Life-threatening stings, bites, infestations, and parasitic diseases

Bites, stings and infestations can be fatal. Anaphylaxis to vespids and bees can be prevented with immunotherapy. Patients should be referred to an allergist. The acute care and prevention of arthropod injury is discussed below.     

Telling good from bad news: ADHD differentially affects processing of positive and negative feedback during guessing

Neuroimaging studies on ADHD suggest abnormalities in brain regions associated with decision-making and reward processing such as the anterior cingulate cortex (ACC) and orbitofrontal cortex. Recently, event-related potential (ERP) studies demonstrated that the ACC is involved in processing feedback signals during guessing and gambling. The resulting negative deflection, the 'feedback-related negativity' (FRN) has been interpreted as reflecting an error in reward prediction. In the present study, ERPs elicited by positive and negative feedback were recorded in children with ADHD and normal controls during guessing. 'Correct' and 'incorrect' guesses resulted in respectively monetary gains and losses. The FRN amplitude to losses was more pronounced in the ADHD group than in normal controls. Positive and negative feedback differentially affected long latency components in the ERP waveforms of normal controls, but not ADHD children. These later deflections might be related to further emotional or strategic processing. The present findings suggest an enhanced sensitivity to unfavourable outcomes in children with ADHD, probably due to abnormalities in mesolimbic reward circuits. In addition, further processing, such as affective evaluation and the assessment of future consequences of the feedback signal seems to be altered in ADHD. These results may further help understanding the neural basis of decision-making deficits in ADHD.     

Atrial fibrillation: multi-detector row CT of pulmonary vein anatomy prior to radiofrequency catheter ablation--initial experience

PURPOSE: To evaluate multi-detector row computed tomographic (CT) depiction of pulmonary veins to provide a road map for radiofrequency catheter ablation. MATERIALS AND METHODS: For patients, institutional review board (IRB) approval was not required, and consent was obtained for treatment. Control subjects were part of an IRB-approved research protocol at the institution, in which they had consented to participate. Multi-detector row CT was performed in 23 patients (17 men, six women; mean age, 48 years +/- 11 [standard deviation]) with atrial fibrillation who were admitted for isolation of pulmonary veins by means of radiofrequency catheter ablation. Pulmonary vein anatomy was evaluated, and diameters of pulmonary vein ostia were measured. To determine the shape of ostia, a venous ostium index was calculated for all veins by dividing anterior-posterior measurements by superior-inferior measurements. Results were compared with those in a control group of 11 patients (eight men, three women; mean age, 56 years +/- 11) without atrial fibrillation. Images were evaluated by two observers in consensus. RESULTS: Pulmonary veins additional to the four main veins were found in seven (30%) of 23 patients. Common ostia of left and right pulmonary veins were detected in 19 (83%) and nine (39%) patients, respectively. Early branching occurred more often with right than with left veins (19 [83%] vs three [13%] cases, P <.05) in both patients and control subjects. Anterior-posterior diameter of ostia was 12.8 mm +/- 3.3 for left veins, 16.2 mm +/- 3.8 for right veins, and 18.8 mm +/- 7.7 and 28.7 mm +/- 5.1 for left and right common ostia, respectively. Ostia of right pulmonary veins were more round than were ostia of left pulmonary veins (venous ostium index in patients, 0.91 +/- 0.21 vs 0.75 +/- 0.17, P <.05; in control subjects, 0.93 +/- 0.12 vs 0.82 +/- 0.17, P <.05). The CT data were used to determine ablation strategy and guide catheters during radiofrequency ablation. CONCLUSION: Multi-detector row CT provides a valuable road map for pulmonary vein anatomy prior to radiofrequency catheter ablation. Variations in number and insertion of pulmonary veins were observed in a considerable number of patients and control subjects.     

Corrected tetralogy of Fallot: delayed enhancement in right ventricular outflow tract

PURPOSE: To evaluate retrospectively the presence of fibrosis and largest diameter of the right ventricular outflow tract (RVOT) by using delayed enhancement magnetic resonance (MR) imaging in patients who had undergone initial correction for tetralogy of Fallot. MATERIALS AND METHODS: MR imaging was performed in 24 consecutive patients (16 male, eight female; mean age, 25 years; age range, 13-47 years) with corrected tetralogy of Fallot. The study protocol was approved by the local ethics committee, and informed consent was not required. Fifteen minutes after injection of 0.2 mmol/kg gadopentetate dimeglumine, an inversion-recovery turbo field-echo sequence was applied for detection of delayed enhancement. Right ventricular volumes, ejection fraction, and anterior-posterior diameter of the RVOT were calculated. Mann-Whitney nonparametric testing was used to compare measurements of ventricular volume, function, and anterior-posterior diameter of the RVOT in the presence or absence of delayed enhancement. Correlation was tested with Pearson coefficient. RESULTS: Delayed enhancement was seen in 17 patients in the RVOT. During initial surgery, transannular patching was performed in 13 (76%) of 17 patients, RVOT patching in one (6%) of 17 patients, and the Brock procedure in two (12%) of 17 patients. In one patient, the type of initial RVOT repair was unknown. Patients with delayed enhancement in the RVOT, as compared with those without delayed enhancement in the RVOT, had increased RVOT diameter (32 mm +/- 7 [standard deviation] vs 22 mm +/- 3, P < .01), decreased right ventricular ejection fraction (43% +/- 6.3 vs 54% +/- 10, P < .001), and increased end-diastolic volume (175 mL/m2 +/- 42 vs 118 mL/m2 +/- 34, P < .01). The diameter of the RVOT correlated with increased right ventricular end-systolic volume (R = 0.86) and was inversely related to ejection fraction (R = -0.65). CONCLUSION: Delayed enhancement occurs frequently in patients after correction for tetralogy of Fallot. Delayed enhancement in the RVOT was associated with RVOT dilatation, which adversely affects right ventricular hemodynamics.     

The use of mathematical models to evaluate pelvic masses; can they beat an expert operator?

The pre-operative characterization of ovarian cysts remains a major challenge. Functional cysts and some other benign cysts should be managed conservatively, whereas persistent tumours may need removal. It is crucial to distinguish between malignant tumours, which are better treated by a gynaecological oncologist, and benign tumours, which may be suitable for minimal-access surgery. Over the past decade several ultrasound-based morphological scoring systems, colour Doppler parameters, logistic regression models and artificial neural networks have been proposed and tested in order to try to predict the histology of ovarian tumours. On prospective testing none of the current models can beat an expert sonologist. Signs of malignancy include the presence of papillary structures, irregular solid areas, septa and a strong vascularization at colour Doppler imaging. Further refinement of mathematical models and the results of multicentre trials need to be reviewed before the clinical use of mathematical models can be advocated.     

Juvenile arrest: a cross-cultural comparison

BACKGROUND: Cross-national studies describing the psychopathological characteristics of arrested adolescents are virtually non-existent. Such studies are important because they have implications for national policy on arrest, case-management, and future research. METHOD: To address this issue, self-report surveys administered to representative groups of 12- to 16-year-old adolescents in New Haven, USA (N = 1138) and Antwerp, Belgium (N = 627) were compared. A number of internalizing and deviant behavior variables were compared between controls (C), non-arrested antisocial (NA), and arrested antisocial (AR) participants. RESULTS: Similar cross-national arrest rates and levels of antisocial behavior were found. NA and AR youths in both countries reported more internalizing problems, except for anxiety, and more deviant characteristics. Contrary to expectations, the level of depression was not higher in AR compared to NA youth when differences in antisocial behavior between NA and AR were controlled. Also unexpected, arrest showed an independent association with a number of deviant behavior variables. CONCLUSIONS: Further research should investigate the underlying mechanisms of these associations, as this insight would be useful for developing future intervention and prevention programs, as well as for developing future national policies regarding juvenile antisocial behavior.