乳児健診で運動発達遅延を指摘されたフロッピーインファントの神経学的予後について  [in Japanese] Neurological prognosis of floppy infants after health examinations  [in Japanese]

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Author(s)

    • 吉岡 三惠子 Yoshioka Mieko
    • 神戸市総合療育センター小児神経科 Department of Pediatric Neurology, Kobe City Pediatric and General Rehabilitation Center for the Challenged

Abstract

 【目的】乳児健診で運動発達遅延を指摘されたフロッピーインファントには種々の疾患が含まれる. この中には筋緊張低下が改善し, 後方視的に先天性良性筋緊張低下と診断される一群があるが, 知的障害や他の脳障害が明らかになる例が多い. 今回, 2歳以上まで経過観察された症例の神経学的予後を検討した. 【方法】乳児健診後, 直接または他院を経て当センターをこの8年6カ月間に受診した症例の内, 全身の筋緊張低下を認め, 腱反射が正常または低下している例で, 在胎37週以上, 生下時体重2,500g以上, Apgar score (5分) 7点以上で出生し, 家族歴・大奇形・頭部画像所見・染色体検査 (Gバンド・fluorescence in situ hybridization) ・血清creatine kinase値・血中乳酸・ピルビン酸・血液アミノ酸分析に異常がない32例 (男15, 女17) を対象とした. 4カ月健診から16例 (以下, 4健群), 9カ月健診から16例 (9健群) が該当した. 【結果】頚定は4健群, 9健群で全例可能. 座位は4健群では全例で, 9健群では14例で可能だが, 2例は不可で, それぞれRett症候群, 脊髄性筋萎縮症と遺伝子診断された. 独歩は4健群の14例, 9健群の13例で可能となり, この27例中知的障害を18例 (67%) に, 自閉症スペクトラムを5例 (19%) に認めた. 独歩不可は4健群2例, 9健群3例で, 先天性ミオパチーや奇形症候群が疑われた. 【結論】筋緊張低下が改善し独歩可能となった例にも知的障害や自閉症スペクトラムを示す例が多く, 早期から知的や行動面に留意した療育が必要であった.

  <i><b>Objective:</b></i> The term benign congenital hypotonia is retrospective and refers to infants who are hypotonic at birth or shortly thereafter but later show a normal tone. It encompasses many different pathological processes that affect the brain, motor unit, or both. The majority of affected children have cerebral hypotonia. An increased incidence of mental retardation, learning disabilities, and other sequelae of cerebral abnormality are evident later in life, despite the recovery of a normal muscle tone. We followed floppy infants who were pointed out as showing motor delay on health examinations at 4 or 9 months of age until at least 2 years of age. <i><b>Methods:</b></i> We selected 32 floppy infants (15 males and 17 females) born uneventfully, with no family history, major anomalies, or abnormal findings on brain imaging, and no chromosomal study (G-banding and fluorescence in situ hybridization), serum creatine kinase level, blood lactate and pyruvate level, or blood amino acid abnormalities. <i><b>Results:</b></i> All 32 infants achieved head control, but 2 failed to learn to sit unsupported. These two were diagnosed based on gene analysis with Rett syndrome and spinal muscular atrophy, respectively. Although 27 among the 32 patients became ambulant, 18 (67%) showed mental retardation and 5 (19%) also had autism spectrum disorder. Five patients who could not walk were suspected to have congenital myopathy or congenital malformation syndrome. <i><b>Conclusions:</b></i> After learning to walk independently and recovery of the normal muscle tone, many floppy infants showing motor delay on health examinations at 4 or 9 months of age developed mental retardation and autism spectrum disorder. Prospective follow-up is necessary for early diagnosis and intervention. For patients showing no motor and mental development, further laboratory studies including appropriate gene analysis are important for a definite diagnosis.

Journal

  • NO TO HATTATSU

    NO TO HATTATSU 47(6), 433-437, 2015

    The Japanese Society of Child Neurology

Codes

  • NII Article ID (NAID)
    130005111625
  • Text Lang
    JPN
  • ISSN
    0029-0831
  • Data Source
    J-STAGE 
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