Mimickers of hypoxic-ischaemic brain injury in term neonates: What the radiologist should know

Patterns of neonatal hypoxic-ischaemic brain injury (HIBI) are fairly well known. There are, however, other diagnoses with imaging patterns that may mimic HIBI. A review of MRI studies was conducted for children with suspected cerebral palsy, correlated with prior imaging, clinical details and laboratory tests where available. In the 63 identified cases, imaging features were, in many cases, very similar to the known patterns of HIBI. The alternative diagnoses can be classified as developmental, vascular, chromosomal, infections, metabolic disorders, and congenital syndromes. These findings are described in this pictorial essay. The potential mimickers of HIBI described in this essay can demonstrate similar imaging appearances to HIBI.

Contribution

There are multiple possible causes of neonatal encephalopathy other than hypoxic-ischaemic encephalopathy. Many conditions may mimic HIBI, each of which can be associated with significant morbidity. It is prudent for the reporting radiologist to be aware of these alternate clinico-radiological diagnoses.

Imaging of Inherited Metabolic and Endocrine Disorders

"Inherited metabolic disorders represent a large group of disorders of which approximately 25% present in neonatal period with acute metabolic decompensation, rapid clinical deterioration, and often nonspecific imaging findings. Neonatal onset signifies the profound severity of the metabolic abnormality compared with cases with later presentation and necessitates rapid diagnosis and urgent therapeutic measures in an attempt to decrease the extent of brain injury and prevent grave neurologic sequela or death. Here, the authors discuss classification and clinical and imaging findings in a spectrum of metabolic and endocrine disorders with neonatal presentation."

MR Neuroimaging in Pediatric Inborn Errors of Metabolism

Inborn errors of metabolism (IEM) are a group of disorders due to functional defects in one or more metabolic pathways that can cause considerable morbidity and death if not diagnosed early. While individually rare, the estimated global prevalence of IEMs comprises a substantial number of neonatal and infantile disorders affecting the central nervous system. Clinical manifestations of IEMs may be nonspecific. Newborn metabolic screens do not capture all IEMs, and likewise, genetic testing may not always detect pathogenic variants. Neuroimaging is a critical component of the work-up, given that imaging sometimes occurs before prenatal screen results are available, which may allow for recognition of imaging patterns that lead to early diagnosis and treatment of IEMs. This review will demonstrate the role of magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (¹H MRS) in the evaluation of IEMs. The focus will be on scenarios where MRI and ¹H MRS are suggestive of or diagnostic for IEMs, or alternatively, refute the diagnosis.

Primary Mitochondrial Disorders of the Pediatric Central Nervous System: Neuroimaging Findings

Primary mitochondrial disorders (PMDs) constitute the most common cause of inborn errors of metabolism in children, and they frequently affect the central nervous system. Neuroimaging findings of PMDs are variable, ranging from unremarkable and nonspecific to florid and highly suggestive. An overview of PMDs, including a synopsis of the basic genetic concepts, main clinical symptoms, and neuropathologic features, is presented. In addition, eight of the most common PMDs that have a characteristic imaging phenotype in children are reviewed in detail. Online supplemental material is available for this article. ^©RSNA, 2020.

Genetic and Metabolic Neonatal Epilepsies

Seizures are a common neonatal neurological disorder with an incidence of 1 to 5 in 1,000 live births. Genetic and metabolic epilepsies account for 10% to 12% of all neonatal seizures. Correct identification and diagnosis are important factors, as they carry treatment and management implications. Clinical history, neurological examination, seizure types, epilepsy syndromes, and electroencephalogram findings can be used to guide the diagnosis of epilepsy. Genetic and metabolic epilepsies in neonates can be categorized practically into two groups: amenably treatable disorders, and the most common genetic epilepsies. The treatable disorders primarily consist of inborn errors of metabolism that have a specific therapy. The most common genetic epilepsies include monogenic disorders, which usually result from channelopathies, synaptic vesicle docking/release defect, or dysfunction of cell signaling. A step-wise diagnostic approach to genetic and metabolic epilepsies is proposed in this article to aid clinicians in providing care for newborns with seizures. [Pediatr Ann. 2020;50(6):e245-e253.].

Inherited paediatric neurometabolic disorders, can brain magnetic resonance imaging predict?

Objectives:

To evaluate diagnostic capability of brain magnetic resonance imaging (MRI) in detection of inherited neurometabolic disorders.

Methods:

This retrospective observational study was performed in Radiology Department at our Hospital in Dhahran, from January 2013 to January 2020. We evaluated brain MRIs of children (under 5) who were referred to pediatric neurology for clinical suspicion of neuro-developmental delay and metabolic disease. Known perinatal ischemia and birth trauma cases were excluded. Imaging criteria included: (i) bilateral symmetric white matter signal abnormality, (ii) diffusion restriction affecting bilateral deep grey nuclei with or without brainstem involvement, (iii) brain atrophy or edema with abnormal white matter signal, (iv) characteristic MR spectroscopic finding. Presence of any one of these findings was considered positive for neurometabolic disease. Two neuroradiologists interpreted MRIs with substantial interobserver agreement. Diagnoses were confirmed on biochemical/ metabolic screening and genetic testing. A 2 × 2 contingency table was used for results. Chi square test was used to determine association.

Results:

Out of 133 cases, 72 (49 males, 90% AR) were found to have neurometabolic disorders. Sensitivity, specificity, positive and negative predictive values were calculated as 81.94% (CI, 71.11-90.02), 67.21% (CI, 54.00-78.69), 74.68% (CI, 66.96-81.11) and 75.93% (CI, 65.16-84.17) respectively. Findings were found significant (p-value=0.0001).

Conclusion:

Brain MRI can help to predict inherited neurometabolic disorders considering certain findings.

Neuroimaging Findings in Lysosomal Disorders: 2018 Update

Lysosomal storage disorders are a heterogeneous group of genetic diseases characterized by defective function in one of the lysosomal enzymes. In this review paper, we describe neuroradiological findings and clinical characteristics of neuronopathic lysosomal disorders with a focus on differential diagnosis. New insights regarding pathogenesis and therapeutic perspectives are also briefly discussed.

Neurometabolic Disorders of the Newborn

There is an extensive and diverse set of medical conditions affecting the neonatal brain within the spectrum of neurometabolic disorders. As such, their clinical presentations can be rather nonspecific, and can often mimic acquired entities such as hypoxic-ischemic encephalopathy and sepsis. Similarly, the radiological findings in these entities can also be frequently nonspecific, but a more detailed analysis of imaging findings (especially magnetic resonance imaging) alongside the relevant clinical details can be a rewarding experience, thus enabling a timely and targeted diagnosis. Early diagnosis of an underlying neurometabolic disorder is vital, as some of these entities are potentially treatable, and laboratory and genetic testing can be precisely targeted. Further, their detection helps with counselling families for future pregnancies. We present a review of neurometabolic disorders specific to the newborns with a focus on how neuroimaging findings match their clinical presentation patterns.

Toxic-Metabolic Neurologic Disorders in Children: A Neuroimaging Review

There are multiple causes of neurotoxicity in children including medications, extrinsic toxins and insults, illicit drugs, built up of toxic metabolites due to genetic or acquired disorders, and metabolic abnormalities. The review is centered on causes of neurotoxicity affecting the pediatric brain and producing typical and easily recognized imaging manifestations. Early identification of common and less common imaging findings may point toward the correct direction, and may facilitate early diagnosis and institution of appropriate treatment to reverse or at least limit the injury to the developing brain. Two common imaging patterns of neurotoxicity in children are the posterior reversible encephalopathy syndrome and acute toxic leukoencephalopathy that are usually related to chemotherapy and immunosuppression for common pediatric malignancies. Another well-described imaging pattern of injury in children involves reversible splenial lesions with or without associated white matter abnormalities. Multiple additional extrinsic causes of neurotoxicity are presented including radiation and chemoradiation, various medications and treatment regimens, poisoning, illicit drug use or accidental exposure, and the respective characteristic neuroimaging findings are highlighted. Intrinsic neurotoxicity may occur in the setting of inborn errors of metabolism or acquired progressive organ failure leading to build up of toxic metabolites. Additional intrinsic causes of neurotoxicity include metabolic derangements and characteristic imaging findings in all instances are reviewed. The goal of the article is to enhance familiarity of neurologists and neuroradiologists with the imaging appearance of common and less common toxic insults to the pediatric brain.

A Urinary Metabolic Signature for Multiple Sclerosis and Neuromyelitis Optica

Urine is a metabolite-rich biofluid that reflects the body's effort to maintain chemical and osmotic homeostasis. Clinical diagnosis routinely relies on urine samples because the collection process is easy and noninvasive. Despite these advantages, urine is an under-investigated source of biomarkers for multiple sclerosis (MS). Nuclear magnetic resonance spectroscopy (NMR) has become a common approach for analyzing urinary metabolites for disease diagnosis and biomarker discovery. For illustration of the potential of urinary metabolites for diagnosing and treating MS patients, and for differentiating between MS and other illnesses, 38 urine samples were collected from healthy controls, MS patients, and neuromyelitis optica-spectrum disorder (NMO-SD) patients and analyzed with NMR, multivariate statistics, one-way ANOVA, and univariate statistics. Urine from MS patients exhibited a statistically distinct metabolic signature from healthy and NMO-SD controls. A total of 27 metabolites were differentially altered in the urine from MS and NMO-SD patients and were associated with synthesis and degradation of ketone bodies, amino acids, propionate and pyruvate metabolism, tricarboxylic acid cycle, and glycolysis. Metabolites altered in urine from MS patients were shown to be related to known pathogenic processes relevant to MS, including alterations in energy and fatty acid metabolism, mitochondrial activity, and the gut microbiota.