Burton B K
Center for Medical Genetics, Michael Reese Hospital and Medical Center, Division of Genetics and Metabolism, University of Illinois College of Medicine, Chicago, IL 60616, USA.
Pediatrics. 1998 Dec;102(6):E69. doi: 10.1542/peds.102.6.e69.
Recent advances in the diagnosis and treatment of inborn errors of metabolism have improved substantially the prognosis for many of these conditions. This makes it essential that the practicing pediatrician be familiar with the clinical presentation of these disorders. A practical clinical approach to the recognition of inborn errors of metabolism in the young infant is presented in this review. Indications for specific laboratory studies are discussed. Guidelines are provided for the stabilization and emergency treatment of critically ill infants. This approach will identify those infants who will benefit from additional evaluation and specific treatment. Many of the inborn errors of metabolism, including urea cycle defects, organic acidemias, and certain disorders of amino acid metabolism, present in the young infant with symptoms of an acute or chronic metabolic encephalopathy. Typical symptoms include lethargy, poor feeding, apnea or tachypnea, and recurrent vomiting. Metabolic acidosis and/or hyperammonemia are observed in many of these conditions, but there are notable exceptions, including nonketotic hyperglycinemia and molybdenum co-factor deficiency. Therefore, appropriate laboratory testing for metabolic disorders should be performed in any infant who exhibits these findings. Although sepsis may be the initial consideration in a neonate with these symptoms, inborn errors of metabolism should always be in the differential diagnosis, particularly in a full-term infant with no specific risk factors. Hypoglycemia may be the predominant finding in a number of inborn errors of metabolism, including glycogen storage disorders, defects in gluconeogenesis, and fatty acid oxidation defects. The latter disorders, among the most common encountered, exhibit marked clinical variability and also may present as a sudden death, a Reye's-like episode, or a cardiomyopathy. Jaundice or other evidence of hepatic dysfunction is the mode of presentation of another important group of inborn errors of metabolism including galactosemia, hereditary tyrosinemia, neonatal hemochromatosis, and a number of other conditions. A subset of lysosomal storage disorders may present very early with coarse facial features, organomegaly, or even hydrops fetalis. Specific patterns of dysmorphic features and congenital anomalies characterize yet another group of inherited metabolic disorders, such as Zellweger syndrome and the Smith-Lemli-Opitz syndrome. Each of these symptom complexes, and the appropriate evaluation of the affected infants, is discussed in more detail in this review.
先天性代谢缺陷的诊断和治疗方面的最新进展已显著改善了许多此类病症的预后。这使得执业儿科医生必须熟悉这些疾病的临床表现。本文综述了一种识别幼儿先天性代谢缺陷的实用临床方法。讨论了特定实验室检查的指征。为危重症婴儿的稳定和紧急治疗提供了指导方针。这种方法将识别出那些将从进一步评估和特定治疗中受益的婴儿。许多先天性代谢缺陷，包括尿素循环缺陷、有机酸血症和某些氨基酸代谢紊乱，在幼儿中表现为急性或慢性代谢性脑病的症状。典型症状包括嗜睡、喂养困难、呼吸暂停或呼吸急促以及反复呕吐。在许多这些病症中都观察到代谢性酸中毒和/或高氨血症，但也有显著例外，包括非酮症高甘氨酸血症和钼辅因子缺乏症。因此，对于出现这些症状的任何婴儿，都应进行适当的代谢紊乱实验室检测。虽然败血症可能是出现这些症状的新生儿的初步考虑因素，但先天性代谢缺陷始终应列入鉴别诊断，特别是对于没有特定危险因素的足月儿。低血糖可能是许多先天性代谢缺陷的主要表现，包括糖原贮积病、糖异生缺陷和脂肪酸氧化缺陷。后一类疾病是最常见的疾病之一，表现出明显的临床变异性，也可能表现为猝死、类瑞氏综合征发作或心肌病。黄疸或肝功能障碍的其他证据是另一组重要的先天性代谢缺陷的表现方式，包括半乳糖血症、遗传性酪氨酸血症、新生儿血色素沉着症和许多其他病症。一部分溶酶体贮积病可能在很早的时候就表现为面部粗糙、器官肿大甚至胎儿水肿。特定的畸形特征和先天性异常模式是另一组遗传性代谢疾病的特征，如脑肝肾综合征和史密斯-莱米-奥皮茨综合征。本文综述将更详细地讨论这些症状组合以及对受影响婴儿的适当评估。
