Paediatric case series of drug reaction with eosinophilia and systemic symptoms (DRESS): 12-year experience at a single referral centre in Hong Kong and the first reported use of infliximab.

Summary: DRESS (drug reaction with eosinophilia and systemic symptoms) is a rare but potentially life-threatening disorder characterized by fever, skin eruption, haematological abnormalities and multi-organ dysfunction after drug exposure. The pathophysiology is thought to be related to interactions between culprit drugs, viral reactivation and T-lymphocytes activation. We report 4 paediatric patients with DRESS who were treated at our centre over the past 12 years. Most cases improved after corticosteroids. Other immunosuppressive medications were attempted in refractory cases with varied outcomes. Patient 3 was the first reported case that involved the use of infliximab, a TNF-α inhibitor, for DRESS. Although clinical efficacy was not observed for this one patient, a previous study demonstrated that patients with DRESS, disease progression and HHV-6 reactivation had elevated pre-treatment TNF- α and IL-6 levels. Further research is needed to explore the role of these cytokines in DRESS.

Hong Kong Institute of Allergy and Hong Kong Society for Paediatric Immunology Allergy & Infectious Diseases joint consensus statement 2018 on vaccination in egg-allergic patients.

Vaccination of egg-allergic individuals has been a historical concern, particularly for influenza and measles-mumps-rubella-varicella vaccines that are developed in chicken egg embryos or chicken cell fibroblasts. The egg proteins in these vaccines were believed to trigger an immediate allergic reaction in egg-allergic individuals. However, recently published international guidelines have updated their recommendations and now state that these vaccines can be safely administered to egg-allergic individuals. This joint consensus statement by the Hong Kong Institute of Allergy and the Hong Kong Society for Paediatric Immunology Allergy & Infectious Diseases summarises the updates and provides recommendations for local general practitioners and paediatricians. Hong Kong Institute of Allergy and Hong Kong Society for Paediatric Immunology Allergy & Infectious Diseases joint consensus statement 2018 on vaccination in egg-allergic patients Background.

Adolescents' attitudes to the COVID-19 vaccination.

Vaccines against COVID-19 are now available for adolescents in Hong Kong but vaccine hesitancy is a major barrier to herd immunity. This survey study explores Hong Kong adolescents' attitudes towards the COVID-19 vaccination. 2609 adolescents from across Hong Kong completed an online survey focused on the intent to vaccinate and the reasons for their choice. 39% of adolescents intended to take the COVID-19 vaccination and significant factors for this decision include: having at least one parent vaccinated, knowing somebody diagnosed with COVID-19 and receiving the influenza vaccine. Adolescents' major concerns were either the safety and efficacy of the vaccine or the risk of infection. This study has proved that even in adolescents the vaccine hesitancy model is prominent with adolescents' intentions highly related to confidence in the vaccine and perception of disease risk. Future interventions should target these specific concerns to ensure adolescents are well educated to overcome vaccine hesitancy.

Complicated infantile meningitis: evaluation by real-time sonography.

Real-time sonographic findings in 20 infants with bacterial meningitis are reported. The spectrum of features included normal scans, ventricular enlargement, focal areas of increased cortical echogenicity, ventricular bands, and cerebral abscess. Areas of increased cortical echogenicity on sonography representing meningoencephalitis corresponded to areas of contrast enhancement seen on computed tomography (CT). Excellent correlation was found between CT and sonography. Because of the advantage of obtaining sonographic scans at the bedside, it appears that sonography offers an attractive alternative to CT in the evaluation of infantile meningitis and meningoencephalitis.

Effect of radiographic contrast material exposure on spiral CT attenuation of renal calculi.

RATIONALE AND OBJECTIVES: The authors performed this study to determine whether exposure of renal calculi to radiographic contrast material has an effect on the attenuation values at computed tomography (CT) performed with varying collimation widths. MATERIALS AND METHODS: Renal calculi (23 stones of various composition) were scanned with 1-, 3-, and 10-mm collimation. Stones were then exposed to a solution of radiographic contrast material for 5 minutes, washed with water, and rescanned 36 hours later. The reproducibility of the CT attenuation measurements on different days was evaluated by obtaining measurements in a subset of 16 renal stones on 4 different days. RESULTS: There was no statistically significant change in attenuation after contrast material exposure at narrow collimation. At wider collimation, statistically significant increases were noted in both attenuation and standard deviation. A small amount of variability between readings was noted on different days, with a minimal increase in attenuation each day. Correlation between readings remained very high. CONCLUSION: Exposure of stones to a radiographic contrast material had a statistically significant effect on CT attenuation values only at wide collimation. This may be related to technical factors including volume averaging. Absence of an effect at narrow collimation suggests that the attenuation values of renal stones do not significantly change after exposure to contrast material.

Correction of helical CT attenuation values with wide beam collimation: in vitro test with urinary calculi.

RATIONALE AND OBJECTIVES: Urinary calculi are now commonly detected with helical computed tomography (CT), and it has been proposed that stone composition can be determined from CT attenuation values. However, typical scans are made with a beam collimation of 5 mm or more, resulting in volume averaging and reduction in accuracy of attenuation measurement. The authors tested a model for correction of errors in attenuation values, even at section widths larger than the width of the object. MATERIALS AND METHODS: Human urinary stones were scanned with helical CT at different beam collimation widths. A computer model was used to predict the effect of beam width and stone size on accuracy of measured attenuation. RESULTS: At 3-mm collimation, the model corrected the attenuation readings with an underestimation of 12% +/- 1 (compared with values at 1-mm collimation; 127 stones; diameters of 1.7-11.3 mm). With attenuation measured at 10-mm collimation, the model underestimated the true value by 34% +/- 3 (103 stones), with a significant negative correlation with stone diameter on magnitude of error (diameters of 3.0-11.3 mm). Correlation of data from patient scans with subsequent in vitro scanning of the same stones confirmed the validity of the model, but corrected in vivo scans consistently yielded lower values for the stones than in vitro. CONCLUSION: Volume averaging effects on attenuation in helical CT are predictable in vitro for urinary calculi--and presumably for other roughly spherical structures--as long as section width does not excessively exceed the diameter of the structure.

Calcium stone fragility is predicted by helical CT attenuation values.

BACKGROUND AND PURPOSE: Helical CT has become the preferred method for imaging urinary calculi, and so it would be useful if data from helical CT could also be used to predict the number of shockwaves (SWs) needed to break a given stone. METHODS AND MATERIALS: We measured the number of SWs required to comminute calcium stones in vitro. RESULTS: The SW requirement correlated with stone size (volume, weight, diameter) and with helical CT attenuation values when the scans were performed at 3-mm collimation. When CT scans were performed at 1-mm collimation, the number of SWs needed for comminution did not correlate with helical CT attenuation values. This result indicates that the correlation with 3-mm scans was attributable to volume-averaging effects, in which smaller stones yield smaller attenuation values. That is, attenuation values from helical CT at larger beam collimation widths contain information about stone size that can be exploited to predict the fragility of calcium stones. We observed that for calcium stones, the number of SWs to comminution was generally less than half the stone CT attenuation value in Hounsfield units. This "half-attenuation rule" predicted the number of SWs needed to complete fragmentation for 95% of calcium stones (24/24 calcium oxalate monohydrate, 13/13 hydroxyapatite, 8/10 brushite stones). CONCLUSION: This in vitro study suggests that it may be possible to predict effective SW dose using helical CT prior to lithotripsy.

Calcific deposits in the heart.

Four case reports are presented which illustrate various patterns of calcific deposits in the heart. Valvular, myocardial, intracavitary, and coronary calcific deposits are illustrated, with emphasis on pathology and clinicopathologic-radiologic correlation. "Dystrophic" and "metastatic" calcifications are terms used to describe calcific deposits in abnormal and normal soft tissues, respectively. These terms are somewhat confusing in relation to the myocardium, however, as the chronologic sequence of cardiac injury is often uncertain. We suggest that these terms be avoided in relation to the heart, in favor of simple descriptive terms such as "myocardial calcific deposits." Many conditions, such as renal failure and hypercalcemia may contribute to the likelihood of soft tissue calcification, although a definite common etiology has not been identified. Likewise, soft tissue calcification has been difficult to diagnose premortem. The advent of ultrafast (cine) computed tomography may provide a quick, noninvasive, highly sensitive and specific method for diagnosis of soft tissue calcific deposits in the future.

Vitamin D status and peripheral arterial disease: evidence so far.

BACKGROUND: Vitamin D deficiency has recently been implicated as a contributory factor in the development of peripheral arterial disease (PAD). METHODS: A review of the published literature on PAD and vitamin D was undertaken using Medline, PubMed, and Embase, and cross-referenced. All relevant published papers on the subject were reviewed. RESULTS: Published studies have shown that there is a significant association between vitamin D and PAD. Populations with lower vitamin D levels are more likely to develop PAD in a graded manner. Higher amputation rates are also observed among patients with PAD and lower vitamin D levels. In addition, vitamin D deficiency is significantly associated with increased risk of cardiovascular adverse events. This was also observed in the mouse model where low vitamin D led to the development of atherosclerosis. CONCLUSION: This study shows that vitamin D deficiency could be an independent risk factor for the development of PAD and that this risk factor is easily correctable. Further studies should look into the effects of vitamin D supplementation in patients with PAD.

The accuracy of preoperative staging for surgically resected laryngeal cancer.

A retrospective analysis was undertaken to evaluate the accuracy of preoperative staging for laryngeal cancers. T (primary tumor) stage was evaluated more accurately by the combined assessment (clinical examination plus computed tomography (CT) for all laryngeal tumors when compared to the clinical examination (75% versus 31%, p less than 0.04). Supraglottic tumors were evaluated more accurately by CT than the clinical examination (86% versus 0%, p less than 0.01). There was no difference between CT and the clinical examination when evaluating glottic and transglottic lesions. The clinical examination, CT and combined assessment equally evaluated N (regional lymph node involvement) stage. The clinical examination and CT are complementary exams that should be used in conjunction when evaluating patients with advanced laryngeal cancers.

Uterine adnexal torsion: a case report.

Uterine adnexal torsion is a surgical condition that requires prompt diagnosis and intervention. An ultrasound examination demonstrating a unilaterally enlarged, hypoechoic ovary with several small spherical, peripherally located sonolucent structures in the involved ovary, in addition to a history and physical consistent with torsion, confirms the need for surgical intervention. In this article, we present a case of uterine adnexal torsion and discuss the etiologic, diagnostic and therapeutic aspects of this entity.

Intraoperative ultrasound of hepatic tumors.

Intraoperative ultrasound (IOUS) scanning of liver masses was compared with those of preoperative computed tomography (CT) and intraoperative palpation. Between March 1989 and May 1991, 24 patients underwent 25 IOUS procedures during laparotomy. Intraoperative ultrasound provided more information than the other modalities in 10 patients (40%) and affected operative management in eight patients (32%). It was concluded that IOUS, when used in conjunction with CT and palpation, is an important technique in the surgical management of patients with hepatic neoplasms.

Delayed posttraumatic diaphragmatic hernia: case report and literature review.

The case of a 36-year-old man with an unsuspected delayed posttraumatic diaphragmatic hernia is described. This entity often presents with vague clinical symptoms and non-specific radiographic findings long after the initiating trauma has been forgotten. Therefore, the preoperative diagnosis of this entity is notoriously difficult, but failure to make this diagnosis carries a high mortality rate. A high index of suspicion must be maintained.

Ultrasound guided drainage of pleural fluid.

Ultrasound guided drainage has been reported as a highly successful drainage procedure. Computed tomography (CT) and fluoroscopy also have been cited as favorable imaging modalities for the treatment of pleural effusion. With its extreme sensitivity to fluid collections and rapid and accurate localization of fluid, real-time ultrasound has become the primary imaging modality for the interventional drainage of pleural fluid. This is a retrospective study of patients with radiographically suspected pleural effusion, using ultrasonic scanning for possible drainage. A special bedside drainage technique in critically ill patients also is described.

Sonography of appendiceal intussusception.

A case in which appendiceal intussusception was diagnosed preoperatively by sonography is described. The sonographic finding of multiple concentric hypoechoic and hyperechoic rings was confirmed at laparotomy to be due to appendiceal intussusception. Demonstration of the sonographic coiled spring sign in the right lower quadrant should raise the possibility of appendiceal intussusception. The differential diagnosis is discussed.

Stone surface area determination techniques: a unifying concept of staghorn stone burden assessment.

The use of stone surface area measurements obtained from standard radiographs provides a more accurate and reproducible assessment of stone burden when reporting results and treatment recommendations for staghorn calculi. Techniques for determining stone surface area include use of graph paper, planimeter or computerized image analysis. The use of graph paper is inefficient while planimeters suffer from significant variation for areas less than 500 mm.2 (more than 5%). Computer image analysis is accurate, rapid and easiest to perform. Software programs compatible with microcomputers are readily available making assessment of stone surface area practical and inexpensive. Stone surface area showed close correlation to stone volume as measured by 3-dimensional computerized tomography (correlation coefficient 0.84, p = 0.005). Stone surface area determination enables more accurate reporting of treatment results and, thus, recommendations based upon stone burden. Comparison of data between institutions becomes more meaningful if stone surface area is used. Stone surface area also provides a useful basis to study and compare trends of treatment within a single institution.

Cribside neurosonography: real-time sonography for intracranial investigation of the neonate.

A prospective study was made of 94 real-time sonographic sector scans of 56 neonates in a 6 month period. The examinations were performed using the anterior fontanelle as an acoustic window. In 17 cases, computed tomography (CT) head scans were available for comparison. In no case did the CT and sonographic examination disagree as to the size of the lateral ventricles. Abnormalities detected by sonography include ventriculomegaly, intracerebral hematomas, a congenital glioma, and several cystic lesions. Sonographic sector scanning produces excellent, detailed images of dilated lateral and third ventricles, uses no ionizing radiation, is less expensive than CT, and can be performed in the isolette, minimizing the risk of hypoxia and hypothermia. At Methodist Hospital Graduate Medical Center, sonography has replaced CT as the initial method of investigation of ventricular size. CT plays a complementary role in the evaluation of the posterior fossa, intracranial hemorrhage, and mass lesions.