발달지연 환아의 진단적 접근과 원인 분석

Abstract

Purpose : The prevalence of developmental delay is 5-10% of the total pediatric population and early diagnosis and proper intervention are essential but a challenge for clinicians. We performed this study for several purposes. First is to know the distribution & characteristics of developmental disorders in Korea. Second is to identify all possible causes of these disorders through a multidisciplinary diagnostic approach, and thus to find out the clinical variables that are helpful in finding the etiology. And finally to develop a useful protocol that eliminates the cost of unnecessary tests and raises the diagnostic rate of the cause.

Methods : 518 patients(M 349, F 169) were studied who visited Ilsan Hospital Developmental Disorder Clinic(DDC) for the evaluation of developmental delay from April 2001 to Jan 2005.

Results : The mean age was 51.5+/-32.9 months, ranging from 2 months to 16.0 years of age with a majority of the preschool children(<6 yr)(79.3%). Phenomenological diagnosis consisted of 133 cases of mental retardation, 122 cases of autistic disorders, 101 cases of delayed language disorders, 27 cases of cerebral palsies, and 91 cases labeled as simple developmental delay requiring follow up due to age less than 2 years of age. Etiologic diagnosis was obtained in 119 cases(22.9%) out the 518 cases of developmental delays. 37 cases of chromosomal anomalies, 23 cases of Periventricular leukomalacia and hypoxic ischemic encephalopathy, 21 cases of syndromes, 7 cases of malformation of cortical development, 4 cases of myopathies, 4 cases of neuropathies, and 4 cases of cerebral infarctions were found. Among the clinical variables, low birth weight, facial dysmorphism, hypotonia, focal neurologic signs, and abnormalities in MRI, chromosome, EEG and EMG studies contributed to the yields of etiologic diagnosis significantly.

Conclusion : Possible etiology was determined in about 23% of the subjects. The most important part of the assessment for the identification of etiology is thorough history taking, physical and neurologic examination. Neuroimaging study is useful in case of micro or macrocephaly, focal neurologic signs. Genetic studies increasingly produce a yield, when there is family history of inherited disorder and there are dysmorphic features. Routine metabolic screening test has limited utility. Development of a useful screening protocol adequate for Korean situation is required.