453 research outputs found
Intestinal tuberculosis in a child living in a country with a low incidence of tuberculosis: a case report
Background: Relatively common in adults, intestinal tuberculosis is considered rare in children and adolescents. The protean manifestations of intestinal tuberculosis mean that the diagnosis is often delayed (sometimes even for years), thus leading to increased mortality and unnecessary surgery. The main diagnostic dilemma is to differentiate intestinal tuberculosis and Crohn’s disease because a misdiagnosis can have dramatic consequences.
Case presentation: A 13-year-old Caucasian, Italian female adolescent attended the Emergency Department complaining of abdominal pain, a fever of up to 38°C, night sweats, diarrhea with blood in stool, and a weight loss of about three kilograms over the previous two months. Physical examination revealed a marked skin pallor and considerable abdominal distension with relevant discomfort in all the abdominal quadrant. Laboratory tests revealed a decreased white blood cell count with anemia and increased C-reactive protein levels. The Mantoux tuberculin skin test was negative. A chest X-ray and an abdominal ultrasonography did not reveal any significant findings. The patient underwent colonoscopy that showed diffuse mucosal congestion and significant blood loss, and laparatomy showed small bowel and colon loops with a whitish appearance. A biopsy of the ileal mucosa revealed inflammation with noncaseating granulomas possibly due to bacterial infection. Given the suspicion of an opportunistic bacterial infection in a child with chronic inflammatory bowel disease (possibly Crohn’s disease), treatment with a third-generation cephalosporin was started. However, the abdominal pain, fever and poor general condition persisted and so, after 11 days, the patient underwent total body computed tomography and magnetic resonance imaging of the brain. On the basis of the radiological findings, miliary tuberculosis was suspected and bronchoscopy was performed and resulted positive for Mycobacterium tuberculosis. Miliary tuberculosis was confirmed and an effective treatment with four drugs was started.
Conclusion: This case shows that the manifestations of intestinal tuberculosis can be very difficult to diagnose and mimic those of Chron’s disease. Total body computed tomography and laparotomy with an intestinal biopsy for the detection of Mycobacterium tuberculosis are the means of avoid the risks of a misdiagnosis in children with unexplained chronic abdominal problems
Case Report: Atypical psychotic onset of type I Arnold-Chiari malformation
Introduction: We report a case of type I Arnold-Chiari malformation that is very peculiar because of its particular onset especially characterized by psychiatric symptoms. These symptoms were so prevailing that, for fifteen years, they masked the neurological aspects and the patient was treated with high doses of psychotropic drugs without any benefit. If the Arnold-Chiari malformation had been diagnosed before the development of severe hydro-syringomyelia, the patient could have underwent decompressive neurosurgery which may have improved her quality of life.
It is worthwhile to highlight that psychotic symptoms may be caused by this congenital malformation, that typically has an aspecific onset. Therefore it\u2019s important to consider an eventual organic etiology while challenging a resistant clinical picture with unusual presentation.
Case description: A 51-year-old woman reported neurological symptoms consisting of headaches, blurred vision, diplopia, tinnitus, vertigo and psychiatric symptoms including obsessive ideas about the fear of killing her son, auditory and visual pseudo-hallucinations. The symptoms had developed suddenly at the age of 35 years and persisted thereafter. She underwent multiple hospitalizations in psychiatric units and was treated with a variety of psychopharmacological approaches without substantial improvement. We performed a brain MRI that identified a type I Arnold-Chiari malformation. We assessed psychiatric symptoms using the Structured Clinical Interview for DSM IV Axis I Disorders, the Brief Psychiatric Rating Scale, and the Yale-Brown Obsessive-Compulsive Scale. A tailored psychopharmacological therapy led to a partial improvement in mood and anxiety but not in hallucinations.
Discussion: We want to highlight how important is, in everyday psychiatric clinical practice, not to focus only on psychiatric aspects but consider the patient globally, because in this case psychiatric problems were the onset presentation of a rare neurological syndrome
Sulfate geoengineering impact on methane transport and lifetime: results from the Geoengineering Model Intercomparison Project (GeoMIP)
Abstract. Sulfate geoengineering (SG), made by sustained injection of SO2 in the tropical lower stratosphere, may impact the CH4 abundance through several photochemical mechanisms affecting tropospheric OH and hence the methane lifetime. (a) The reflection of incoming solar radiation increases the planetary albedo and cools the surface, with a tropospheric H2O decrease. (b) The tropospheric UV budget is upset by the additional aerosol scattering and stratospheric ozone changes: the net effect is meridionally not uniform, with a net decrease in the tropics, thus producing less tropospheric O(1D). (c) The extratropical downwelling motion from the lower stratosphere tends to increase the sulfate aerosol surface area density available for heterogeneous chemical reactions in the mid-to-upper troposphere, thus reducing the amount of NOx and O3 production. (d) The tropical lower stratosphere is warmed by solar and planetary radiation absorption by the aerosols. The heating rate perturbation is highly latitude dependent, producing a stronger meridional component of the Brewer–Dobson circulation. The net effect on tropospheric OH due to the enhanced stratosphere–troposphere exchange may be positive or negative depending on the net result of different superimposed species perturbations (CH4, NOy, O3, SO4) in the extratropical upper troposphere and lower stratosphere (UTLS). In addition, the atmospheric stabilization resulting from the tropospheric cooling and lower stratospheric warming favors an additional decrease of the UTLS extratropical CH4 by lowering the horizontal eddy mixing. Two climate–chemistry coupled models are used to explore the above radiative, chemical and dynamical mechanisms affecting CH4 transport and lifetime (ULAQ-CCM and GEOSCCM). The CH4 lifetime may become significantly longer (by approximately 16 %) with a sustained injection of 8 Tg-SO2 yr−1 starting in the year 2020, which implies an increase of tropospheric CH4 (200 ppbv) and a positive indirect radiative forcing of sulfate geoengineering due to CH4 changes (+0.10 W m−2 in the 2040–2049 decade and +0.15 W m−2 in the 2060–2069 decade)
Upper tropospheric ice sensitivity to sulfate geoengineering
Aside from the direct surface cooling that sulfate geoengineering (SG) would
produce, investigations of the possible side effects of this method are still
ongoing, such as the exploration of the effect that SG may have on upper
tropospheric cirrus cloudiness. The goal of the present study is to better
understand the SG thermodynamical effects on the freezing mechanisms leading
to ice particle formation. This is undertaken by comparing SG model
simulations against a Representative Concentration Pathway 4.5 (RCP4.5)
reference case. In the first case, the aerosol-driven surface cooling is
included and coupled to the stratospheric warming resulting from the aerosol
absorption of terrestrial and solar near-infrared radiation. In a second SG
perturbed case, the surface temperatures are kept unchanged with respect to
the reference RCP4.5 case. When combined, surface cooling and lower
stratospheric warming tend to stabilize the atmosphere, which decreases the
turbulence and updraft velocities (−10 % in our modeling study). The
net effect is an induced cirrus thinning, which may then produce a
significant indirect negative radiative forcing (RF). This RF would go in the
same direction as the direct effect of solar radiation scattering by
aerosols, and would consequently influence the amount of sulfur needed to
counteract the positive RF due to greenhouse gases. In our study, given an
8 Tg-SO2 yr−1 equatorial injection into the lower
stratosphere, an all-sky net tropopause RF of −1.46 W m−2 is
calculated, of which −0.3 W m−2 (20 %) is from the indirect
effect on cirrus thinning (6 % reduction in ice optical depth). When
surface cooling is ignored, the ice optical depth reduction is lowered to
3 %, with an all-sky net tropopause RF of −1.4 W m−2, of which
−0.14 W m−2 (10 %) is from cirrus thinning. Relative to the
clear-sky net tropopause RF due to SG aerosols (−2.1 W m−2), the
cumulative effect of the background clouds and cirrus thinning accounts for
+0.6 W m−2, due to the partial compensation of large positive
shortwave (+1.6 W m−2) and negative longwave adjustments
(−1.0 W m−2). When surface cooling is ignored, the net cloud
adjustment becomes +0.8 W m−2, with the shortwave contribution
(+1.5 W m−2) almost twice as much as that of the longwave
(−0.7 W m−2). This highlights the importance of including all of the
dynamical feedbacks of SG aerosols.</p
Annihilation of low energy antiprotons in silicon
The goal of the AEIS experiment at the Antiproton
Decelerator (AD) at CERN, is to measure directly the Earth's gravitational
acceleration on antimatter. To achieve this goal, the AEIS
collaboration will produce a pulsed, cold (100 mK) antihydrogen beam with a
velocity of a few 100 m/s and measure the magnitude of the vertical deflection
of the beam from a straight path. The final position of the falling
antihydrogen will be detected by a position sensitive detector. This detector
will consist of an active silicon part, where the annihilations take place,
followed by an emulsion part. Together, they allow to achieve 1 precision on
the measurement of with about 600 reconstructed and time tagged
annihilations.
We present here, to the best of our knowledge, the first direct measurement
of antiproton annihilation in a segmented silicon sensor, the first step
towards designing a position sensitive silicon detector for the
AEIS experiment. We also present a first comparison with
Monte Carlo simulations (GEANT4) for antiproton energies below 5 MeVComment: 21 pages in total, 29 figures, 3 table
Sulfate geoengineering impact on methane transport and lifetime: results from the Geoengineering Model Intercomparison Project (GeoMIP)
Sulfate geoengineering (SG), made by sustained injection of SO2 in the
tropical lower stratosphere, may impact the CH4 abundance through several
photochemical mechanisms affecting tropospheric OH and hence the methane
lifetime. (a)Â The reflection of incoming solar radiation increases the
planetary albedo and cools the surface, with a tropospheric H2O decrease.
(b)Â The tropospheric UV budget is upset by the additional aerosol scattering
and stratospheric ozone changes: the net effect is meridionally not uniform,
with a net decrease in the tropics, thus producing less tropospheric
O(1D). (c)Â The extratropical downwelling motion from the lower
stratosphere tends to increase the sulfate aerosol surface area density
available for heterogeneous chemical reactions in the mid-to-upper troposphere,
thus reducing the amount of NOx and O3 production. (d)Â The tropical
lower stratosphere is warmed by solar and planetary radiation absorption by
the aerosols. The heating rate perturbation is highly latitude dependent,
producing a stronger meridional component of the Brewer–Dobson circulation.
The net effect on tropospheric OH due to the enhanced
stratosphere–troposphere exchange may be positive or negative depending on
the net result of different superimposed species perturbations (CH4,
NOy, O3, SO4) in the extratropical upper troposphere and lower
stratosphere (UTLS). In addition, the atmospheric stabilization resulting
from the tropospheric cooling and lower stratospheric warming favors an
additional decrease of the UTLS extratropical CH4 by lowering the
horizontal eddy mixing. Two climate–chemistry coupled models are used to
explore the above radiative, chemical and dynamical mechanisms affecting
CH4 transport and lifetime (ULAQ-CCM and GEOSCCM). The CH4 lifetime may
become significantly longer (by approximately 16 %) with a sustained
injection of 8 Tg-SO2 yr−1 starting in the year 2020, which implies an increase of tropospheric
CH4 (200 ppbv) and a positive indirect radiative forcing of sulfate
geoengineering due to CH4 changes (+0.10 W m−2 in the 2040–2049
decade and +0.15 W m−2 in the 2060–2069 decade)
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