Congenital inflammatory myopathy: a demonstrative case and proposed diagnostic classification.

There have been few reports of congenital inflammatory myopathy in the literature, and most of these have been associated with congenital muscular dystrophy. We review the literature and present a case with electromyographic and muscle biopsy evidence of congenital inflammatory myopathy with onset in the perinatal period and no evidence of a congenital muscular dystrophy. There was evidence of subjective improvement following corticosteroid administration (approximately 1 mg/kg per day) with a concomitant normalization of the serum creatine kinase activity. Of particular interest in the case was the history of maternal infection, suggesting a possible postinfectious molecular mimicry as the etiology of the muscle inflammation. This case suggests that a rare form of congenital inflammatory myopathy does exist that is not associated with a congenital muscular dystrophy. A preliminary classification scheme is proposed to separate true congenital cases from those acquired after birth and those cases associated with congenital dystrophy.

Fibrodysplasia (myositis) ossificans progressiva. Clinical lessons from a rare disease.

Fibrodysplasia (myositis) ossificans progressiva is a rare dominantly inherited disorder, in which defects in skeletal patterning particularly affecting the big toes, are associated with progressive endochondral ossification of the large striated muscles in a specific order leading to prolonged disability. A recent series of 28 patients studied for as many as 24 years exemplifies the presentation and course of this disease. Painful swelling of muscles (myositis) leading to ossification began at a mean age of 4.6 years (range, 0-16 years) initially in the neck and upper spine (in 25 subjects) and later around the hips, other major joints, and jaw. The rate and extent of disability was unrelated to the time of onset. No form of treatment produced consistent benefit. Despite the unique clinical features, the initial diagnosis of fibrodysplasia ossificans progressiva was often wrong and usually considerably delayed. Mistaken histologic diagnoses such as soft tissue sarcoma or fibromatosis could lead to inappropriate treatment.

Congenital inflammatory myopathy.

We present 3 patients with congenital inflammatory myopathy and summarize the literature. CNS involvement (microcephaly/intellectual delay) may or may not be present. Serum creatine kinase activity is elevated, the EMG is myopathic, and the muscle biopsy reveals inflammatory infiltrates, muscle fiber damage, and class I major histocompatibility complex products in muscle sarcolemma. Possible etiologies include intrauterine viral infection or an autoimmune process. Treatment with steroids may result in some motor improvement but has no effect on the CNS involvement. Despite a common time of presentation, these patients have a heterogeneous clinical profile, often suggesting a congenital muscular dystrophy syndrome.

Infantile myositis: a case diagnosed in the neonatal period.

Infantile myositis is an inflammatory myopathy occurring in children under one year of age. This condition is extremely rare in the neonatal period and may be confused with other causes of generalized weakness. Creatine kinase activity is usually markedly elevated and electromyography demonstrates low amplitude, polyphasic motor unit activity. Muscle biopsy, necessary for diagnosis, documents characteristic findings of perifascicular atrophy and the presence of perivascular inflammatory cells. The diagnosis should be followed by corticosteroid treatment. The patient presented is the youngest biopsy-proved case of infantile myositis. In this report, his symptoms and clinical course are compared with those of previously described patients. The role of infectious agents and the immune state in the etiology of infantile myositis is considered.