Clinical outcome of children presenting with a severe manifestation of acute disseminated encephalomyelitis

The Impact of Neuroimmunologic Disease and Developing Nervous System

Over the last two decades, neuroimmunologic disorders of childhood have been increasingly described, phenotyped, and treated. These disorders remain rare in the general population and while sharing common therapeutic interventions due to their immune pathophysiology, are heterogeneous with regard to presentation and risk of recurrence. As such, the impact of these disorders on the developing brain has come into the forefront of emerging research in pediatric neuroimmunology. Investigations into the singular impact of monophasic disease on long-term development and the impact of early and aggressive disease-modifying therapy in relapsing conditions are quickly becoming areas of ripe investigation as the field's most optimal way to treat and monitor these conditions over time. Although critically important in evaluating the developing brain, research has been heterogeneous among these diseases and limited by small cohort size. This narrative review details the role of common neuroimmunologic disorders in long-term neurological and cognitive outcomes in children as they develop.

Transverse myelitis in children and adults

Transverse myelitis is a noncompressive myelopathy of inflammatory origin. The causes are broad, ranging from infective or toxic to immuno-mediated etiology. They can be manifestations of systemic diseases, such as sarcoidosis and systemic lupus erythematous, or phenotypes of neuroinflammation; in a portion of cases, the etiology remains unknown, leading to the designation idiopathic. The clinical presentation of transverse myelitis depends on the level of spinal cord damage and may include sensorimotor deficits and autonomic dysfunction. The age of onset of the disorder can impact the symptoms and outcomes of affected patients, with differences in manifestation and prognosis between children and adults. Spinal cord magnetic resonance imaging and cerebrospinal fluid examination are the main diagnostic tools that can guide clinicians in the diagnostic process, even though the search for antibodies that target the structural components of the neural tissue (anti-aquaporin4 antibodies and anti-myelin-oligodendrocyte antibodies) helps in the distinction among the immune-mediated phenotypes. Management and outcomes depend on the underlying cause, with different probabilities of relapse according to the phenotypes. Hence, immunosuppression is often recommended for the immune-mediated diseases that may have a higher risk of recurrence. Age at onset has implications for the choice of treatment.

Prognostic factors for functional recovery in children with moderate to severe acute disseminated encephalomyelitis

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) is an immune-mediated encephalopathy with heterogeneous disease courses. However, clinical characteristics for a prognostication of functional recovery from acute episodes of ADEM remain limited. The study aims to characterize the clinical presentations and neuroimaging findings of children with poor functional recoveries from acute episodes of moderate to severe ADEM.

METHODS

The multicenter retrospective cohort study included children under 18 years of age who presented with moderate to severe ADEM (modified Rankin Scale [mRS] ≥ 3 at nadir) from 2002 to 2019. Children were assigned to a good recovery group (mRS ≤ 2) and a poor recovery group (mRS ≥ 3) after mean 4.3 months of follow-up. The clinical presentations and the distribution of brain lesions on magnetic resonance imaging were compared between the two groups by the t-test for numerical variables and Fisher's exact test for categorical variables. Analyses of logistic regression were conducted and significant variables in the multivariate model were examined by the receiver operating characteristic curve for the prediction of functional recovery.

RESULTS

Among the 73 children with moderate to severe ADEM, 56 (77%) had good functional recoveries and 17 (23%) showed poor functional recoveries. Children with poor recoveries had a lower rate of prodromal headache (12% vs. 39%, p = 0.04), and presented with higher proportions of dystonia (29% vs. 9%, p = 0.046), myoclonus (24% vs. 2%, p = 0.009), and cerebellar lesions on neuroimages (59% vs. 23%, p = 0.01). The multivariate analyses identified that a lack of prodromal headache (OR 0.1, 95% CI 0.005 - 0.7, p = 0.06) and the presentations of myoclonus (OR 21.6, 95% CI 1.7 - 874, p = 0.04) and cerebellar lesions (OR 4.8, 95% CI 1.3 - 19.9, p = 0.02) were associated with poor functional recoveries. These three factors could prognosticate poor outcomes in children with moderate to severe ADEM (area under the receiver operating characteristic curve 0.80, 95% CI 0.68 - 0.93, p = 0.0002).

CONCLUSION

Nearly one-fourth of children with moderate to severe ADEM had a poor functional recovery from acute episodes, who were characterized by a lack of prodromal headache, the presentation of myoclonus, and the neuroimaging finding of cerebellar lesions. The clinical variables associated with poor functional recoveries could assist in the planning of immunotherapies during hospitalization for a better outcome in moderate to severe ADEM.

School performance and psychiatric morbidity 6 years after pediatric acute disseminated encephalomyelitis: A nationwide population-based cohort study

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) can cause cognitive impairment in children. However, long-term consequences for school performance and psychiatric morbidity have never been characterized. Our aim was to investigate long-term school performance and psychiatric morbidity after pediatric ADEM (<18 years).

METHODS

We identified all children with ADEM 2008-2015 in Denmark using hospital diagnostic codes for acquired demyelinating syndromes. We reviewed all medical records to validate ADEM including blinded MRI review. Reference children were the entire pediatric (<18 years) population or randomly sampled sex and age-matched reference children. Outcomes were from nationwide population-based registers on special needs assistance, grade point average, highest completed education, in-hospital psychiatric hospital diagnoses, out-of-hospital psychiatric consultations or psychopharmacological drug prescriptions.

RESULTS

52 children had ADEM (median onset age: 5.5 years; median age at follow-up end: 13.4 years). Secondary school grade point average was similar among children with ADEM and reference children; however, children with ADEM had increased psychiatric morbidity (hazard ratio = 2.4; 95% confidence interval = 1.2-5.1; p = 0.02), primarily due to increased drug prescriptions for sleep problems and depression.

CONCLUSION

Children with prior ADEM have increased sleep problems and possibly also depression; however, school performance is seemingly unaffected. Clinicians should consider problems with sleep and mood at follow-up.

Diagnostic Considerations in Acute Disseminated Encephalomyelitis and the Interface with MOG Antibody

Acute disseminated encephalomyelitis (ADEM) is a common yet clinically heterogenous syndrome characterized by encephalopathy, focal neurologic findings, and abnormal neuroimaging. Differentiating ADEM from other demyelinating disorders of childhood can be difficult and appropriate interpretation of the historical, clinical, and neurodiagnostic components of a patient's presentation is critical. Myelin oligodendrocyte glycoprotein (MOG) antibody-associated diseases are a recently recognized set of disorders, which include ADEM presentations, among other phenotypes. This review article discusses the clinical diagnosis, differential diagnosis, interpretation of data, and treatment/prognosis of this unique syndrome with distinctive review of the spectrum of MOG antibodies.

Clinical and neuroradiological differences of paediatric acute disseminating encephalomyelitis with and without antibodies to the myelin oligodendrocyte glycoprotein

BACKGROUND

Myelin oligodendrocyte glycoprotein (MOG) antibodies have been recently described in children with acute disseminating encephalomyelitis (ADEM), but the clinical and neuroradiological characterisation of this subgroup is lacking.

OBJECTIVE

To compare the clinical and neuroradiological features of paediatric ADEM with and without MOG antibodies.

METHODS

Clinical course, cerebrospinal fluid (CSF)-, MRI studies, outcome and MOG status of 33 paediatric ADEM prospectively studied were reviewed.

RESULTS

MOG antibodies (median 1:2560; range 1:160-1:20 480) were detected in 19 children with ADEM. The majority of children showed a decline of serum MOG-IgG titres over time. Children with MOG antibodies did not differ in their age at presentation, sex ratio, the presence of oligoclonal bands, clinical symptoms or initial severity, apart from a higher CSF cell count (p=0.038), compared with children without MOG antibodies. In addition, further relapsing demyelinating episodes associated with MOG antibodies were observed only in children with MOG antibodies. All 19 children with MOG antibodies had a uniform MRI pattern, characterised by large, hazy and bilateral lesions and the absence of atypical MRI features (eg, mainly small lesions, well-defined lesions), which was significantly different compared to that of children without MOG antibodies (p=0.003; and p=0.032, respectively). In addition, children with MOG antibodies had involvement of more anatomical areas (p=0.035) including the myelon characterised by a longitudinally extensive transverse myelitis (p=0.003), more often a complete resolution of lesions (p=0.036) and a better outcome (p=0.038).

CONCLUSIONS

Patients with ADEM with MOG antibodies in our cohort had a uniform MRI characterised by large, bilateral and widespread lesions with an increased frequency of longitudinal extensive transverse myelitis and a favourable clinical outcome in contrast to children lacking MOG antibodies.

Long-term neurocognitive outcome and quality of life in pediatric acute disseminated encephalomyelitis

BACKGROUND

Acute disseminated encephalomyelitis is an inflammatory-demyelinating disorder of the central nervous system usually with a monophasic course and a favorable neurological outcome. Long-term neurocognitive sequelae and quality of life have not yet been fully investigated.

AIM

To examine neurocognitive outcome and quality of life in pediatric monophasic acute disseminated encephalomyelitis.

METHODS

Of the 36 patients diagnosed with acute disseminated encephalomyelitis at our institution, six were lost to follow-up and eight relapsed (two with multiphasic forms and six with multiple sclerosis). The outcome of the 22 remaining patients was evaluated using four subscales of the Wechsler Intelligence Scales for estimation of IQ, a battery of neuropsychological tests, and semistructured and PedsQL questionnaires for quality of life. The effect of age at onset, neuroradiological recovery, and time elapsed from the acute event on outcome was also investigated.

RESULTS

Estimated IQ, neuropsychological mean group scores, and quality of life at follow-up were within the normal range, but 23% of the patients had pathological scores in various neuropsychological functions, among which attention was the most clearly affected. The neuroradiological recovery was not correlated with the result of the neuropsychological tests. Age at onset correlated with linguistic skills, whereas the time elapsed from the acute event had a significant effect on attention tasks: scores were worse in the group of patients with a follow-up shorter than 7 years.

CONCLUSION

Our results suggest that pediatric monophasic acute disseminated encephalomyelitis has a favorable neurocognitive outcome. Patients with longer follow-up had a better outcome, suggesting a neurocognitive course that is different from that of multiple sclerosis and a potential for long-term recovery of affected functions.

Fatigue and depression in children with demyelinating disorders

Fatigue and depression have been shown to be significant problems in children with multiple sclerosis. The rate at which these conditions occur in children with other acquired demyelinating syndromes is unknown. In this cross-sectional study, the authors evaluated 49 children with demyelinating disorders (multiple sclerosis and acute disseminated encephalomyelitis) and 92 healthy controls for depression and/or fatigue using the Behavior Assessment System for Children, Second Edition behavior and mood rating scale and Varni PedsQL Multidimensional Fatigue Scale. The parents of acquired demyelinating syndrome patients were more likely to report elevated depressive symptoms (30.8% vs 10.8%, P = .008). Elevated parent and self-reported total fatigue (25% vs 0%, P < .001, 26.7% vs 8.6%, P = .024) was seen in the patient cohort. The authors conclude that fatigue and depression are far more common in children with acquired demyelinating syndromes than in controls. Clinical attention to and implementation of effective therapies oriented toward these conditions in children with acquired demyelinating syndromes is needed.

International Pediatric Multiple Sclerosis Study Group criteria for pediatric multiple sclerosis and immune-mediated central nervous system demyelinating disorders: revisions to the 2007 definitions

BACKGROUND

There has been tremendous growth in research in pediatric multiple sclerosis (MS) and immune mediated central nervous system demyelinating disorders since operational definitions for these conditions were first proposed in 2007. Further, the International Pediatric Multiple Sclerosis Study Group (IPMSSG), which proposed the criteria, has expanded substantially in membership and in its international scope.

OBJECTIVE

The purpose of this review is to revise the 2007 definitions in order to incorporate advances in delineating the clinical and neuroradiologic features of these disorders.

METHODS

Through a consensus process, in which input was sought from the 150 members of the Study Group, criteria were drafted, revised and finalized. Final approval was sought through a web survey.

RESULTS

Revised criteria are proposed for pediatric acute disseminated encephalomyelitis, pediatric clinically isolated syndrome, pediatric neuromyelitis optica and pediatric MS. These criteria were approved by 93% or more of the 56 Study Group members who responded to the final survey.

CONCLUSIONS

These definitions are proposed for clinical and research purposes. Their utility will depend on the outcomes of their application in prospective research.

Acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis is an immune-mediated inflammatory and demyelinating disorder of the central nervous system, commonly preceded by an infection. It principally involves the white matter tracts of the cerebral hemispheres, brainstem, optic nerves, and spinal cord. Acute disseminated encephalomyelitis mainly affects children. Clinically, patients present with multifocal neurologic abnormalities reflecting the widespread involvement in central nervous system. Cerebrospinal fluid may be normal or may show a mild pleocytosis with or without elevated protein levels. Magnetic resonance image (MRI) shows multiple demyelinating lesions. The diagnosis of acute disseminated encephalomyelitis requires both multifocal involvement and encephalopathy by consensus criteria. Acute disseminated encephalomyelitis typically has a monophasic course with a favorable prognosis. Multiphasic forms have been reported, resulting in diagnostic difficulties in distinguishing these cases from multiple sclerosis. In addition, many inflammatory disorders may have a similar presentation with frequent occurrence of encephalopathy and should be considered in the differential diagnosis of acute disseminated encephalomyelitis.

Therapies for multiple sclerosis: considerations in the pediatric patient

Current and emerging therapies for multiple sclerosis (MS) offer promise for improved disease control and long-term clinical outcome. To date, these therapies have been evaluated solely in the context of adult MS. However, onset of MS in children is being increasingly recognized, and recent studies have identified a significant impact of MS onset during childhood on cognitive and physical functioning. Optimization of pediatric MS care requires that promising new therapies be made available to children and adolescents, but also that safety and tolerability and potential influence of therapies on the developing immune and neural networks of pediatric patients be closely considered. We propose care algorithms illustrating models for therapy that detail careful monitoring of pediatric patients with MS, provide definitions for inadequate treatment response and treatment escalation, and foster multinational collaboration in future therapeutic trials.