Acute Acalculous Cholecystitis Due to a Primary Epstein Barr Virus Infection in a Pediatric Patient

Epstein-Barr virus (EBV) is estimated to infect more than 98% of adults worldwide and is one of the most common human viruses. Acute acalculous cholecystitis (AAC) of the gallbladder is an atypical complication of infectious mononucleosis caused by EBV. Conservative management has been described in the context of AAC caused by EBV. A surgical approach must be considered in the case of acute complications such as perforation or gallbladder gangrene. We present the case of a 10-year-old female patient with AAC due to infectious mononucleosis syndrome caused by primary EBV infection

Insulinoma : a Rare Cause of Hypoglycemia in Childhood

Rare disease. Insulinomas are pancreatic neuroendocrine tumors that cause non-ketotic hypoglycemia due to hyperinsulinism; they are extremely rare, especially in children. We present a case of a sporadic insulinoma in an 11-year-old boy who had episodes of self-limited drowsiness and behavior changes over a 3-month period, thought to be caused by psychological issues. Non-ketotic hypoglycemia was confirmed at our center. A fasting blood test found inappropriately elevated insulin levels during hypoglycemia, undetectable β-hydroxybutyrate, and increased C-peptide levels in line with insulin levels. Anti-insulin antibodies were negative and antidiabetic drugs untraceable. The glucagon-stimulation test was positive. Growth hormone, adrenocorticotropin hormone, and phosphorus and calcium metabolism were normal. Dual-phase computed tomography detected a lesion compatible with an insulinoma. Endoscopic ultrasound showed a homogenous lesion at the junction of the body and tail of the pancreas. Histologic analysis of a fine-needle aspiration biopsy was compatible with neuroendocrine neoplasia. Preoperatively, a fractional diet avoiding fast-absorbing carbohydrates maintained normal glucose blood levels. Enucleation was not possible, so the lesion was resected along with portions of the body and tail of the pancreas. The well-differentiated tumor measured 15×13 mm. Postoperative blood glucose levels were correct, allowing a normal diet. In children with unspecific symptoms compatible with hypoglycemia, blood glucose must be evaluated to confirm low blood glucose levels. Determining blood ketone levels is important for the differential diagnosis. The diagnostic approach to pediatric insulinoma represents a challenge for multidisciplinary teamwork

Acute Acalculous Cholecystitis Due to a Primary Epstein Barr Virus Infection in a Pediatric Patient

Epstein-Barr virus (EBV) is estimated to infect more than 98% of adults worldwide and is one of the most common human viruses. Acute acalculous cholecystitis (AAC) of the gallbladder is an atypical complication of infectious mononucleosis caused by EBV. Conservative management has been described in the context of AAC caused by EBV. A surgical approach must be considered in the case of acute complications such as perforation or gallbladder gangrene. We present the case of a 10-year-old female patient with AAC due to infectious mononucleosis syndrome caused by primary EBV infection

A Case of Persistent Air Leak Managed by Selective Left Main Bronchus Intubation in an Infant with Pulmonary Tuberculosis

Unusual clinical course Persistent air leak, or persistent pneumothorax, is defined as a pneumothorax that persists beyond the first week, or air leak through a chest drain for more than 48 hours. The most common findings in pediatric pulmonary tuberculosis are parenchymal disease and mediastinal lymphadenopathy, but airway obstruction can cause emphysema and pneumothorax. A case is presented of persistent air leak in a 3-month-old infant with pulmonary tuberculosis that was managed by selective left main bronchus intubation. A 3-month-old boy presented with respiratory distress and fever. Imaging findings suggested pulmonary tuberculosis, and first-line anti-tuberculous treatment was initiated with isoniazid, rifampicin, pyrazinamide, and ethambutol (HRZE). He was discharged home after eight days, but was admitted four days later with respiratory distress. Chest X-rays showed a tension pneumothorax that required drainage and chest computed tomography (CT) showed right lung emphysema. Bronchoscopy found extrinsic obstruction of both main bronchi. Chest drains continued to leak air leak after 48 h. Right middle and lower lobectomy and drainage of multiple lymph nodes resulted in significant improvement. He developed pneumonia and acute respiratory distress syndrome, which prevented mechanical ventilation. The left main bronchus was selectively intubated to allow the air leak to heal and to ventilate the lung. He was extubated 10 days later and recovered completely. This case highlights that when medical management of persistent air leak associated with tuberculosis is not effective, surgery, active ventilation, and selective main bronchus intubation should be considered

Chasing Gravitational Waves with the Chereknov Telescope Array

Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 2023 (arXiv:2309.08219)2310.07413International audienceThe detection of gravitational waves from a binary neutron star merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this gravitational wave event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100GeV) photons which have yet to be detected in coincidence with a gravitational wave signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. New observing modes and follow-up strategies are being developed for CTA to rapidly cover localization areas of gravitational wave events that are typically larger than the CTA field of view. This work will evaluate and provide estimations on the expected number of of gravitational wave events that will be observable with CTA, considering both on- and off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA

Sensitivity of the Cherenkov Telescope Array to the gamma-ray emission from neutrino sources detected by IceCube

Gamma-ray observations of the astrophysical neutrino sources are fundamentally important for understanding the underlying neutrino production mechanism. We investigate the Cherenkov Telescope Array (CTA) ability to detect the very-high-energy (VHE) gamma-ray counterparts to the neutrino-emitting Active Galaxies. The CTA performance under different configurations and array layouts is computed based on the neutrino and gamma-ray simulations of steady and transient types of sources, assuming that the neutrino events are detected with the IceCube neutrino telescope. The CTA detection probability is calculated for both CTA sites taking into account the visibility constraints. We find that, under optimal observing conditions, CTA could observe the VHE gamma-ray emission from at least 3 neutrino events per year

Chasing Gravitational Waves with the Chereknov Telescope Array

Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 2023 (arXiv:2309.08219)2310.07413International audienceThe detection of gravitational waves from a binary neutron star merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this gravitational wave event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100GeV) photons which have yet to be detected in coincidence with a gravitational wave signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. New observing modes and follow-up strategies are being developed for CTA to rapidly cover localization areas of gravitational wave events that are typically larger than the CTA field of view. This work will evaluate and provide estimations on the expected number of of gravitational wave events that will be observable with CTA, considering both on- and off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA

Interpolation of Instrument Response Functions for the Cherenkov Telescope Array in the Context of pyirf

The Cherenkov Telescope Array (CTA) will be the next generation ground-basedvery-high-energy gamma-ray observatory, constituted by tens of Imaging AtmosphericCherenkov Telescopes at two sites once its construction and commissioning are finished. Like its predecessors, CTA relies on Instrument Response Functions (IRFs) to relate the observed and reconstructed properties to the true ones of the primary gamma-ray photons. IRFs are needed for the proper reconstruction of spectral and spatial information of the observed sources and are thus among the data products issued to the observatory users. They are derived from Monte Carlo simulations, depend on observation conditions likethe telescope pointing direction or the atmospheric transparency and can evolve with time as hardware ages or is replaced. Producing a complete set of IRFs from simulations for every observation taken is a time-consuming task and not feasible when releasing data products on short timescales. Consequently, interpolation techniques on simulated IRFs are investigated to quickly estimate IRFs for specific observation conditions. However, as some of the IRFs constituents are given as probability distributions, specialized methods are needed. This contribution summarizes and compares the feasibility of multiple approaches to interpolate IRF components in the context of the pyirf python software package and IRFs simulated for the Large-Sized Telescope prototype (LST-1). We will also give an overview of the current functionalities implemented in pyirf

Performance of a proposed event-type based analysis for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) will be the next-generation observatory in the field of very-high-energy (20 GeV to 300 TeV) gamma-ray astroparticle physics. Classically, data analysis in the field maximizes sensitivity by applying quality cuts on the data acquired. These cuts, optimized using Monte Carlo simulations, select higher quality events from the initial dataset. Subsequent steps of the analysis typically use the surviving events to calculate one set of instrument response functions (IRFs). An alternative approach is the use of event types, as implemented in experiments such as the Fermi-LAT. In this approach, events are divided into sub-samples based on their reconstruction quality, and a set of IRFs is calculated for each sub-sample. The sub-samples are then combined in a joint analysis, treating them as independent observations. This leads to an improvement in performance parameters such as sensitivity, angular and energy resolution. Data loss is reduced since lower quality events are included in the analysis as well, rather than discarded. In this study, machine learning methods will be used to classify events according to their expected angular reconstruction quality. We will report the impact on CTA high-level performance when applying such an event-type classification, compared to the classical procedure