Infantile Polymyositis: A Case Report Toshiro Nagai, MD, Tomonobu Hasegawa, MD, Masamine Saito, MD, Shuuhei Hayashi, MD and Ikuya Nonaka, MD
A 10-month-old Japanese boy developed progressive muscle weakness and hypotonia at 3 months of age. Because of striking inflammatory cellular infiltration in his muscle biopsy, he was diagnosed as having infantile polymyositis and was placed on steroid and immunosuppressive medication when he was 10-month-old. His physical condition was not significantly altered, though serum creatine kinase (CK) level was normalized (1,500 iu/l ~ 90 iu/l). These findings contrast with previous reports documenting improvement with steroid administration. Key words: Infantile polymyositis, congenital muscular dystrophy, nuclear change. Nagai T, Hasegawa T, Saito M, Hayashi S, Nonaka I. Infantile polymyositis: a case report. Brain Dev 1992;14: 167-9
Infantile polymyositis, an inflammatory myopathy manifesting with muscle weakness starting in infancy younger than 12 months of age, is a poorly defined muscle disorder with only a limited number of patients are described in the literature [1-5]. The affected infants may be diagnosed as having congenital muscular dystrophy if there is no definite inflammatory cellular infIltration in their biopsies because both diseases share similar clinical and morphological features. Carpenter et al [1] emphasized that responsiveness to corticosteroid and abnormal nuclei of muscle fibers were crucial findings for this disease. In this communication, we describe a Japanese boy with infantile polymyositis showing his muscle weakness from 3-month-old and no responsiveness to corticosteroid, 6mercaptopurine, or cyclosporine administration. CASE REPORT This male infant was born normally after 37 weeks' gestation as the 3rd child to a 33-year-old mother. Fetal movements were normal and Apgar score was 9 at 5 minutes. Birth weight was 2,690 gm and body length was 45 .6 cm.
From the Department of Neurology, Tokyo Metropolitan Kiyose Children's Hospital (TN, TH, SH); Department of Pediatrics, Keio University School of Medicine (TN, MS); and Division of Ultrastructural Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (TN, IN), Tokyo. Received for publication : November 6, 1991. Accepted for publication: March 5, 1992. Correspondence address: Dr. Toshiro Nagai, Department of Neurology, Tokyo Metropolitan Kiyose Children's Hospital, 1-3-1 Umezono, Kiyose, Tokyo 204, Japan.
Neither sucking nor swallowing difficulties were observed. He developed normally until 3 months of age when his gross motor development began to deteriorate. At 10 months of age, he was noticed to have high serum CK levels above 1,000 iu/l (normal, < 110) and was referred to our hospital for evaluation. On admission, he measured 74 cm (50th percentile) and weighed 7.9 kg (1 Oth percentile). His cognitive ability was considered as normal for age. Muscle weakness and atrophy were prominent in the neck, shoulders and proximal upper extremities. Muscle strength of hip and lower extremities were relatively well preserved. He could sit with support for a while, but could not hold his head straight up. Neither facial muscle involvement nor joint contracture was observed. Skin rash was not noted. All deep tendon reflexes were absent. Laboratory data were as follows: WBC 9,800/ul, ESR lO/hr, CRP 0 mg/dl, serum CK 1,487 iu/l, SGOT 103 iu/l (normal,
A 10-month-old Japanese boy developed progressive muscle weakness and hypotonia at 3 months of age. Because of striking inflammatory cellular infiltration in his muscle biopsy, he was diagnosed as having infantile polymyositis and was placed on steroid and immunosuppressive medication when he was 10-month-old. His physical condition was not significantly altered, though serum creatine kinase (CK) level was normalized (1,500 iu/l ~ 90 iu/l). These findings contrast with previous reports documenting improvement with steroid administration. Key words: Infantile polymyositis, congenital muscular dystrophy, nuclear change. Nagai T, Hasegawa T, Saito M, Hayashi S, Nonaka I. Infantile polymyositis: a case report. Brain Dev 1992;14: 167-9
Infantile polymyositis, an inflammatory myopathy manifesting with muscle weakness starting in infancy younger than 12 months of age, is a poorly defined muscle disorder with only a limited number of patients are described in the literature [1-5]. The affected infants may be diagnosed as having congenital muscular dystrophy if there is no definite inflammatory cellular infIltration in their biopsies because both diseases share similar clinical and morphological features. Carpenter et al [1] emphasized that responsiveness to corticosteroid and abnormal nuclei of muscle fibers were crucial findings for this disease. In this communication, we describe a Japanese boy with infantile polymyositis showing his muscle weakness from 3-month-old and no responsiveness to corticosteroid, 6mercaptopurine, or cyclosporine administration. CASE REPORT This male infant was born normally after 37 weeks' gestation as the 3rd child to a 33-year-old mother. Fetal movements were normal and Apgar score was 9 at 5 minutes. Birth weight was 2,690 gm and body length was 45 .6 cm.
From the Department of Neurology, Tokyo Metropolitan Kiyose Children's Hospital (TN, TH, SH); Department of Pediatrics, Keio University School of Medicine (TN, MS); and Division of Ultrastructural Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (TN, IN), Tokyo. Received for publication : November 6, 1991. Accepted for publication: March 5, 1992. Correspondence address: Dr. Toshiro Nagai, Department of Neurology, Tokyo Metropolitan Kiyose Children's Hospital, 1-3-1 Umezono, Kiyose, Tokyo 204, Japan.
Neither sucking nor swallowing difficulties were observed. He developed normally until 3 months of age when his gross motor development began to deteriorate. At 10 months of age, he was noticed to have high serum CK levels above 1,000 iu/l (normal, < 110) and was referred to our hospital for evaluation. On admission, he measured 74 cm (50th percentile) and weighed 7.9 kg (1 Oth percentile). His cognitive ability was considered as normal for age. Muscle weakness and atrophy were prominent in the neck, shoulders and proximal upper extremities. Muscle strength of hip and lower extremities were relatively well preserved. He could sit with support for a while, but could not hold his head straight up. Neither facial muscle involvement nor joint contracture was observed. Skin rash was not noted. All deep tendon reflexes were absent. Laboratory data were as follows: WBC 9,800/ul, ESR lO/hr, CRP 0 mg/dl, serum CK 1,487 iu/l, SGOT 103 iu/l (normal,
