Exanthematous Drug Eruption to Intravenous Iron: A Case Report.

The authors present a rare case of an exanthematous drug reaction to intravenous iron. Exanthematous drug eruptions, also called morbilliform or maculopapular drug rashes, can occur in first-time drug exposures and represent a subtype of delayed-type IV hypersensitivity reactions.  This patient is a 49-year-old female with a history of iron deficiency anemia and hypothyroidism who presented to the emergency department after experiencing a diffuse whole-body maculopapular rash following ferumoxytol 510 mg intravenously received once two days prior to her presentation. A clinical examination was suspicious of an exanthematous drug eruption. The patient was treated with methylprednisolone 40 mg intravenously twice a day for three days, followed by prednisone 40 mg orally twice a day for two days with a steroid taper upon discharge. The patient's rash resolved within five days of steroid treatment. There is a high global prevalence of iron deficiency anemia for which intravenous iron replacement may be required. However, there is limited research addressing its adverse effects, particularly those that include delayed hypersensitivity reactions. This paper aims to alert healthcare professionals of a rare type of delayed hypersensitivity reaction to intravenous iron to better guide management in the clinical setting.

Aortic arch anomalies, embryology and their relevance in neuro-interventional surgery and stroke: A review.

BACKGROUND: Congenital aortic arch anomalies are commonly encountered during neurointerventional procedures. While some anomalies are identified at an early age, many are incidentally discovered later in adulthood during endovascular evaluations or interventions. Proper understanding of the normal arch anatomy and its variants is pivotal to safely navigate normal aortic arch branches and to negotiate the catheter through anomalies during neurointerventional procedures. This is particularly relevant in the increasingly "transradial first" culture of neurointerventional surgery. Moreover, some of these anomalies have a peculiar predilection for complications including aneurysm formation, dissection, and rupture during the procedure. Therefore, an understanding of these anomalies, their underlying embryological basis and associations, and pattern of circulation will help endovascular neurosurgeons and interventional radiologists navigate with confidence and consider relevant pathologic associations that may inform risk of cerebrovascular disease. METHODS: Here, we present a brief review of the basic embryology of the common anomalies of the aortic arch along with their neurological significances and discuss, through illustrative cases, the association of aortic arch anomalies with cerebral vascular pathology. CONCLUSIONS: Understanding the aortic arch anomalies and its embryological basis is essential to safely navigate the cerebral vascular system during neurointerventional surgeries.

Current applications and safety profile of laser interstitial thermal therapy in the pediatric population: a systematic review of the literature.

OBJECTIVE: Laser interstitial thermal therapy (LITT) provides a minimally invasive alternative to open brain surgery, making it a powerful neurosurgical tool especially in pediatric patients. This systematic review aimed to highlight the indications and complications of LITT in the pediatric population. METHODS: In line with the PRISMA guidelines, the authors conducted a systematic review to summarize the current applications and safety profiles of LITT in pediatrics. PubMed and Embase were searched for studies that reported the outcomes of LITT in patients < 21 years of age. Retrospective studies, case series, and case reports were included. Two authors independently screened the articles by title and abstract followed by full text. Relevant variables were extracted from studies that met final eligibility, and results were pooled using descriptive statistics. RESULTS: The selection process captured 303 pediatric LITT procedures across 35 studies. Males comprised approximately 60% of the aggregate sample, with a mean age of 10.5 years (range 0.5-21 years). The LITT technologies used included Visualase (89%), NeuroBlate (9%), and Multilase 2100 (2%). The most common indication was treatment of seizures (86%), followed by brain tumors (16%). The mean follow-up duration was 15.6 months (range 1.3-48 months). The overall complication rate was 15.8%, which comprised transient neurological deficits, cognitive and electrolyte disturbances, hemorrhage, edema, and hydrocephalus. No deaths were reported. CONCLUSIONS: As of now, LITT's most common applications in pediatrics are focused on treating medically refractory epilepsy and brain tumors that can be difficult to resect. The safety of LITT can provide an attractive alternative to open brain surgery in the pediatric population.

Dendritic Spines in Early Postnatal Fragile X Mice Are Insensitive to Novel Sensory Experience.

Autism spectrum disorders are often associated with atypical sensory processing and sensory hypersensitivity, which can lead to maladaptive behaviors, such as tactile defensiveness. Such altered sensory perception in autism spectrum disorders could arise from disruptions in experience-dependent maturation of circuits during early brain development. Here, we tested the hypothesis that synaptic structures of primary somatosensory cortex (S1) neurons in Fragile X syndrome (FXS), which is a common inherited cause of autism, are not modulated by novel sensory information during development. We used chronic in vivo two-photon microscopy to image dendritic spines and axon "en passant" boutons of layer 2/3 pyramidal neurons in S1 of male and female WT and Fmr1 KO mice, a model of FXS. We found that a brief (overnight) exposure to dramatically enhance sensory inputs in the second postnatal week led to a significant increase in spine density in WT mice, but not in Fmr1 KO mice. In contrast, axon "en passant" boutons dynamics were impervious to this novel sensory experience in mice of both genotypes. We surmise that the inability of Fmr1 KO mice to modulate postsynaptic dynamics in response to increased sensory input, at a time when sensory information processing first comes online in S1 cortex, could play a role in altered sensory processing in FXS.SIGNIFICANCE STATEMENT Very few longitudinal in vivo imaging studies have investigated synaptic structure and dynamics in early postnatal mice. Moreover, those studies tend to focus on the effects of sensory input deprivation, a process that rarely occurs during normal brain development. Early postnatal imaging experiments are critical because a variety of neurodevelopmental disorders, including those characterized by autism, could result from alterations in how circuits are shaped by incoming sensory inputs during critical periods of development. In this study, we focused on a mouse model of Fragile X syndrome and demonstrate how dendritic spines are insensitive to a brief period of novel sensory experience.

Tactile Defensiveness and Impaired Adaptation of Neuronal Activity in the Fmr1 Knock-Out Mouse Model of Autism.

Sensory hypersensitivity is a common symptom in autism spectrum disorders (ASDs), including fragile X syndrome (FXS), and frequently leads to tactile defensiveness. In mouse models of ASDs, there is mounting evidence of neuronal and circuit hyperexcitability in several brain regions, which could contribute to sensory hypersensitivity. However, it is not yet known whether or how sensory stimulation might trigger abnormal sensory processing at the circuit level or abnormal behavioral responses in ASD mouse models, especially during an early developmental time when experience-dependent plasticity shapes such circuits. Using a novel assay, we discovered exaggerated motor responses to whisker stimulation in young Fmr1 knock-out (KO) mice (postnatal days 14-16), a model of FXS. Adult Fmr1 KO mice actively avoided a stimulus that was innocuous to wild-type controls, a sign of tactile defensiveness. Using in vivo two-photon calcium imaging of layer 2/3 barrel cortex neurons expressing GCaMP6s, we found no differences between wild-type and Fmr1 KO mice in overall whisker-evoked activity, though 45% fewer neurons in young Fmr1 KO mice responded in a time-locked manner. Notably, we identified a pronounced deficit in neuronal adaptation to repetitive whisker stimulation in both young and adult Fmr1 KO mice. Thus, impaired adaptation in cortical sensory circuits is a potential cause of tactile defensiveness in autism.SIGNIFICANCE STATEMENT We use a novel paradigm of repetitive whisker stimulation and in vivo calcium imaging to assess tactile defensiveness and barrel cortex activity in young and adult Fmr1 knock-out mice, the mouse model of fragile X syndrome (FXS). We describe evidence of tactile defensiveness, as well as a lack of L2/3 neuronal adaptation in barrel cortex, during whisker stimulation. We propose that a defect in sensory adaptation within local neuronal networks, beginning at a young age and continuing into adulthood, likely contributes to sensory overreactivity in FXS and perhaps other ASDs.