The floppy infant: retrospective analysis of clinical experience (1990-2000) in a tertiary care facility.

We describe the results of a retrospective study of floppy infants evaluated at the Children's Hospital of Winnipeg, a tertiary care children's facility. Cases were ascertained by a systematic search of clinical databases, hospital and electromyographic records for "floppy" infants age < 1 year, referred over a period of 11 years (1990-2000). Eighty-nine infants, 42 female (47.2%) and 47 male (52.8%), were included in the study. A definitive diagnosis was established in 60 (67.4%) cases, in 24 cases (40%) on purely clinical grounds, whereas in 36 (60%) cases, additional investigations were necessary. Karyotype, molecular diagnostics, cranial imaging, and muscle and skin biopsy provided diagnostic information. Genetic disorders in 18 of 60 (20.2%), congenital or acquired disorders of the central nervous system in 22 of 60 (24.7%), and disorders of the lower motor unit in 9 of 60 (10.1%) contributed to the majority of diagnoses. Eight of 89 (8.9%) infants died in the first year, and 2 of 89 (2.6%) were on home ventilation. Of the 61 infants surviving beyond 12 months, 38 of 61 (62.3%) were found to be globally delayed, and only 30 of 61 (49.2%) achieved independent ambulation at their last clinical evaluation. Systematic evaluation of a floppy infant followed by careful selection of investigations (karyotype, DNA-based diagnostic tests, and cranial imaging) can maximize diagnostic yield.