先天性代谢病代谢危象的急诊识别与处理

先天性代谢病代谢危象并非罕见,其临床表现常为非特异性,临床医生常倾向于在除外其他常见病后才考虑.未能得到及时治疗者可在数小时至数日内迅速恶化甚至死亡,存活者可遗留严重后遗症.诊断先天性代谢病代谢危象不需广泛了解生物化学代谢途径或每种代谢性疾病.熟悉可提示诊断线索的主要临床表现和初始辅助检查特征最为重要.早期诊断和恰当的治疗常可挽救生命、预防存活者的永久性神经系统后遗症.     

Cardiac manifestations in children with inborn errors of metabolism

Need and purpose

Cardiac involvement is a part of many inborn errors of metabolism, but has not been systematically studied. This review focuses on studies describing cardiac manifestations of inborn errors of metabolism in childhood.

Methods

Two independent reviewers searched the topic using PubMed database. Studies published within 20 years were considered, without applying any restrictions related to study design.Despite the small number of existing systematic studies on the topic, several case series/reports were identified.

Conclusions

Cardiomyopathy is the most frequent heart disorder in most metabolic defects. Heart rhythm disorders are mainly encountered in mitochondrial disorders and acidemias, whereas valvular dysfunction is a prominent finding in storage disorders. Cardiac involvement in mitochondrial disorders, congenital disorders of glycosylation and acidemias usually constitute an early symptom. On the contrary, in storage disorders, heart problems are revealed in later stages during routine multisystemic evaluation, with the exception of Pompe disease. As a variety of cardiac manifestations can be found in inborn errors of metabolism, these children should be systematically screened for heart problems during their follow-up.

     

Osteoporosis in children with neuromuscular diseases and inborn errors of metabolism

The effects on bone of cerebral palsy (CP), Duchenne's muscular dystrophy and different metabolic diseases are reviewed from the literature. Children affected with neuromuscular diseases and inborn errors of metabolism may develope osteoporosis. Mechanical stimulation is paramount for bone strengthening, and immobilization is a well-known cause of osteoporosis. CP is the most common cause of disability in pediatrics. The main cause of low bone density in children and adolescents with CP and muscular dystrophy is lack of activity, but nutritional issues and pharmacological treatments can contribute to the clinical picture. Programs to exert mechanical stimulation of their bones are warranted, as much as nutritional programs. Treatment with bisphosphonates shows promising results in this population. The term 'inborn errors of metabolism' comprise a large list of defects in the metabolism of amino acid transport and metabolism of peptides, carbohydrates, vitamins, minerals, and fatty acids. Other disorders included are errors in mitochondrial energy metabolism, problems with biosynthesis and breakdown of complex molecules, and neurotransmitter defects. Low bone density and fractures in these patients may be consequence of immobilization and muscle weakness, but also of treatments (e.g. steroids, dietary restrictions), and the primary disease. Adequate control of the primary disease is paramount to prevent bone problems.     

遗传性代谢病146例临床研究

目的 探讨遗传性代谢病患儿的疾病谱、年龄特点及临床症状.方法 对2003年1月-2007年12月在首都儿科研究所附属儿童医院住院的146例遗传性代谢病患儿的临床资料进行回顾性分析.依据患儿典型症状结合特殊生化检测、尿GC/MS、酶学、基因学检测、肌肉活检、影像学及实验性治疗等作出实验室诊断或临床诊断.结果 检出遗传性代谢病共9大类17个病种,有机酸血症检出率占首位(36.3%),其次为线粒体病(16.4%).1岁内出现症状者91例(62.3%),确诊53例(36.3%);～3岁出现症状者21例(14.4%),确诊40例(27.4%);～6岁出现症状者16例(11.0%),确诊15例(10.3%);>6岁出现症状者18例(12.3%),确诊38例(26.0%).146例主要表现为智力运动发育落后或倒退(85.9%)、肌张力异常(51.4%)、惊厥(41.8%)、肝大(30.8%)、血液系统异常(24.7%)、共济失调(12.3%).结论 儿童期发病的遗传性代谢病病种多,其中有机酸血症检出率最高;遗传性代谢病息儿症状出现年龄早、确诊年龄滞后,且随年龄增长发病人数减少;对以智力运动发育落后/倒退、惊厥、肌张力异常就诊的患儿应注意除外遗传性代谢病.     

Laboratory diagnosis of inborn errors of metabolism in children

A compendium of tests available to diagnose children with inborn errors of metabolism is presented. It is intended to provide the pediatric pathologist with a rational way of using laboratory tests to investigate a patient who is suspected of having an inborn error of metabolism. It is intended to bridge the gap between the ward and the laboratory by providing a framework for investigations of such children.     

无高危因素的脑瘫儿童先天性代谢异常的筛查

先天性代谢异常(inbom errors of metabolism)包括氨基酸、有机酸、糖、脂肪、激素等多种代谢缺陷,系由于遗传性代谢途径缺陷,导致异常代谢物的蓄积或生理必需物质的缺乏.一些先天性代谢异常临床表现缺乏特异性,早期诊断存在一定困难.近几年,随着尿气相色谱-质谱法(CC/MS法)的临床应用,使既往许多易漏诊的先天性代谢异常得到了早期诊断.本研究对我院康复科住院的34例无脑瘫的三大主要致病高危因素(窒息、早产、黄疸)的脑瘫儿童进行了先天性代谢异常的筛查,现将结果报道如下.     

Screening for inborn errors of metabolism in high-risk children from Rio de Janeiro, Brazil

From 1988 to 1995, our laboratory at the Institute of Chemistry of the Federal University of Rio de Janeiro, in Rio de Janeiro, screened 2650 samples from 2000 high-risk patients (mostly children) for Inborn Errors of Metabolism (IEM). Chemical tests, various chromatographic techniques and enzyme assays were performed on urine, plasma and in some cases, cerebrospinal fluid (CSF). A total of 145 cases of IEM (7.2%) was identified. These were related to: the metabolism of amino acids (41) and carbohydrates (17), organic acids (7), lysosomal enzymes (61), membrane transport system (16), metals (2), intestinal disaccharidases (1) and porphyrin metabolism (3). Furthermore, a relevant number of patients with abnormal findings is still under investigation. Biochemical results and clinical symptoms are presented and the importance of reference laboratories for the detection of IEM is stressed.     

遗传性代谢病致儿童脑发育落后的治疗与预后

目的探讨遗传性代谢疾病致儿童脑发育落后中治疗及影响预后的相关因素。方法用串联质谱仪对278例原因不明的脑发育落后患儿进行血氨基酸谱和酰基肉碱谱筛查,对疑似代谢性疾病患儿进行尿气相色谱/质谱（GC/MS）及相关酶活性检测,对检出的遗传性代谢病患儿的临床资料进行综合分析。结果17/278例（6.15%）确诊为遗传性代谢病,其中甲基丙二酸血症4例,甲基丙二酸血症伴同型胱氨酸尿症4例,丙酸血症3例,鸟氨酸氨甲酰转移酶缺乏症、枫糖尿病、Ⅰ型戊二酸血症、异染色性白质脑病、苯丙酮尿症、生物素酶缺乏症各1例。临床表现为智能及运动发育落后或倒退、惊厥、昏迷、呕吐、肌张力降低、营养不良、嗜睡、反复感染等。实验室检查显示代谢性酸中毒、血氨及血乳酸增高、贫血等。MRI表现为脑萎缩、双侧脑白质T2w高信号或伴T1w低信号、多发性脑软化或囊样变等。起病早、伴严重酸中毒及昏迷的维生素B12无效型甲基丙二酸血症预后极差。患儿经特殊奶方、低蛋白饮食、肉碱、维生素B12及生物素等治疗后,好转11例,死亡5例,未愈1例。结论对原因不明的脑发育落后患儿应予遗传代谢性病筛查;早期、合理治疗有助于改善预后。     

Children with inborn errors of phenylalanine metabolism: prognosis and phenylalanine tolerance

Twenty-three children, who were detected by neonatal PKU screening, were followed for 8-18 years in one paediatric centre. Dietary treatment was started if the blood phenylalanine level exceeded 0.72 mmol/l. All 23 infants were initially given a low phenylalanine diet. The growth and development rates of the children did not differ significantly from those in a reference population, although one child had mild mental retardation and another had a short attention span. Fourteen children were still on a strict phenylalanine-restricted diet on their last follow-up (at 8-18 years of age). In nine children who were initially put on a low phenylalanine diet, it was possible to normalize the diet between 1/2 and 10 years of age, while maintaining the blood phenylalanine levels between 0.25 and 0.72 mmol/l. It seems likely that those of our patients who markedly increased their phenylalanine tolerance during childhood had a regulatory mutation of the phenylalanine hydroxylase system. A continuous reevaluation of each child treated with a low phenylalanine diet reduces the use of unnecessarily restricted diets.     

Selenium requirements in patients with inborn errors of amino acid metabolism and selenium deficiency

The diets of 5 patients with phenylketonuria or maple-syrup-urine disease were supplemented with yeast which was rich in selenium. For 120 days the patients received 45 g Se/day to increase the Se content of their diets to 10–12ng Se/Kjoule. Before supplementation the selenium content of serum (5–15 ng/ml) and whole blood (10–27 ng/ml), and the activity of the erythrocyte glutathione peroxidase (0.19–2.69 U₃₇/g Hb), amounted to only 10–20% of normal. The serum selenium content reached normal values within 4 weeks of supplementation, followed by normalisation of the selenium content of whole blood within 4–8 weeks. Restoration of the activity of erythrocyte glutathione peroxidase took 9 to 15 weeks —the red cell life span. There was a significant positive correlation between the selenium content of the erythrocytes and the activity of erythrocyte glutathione peroxidase.With support of Deutsche Forschungsgemeinschaft     

Management and emergency treatments of neonates with a suspicion of inborn errors of metabolism

During the neonatal period, inborn errors of metabolism mostly present with an overwhelming illness that requires prompt diagnosis and both supportive and specific treatments. The most frequent situations are due to branched-chain organic acidurias that present with ketoacidosis and urea cycle defects that are characterized by hyperammonaemia. During both situations, toxin removal procedures and nutritional support with a free-protein and high-energy diet are pivotal treatments. In patients presenting with hypoglycaemia blood glucose levels must be corrected. Progress following glucose provision is useful in recognizing the disorders that are mainly implicated. Hyperinsulinism requires high-glucose infusion. Glycogen storage diseases and gluconeogenesis defects are easily treated with a permanent glucose provision while hypoglycaemias quickly recur. In patients with galactosaemia, hereditary fructose intolerance or tyrosinaemia type I, the presentation is dominated by a liver failure requiring galactose and fructose exclusion associated with a low-protein diet. Many patients with β-oxidation defects may present with hypoglycaemia that is usually easily corrected. The precise diagnosis can be easily missed in those patients that do well in the following weeks but may develop cardiac failure, arrhythmia and/or liver failure. Patients presenting with intractable convulsions, vitamin responsiveness to biotin, pyridoxine and folate must be considered.     

串联质谱技术选择性筛查遗传代谢病高危患儿552例初步分析

目的：应用串联质谱（tandem mass spectrometry, MS/MS）技术进行遗传代谢病（IEM）高危儿筛查,初步了解我国 IEM 的发病种类和阳性率,为其有效防治提供科学依据。方法：利用MS/MS技术对在河北省石家庄市8所省、市级医院就医的552例可疑 IEM 患儿的血液样本进行 IEM 筛查。结果：发现阳性患儿64例,阳性率为11.6%。其中甲基丙二酸血症或丙酸血症33例,苯丙酮尿症2例,肉碱棕榈酰转移酶缺乏Ⅰ型3例,长链酰基辅酶 A 脱氢酶缺乏症1例,中链酰基辅酶A脱氢酶缺乏症2例,枫糖尿症6例,短链酰基辅酶A脱氢酶缺乏症2例,戊二酸血症Ⅰ型2例,异戊酸血症2例,同型胱氨酸尿症2例,肉碱缺乏症4例,酪氨酸血症1例,精氨酸琥珀酸尿症1例,瓜氨酸血症2例,精氨酸血症1例。结论：MS/MS技术是筛查诊断IEM的有效工具。     

Agenesis of the corpus callosum and cerebral anomalies in inborn errors of metabolism

Dysgenesis of the corpus callosum has been recognized as a marker for aberrant development of the central nervous system. It has been suggested that developmental defects of the corpus callosum may be more frequently encountered in patients with inborn errors of metabolism. The objectives of the present study were to determine the prevalence of developmental defects of the corpus callosum in patients attending a genetics-metabolic disorders clinic, to describe the spectrum of abnormalities in brain development in patients with confirmed inborn errors of metabolism and abnormalities of the corpus callosum as ascertained by neuroimaging and/or postmortem studies. Nineteen patients (10 males, 9 females) with confirmed metabolic diagnoses were identified by systematic search of the genetics clinic database. All 19 (100%) expressed variable degrees of hypoplasia, complete or partial agenesis (ACC). Abnormalities of head size were noted in 17/19 (89.5%). The majority 12/17 (70.5%) were associated with microcephaly, while macrocrania was noted in 5/17 (29.5%). Associated central nervous system (CNS) anomalies included abnormalities in ventricular morphology in 18/19 (94.7%), ventriculomegaly in 11/19 (63.1%), increased extraxial cerebrospinal fluid space in 11/19 (57.9%), changes in the gray matter (neuronal migration defects, porencephaly) in 9/19 (47.3%), white matter changes in 12/19 (63.1%) and abnormalities of the posterior fossa and hindbrain in 12/19 (63.1%). In patients with inborn errors of metabolism, dysgenesis of the corpus callosum serves as a marker for other developmental defects within the nervous system. We discuss here potential mechanisms by which metabolic defects affect diverse biochemical pathways, altering key neurobiological processes (e.g. defective cell membrane formation, cellular bioenergetics and cell-to-cell signaling), that eventually lead to structural abnormalities in the developing nervous system.     

Expressed emotion,attributions and depression in mothers of children with problem behaviour

BACKGROUND: This was an initial study seeking to examine the relationship between Expressed Emotion (EE), spontaneous causal attributions and depression in mothers of children referred for problem behaviour. METHOD: Sixty-one mothers were interviewed using the Camberwell Family Interview (CFI). The CFI was coded for maternal EE and spontaneous causal attributions regarding the child's behaviour. Self-report measures of child problem behaviour and maternal depressive symptoms were also completed. RESULTS: Consistent with previous research, high EE mothers, compared to low EE mothers, were more likely to make attributions thatjudged the cause of problem behaviour to be personal to and controllable by the child and also made more 'child-blaming' attributions than low EE mothers. Mothers' scores on the Beck Depression Inventory were found to be associated with 'child-blaming' attributions and higher levels of EE. Regression analyses did not support the hypothesised role of attributions as a mediator between depression and EE but did identify EE as a potential mediator in the relationship between maternal depressed mood and ratings of child problem behaviour. CONCLUSIONS: These results indicate the relevance of both EE and attributions in mothers of children with problem behaviour and suggest that maternal depressed mood is an important factor which is related to both of these.