Pediatric Multiple Sclerosis: Distinguishing Clinical and MR Imaging Features

Diagnostic challenge in children with an acquired demyelinating syndrome: an illustrative case report

The clinical-radiological and biological overlap of the spectrum of pediatric demyelinating disorders makes the diagnostic process of a child with an acquired demyelinating syndrome truly challenging. We present a 9-year-old girl with subacute symptoms of severe decrease in bilateral visual acuity and gait ataxia. An urgent MRI showed inflammatory-demyelinating lesions affecting the periaqueductal gray matter, the cerebellar hemispheres, the area postrema as well as both optic nerves and chiasm. Likewise, multisegmental involvement of the cervical and dorsal spinal cord was found, with short and peripheral lesions. Anti myelin oligodendrocyte glycoprotein (MOG) antibodies (Abs) were positive in cerebrospinal fluid (CSF) and weakly in serum. Oligoclonal bands (OB) were positive in CSF. Based on all this, the diagnosis of MOG antibody disease (MOGAD) with a neuromyelitis optica spectrum disorder (NMOSD)-like picture was made. Given the good clinical and radiological recovery after the acute phase treatment, and that anti MOG Abs became negative, it was decided to keep the patient without specific treatment. However, during follow-up, while the patient was asymptomatic, a control brain MRI showed the appearance of new lesions with morphology and topography suggestive of multiple sclerosis (MS). This, added to the presence of OB, made the diagnosis of pediatric-onset MS (POMS) likely. Immunosuppressive treatment was restarted with a good response since then. Unlike adult-onset MS, children with POMS may usually not have entirely typical clinical and radiological features at presentation. In many cases, the time factor and close clinical and radiological monitoring could be critical to make an accurate diagnosis.

Understanding Pediatric Neuroimmune Disorder Conflicts: A Neuroradiologic Approach in the Molecular Era

Neuroimmune disorders in children are a complex group of inflammatory conditions of the central nervous system with diverse pathophysiologic mechanisms and clinical manifestations. Improvements in antibody analysis, genetics, neuroradiology, and different clinical phenotyping have expanded knowledge of the different neuroimmune disorders. The authors focus on pediatric-onset myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease, which is a new entity in the spectrum of inflammatory demyelinating diseases, distinct from both multiple sclerosis (MS) and anti-aquaporin-4 (AQP4) antibody neuromyelitis optica spectrum disorders (NMOSDs). The authors review the importance of an optimized antibody-detection assay, the frequency of MOG antibodies in children with acquired demyelinating syndrome (ADS), the disease course, the clinical spectrum, proposed diagnostic criteria, and neuroimaging of MOG antibody-associated disease. Also, they outline differential diagnosis from other neuroimmune disorders in children according to the putative primary immune mechanism. Finally, they recommend a diagnostic algorithm for the first manifestation of ADS or relapsing ADS that leads to four demyelinating syndromes: MOG antibody-associated disease, AQP4 antibody NMOSDs, MS, and seronegative relapsing ADS. This diagnostic approach provides a framework for the strategic role of neuroradiology in diagnosis of ADS and decision making, to optimize patient care and treatment outcome in concert with clinicians. Online supplemental material is available for this article. ^©RSNA, 2020.

Relapsing Demyelinating Syndromes in Children: A Practical Review of Neuroradiological Mimics

Relapsing demyelinating syndromes (RDS) in children encompass a diverse spectrum of entities including multiple sclerosis (MS) acute disseminated encephalomyelitis (ADEM), aquaporin-4 antibody associated neuromyelitis optica spectrum disorder (AQP4-NMOSD) and myelin oligodendrocyte glycoprotein antibody disease (MOG-AD). In addition to these, there are “antibody-negative” demyelinating syndromes which are yet to be fully characterized and defined. The paucity of specific biomarkers and overlap in clinical presentations makes the distinction between these disease entities difficult at initial presentation and, as such, there is a heavy reliance on magnetic resonance imaging (MRI) findings to satisfy the criteria for treatment initiation and optimization. Misdiagnosis is not uncommon and is usually related to the inaccurate application of criteria or failure to identify potential clinical and radiological mimics. It is also notable that there are instances where AQP4 and MOG antibody testing may be falsely negative during initial clinical episodes, further complicating the issue. This article illustrates the typical clinico-radiological phenotypes associated with the known pediatric RDS at presentation and describes the neuroimaging mimics of these using a pattern-based approach in the brain, optic nerves, and spinal cord. Practical guidance on key distinguishing features in the form of clinical and radiological red flags are incorporated. A subsection on clinical mimics with characteristic imaging patterns that assist in establishing alternative diagnoses is also included.

Imaging in Pediatric Multiple Sclerosis : An Iconographic Review

Pediatric-onset multiple sclerosis (POMS) is defined by a first multiple sclerosis (MS) attack occurring before 18 years old and is diagnosed by demonstration of dissemination in time (DIT) and space (DIS). Although guidelines evolved over the years, they always recognized the importance of magnetic resonance imaging (MRI) for diagnosis. The 2017 McDonald criteria are increasingly used and have been validated in several cohorts. The use of MRI is the most important tool for the early diagnosis, monitoring, and assessment of treatment response of MS and standard protocols include precontrast and postcontrast T1, T2, fluid attenuation inversion recovery (FLAIR) and diffusion sequences. A distinctive MS lesion compromises white matter and it is well-demarcated and confluent, showing demyelination, inflammation, gliosis, and relative axonal preservation. Considering the growing recognition of pediatric MS as a differential diagnosis for children presenting with a clinical central nervous system event, we present a POMS lesions guide (periventricular, juxtacortical, infratentorial, spinal cord, cortical, tumefactive, black hole, contrast-enhanced). Owing to its rareness, POMS is a diagnosis by exclusion and MRI plays a fundamental role in distinguishing POMS from other demyelinating and non-demyelinating conditions. Three main groups of disorders can mimic POMS: inflammatory, metabolic and tumoral; however, imaging patterns earlier described lower the possibilities of alternative diagnoses and strongly suggest POMS when likely.

Viral encephalitis: a practical review on diagnostic approach and treatment

OBJECTIVES

To review the diagnostic criteria for encephalitis and encephalopathy of presumed infectious etiology, as well as the diagnostic workup for viral encephalitis and its treatment approaches. The authors also intended to summarize relevant information on specific viruses frequently found in Brazil.

SOURCE OF DATA

Literature search on Pubmed/MEDLINE using the following keywords: "viral", "encephalitis", "child", or "adolescents", filtering for articles on humans and in English.

SUMMARY OF DATA

Viral encephalitis is the most common cause of encephalitis and is responsible for high rates of morbidity, permanent neurologic sequelae, and according to the virus, may have high mortality rates. The most common etiologies are herpesviruses 1 and 2 (HSV-1 and HSV-2), non-polio enterovirus, and arboviruses (in Brazil, dengue, Zika, and chikungunya). Other relevant etiologies are seasonal influenza, cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), and the re-emergent measles.

CONCLUSION

Clinical data, laboratory results, and neuroimaging findings support the diagnosis of encephalitis and the specific viral etiology. To increase the likelihood of etiologic confirmation, it is important to know the best approach to collecting samples and to choose the best identification technique for each virus. The differential diagnosis of viral encephalitis includes other infections and immune-mediated inflammatory central nervous system disorders.

Assessment of acute motor deficit in the pediatric emergency room

OBJECTIVES

This review article aimed to present a clinical approach, emphasizing the diagnostic investigation, to children and adolescents who present in the emergency room with acute-onset muscle weakness.

SOURCES

A systematic search was performed in PubMed database during April and May 2017, using the following search terms in various combinations: "acute," "weakness," "motor deficit," "flaccid paralysis," "child," "pediatric," and "emergency". The articles chosen for this review were published over the past ten years, from 1997 through 2017. This study assessed the pediatric age range, from 0 to 18 years.

SUMMARY OF THE DATA

Acute motor deficit is a fairly common presentation in the pediatric emergency room. Patients may be categorized as having localized or diffuse motor impairment, and a precise description of clinical features is essential in order to allow a complete differential diagnosis. The two most common causes of acute flaccid paralysis in the pediatric emergency room are Guillain-Barré syndrome and transverse myelitis; notwithstanding, other etiologies should be considered, such as acute disseminated encephalomyelitis, infectious myelitis, myasthenia gravis, stroke, alternating hemiplegia of childhood, periodic paralyses, brainstem encephalitis, and functional muscle weakness. Algorithms for acute localized or diffuse weakness investigation in the emergency setting are also presented.

CONCLUSIONS

The clinical skills to obtain a complete history and to perform a detailed physical examination are emphasized. An organized, logical, and stepwise diagnostic and therapeutic management is essential to eventually restore patient's well-being and full health.