근긴장저하를 보인 영아의 원인적 질환에 따른 임상적 특성

Abstract

[한글]

근긴장저하는, 신생아시기에는 주로 비정상적인 자세와, 자발적 움직임이 부족한 양상으로 나타나며, 신생아기후의 영유아기에는 운동발달단계(motor milestone)의 지연으로 나타나기 때문에 재활의학과, 소아과, 신경과 의사들의 관심대상이 되어왔으나 그 원인질환의 범위가 매우 방대하며, 아직 밝혀지지 않은 부분도 많아 지속적인 연구가 필요한 부분이다. 근긴장저하 소견을 보이는 영유아의 가족에게 질환의 예후, 재발률, 적절한 치료법에 관한 정확한 정보를 주기 위해 근육긴장저하를 유발하는 원인 질환을 찾기 위한 연구는 매우 중요하며, 더욱이 여러가지 염색체나 유전자 질환, 특히 대사성 질환을 조기에 발견하게 되면 적절한 치료방법이 있을 수 있어 예후가 크게 달라질 수 있다. 이에 본 연구에서는 전향적 분석(prospective analysis)을 통하여 초진시 근긴장저하를 보인 71명의 영유아를 대상으로 원인 질환을 가능한한 규명하고 초진시 임상 양상을 분석하며, 추적관찰결과를 분류하여 영유아기 근긴장저하를 보이는 환아의 진단과 치료에 도움을 주고자 하였다.결과는 다음과 같다.1. 근긴장저하를 보이는 영유아의 현상학적 진단으로는 두가지 이상의 발달 영역에서 지연이 있는 전반적 발달지연이 전체의 81.7%로, 단순히 대근육/소근육 운동지연만 두드러진 운동발달지연에 비해 훨씬 많았다.2. 운동단위(motor unit)의 질환으로 인한 말초성 근긴장저하아는 원인 질환의 진단이 가능했던 65명의 환아 중 6명으로 9.2%에 불과했다.3. 중추성 근긴장저하는 원인 질환을 찾을 수 있었던 65명의 환아 중 59명(90.8%)으로, 저산소성 허혈성 뇌병증(hypoxic ischemic encephalopathy), 대뇌피질 형성이상(cortical dysplasia) 등의 대뇌질환이 가장 많았고, 염색체 이상, 증후군 등이 있었다4. 초진시 소두증, 머리안면 이상형태증, 동반된 기형이 있는 경우는 중추성 긴장저하군에서 더 많은 비율을 보였으나 통계적 유의성은 없었다.5. 초진시 실시한 발달평가 결과는 원인질환을 예측하는데에 도움이 되지 않았다.6. 초진시 전반적인 근긴장저하를 보인 환아들 중 1년 이상 추적관찰이 가능했던 환아들을 대상으로 재평가를 실시한 결과 전반적 증중 장애(severe global impairment)가 전체 환아의 69.2%로 가장 많았고, 일시적 발달지연(transient delay)은 15.4%에 불과했다.이상의 결과로 보아 근긴장저하를 보이는 영유아를 진찰할 때, 운동영역만 평가할 것이 아니라 다른 발달 영역을 포함하는 포괄적인 평가가 필요함을 알 수 있었으며, 원인 질환으로 운동단위의 질환은 전체 환아의 10% 미만으로, 매우 적다는 것을 확인할 수 있었다. 또한 이들의 원인 질환과 추적관찰에 대한 보다 광범위하고 지속적인 연구가 필요하다고 하겠다.

[영문]The children with hypotonia have unusual postures and paucity of active movements in the newborn period, and delay in motor milestones in the older infants. The list of disorders that may present with neonatal hypotonia is long, and the diagnostic process often is complex. Searching for and determining the profile of etiologies are very important because the family with the hypotonic infant wants to get informations about the prognosis, recurrence rate, and therapeutic plan.We took a prospective study undertaken to evaluate the phenomenologic diagnoses, and the etiologic disease across the spectrum of neonatal hypotonia. Addition to profiling the etiologic disease determined, factors present on initial evaluation, developmental profiles, and the outcomes following over 1 year after initial evaluation were taken.The results were as follows;1. As regard to the phenomenologic diagnoses, The hypotonia was classified as global developmental delay in 58 patients(81.7%), which are much more than predominant motor delay.2. The hypotonia was classified as peripheral in 6 patients (9.2%).3. The hypotonia was classified as central in 59 patients (90.8%), and the brain lesion such as hypoxic-ischemic encephalopathy, cortical dysplasia were the most common diagnoses.4. Microcephaly, craniofacial dysmorphism, and associated anomalies are more frequent in central hypotonia, but these are not significant.5. The developmental profiles at the first visit are not helpful in determining the etiologies.6. Following over 1 year after the initial evaluation, the hypotonia was classified as severe global impairment in 69.2%, as transient delay in 15.4%.This study revealed that the profile of disorders presenting with neonatal hypotonia is diverse, and the careful and comprehensive evaluation of all developmental field is very important in the differential diagnosis of the infants with hypotonia. And the neuromuscular disorders are relatively rare, accounting for less than 10% of infants with hypotonia. Further long-term studies for proper evaluation and the developmental outcomes of the neonatal hypotonia are needed.The children with hypotonia have unusual postures and paucity of active movements in the newborn period, and delay in motor milestones in the older infants. The list of disorders that may present with neonatal hypotonia is long, and the diagnostic process often is complex. Searching for and determining the profile of etiologies are very important because the family with the hypotonic infant wants to get informations about the prognosis, recurrence rate, and therapeutic plan.We took a prospective study undertaken to evaluate the phenomenologic diagnoses, and the etiologic disease across the spectrum of neonatal hypotonia. Addition to profiling the etiologic disease determined, factors present on initial evaluation, developmental profiles, and the outcomes following over 1 year after initial evaluation were taken.The results were as follows;1. As regard to the phenomenologic diagnoses, The hypotonia was classified as global developmental delay in 58 patients(81.7%), which are much more than predominant motor delay.2. The hypotonia was classified as peripheral in 6 patients (9.2%).3. The hypotonia was classified as central in 59 patients (90.8%), and the brain lesion such as hypoxic-ischemic encephalopathy, cortical dysplasia were the most common diagnoses.4. Microcephaly, craniofacial dysmorphism, and associated anomalies are more frequent in central hypotonia, but these are not significant.5. The developmental profiles at the first visit are not helpful in determining the etiologies.6. Following over 1 year after the initial evaluation, the hypotonia was classified as severe global impairment in 69.2%, as transient delay in 15.4%.This study revealed that the profile of disorders presenting with neonatal hypotonia is diverse, and the careful and comprehensive evaluation of all developmental field is very important in the differential diagnosis of the infants with hypotonia. And the neuromuscular disorders are relatively rare, accounting for less than 10% of infants with hypotonia. Further long-term studies for proper evaluation and the developmental outcomes of the neonatal hypotonia are needed.