Inborn errors of metabolism (IEM) — an Indian perspective

The inborn errors of metabolism (IEM) constitute a diverse heterogeneous group of disorders with protean clinical manifestations presenting mainly in the pediatric population. Though individually rare, together they constitute a significant percentage of children seen in genetic and neurology clinics. This review focuses on selected IEMs and highlights those seen in the neonatal period. Data from Indian centers are presented. It also emphasizes principles of management in these difficult disorders in the context of a developing country     

Designing Better Radiology Workstations: Impact of Two User Interfaces on Interpretation Errors and User Satisfaction

This paper presents our solution for supporting radiologists interpretation of digital images by automating image presentation during sequential interpretation steps. We extended current hanging protocols with support for stages which reflect the presentation of digital information required to complete a single step within a complex task. We demonstrated the benefits of staging in a user experiment with 20 lay subjects involved in a comparative visual search for targets, similar to a radiology task of identifying anatomical abnormalities. We designed a task and a set of stimuli that allowed us to simulate the interpretation workflow from a typical radiology scenario—reading a chest radiography exam when a prior study is also available. The simulation was enabled by abstracting both the radiologists task and the basic workstation navigation functionality. The staged interface was significantly faster than the traditional user interface, provided a 37% reduction in the interpretation errors, and improved user satisfaction.     

Clinical presentation and follow-up of patients with the attenuated phenotype of mucopolysaccharidosis type I

Aim: To review the heterogeneity and severity of the clinical features at the attenuated end of the mucopolysaccharidosis (MPS) type I disease spectrum. Methods: The course of disease in 29 patients with attenuated mucopolysaccharidosis I who attended the MPS clinic in Manchester, UK, was reviewed. Results: For more than half of the patients, onset of symptoms was in the first 2 y of life, and the age at diagnosis ranged from 15 mo to 40 y. Joint stiffness, corneal clouding, umbilical hernia and recurrent ear, nose and throat symptoms were the commonest features at presentation. Patients experienced significant morbidity during the course of this inherited disease. Skeletal problems predominated and cardiac valve pathology, upper airway obstruction and hearing deficits were detected in a notable number of patients. Nerve decompression for carpal tunnel syndrome, cervical cord decompression, and grommet insertion for serous otitis media were the most frequent surgical interventions.

Conclusion: Clinical presentation of attenuated (“non-Hurler”) mucopolysaccharidosis type I is heterogeneous in time of onset and types of clinical features. A better understanding of the spectrum of disease and of the related disease progression will contribute to more accurate diagnosis, and patients will benefit from early intervention.     

Economic evaluation of neonatal screening for phenylketonuria and congenital hypothyroidism

OBJECTIVE: To evaluate the costs and benefits of neonatal screening for phenylketonuria (PKU) and congenital hypothyroidism (CH). Neonatal screening for PKU and CH is common throughout the developed world. It represents a model of preventive care in that the screening procedure is simple and intellectual disability is otherwise irreversible. Changes in treatment and care, and in particular the advent of maternal PKU, require regular evaluation of a programme that also impacts on a large healthy population. METHOD: Costs of screening were based on the programme provided within Western Australia. Costs averted were derived using patterns of care currently adopted in Western Australia and applied according to historical patterns of intellectual disability for each condition. RESULTS: A net saving of dollar A2.9 million is attributable to the programme annually. The economic benefits derive from the prevention of intellectual disability which otherwise incurs costs throughout the life of the affected individual. Maternal PKU represented a minor proportion of overall costs. Sensitivity analysis showed that the cost savings were robust, given changes in the levels of intellectual disability, but varied according to the discount rate. The result of a net saving was evident under all assumptions. CONCLUSION: Neonatal screening for PKU and CH is a cost saving use of resources and the emergence of maternal PKU has not had a significant effect on the economic outcomes.     

Peak-combination HARP: a method to correct for phase errors in HARP

PURPOSE: To introduce a method to correct phase errors (e.g., from B0 inhomogeneity) in tagging images, which may affect harmonic phase (HARP) evaluation. MATERIALS AND METHODS: The phase images corresponding to the negative and positive harmonic peaks in k-space are combined before HARP evaluation to eliminate any spurious phase. To validate in vivo, two complementary spatial modulation of magnetization (CSPAMM) data sets were collected for each volunteer and evaluated with conventional HARP, using either the positive or the negative harmonic peak, and with peak-combination HARP. RESULTS: Elimination of phase distortion by peak combination was observed in vitro and in vivo. Improved reproducibility of motion parameters was found with peak-combination HARP. CONCLUSION: With peak-combination HARP, reproducibility of contractile parameters is improved, and consequently, the number of subjects needed to detect statistically significant changes in contractile function can be reduced to one third compared to conventional HARP evaluation.     

A clinical evaluation of ophthalmic assessment in children with sensori-neural deafness

BACKGROUND: Since 1991, children with sensori-neural deafness and their families within Southern Derbyshire have been supported by a multiagency approach to their diagnosis and management. RESULTS: One hundred and twenty-two children were seen at the Child Development Centre for an holistic assessment, and 110 of these children have had an ophthalmic assessment, of whom 48 (43.6%) were found to have ophthalmic abnormalities. These included 43 children (39.1%) with refractive errors, ranging from mild to severe. Of 82 children with uncomplicated deafness, 26 (31.7%) had refractive errors. The prevalence of ophthalmic problems was higher than the prevalence in hearing school children in the literature and in local pre-school children. There were six cases of Usher syndrome. Twenty-one children had more than one eye defect. The findings indicate that deaf and hearing impaired children are two to three times more likely to develop ophthalmic abnormalities than their hearing peers, which makes early detection of paramount importance. An important local outcome has been the establishment of guidelines for ophthalmic assessment to include assessment of vision and screening for Usher syndrome by electro-physiological testing at aged 7 years and above. Screening has been completed to date in 78 children with congenital sensori-neural deafness. CONCLUSIONS: Sensitive and efficient ophthalmic assessment and management are essential for all deaf and hearing impaired children and national guidelines need to be established for both assessment of vision and screening for Usher syndrome, based on further evaluated research.     

Biologic and physical fractionation effects of random geometric errors

PURPOSE: We are developing a system to model the effect of random and systematic geometric errors on radiotherapy delivery. The purpose of this study was to investigate biologic and physical fractionation effects of random geometric errors and respiration motion and compare the resulting dose distributions with Gaussian blurring of the planned dose. MATERIALS AND METHODS: A hypothetical dose distribution with Gaussian penumbra was used. Random errors drawn from a normal distribution, optionally combined with simulated respiration motion (in the cranio-caudal direction), were used to displace the dose distribution for N simulated fractions. To simulate biologic effects of fractionation, the physical dose was converted to a biologically effective dose using the linear-quadratic model (including repopulation), then summed and converted back to physical dose for comparison. Differences between dose distributions were quantified in terms of the distance between selected isodose levels. RESULTS: A limited number of fractions led to an uncertainty in the position of isodose levels in the total dose with as standard deviation (SD) the SD of the random error divided by radical N. Due to biologic fractionation effects, the total dose distribution became slightly wider: 0.4 mm for alpha/beta = 1 Gy and a random error SD of 3 mm. The widening increased with random error and reduced with increasing alpha/beta but does not depend on the number of fractions or on repopulation. Respiration motion caused an asymmetric deviation in the shape of the total dose distribution, but no additional dose widening was seen from the biologic effect of fractionation. With a random error SD of 3 mm and respiration amplitude, A, of 1 cm or less (SD < 0.36 cm), the asymmetry was negligible. For larger respiration amplitudes (combined with the same random error), the shift of the 95% isodose level was about 0.25*A caudally, and 0.45*A cranially. CONCLUSIONS: Gaussian blurring with a combined SD of organ motion, setup error, and respiration motion is a valid approximation for the effect of purely random errors in fractionated radiotherapy. For respiration motion in excess of 1 cm in amplitude, isodose lines shift in a distinctly asymmetric fashion and asymmetric margins need to be used.     

Errors: can indicators measure the magnitude?

Errors in medicine, especially medication errors, have long been recognized as a dimension of quality of care and organizational performance. Recently, however, the magnitude of the issue, or its potential impact on cost, quality of care and patient safety have catapulted this issue to the forefront of national debate on the appropriateness of patient care management. There are still fundamental issues associated with the measurement of errors. Should errors that do not cause patient harm receive much attention? Could there be organizational or system issues that predispose to errors? Are there acceptable measurement models that allow comparative analysis and trending of institutional error rate profiles? This paper presents a systematic review of the measurement aspects for errors in medicine, emphasizing the medication errors' dimension. An indicator-based, epidemiological model of measurement is proposed which will allow a systematic inquiry into the issues of both preventable and non-preventable errors and their potential for patient harm.     

Information Technology in Emergency Medicine Residency–Affiliated Emergency Departments

OBJECTIVES: To describe acquisition and implementation of information technology (IT) in U.S. emergency medicine (EM) residency-affiliated emergency departments (EDs), including automatic medication error checking. METHODS: This was a survey of all U.S. EM residencies active in September 2000. Respondents specified whether specific IT tools had been "acquired" and "implemented fully." EDs were categorized according to primary versus affiliated training site, trauma level, and census. Numbers of "yes" responses were compared according to ED type (Kruskal-Wallis test, p < or = 0.05 significant). RESULTS: Of 121 residency programs, data were obtained from 93 (77%) for a total of 149 EDs. The percentages of EDs that reported full implementation for each technology are as follows: medication error checking, 7%; medication order entry, 18%; nonmedication orders, 7%; clinical documentation, 21%; old electrocardiograms, 62%; laboratory results, 84%; radiography order entry, 62%; image retrieval, 29%; radiologists' interpretations, 67%; cardiology reports, 62%; pathology reports, 70%; surgical reports/dictations, 60%; triage, 34%; tracking, 46%; electronic reference materials, 56%; registration, 84%; accounts, 72%; patient management software package, 20%; voice recognition, 7%. Trauma centers reported more IT tools than nontrauma centers (p = 0.01), and primary training sites reported fewer IT tools than affiliated EDs (p = 0.027). CONCLUSIONS: Incorporation of IT is not uniform in EDs where EM residents train. Acquisition of effective IT tools varies, and implementation lags behind acquisition. Fully implemented IT for medication error checking was reported in 7% of EDs; an additional 12% had acquired IT without implementing it fully.     

儿童屈光不正及近视的视力筛查标准

目的探讨快速筛查儿童屈光不正及近视的视力标准。方法 横断面调查研究。使用2002年10月至2003年1月中山大学中山眼科中心对广州市荔湾区进行的屈光不正研究（RESC）数据,检查包含裸眼视力（ETDRS视力表）、散瞳下自动电脑验光（ARK-30;Nidek Corp.）及眼部健康检查。屈光不正定义为SE≤-0.50 D、SE≥+2.00 D或散光≤-1.00 D;近视定义为：等效球镜度（SE）≤-0.50 D、或SE≤-0.75 D、或SE≤-1.00 D;统计灵敏度、特异度、阳性和阴性预测值,并作ROC曲线图。结果 共统计3 715名7~15岁儿童数据。屈光不正ROC曲线图显示灵敏度,特异度都相对高的视力为0.625,其灵敏度、特异度、阳性和阴性预测值分别为71.7%、93.3%、92.9%和72.9%。近视ROC曲线图显示灵敏度、特异度都相对高的视力为0.5。等效球镜度≤-0.50、-0.75或-1.00 D的灵敏度分别为66.3%、73.5%和80.7%,特异度分别为94.3%、94.0%和93.5%,阳性预测值分别为89.7%、88.0%和86.3%,阴性预测值分别为78.9%、85.4%和90.5%。结论 对于7~15岁儿童,0.625为筛查屈光不正的视力截点,0.5为筛查高于-1.00D近视的视力截点。