathology in the cerebral white matter extending into or deriving from the splenium, with special emphasis on tumors, and (C) splenial involvement in generalized conditions affecting the entire brain, with a hypothesis for pathophysiological mechanisms for the different diseases.

RESULTS

The development of the splenium is preceded by the formation of the hippocampal commissure. It is bordered by the falx and the tentorium and is perfused by the anterior and posterior circulation. It contains different caliber axonal fibers and the most compact area of callosal glial cells. These findings may explain the affinity of specific forms of pathology for this region. The fibers interconnect the temporal and occipital regions of both hemispheres reciprocally and are important in language, visuospatial information transfer and behavior. Acquired pathology may lead to changes in consciousness.

CONCLUSION

The development, location, fiber composition and vascularization of the splenium make it vulnerable to specific pathological processes. It appears to play an important role in consciousness.

Hypoglycemic encephalopathy mimicking acute ischemic stroke in clinical presentation and magnetic resonance imaging: a case report

Background

The imaging findings of hypoglycemic encephalopathy can be considerably similar to those of ischemic infarction or toxic leukoencephalopathy. We demonstrated unusual magnetic resonance (MR) imaging features of hypoglycemic encephalopathy which can be confused with other pathology both on imaging and acute clinical presentation. The diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADC) map findings in our case further supports the hypothesis of hypoglycemia-induced “excitotoxic injury” of glial cells and myelin sheath that might protect neuron axons from intracellular edema and irreversible damage.

Case presentation

A 72-year-old woman presented with poor appetite and was initially drowsy at home; the symptoms progressed to loss of consciousness accompanied by mild incontinence. The initial glucose level was 44 mg/dL, but no nausea, vomiting, fever, or cold sweating was reported. Physical examination after intravenous glucose supplementation revealed the absence of focal neurological signs, facial palsy, and tongue or eye deviations. The images obtained 24 h after symptoms onset revealed symmetrical hyperintensities on DWI (b-value: 1000) associated with hypointensities on ADC map along the corticospinal tract, from the levels of the cerebral peduncle and the posterior limbs of the internal capsule to the level of the corona radiata, which may mimic the imaging findings of acute ischemic infarction or amyotrophic lateral sclerosis. The patient received sliding-scale insulin therapy and rehabilitation, and she recovered consciousness without motor function deficits after 1 month. Moreover, repeat DWI and ADC map showed the complete disappearance of the lesions.

Conclusions

In the phenomenon of excitotoxic injury, axons could be protected from intracellular edema and irreversible damage, which may explain the reversible clinical symptoms and imaging abnormality after controlling for blood glucose because of the preserved motor axon. The diagnosis of acute symptomatic hypoglycemic encephalopathy through clinical and imaging features can be challenging. It is crucial to differentiate it from ischemic encephalopathy since the management and clinical outcome are different.

Electronic supplementary material

The online version of this article (10.1186/s12880-019-0310-z) contains supplementary material, which is available to authorized users.

Reversible Splenial Lesion Syndrome After Intravenous Immunoglobulin Treatment for Guillain-Barre Syndrome

Reversible corpus callosum splenial (CCS) lesions have been described in patients with varied etiologies. The most common causes of previously reported reversible focal lesions of the CCS are viral encephalitis, antiepileptic drug toxicity/withdrawal, and metabolic disorders. Intravenous immunoglobulin (IVIG) therapy is used for different immune-mediated diseases. It is generally safe, and serious adverse reactions are uncommon. We presented a rare case of disturbed consciousness with reversible CCS lesions after IVIG therapy for Guillain-Barre syndrome in an adult woman. In this case, we believe that IVIG therapy caused reversible CCS lesions with encephalopathy and probably result of cytotoxic edema and/or cerebral arterial vasospasm.

Reversible splenial lesions presenting in conjunction with febrile illness: a case series and literature review

Transient restricted diffusion and increased T2 signal intensity within the splenium of the corpus callosum is an increasingly recognized albeit uncommon imaging feature in the setting of acute encephalitis and antecedent viral illness. This review will discuss three index cases obtained from an institutional databank. Additionally, the current understanding of the underlying neurophysiologic pathogenesis will be discussed together with differential clinical and imaging diagnostic considerations, treatment options, and outcome metrics.

MR imaging of adult acute infectious encephalitis

BACKGROUND

Imaging is a key tool for the diagnosis of acute encephalitis. Brain CT scan must be urgently performed to rule out a brain lesion with mass effect that would contraindicate lumbar puncture. Brain MRI is less accessible than CT scan, but can provide crucial information with patients presenting with acute encephalitis.

METHOD

We performed a literature review on PubMed on April 1, 2015 with the search terms "MRI" and "encephalitis".

RESULTS

We first described the various brain MRI abnormalities associated with each pathogen of acute encephalitis (HSV, VZV, other viral agents targeting immunocompromised patients or travelers; tuberculosis, listeriosis, other less frequent bacterial agents). Then, we identified specific patterns of brain MRI abnomalies that may suggest a particular pathogen. Limbic encephalitis is highly suggestive of HSV; it also occurs less frequently in encephalitis due to HHV6, syphillis, Whipple's disease and HIV primary infection. Rhombencephalitis is suggestive of tuberculosis and listeriosis. Acute ischemic lesions can occur in patients presenting with severe bacterial encephalitis, tuberculosis, VZV encephalitis, syphilis, and fungal infections.

CONCLUSION

Brain MRI plays a crucial role in the diagnosis of acute encephalitis. It detects brain signal changes that reinforce the clinical suspicion of encephalitis, especially when the causative agent is not identified by lumbar puncture; it can suggest a particular pathogen based on the pattern of brain abnormalities and it rules out important differential diagnosis (vascular, tumoral or inflammatory causes).

Mycoplasma pneumoniae-associated mild encephalitis/encephalopathy with a reversible splenial lesion: report of two pediatric cases and a comprehensive literature review

BACKGROUND

No literature review exists on Mycoplasma pneumoniae-associated mild encephalitis/encepharopathy with a reversible splenial lesion (MERS).

METHODS

M.pneumoniae-associated MERS cases were searched till August 2016 using PubMed/Google for English/other-language publications and Ichushi ( http://www.jamas.or.jp/ ) for Japanese-language publications. Inclusion criteria were children fulfilling definition for encephalitis, M.pneumoniae infection, and neuroimaging showing hyperintensity in the splenium of the corpus callosum (SCC) alone (type I) or SCC/other brain areas (type II).

RESULTS

We described two children with type I and II M.pneumoniae-associated MERS. Thirteen cases found by the search and our 2 cases were reviewed. Mean age, male/female ratio, duration of prodromal illness was 8.3 years, 1.5 and 3.5 days. The most common neurological symptom was drowsiness, followed by abnormal speech/behavior, ataxia, seizure, delirium, confusion, tremor, hallucination, irritability, muscle weakness, and facial nerve paralysis. Fever was the most common non-neurological symptom, followed by cough, headache, gastrointestinal symptoms, headache, lethargy and dizziness. Seizure and respiratory symptoms were less common. All were diagnosed for M.pneumoniae by serology. Cerebrospinal fluid (CSF) M.pneumoniae was undetectable by PCR in the 3 patients. Three patients were clarithromycin-resistant. Leukocytosis, positive C-reactive protein, hyponatremia, CSF pleocytosis and slow wave on electroencephalography frequently occurred. All except 2 were type I MERS. Neuroimaging abnormalities disappeared within 18 days in the majority of patients. All type I patients completely recovered within 19 days. Two type II patients developed neurological sequelae, which recovered 2 and 6 months after onset.

CONCLUSIONS

Prognosis of M.pneumoniae-associated MERS is excellent. Type II MERS may increase a risk of neurological sequelae.

Reversible splenial lesion syndrome in children: Retrospective study and summary of case series

OBJECTIVE

To describe clinical features of reversible splenial lesion syndrome (RESLES) in children.

METHODS

Retrospectively analyzed clinical features of RESLES in children and compared differences between severe and non-severe group, classified by clinical global impression-scale; summarized clinical features of children with mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) from case series.

RESULTS

16 episodes of RESLES occurring in 15 Chinese children were analyzed, with 13 episodes having MERS and 3 episodes with epilepsy. 10 episodes were associated with various pathogens including rotavirus (n=5), adenovirus (n=1), influenza A (n=1), mycoplasma (n=2), and jejunum campylobacter (n=1). The common neurological symptoms included seizure, behavioral changes, altered consciousness and motor deterioration. The lesions of splenium of corpus callosum (SCC), extra-SCC (n=2) or extra-CC (n=1) showed T2-weight and FLAIR hyper-intensity, with the corresponding reduced diffusion. All had complete resolution of radiological changes except 1 episode with small residual. 8 episodes had EEG abnormalities, while elevated white blood count, increased hs-CRP, and hyponatremia were commonly revealed. 7 episodes were given steroid plus therapy, while 3 episodes were treated with antiepileptic drugs. Compared with non-severe group, the number of patients with altered consciousness, EEG abnormalities, motor deterioration, or extra-SCC lesions in severe group was significantly increased. The patients in severe group tended to need longer hospital stay interval. No case caused neurological sequelae, except 1 patient in severe group with recurrent episode and extra-CC lesions having intellectual disability (ID). Five pediatric MERS case series were summarized, including 67 episodes (40 male and 27 female; age ranging 10 m∼13y) from 65 patients, with 33 episodes in Japan, 27 in China, and 7 in Caucasian Australian children, and all patients have a good prognosis except 1 patient with ID (current study).

CONCLUSION

Although RESLES in children tend to be a good outcome, the prognosis of patient in severe group, especially with extra-CC lesions, might have neurological sequelae.

Marchiafava-Bignami disease in chronic alcoholic patient

Marchiafava–Bignami disease is a rare toxic encephalopathy seen mostly in chronic alcoholics due to progressive demyelination and necrosis of the corpus callosum. It may involve adjacent white matter and subcortical regions. We present here the magnetic resonance imaging findings of Machiafava–Bignami disease in a chronic alcoholic patient. In 1903, Italian pathologists Marchiafava and Bignami described 3 alcoholic men who died after having seizures and coma. All 3 patients were chronic alcoholics and had consumed considerable amounts of red wine.

The Pattern of Brain Microhemorrhages After Severe Lung Failure Resembles the One Seen in High-Altitude Cerebral Edema

OBJECTIVES

After suffering from severe acute respiratory distress syndrome, several patients show generalized brain alterations and atrophy. A distinctive morphologic pattern of cerebral injury, however, has not been found so far.

DATA SOURCES

We present the history of three patients who survived severe acute respiratory distress syndrome. In these patients, MRI of the brain showed multiple microhemorrhages predominantly in the splenium of the corpus callosum. An identical pattern of microhemorrhages has previously been described in mountaineers who suffered from high-altitude cerebral edema.

CONCLUSIONS

This report demonstrates that patients after treatment for acute respiratory distress syndrome and high-altitude cerebral edema show congruent cerebral injuries. Further investigation into the similarities of the causative conditions and neurologic consequences might reveal underlying pathophysiologic mechanisms and clinical implications of this observation.

Reversible Focal Splenial Lesion on Diffusion-Weighted MRI in Sulfonylurea Intoxication

Hypoglycemic brain injury is usually reversible, and partial recovery or mortality depends on the affected area. Diffusion-weighted imaging (DWI) may be useful in predicting the prognosis according to the site of involvement. Isolated lesions of the splenium of corpus callosum (SCC) in hypoglycemic brain injury are very rare, and DWI findings of a reversible lesion of the SCC due to deep hypoglycemia associated with sulfonylurea intoxication has been reported only once in the literature. We report the case of a 15-year-old girl admitted to the emergency department who had attempted suicide using sulfonylurea and subsequently went into a coma. The patient had no known previous disease. Except for a blood glucose level of 10 mg/dl, all other blood laboratory tests were normal. DWI performed two hours after admission showed diffusion restriction in the SCC. After receiving treatment for 24 hours, the patient became conscious, and her blood glucose level returned to normal. Two days later, complete resolution of the SCC lesion was revealed by control DWI. We discuss both the DWI findings of the reversible SCC lesion due to hypoglycemic brain injury resulting from sulfonylurea intoxication and the role of DWI in predicting the clinical outcome.

Hypoglycemia with focal neurological signs as stroke mimic: Clinical and neuroradiological characteristics

Our aim was to investigate the clinical and radiological features of patients with hypoglycemia with focal neurological signs (HFNS). Among 80 consecutive hypoglycemic patients (blood glucose levels less than 50mg/dL), who had been admitted between October 2008 and May 2012, we selected 11 patients (6 men and 5 women; mean age, 73.2 ± 12 years) with focal neurological signs. The mean initial blood glucose level was 27.9 mg/dL (range, 13-39 mg/dL). The most frequent symptom was unilateral motor weakness (n = 9), which was usually accompanied with mild or moderate alteration of consciousness. All patients had improved initial neurological signs within 1h of glucose injection. The initial DWI demonstrated a hyperintense lesion in the contralateral internal capsule with decreased values on the ADC (apparent diffusion coefficient) map in 2 of the patients (18%). The DWI performed one day later shows only faint lesion. The initial DWI in patients with HFNS may display a hyperintense lesion, which was difficult to distinguish from acute cerebral infarction. Hypoglycemia should be considered in cases with DWI showing a disproportionally small lesion in contrast to neurological signs.

Reversible Splenial Lesion Syndrome (RESLES) Following Glufosinate Ammonium Poisoning

Isolated and reversible lesion restricted to the splenium of the corpus callosum, known as reversible splenial lesion syndrome, have been reported in patients with infection, high-altitude cerebral edema, seizures, antiepileptic drug withdrawal, or metabolic disturbances. Here, we report a 39-year-old female patient with glufosinate ammonium (GLA) poisoning who presented with confusion and amnesia. Diffusion-weighted magnetic resonance imaging of the brain revealed cytotoxic edema of the splenium of the corpus callosum. The lesion was not present on follow-up MR imaging performed 9 months later. We postulate that a GLA-induced excitotoxic mechanism was the cause of this reversible splenial lesion.

Clinicoradiological spectrum of reversible splenial lesion syndrome (RESLES) in adults: a retrospective study of a rare entity

The presence of reversible lesions that involve the splenium of the corpus callosum (SCC) has been reported in patients with a broad spectrum of diseases and conditions and is referred to as reversible splenial lesion syndrome (RESLES).To describe the clinicoradiological features and establish a clinical position for this disease, we retrospectively examined the clinicoradiological features of adult RESLES patients, as well as discuss the potential pathophysiological mechanisms of this disease.The clinical and MRI findings of patients who presented with RESLES accompanied by symptoms of neurological disorders were retrospectively reviewed. The patients were classified into 2 subgroups (favorable and poor outcome subgroups), which corresponded to the severity of the disability using the Modified Oxford Handicap Scale. In addition, we compared the clinical and neuroimaging features between the 2 outcome subgroups.Eight patients with RESLES associated with various diseases and conditions were included. The clinical presentation was nonspecific; however, MRI exhibited consistent lesions in the SCC with a hypointensity on apparent diffusion coefficient maps and a hyperintensity via diffusion-weighted imaging, which disappeared after a variable lapse. The number of patients with a severe disturbance of consciousness, extracallosal lesions, or diffuse slow waves in the poor outcome subgroup was significantly increased compared with the favorable outcome subgroup (P < 0.05). Thus, the clinicoradiological spectrum of RESLES could be classified into 2 principal categories according to differential outcomes.RESLES is a rare entity with a broad clinicoradiological spectrum because of the various diseases and conditions. Although the overall symptoms of RESLES patients tend to be alleviated, the prognosis of patients with a severe disturbance of consciousness, extracallosal lesions, or diffuse slow waves is likely unfavorable.

Metronidazole-induced encephalopathy after prolonged metronidazole course for treatment of C. difficile colitis

A 65-year-old woman with a diagnosis of Clostridium difficile colitis undergoing prolonged treatment with metronidazole was admitted to hospital for altered mentation, slurred speech and weakness. She was diagnosed with metronidazole-induced encephalopathy, confirmed with brain MRI and improved when the offending agent was removed. This case report highlights encephalopathy as a complication of prolonged metronidazole treatment, which has become more common in clinical practice for the treatment of C. difficile infection.

Reversible splenial lesion on the corpus callosum in nonfulminant hepatitis A presenting as encephalopathy

Reversible focal lesions on the splenium of the corpus callosum (SCC) have been reported in patients with mild encephalitis/encephalopathy caused by various infectious agents, such as influenza, mumps, adenovirus, Varicella zoster, Escherichia coli, Legionella pneumophila, and Staphylococcus aureus. We report a case of a reversible SCC lesion causing reversible encephalopathy in nonfulminant hepatitis A. A 30-year-old healthy male with dysarthria and fever was admitted to our hospital. After admission his mental status became confused, and so we performed electroencephalography (EEG) and magnetic resonance imaging (MRI) of the brain, which revealed an intensified signal on diffusion-weighted imaging (DWI) at the SCC. His mental status improved 5 days after admission, and the SCC lesion had completely disappeared 15 days after admission.

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.

Metronidazole-Induced Encephalopathy: Case Report and Review of MRI Findings

A 74-year-old man presented with a four week history of behavioural disturbances, upper and lower extremity numbness and impaired balance. He had been treated with metronidazole for six months for osteomyelitis of the right hallux. Examination revealed encephalopathy, and glove-and-stocking sensory loss to pinprick with reduced vibration threshold at the toe. The gait was wide based and ataxic. Nerve conduction studies showed a large fibre sensory-motor axonal polyneuropathy. Magnetic resonance imaging (MRI) revealed a solitary restricted diffusion lesion in the splenium of the corpus callosum (Figure A, B) with subtle prolongation of T2 (Figure C). The radiographic differential diagnosis included hypoglycaemia, viral encephalitis, antiepileptic drug toxicity/withdrawal and metronidazole toxicity. The combination of the imaging finding with the history of prolonged metronidazole use suggested metronidazole induced encephalopathy.

Effect of hypoglycemia on brain structure in people with type 2 diabetes: epidemiological analysis of the ACCORD-MIND MRI trial

OBJECTIVE

The effect of hypoglycemia related to treatment of type 2 diabetes mellitus (T2DM) on brain structure remains unclear. We aimed to assess whether symptomatic severe hypoglycemia is associated with brain atrophy and/or white matter abnormalities.

RESEARCH DESIGN AND METHODS

We included T2DM participants with brain MRI from the Action to Control Cardiovascular Risk in Diabetes-Memory in Diabetes (ACCORD-MIND) trial. Symptomatic severe hypoglycemia was defined as blood glucose <2.8 mmol/L or symptoms resolved with treatments that required the assistance of another person or medical assistance (hypoglycemia requiring assistance [HA]). Standardized brain MRI was performed at baseline and at 40 months. Total brain volume (TBV) and abnormal white matter (AWM) volume were calculated using an automated computer algorithm. Brain MRI scans of hypoglycemic participants were also reviewed for local disease.

RESULTS

Of the 503 T2DM participants (mean age, 62 years) with successful baseline and 40-month brain MRI, 28 had at least one HA episode during the 40-month follow-up. Compared with participants without HA, those with HA had marginally significant less atrophy (less decrease in TBV) from baseline to 40 months (-9.55 [95% CI -15.21, -3.90] vs. -15.38 [95% CI -16.64, -14.12], P = 0.051), and no significant increase of AWM volume (2.06 [95% CI 1.71, 2.49] vs. 1.84 [95% CI 1.76, 1.91], P = 0.247). In addition, no unexpected local signal changes or volume loss were seen on hypoglycemic participants' brain MRI scans.

CONCLUSIONS

Our study suggests that hypoglycemia related to T2DM treatment may not accentuate brain pathology, specifically brain atrophy or white matter abnormalities.

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.

Diagnosis and management of Marchiafava-Bignami disease: a review of CT/MRI confirmed cases

OBJECTIVE

Marchiafava-Bignami disease (MBD) is a rare condition mainly associated with alcoholism, although it may be mimicked by several other disorders that cause corpus callosum lesions. Our objective was to identify helpful features for differential diagnosis and assess whether any treatment can be recommended.

METHODS

We reviewed 122 reports containing data on 153 subjects with confirmed MBD that was associated with either alcoholism or malnutrition, and 20 reports with data on 53 subjects with conditions mimicking MBD. All the cases had been verified antemortem by brain imaging. Unconditional logistic regression was used to demonstrate factors that were associated with the outcome of MBD.

RESULTS

The mimicking conditions were differentiated from MBD by the occurrence of solitary and rapidly disappearing splenial lesions; fewer signs and symptoms with exception of seizures, hemiparesis and tetraparesis; nystagmus; and rapid and complete recovery. MBD occurred most frequently among alcoholics, but it was also reported in 11 non-alcoholics (7.2% of all the MBD cases). A better outcome was observed among those who were treated within 2 weeks after onset of symptoms with parenteral thiamine (p=0.033).

CONCLUSIONS

As thiamine deficiency is frequently associated with alcoholism, malnutrition and prolonged vomiting; we recommend prompt treatment of MBD with parenteral thiamine in such subjects. Recovery should be followed by repeated neuropsychological and MRI examinations, preferably using diffusion tensor imaging.

Transient hemiparesis and hemianesthesia in an atypical case of adult-onset clinically mild encephalitis/ encephalopathy with a reversible splenial lesion associated with adenovirus infection

We herein report the case of a previously healthy 24-year-old Japanese woman who developed adult-onset clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) presenting with hemiparesis and hemianesthesia secondary to adenovirus infection. The patient's neurological symptoms and the lesion in the splenium resolved within 17 days without therapy. The radiographic features and clinical course observed in this case were consistent with a diagnosis of MERS; however, the only neurological symptoms were hemiparesis and hemianesthesia. This is the first reported case of MERS involving only hemiparesis and hemianesthesia at onset. This case suggests that a diagnosis of MERS should be suspected in patients with hemiparesis and hemianesthesia, especially when these conditions are preceded by infection.

Early diffusion MR imaging findings and short-term outcome in comatose patients with hypoglycemia

BACKGROUND AND PURPOSE

The relationship between the MR imaging features and clinical outcomes in patients with hypoglycemic encephalopathy has always been evaluated retrospectively. The aim of this study was to prospectively evaluate whether MR imaging features of patients presenting with hypoglycemic coma are predictive of short-term (1-week) outcomes.

MATERIALS AND METHODS

Subjects were 36 consecutive patients with hypoglycemia who were in a comatose state on arrival at our hospital from April 2006 to March 2010. MR imaging findings on arrival in relation to the patients' clinical course after glucose infusion were evaluated.

RESULTS

Thirteen of the 36 patients showed no MR imaging abnormalities on arrival. DWI revealed focal lesions involving the internal capsule in 13 patients and lesions involving bilateral hemispheric white matter in 10 patients. After glucose administration, the patients without lesions and patients with focal internal capsule lesions recovered completely within 1 day. However, patients with diffuse white matter lesions did not recover even within 1 week despite glucose administration. There was no statistical difference in the initial blood glucose levels among patients with the various types of MR imaging findings.

CONCLUSIONS

On early MR imaging, hypoglycemic brain injury may first appear in the internal capsule and then spread into the hemispheric white matter. The absence of a lesion or the presence of a focal internal capsule lesion may suggest a good outcome. However, diffuse hemispheric white matter lesions may indicate a poor 1-week outcome.

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.

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

Background

Reduction of apparent diffusion coefficient (ADC) values in white matter is not always ischaemic in nature.

Methods

We retrospectively analysed our MRI records featuring reduced ADC values in the centrum semiovale without grey matter involvement or significant vasogenic oedema.

Results

Several 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.

Conclusion

Neuroradiologists must be familiar with these features, thereby preventing misdiagnosis and inappropriate management.

Kawasaki disease complicated with reversible splenial lesion and acute myocarditis

Kawasaki disease, a systemic vasculitis of unknown etiology, develops frequently in infants and demonstrates a variety of clinical symptoms during the disease course. The most important complication, coronary artery lesions, is found in 15-25% of untreated patients. Meanwhile, acute myocarditis, another complication that can occur during the acute phase of severe systemic vasculitis, has been found in more than 50% of affected individuals when asymptomatic cases are included. However, cases that require treatment are rare as reported by Yoshikawa et al. (Circ J 70:202-205, 2006). As for neural complications, aseptic meningitis is well known, but it is extremely rare for these patients to develop encephalitis or encephalopathy as reported by Imai et al. (Jpn Soc Emerg Pediatr 8:50-55, 2009). Recently reported magnetic resonance images (MRIs) have shown reversible lesions in the median splenium of patients complicated with encephalitis or encephalopathy. Reversible lesions have also been observed after the administration of an antiepileptic agent, drastic weight loss, and development of metabolic abnormalities as reported by Massimo et al. (Neuroradiology 49:541-544, 2007) and Tada et al. (Neurology 63:1854-1858, 2004). Aggressive therapy for such lesions is not considered necessary because most disappear without neurologic aftereffects. However, the clinical significance and pathogenesis of the condition remain largely unknown. We present the first known report of a Kawasaki disease case complicated with acute myocarditis and mild encephalitis/encephalopathy with a reversible splenial lesion (MERS). These findings may be valuable for the diagnosis and treatment of affected patients.

Acute urinary retention in a 23-year-old woman with mild encephalopathy with a reversible splenial lesion: a case report

INTRODUCTION

Patients with clinically mild encephalitis/encephalopathy with a reversible splenial lesion present with relatively mild central nervous system disturbances. Although the exact etiology of the condition remains poorly understood, it is thought to be associated with infective agents. We present a case of a patient with mild encephalitis/encephalopathy with a reversible splenial lesion, who had the unusual feature of acute urinary retention.

CASE PRESENTATION

A 23-year-old Japanese woman developed mild confusion, gait ataxia, and urinary retention seven days after onset of fever and headache. Magnetic resonance imaging demonstrated T2 prolongation in the splenium of the corpus callosum and bilateral cerebral white matter. These magnetic resonance imaging abnormalities disappeared two weeks later, and all of the symptoms resolved completely within four weeks. Except for the presence of acute urinary retention (due to underactive detrusor without hyper-reflexia), the clinical and radiologic features of our patient were consistent with those of previously reported patients with mild encephalitis/encephalopathy with a reversible splenial lesion. To the best of our knowledge, this is the first report of acute urinary retention recognized in a patient with mild encephalitis/encephalopathy with a reversible splenial lesion.

CONCLUSION

Our findings suggest that mild encephalitis/encephalopathy with a reversible splenial lesion can be associated with impaired bladder function and indicate that acute urinary retention in this benign disorder should be treated immediately to avoid bladder injury.

Reversible cytotoxic oedema in the splenium of the corpus callosum related to tetracycline therapy

We report a symptomatic girl with reversible circumscribed cytotoxic oedema in the splenium of the corpus callosum (CC) that occurred, to our knowledge, for the first time in relation to tetracycline treatment. After stopping tetracycline therapy the girl recovered completely and the CC lesion, clearly visible on diffusion-weighted MR imaging (DWI), disappeared. Reversible circumscribed cytotoxic oedema (CCO) of the splenium of the CC is a well-defined entity that is found to be associated with administration of antiepileptic drugs, alterations in therapy using arginin-vasopressin and metronidazole or infections with influenza and rotavirus. CCO of splenium of the CC is clearly visible on DWI, shows no enhancement after administration of contrast medium and is completely reversible in most cases.

Reversible splenium lesion of the corpus callosum in hemorrhagic fever with renal failure syndrome

This is the first case of virus-associated encephalitis/encephalopathy in which the pathogen was Hantaan virus. A 53-yr-old man presented fever, renal failure and a hemorrhagic tendency and he was diagnosed with hemorrhagic fever with renal failure syndrome (HFRS). In the course of his illness, mild neurologic symptoms such as dizziness and confusion developed and magnetic resonance images revealed a reversible lesion in the splenium of the corpus callosum. This case suggests that HFRS patients with neurologic symptoms like dizziness and mental slowing should be considered to have structural brain lesions and to require brain imaging studies.

Reversible splenial lesion syndrome in cerebral malaria

A 71-year-old Caucasian man living in Congo was investigated by serial magnetic resonance imaging (MRI) after having presented cerebral malaria due to Plasmodium falciparum. The clinical picture was characterized initially by coma and seizures. The patient developed multiple organ failure. There was, at 4 months follow-up only, a minimal neurological improvement consistent with minimally conscious state. The first cerebral MRI on day 17 showed a lesion of the splenium of corpus callosum with high signal intensity on DWI and FLAIR sequence and reduced ADC, and small cortical infarcts in the internal occipital regions. Follow-up MRI obtained 36 days later showed a complete resolution of splenial lesion, though without clinical improvement. Cerebral malaria should be added to the list of possible causes of reversible lesion of the splenium of corpus callosum.