Acute hemorrhagic leukoencephalitis: recovery and reversal of magnetic resonance imaging findings in a child

From Gut Microbiomes to Infectious Pathogens: Neurological Disease Game Changers

Gut microbiota and infectious diseases affect neurological disorders, brain development, and function. Compounds generated in the gastrointestinal system by gut microbiota and infectious pathogens may mediate gut-brain interactions, which may circulate throughout the body and spread to numerous organs, including the brain. Studies shown that gut bacteria and disease-causing organisms may pass molecular signals to the brain, affecting neurological function, neurodevelopment, and neurodegenerative diseases. This article discusses microorganism-producing metabolites with neuromodulator activity, signaling routes from microbial flora to the brain, and the potential direct effects of gut bacteria and infectious pathogens on brain cells. The review also considered the neurological aspects of infectious diseases. The infectious diseases affecting neurological functions and the disease modifications have been discussed thoroughly. Recent discoveries and unique insights in this perspective need further validation. Research on the complex molecular interactions between gut bacteria, infectious pathogens, and the CNS provides valuable insights into the pathogenesis of neurodegenerative, behavioral, and psychiatric illnesses. This study may provide insights into advanced drug discovery processes for neurological disorders by considering the influence of microbial communities inside the human body.

Neurological Manifestations of Infectious Diseases: Insights From Recent Cases

This narrative review examines the complex connection between infectious diseases and their neurological effects. It provides a detailed analysis of recent instances and insights derived from various pathogens. As we explore the realm of infectious agents, including viruses, bacteria, parasites, and fungi, a thorough and diverse analysis reveals the intricacies of neurological problems. The review begins by examining viral infections, specifically focusing on how viruses invade the neurological system and its subsequent effects. Significant instances from recent widespread disease outbreaks function as instructive benchmarks, highlighting the progressing comprehension of these ever-changing interconnections. The article examines the complex pathophysiology of neurological problems caused by bacterial infections. It presents current cases that illustrate the various ways these complications might manifest and the difficulties faced in their therapeutic management. Parasitic and fungal infections, which are typically overlooked, are being carefully examined to emphasize their distinct role in causing neurological complications. The mentioned cases highlight the importance of being thoroughly aware of these less-explored areas ranging from protozoan parasites to opportunistic fungal infections. In addition to the immediate effects caused by infectious agents, the review investigates autoimmune responses activated by infections. It provides a detailed examination of specific instances that shed light on the complex relationship between viral triggers and future neurological problems. This text elaborates on the intricacy of autoimmune-related neurological issues, highlighting the necessity for a comprehensive approach to diagnosing and treating them. The narrative next redirects its attention to the diagnostic difficulties that arise when interpreting the neurological symptoms of viral disorders. This article provides a thorough examination of existing diagnostic tools, along with an investigation into new technologies that have the potential to improve our capacity to identify and comprehend complex presentations. This debate connects to the following examination of treatment methods, where current cases that showcase successful interventions are carefully examined to extract valuable insights into good clinical management. The discussion focuses on the public health implications of preventive efforts against infectious infections, including their neurological consequences. The story emphasizes the link between infectious diseases and overall societal health, advocating for a proactive strategy to reduce the impact of neurological complications. The abstract concludes by providing a prospective viewpoint, highlighting areas of research that still need to be addressed, and suggesting potential future avenues. This narrative review seeks to provide a comprehensive resource for physicians, researchers, and public health professionals dealing with the complex field of neurological manifestations in infectious diseases. It combines recent examples, synthesizes current information, and offers a holistic perspective.

Paediatric acute haemorrhagic leukoencephalitis

We report a case of a preschool age girl, previously healthy, referred to our hospital on ventilatory support with a history of vomiting, headache, and rapid neurological worsening within 24 hours in the form of seizures, encephalopathy and loss of consciousness. On presentation, she was deeply comatose with dilated non-reactive pupils, absent brainstem reflexes and flaccid quadriplegia. Diagnosis of acute haemorrhagic leukoencephalitis was considered based on laboratory and neuroimaging findings. MRI of the brain showed fluffy white matter hyperintensities and microhaemorrhages in bilateral cerebral hemispheres and thalami. Aggressive treatment with methylprednisolone, plasmapheresis and intravenous immunoglobulin showed dramatic improvement with no neurological sequelae. Our case is unique in a way that despite the hyperacute onset and rapid deterioration, with a fulminant course in the intensive care unit, the child recovered dramatically with aggressive management.

A Rare Case of Acute Hemorrhagic Leukoencephalitis in a Neonate

Acute hemorrhagic leukoencephalitis (AHLE) is a fulminant demyelinating disease associated with severe inflammation of the white matter. In this article, we reported a case of previously healthy 27 days old baby admitted to the hospital with fever, excessive crying, seizures, and respiratory distress. A diagnosis of AHLE was made based on the clinical and radiological findings. The infant patient was managed in the neonatal intensive care unit; however, he died unfortunately on the 35th day of his life. Although this highly fatal disease is very rare in this age group, early diagnosis can help in reducing morbidity and mortality.

Fatal Acute Hemorrhagic Leukoencephalitis Following Immunization Against Human Papillomavirus in a 14-Year-Old Boy

Human papilloma virus (HPV) is a prevalent pathogen whose persistent infection can lead to a variety of cancers. To protect against this threat, an HPV vaccine has been developed and is routinely administered to adolescents. The HPV vaccine has a reassuring safety profile, but reports have emerged of acute disseminated encephalomyelitis following its administration. Acute hemorrhagic leukoencephalitis (AHLE) is a severe inflammatory disease of the central nervous system and the most fulminant form of ADEM. We report a previously healthy 14-year-old boy who developed headache, fatigue, focal weakness, and confusion 3 weeks after receiving the HPV vaccine. Neuroimaging demonstrated multifocal demyelination. Despite treatment with high-dose steroids, his encephalopathy worsened. He developed severe cerebral edema and died of cerebral herniation. Postmortem histology revealed perivenular sleeves of tissue damage, myelin loss surrounding small parenchymal vessels, and diffuse hemorrhagic necrosis, consistent with AHLE. This is the first report of AHLE following HPV vaccination.

All the More Reason to Get a Flu Shot: An Instance of Acute Hemorrhagic Leukoencephalitis in a Patient With Influenza A

Acute hemorrhagic leukoencephalitis (AHLE) is a rare demyelinating disease of the central nervous system that typically follows a viral or bacterial respiratory infection. We report the first described case of AHLE following influenza A (H3N2) in an otherwise healthy 15-year-old girl with no relevant past medical history who initially presented to the emergency department (ED) by emergency medical services (EMS) with decorticate posturing and right gaze deviation after being found unresponsive at home. Subsequent testing for Influenza A H3N2 via viral polymerase chain reaction (PCR) was positive. Clinical correlation and brain MRI confirmed AHLE. At follow-up three months after discharge, she was found to have intellectual functioning in the extremely low range and she still had deficits in motor skills eight months after discharge. While the patient was reportedly up-to-date on her routine scheduled childhood vaccinations, she had not received her annual influenza vaccination that year. Pediatric infectious disease physicians and neurologists should consider the diagnosis of AHLE in unvaccinated, previously healthy patients with new and rapid onset of neurological symptoms following influenza infection. 

Acute Hemorrhagic Leukoencephalopathy: Pathological Features and Cerebrospinal Fluid Cytokine Profiles

BACKGROUND

Acute hemorrhagic leukoencephalopathy is a rare encephalopathy of unknown etiology, causing fulminant, hemorrhagic central nervous system demyelination with high mortality. It is unclear whether acute hemorrhagic leukoencephalopathy is an entirely distinct entity from acute disseminated encephalomyelitis.

PATIENTS AND METHODS

We report two patients with rapidly progressive neurological illness resulting in raised intracranial pressure and coma, with biopsy-proven acute hemorrhagic leukoencephalopathy (perivascular hemorrhages and demyelination, predominantly neutrophil infiltrates).

RESULTS

Acute cerebrospinal fluid showed pronounced T cell-associated cytokine elevation (interleukins 6, 8, and 17A) and CCL2 or CCL3, higher than in patients with acute disseminated encephalomyelitis, but no B cell-associated cytokine elevation.

CONCLUSION

Improved understanding of the immune process may provide rationale for use of anticytokine biologic agents.

Fulminant acute disseminated encephalomyelitis in children

Acute disseminated encephalomyelitis (ADEM) is a typically monophasic inflammatory demyelinating disease of the central nervous system with a favorable outcome. However, 2% of ADEM involves acute hemorrhagic leukoencephalitis (AHLE), which is a fulminant and hyperacute variant of ADEM with a poor outcome and high mortality. There are limited case reports of fulminant ADEM including AHLE in children. Herein, we report two pediatric cases of fulminant ADEM. Both cases had a rapid deterioration of consciousness, repetitive seizures, and brain edema on neuroimaging, in addition to atypical neuroradiological findings on magnetic resonance imaging (MRI), a reversible splenial lesion in case 1, and bilateral frontal and occipital cortical lesions in case 2. Both cases were treated with early high-dose methyl-prednisolone and immunoglobulin, while therapeutic hypothermia was also initiated in case 2 after the patient exhibited a decerebrate posture and irregular breathing pattern. Both cases had a favorable outcome. Further case reports on pediatric fulminant ADEM are required to clarify the various clinical types, and to examine the efficacy of various treatment modalities for fulminant ADEM and AHLE in children.

Acute Hemorrhagic Encephalitis Responding to Combined Decompressive Craniectomy, Intravenous Immunoglobulin, and Corticosteroid Therapies: Association with Novel RANBP2 Variant

Background

Acute hemorrhagic encephalomyelitis (AHEM) is considered as a rare form of acute disseminated encephalomyelitis characterized by fulminant encephalopathy with hemorrhagic necrosis and most often fatal outcome.

Objective

To report the association with Ran Binding Protein (RANBP2) gene variant and the response to decompressive craniectomy and high-dose intravenous methylprednisolone (IVMP) in life-threatening AHEM.

Design

Single case study.

Case report

A 6-year-old girl known to have sickle cell disease (SCD) presented an acquired demyelinating syndrome (ADS) with diplopia due to sudden unilateral fourth nerve palsy. She received five pulses of IVMP (30 mg/kg/day). Two weeks after steroid weaning, she developed right hemiplegia and coma. Brain magnetic resonance imaging showed a left frontal necrotico-hemorrhagic lesion and new multifocal areas of demyelination. She underwent decompressive craniotomy and evacuation of an ongoing left frontoparietal hemorrhage. Comprehensive investigations ruled out vascular and infectious process. The neurological deterioration stopped concomitantly with combined neurosurgical drainage of the hematoma, decompressive craniotomy, IVMP, and intravenous immunoglobulins (IVIG). She developed during the following months Crohn disease and sclerosing cholangitis. After 2-year follow-up, there was no new neurological manifestation. The patient still suffered right hemiplegia and aphasia, but was able to walk. Cognitive/behavioral abilities significantly recovered. A heterozygous novel rare missense variant (c.4993A>G, p.Lys1665Glu) was identified in RANBP2, a gene associated with acute necrotizing encephalopathy. RANBP2 is a protein playing an important role in the energy homeostasis of neuronal cells.

Conclusion

In any ADS occurring in the context of SCD and/or autoimmune condition, we recommend to slowly wean steroids and to closely monitor the patient after weaning to quickly treat any recurrence of neurological symptom with IVMP. This case report, in addition to others, stresses the likely efficacy of combined craniotomy, IVIG, and IVMP treatments in AHEM. RANBP2 mutations may sensitize the brain to inflammation and predispose to AHEM.

Multiple Sclerosis

Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS) characterized by loss of motor and sensory function that results from immune-mediated inflammation, demyelination, and subsequent axonal damage.

Clinically, most MS patients experience recurrent episodes (relapses) of neurological impairment, but in most cases (60–80%) the course of the disease eventually becomes chronic and progressive, leading to cumulative motor, sensory, and visual disability, and cognitive deficits.

The course of the disease is largely unpredictable and its clinical presentation is variable, but its predilection for certain parts of the CNS, which includes the optic nerves, the brain stem, cerebellum, and cervical spinal cord, provides a characteristic constellation of signs and symptoms. Several variants of MS have been nowadays defined with variable immunopathogenesis, course and prognosis. Many new treatments targeting the immune system have shown efficacy in preventing the relapses of MS and have been introduced to its management during the last decade.

Acute disseminated encephalomyelitis presenting as a brainstem encephalitis

Acute disseminated encephalomyelitis (ADEM) is a disease characterized by inflammation and destruction of myelin. Acute hemorrhagic leukoencephalitis (AHLE) is a severe form of ADEM known for its particularly poor outcome. We present a case of a young Caucasian female who presented with drowsiness and slurred speech followed by rapid brainstem involvement resembling rhomboencephalitis. Despite multiple diagnostic tests and empiric therapy with immunosuppressants, immunoglobulins, and antimicrobials, she lost most brainstem reflexes within a few weeks and ultimately passed away. Magnetic resonance imaging (MRI) showed progression of lesions from the brainstem to eventually involve bilateral cerebral hemispheres. Autopsy and microscopic examination of the brain revealed several hemorrhagic lesions throughout the brain and rendered a diagnosis of AHLE. AHLE was initially described in 1941 and is thought to be autoimmune related, possibly related to cross reactivity between the immune system and CNS tissues like myelin. While a definitive inciting pathogen was not discovered, this case emphasizes the importance of considering AHLE in the differential diagnosis of patients with rapid loss of neurologic function and highlights an atypical presentation of ADEM/AHLE.

The diagnosis of multiple sclerosis and the various related demyelinating syndromes: a critical review

Multiple sclerosis (MS), is a chronic disease of the central nervous system (CNS) characterized by loss of motor and sensory function, that results from immune-mediated inflammation, demyelination and subsequent axonal damage. MS is one of the most common causes of neurological disability in young adults. Several variants of MS (and CNS demyelinating syndromes in general) have been nowadays defined in an effort to increase the diagnostic accuracy, to identify the unique immunopathogenic profile and to tailor treatment in each individual patient. These include the initial events of demyelination defined as clinically or radiologically isolated syndromes (CIS and RIS respectively), acute disseminated encephalomyelitis (ADEM) and its variants (acute hemorrhagic leukoencephalitis-AHL, Marburg variant, and Balo's concentric sclerosis), Schilder's sclerosis, transverse myelitis, neuromyelitis optica (NMO and NMO spectrum of diseases), recurrent isolated optic neuritis and tumefactive demyelination. The differentiation between them is not only a terminological matter but has important implications on their management. For instance, certain patients with MS and prominent immunopathogenetic involvement of B cells and autoantibodies, or with the neuromyelitic variants of demyelination, may not only not respond well but even deteriorate under some of the first-line treatments for MS. The unique clinical and neuroradiological features, along with the immunological biomarkers help to distinguish these cases from classical MS. The use of such immunological and imaging biomarkers, will not only improve the accuracy of diagnosis but also contribute to the identification of the patients with CIS or RIS who, are at greater risk for disability progression (worse prognosis) or, on the contrary, will have a more benign course. This review summarizes in a critical way, the diagnostic criteria (historical and updated) and the definitions/characteristics of MS of the various variants/subtypes of CNS demyelinating syndromes.

Acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) is an acute multifocal demyelinating disease of the central nervous system that typically follows an infectious illness. Its clinical course in most cases is monophasic; however, relapsing ADEM is rarely seen, which poses a diagnostic challenge for distinguishing this disease from multiple sclerosis (MS). Although typically encountered in children, it also occurs in adults with disease characteristics slightly different from the pediatric cases. Formerly, ADEM occurred particularly often in children with measles. However, the illness most often follows a non-descript viral or even bacterial infectious illness. ADEM occurs throughout the world, and may even be more common in less-developed countries, where MS is rare, than in developed ones, where MS is common. Children seldom get MS as opposed to adults, indicating that ADEM constitutes a distinct entity from MS. The prognosis of ADEM is generally good, but severe neurologic sequelae after ADEM are occasionally seen. In this chapter, the etiology, clinical/laboratory/radiologic characteristics, treatment options, and prognosis of ADEM are discussed.

Updates on clinically isolated syndrome and diagnostic criteria for multiple sclerosis

Clinically isolated syndrome (CIS) is a central nervous system demyelinating event isolated in time that is compatible with the possible future development of multiple sclerosis (MS). Early risk stratification for conversion to MS helps with treatment decisions. Magnetic resonance imaging (MRI) is currently the most useful tool to evaluate risk. Cerebrospinal fluid studies and evoked potentials may also be used to assess the likelihood of MS. Four clinical trials evaluating the benefits of either interferon β (IFN-β) or glatiramer acetate (GA) within the first 3 months after a high-risk CIS demonstrate decreased rates of conversion to clinically definite MS (CDMS) and a lesser degree of MRI progression with early treatment. In the 3-, 5-, and 10-year extension studies of 2 formulations of IFN-β, the decreased conversion rate to CDMS remained meaningful when comparing early treatment of CIS to treatment delayed by a median of 2 to 3 years. Diagnostic criteria have been developed based on the clinical and MRI follow-up of large cohorts with CIS and provide guidance on how to utilize clinical activity in combination with radiographic information to diagnose MS. The most recent 2010 McDonald criteria simplify requirements for dissemination in time and space and allow for diagnosis of MS from a baseline brain MRI if there are both silent gadolinium-enhancing lesions and nonenhancing lesions on the same imaging study. The diagnostic criteria for MS require special consideration in children at risk for acute disseminated encephalomyelitis (ADEM), in older adults who may have small vessel ischemic disease, and in ethnic groups that more commonly develop neuromyelitis optica (NMO).

Acute hemorrhagic encephalomyelitis in childhood: Case report and literature review

Acute disseminated encephalomyelitis (ADEM) is an inflammatory immune-mediated disorder which is more common in pediatric patients. The clinical setting is characterized by a rapid onset of encephalopathy and multifocal neurological features. Acute hemorrhagic encephalomyelitis (AHEM) is considered a rare form of ADEM. This report shows a 2-year-old patient who presented with the classical features of ADEM and after 8 weeks developed severe neurological worsening. The second magnetic resonance image (MRI) showed hemorrhagic lesions. Differences in prognosis between ADEM and AHEM justify the investigation of AHEM whenever a patient has neurological recrudescence in a known patient of ADEM.

Acute hemorrhagic leukoencephalitis with severe brainstem and spinal cord involvement: MRI features with neuropathological confirmation

Acute hemorrhagic leukoencephalitis (AHLE) is a rare and fulminant demyelinating disease considered to be the most severe form of acute disseminated encephalomyelitis (ADEM). A 70-year-old man was admitted to our emergency department (ED) after 1 week of unspecific abdominal symptoms and moderate fever in the first 3 days. Within the ED he developed a rapid onset coma and flaccid tetraparesis. Cerebrospinal fluid (CSF) analysis showed mild polymorphonuclear pleocytosis and magnetic resonance imaging (MRI) revealed supratentorial focal white matter lesions and diffuse involvement of the medulla and spinal cord. A presumptive diagnosis of ADEM was made and the patient was treated with corticosteroids followed by intravenous immunoglobulin. His neurological state did not improve and the MRI on day 8 after admission showed an increased number of lesions, mainly in the brainstem, with hemorrhagic foci. The patient died the following day and pathological features confirmed the diagnosis of AHLE. This is a unique presentation of a rare disease with detailed MRI characteristics and pathological confirmation. Although this condition is usually fatal, early recognition and aggressive therapeutic management can facilitate survival.

Acute disseminated encephalomyelitis: clinical and pathogenesis features

Acute disseminated encephalomyelitis (ADEM) is an immune-mediated disorder of the central nervous system (CNS). Disease typically starts with an abrupt onset of neurologic symptoms and signs within days to weeks after a viral infection or immunization. Neuropathological examination of the CNS in ADEM reveals involvement of white matter, with infiltration of monocytoid cells and perivenous demyelination.

Acute hemorrhagic demyelination in a murine model of multiple sclerosis

Acute hemorrhagic leukoencephalomyelitis (AHLE) is a rare neurological condition characterized by the development of acute hemorrhagic demyelination and high mortality. The pathomechanism of AHLE, as well as potential therapeutic approaches, have remained elusive due to the lack of suitable animal models. We report the first murine model of AHLE using a variation of the Theiler's Murine Encephalitis Virus (TMEV) MS model. During acute TMEV infection, C57BL/6 mice do not normally undergo demyelination. However, when 7 day TMEV infected C57BL/6 mice are intravenously administered the immunodominant CD8 T cell peptide, VP2_121–130, animals develop characteristics of human AHLE based on pathologic, MRI and clinical features including microhemorrhages, increased blood-brain barrier permeability, and demyelination. The animals also develop severe disability as assessed using the rotarod assay. This study demonstrates the development of hemorrhagic demyelination in TMEV infected C57BL/6 mice within 24 hours of inducing this condition through intravenous administration of CD8 T cell restricted peptide. This study is also the first demonstration of rapid demyelination in a TMEV resistant non-demyelinating strain without transgenic alterations or pharmacologically induced immunosuppression.

[Acute disseminated encephalomyelitis and severe post-infectious encephalitis]

L’encéphalomyélite aiguë disséminée, acute disseminated encephalomyelitis, (ADEM), est une maladie inflammatoire démyélinisante du système nerveux central (SNC). Également appelée encéphalite post-infectieuse, elle est liée à un mécanisme auto-immun et s’installe typiquement dans les suites d’une infection après un intervalle libre de deux à 30 jours. L’ADEM est caractérisée cliniquement par un tableau d’encéphalopathie aiguë avec signes neurologiques multifocaux. Les patients peuvent nécessiter une admission en réanimation du fait de troubles de la conscience, de crises convulsives ou d’une tétraplégie. L’analyse du liquide céphalorachidien peut montrer une méningite lymphocytaire, mais on ne retrouve pas d’infection évolutive du SNC. Il n’existe pas de marqueur spécifique de la maladie et l’imagerie par résonance magnétique cérébrale est essentielle au diagnostic, permettant de mettre en évidence des lésions multifocales de la substance blanche du SNC sur les séquences T2 et FLAIR. Le traitement de l’ADEM est basé sur les corticoïdes fortes doses, éventuellement associés aux immunoglobulines polyvalentes ou aux échanges plasmatiques. Le pronostic est généralement favorable sous traitement, des récurrences peuvent néanmoins survenir dans l’évolution.

Use of therapeutic plasma exchange in the management of acute hemorrhagic leukoencephalitis: a case report and review of the literature

BACKGROUND

Acute hemorrhagic leukoencephalitis (AHLE) is a rare, fatal, central nervous demyelinating disease characterized by a rapid fulminant clinical course. Successful management requires early diagnosis, aggressive management of cerebral edema, and immunosuppression. Therapeutic plasma exchange (TPE) is infrequently used and commences after initial management fails.

CASE REPORT

A 31-year-old man presented with right arm weakness, whose symptoms rapidly progressed to hemiplegia and aphasia. The patient was initially managed with glucocorticosteroids. Decompressive craniotomy and brain biopsies were performed when his intracranial pressure increased. Brain biopsy findings were consistent with AHLE. Mycoplasma pneumonia immunoglobulin G and immunoglobulin M serologies revealed recent infection. Despite surgical and medical management, he decompensated on Day 11, and TPE was initiated. The patient received a total of 10 TPE treatments. On the fourth day of TPE treatment, he was extubated. Twenty-one days after TPE began, he was ambulating with near normal muscle strength and was discharged. Four months after initial presentation, the patient has normal strength and is working full-time.

CONCLUSIONS

AHLE has a fulminant course requiring accurate and rapid diagnosis. Successful therapy requires aggressive management of intracranial pressure and immunosuppression. Two other reports of AHLE document successful management with TPE. Each of these patients survived with minimal neurologic impairments. Given the likely immune-mediated nature of this disease, combined treatment of steroids, surgery, and TPE may lead to shorter hospital stays and improved neurologic outcomes. Clinical studies are needed to further study the effect of TPE on neurologic outcome in AHLE.

Treatment leading to dramatic recovery in acute hemorrhagic leukoencephalitis

The clinical course, neuroimaging, neuropathological features, and management of a 7-year-old girl with acute hemorrhagic leukoencephalitis are reported. Treatment with subtotal bifrontal craniectomies for symptoms of imminent uncal herniation followed by high-dose corticosteroid therapy was associated with dramatic clinical recovery. This report highlights the utility of aggressive intervention in acute hemorrhagic leukoencephalitis, an otherwise fatal disorder.

Post-infectious encephalomyelitis

The term post-infectious encephalomyelitis (PIEM) is frequently used interchangeably with acute disseminated encephalomyelitis (ADEM), although technically PIEM occurs after a known infection whereas with ADEM there is no antecedent infection. PIEM represents one of the primary demyelinating disorders of the central nervous system, along with multiple sclerosis and Devic's disease. There is no specific diagnostic test for any of these conditions and at onset it may be difficult to differentiate between ADEM and the first attack of multiple sclerosis. However, there are clinical and magnetic resonance imaging features that allow differentiation between PIEM/ADEM and a relapsing disease such as multiple sclerosis. Some patients improve spontaneously; most improve with methylprednisolone. If that fails, plasma exchange or intravenous immunoglobulin may be effective.

Acute hemorrhagic leukoencephalitis: neuroimaging features and neuropathologic diagnosis

A case of biopsy-proven acute hemorrhagic leukoencephalitis is reported. The early computed tomography scans showed extensive bilateral hypodensities with mass effects and foci of microhemorrhages. Bilateral asymmetric hyperintensities in the mesiotemporal and frontal lobes and massive edema were found on T2-weighted and fluid-attenuated inversion recovery magnetic resonance images in a pattern classic for herpes simplex encephalitis. This fulminant demyelinating disease progresses to coma and death within days. Early diagnosis with neuroimaging studies and rapid correlation with the clinical findings of this disease are vital for the institution of potentially lifesaving treatments.

Acute disseminated encephalomyelitis in childhood: epidemiologic, clinical and laboratory features

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) is a central nervous system demyelinating disease that usually follows an apparently benign infection in otherwise healthy young persons. The epidemiology, infectious antecedents and pathogenesis of ADEM are poorly characterized, and some ADEM patients are subsequently diagnosed with multiple sclerosis (MS).

METHODS

We retrospectively (1991-1998) and prospectively (1998-2000) studied all persons aged < 20 years diagnosed with ADEM from the 3 principal pediatric hospitals in San Diego County, CA, during 1991-2000. Acute neurologic abnormalities and imaging evidence of demyelination were required for study inclusion. Epidemiologic variables, risk factors, clinical course, laboratory and radiographic findings, neuropathology and treatment data were analyzed. Interleukin (IL)-12, interferon-gamma (IFN-gamma) and IL-10 were assayed in blinded manner on cerebrospinal fluid (CSF) obtained prospectively from a subset of ADEM cases and compared with CSF from patients with enteroviral (EV) meningoencephalitis confirmed by polymerase chain reaction (PCR) and controls without pleocytosis.

RESULTS

Data were analyzed on 42 children and adolescents diagnosed with ADEM during 1991-2000, and CSF IL-12, IFN-gamma and IL-10 levels were compared among ADEM (n = 14), EV meningoencephalitis (n = 14) and controls without pleocytosis (n = 28). Overall incidence of ADEM was 0.4/100,000/year; incidence quadrupled during 1998-2000 compared with earlier years. No gender, age stratum, ethnic group or geographic area was disproportionately affected. A total of 4 (9.5%) patients initially diagnosed with ADEM were subsequently diagnosed with MS after multiple episodes of demyelination. Although most children eventually recovered, 2 died, including 1 of the 3 ultimately diagnosed with MS. Magnetic resonance imaging was required for diagnosis among 74% of patients; computerized tomography findings were usually normal. Patients with EV had significantly higher mean CSF IFN-gamma (P = 0.005) and IL-10 (P = 0.05) than patients with ADEM and controls without CSF pleocytosis. CSF from ADEM patients had CSF cytokine values statistically similar to those of 3 patients subsequently diagnosed with MS.

CONCLUSIONS

ADEM is a potentially severe demyelinating disorder likely to be increasingly diagnosed as more magnetic resonance imaging studies are performed on patients with acute encephalopathy. Further characterization of the central nervous system inflammatory response will be needed to understand ADEM pathogenesis, to improve diagnostic and treatment strategies and to distinguish ADEM from MS.

Acute haemorrhagic leukoencephalopathy: two case reports and review of the literature

Acute haemorrhagic leukoencephalopathy is a rare, rapidly progressive disease of cerebral white matter associated with high fatality. The few known patients surviving have all been treated with early instigation of immuno-modulatory therapy. Here we describe two cases of this disease and underscore the importance of considering this diagnosis in the differential for any individual presenting with progressive neurological signs, an antecedent flu-like illness, and early changes on CT showing widespread disease of white matter.

Possible acute hemorrhagic leukoencephalitis manifesting as intracerebral hemorrhage on computed tomography--case report

A 15-year-old girl presented with meningeal irritation and bilateral cerebral signs after contracting influenza. A lumbar puncture revealed bloody cerebrospinal fluid and polymorphonuclear predominant pleocytosis with an elevated protein level and normal glucose level. Computed tomography showed a hematoma in the right basal ganglia and lateral ventricles. Symmetrical low density areas were also noted in the bilateral white matter. The preliminary diagnosis was hemorrhagic cerebrovascular disease of unknown cause. However, her neurological condition deteriorated. Magnetic resonance (MR) imaging showed diffuse high intensity signals in the bilateral white matter and small spotty lesions, indicating hemorrhages in various stages. The final diagnosis was acute hemorrhagic leukoencephalitis (AHL). However, high-dose steroid administration and plasmapheresis failed to improve her condition. Hypothermia could not control her intracranial pressure and she died 12 days after admission. The neuroimaging findings indicated the histological characteristics of AHL, but the hematoma formation is rare. AHL is a fulminant form of brain demyelination and can be fatal, so early diagnosis and aggressive treatment are important for successful recovery. Therefore, early investigation by MR imaging is necessary.

Pediatric acute hemorrhagic leukoencephalitis: report of a surviving patient and review

Acute hemorrhagic leukoencephalitis (AHLE) is a rare, fulminant CNS demyelinating condition usually diagnosed at autopsy. We report the clinical, laboratory, radiographic, and pathologic features of the first nonfatal case of pediatric AHLE confirmed by brain biopsy. Pathologic diagnosis of this condition may be critical to exclude more-common processes and to expedite the decision to administer high-dose corticosteroid therapy, which is potentially lifesaving.

Acute haemorrhagic leucoencephalitis complicating sepsis

A case of acute haemorrhagic leucoencephalitis presenting as fatal septic encephalopathy is reported. The clinical features of this condition are reviewed and the potential for earlier diagnosis is considered.

Disorders that mimic central nervous system infections

Many noninfectious diseases can cause signs, symptoms, and cerebrospinal fluid (CSF) abnormalities simulating central nervous system (CNS) infection. Infection usually can be excluded in these cases by the judicious use of serologic tests and CSF stains and cultures. Then, the correct diagnosis is typically suggested by the history and the concomitant presence of clinical and laboratory evidence of disease in other organ systems. Occasionally, particularly when such evidence is absent, the distinction requires meningeal or brain biopsy.

Fulminant form of acute disseminated encephalomyelitis: successful treatment with hypothermia

We described herein a case of the fulminant form of acute disseminated encephalomyelitis (ADEM) that developed after mycoplasma pneumonia. A 28-year-old man who presented with fever, headache, and writing difficulty was admitted to our hospital in August 1997. He developed hernia on the 3rd hospital day. Surgical decompression and intravenous prednisolone failed to halt his progressive deterioration. We introduced systemic hypothermia and he has shown marked recovery; despite having Broca's type aphasia, he could comprehend spoken language and communicate with others by gesture. Head MRI demonstrated diffuse high signals over the white matter on fluid attenuated inversion recovery (FLAIR) images, which suggested extensive demyelination. The clinical course, imaging studies and presence of polymorphonuclear dominant leucocytosis in the blood and CSF in the patient are somewhat similar to findings in acute hemorrhagic leukoencephalitis, however, the result of a brain biopsy was inconclusive. The fulminant form of ADEM is usually fatal. Treatments such as corticosteroids, intravenous immunoglobulin, and surgical decompression have been performed to improve the prognosis. Our case results indicate that hypothermia, which suppresses both brain edema and immune response, may be included in the repertoire of treatment for the fulminant form of ADEM.