Study of Subcutaneous Rehydration With Recombinant Human Hyaluronidase for Infants and Children

Inclusion Criteria: * Child, 2 months to 10 years of age * Body weight less than 42 kg * Presenting at emergency department with mild to moderate dehydration (Gorelick dehydration classification: presence of 1 to 6 \[of possible 10\] moderate or severe signs and symptoms) requiring parenteral rehydration Exclusion Criteria: * In shock or life-threatening situation (other than dehydration) * Severe dehydration * Requires intravenous (IV) therapy for another indication * Indwelling IV catheter (excepting one intended strictly for clinical laboratory sample collection) * Already received rehydration therapy IV within prior 48 hours or substantial oral fluid immediately before enrollment * Condition precluding subcutaneous injection or infusion site evaluation in anterior thigh or other elected infusion site * Reason for hospital admission or extended emergency department stay other than dehydration * Known hypersensitivity to hyaluronidase or another ingredient in HYLENEX * Hyponatremia or hypernatremia * Hypokalemia * Medical condition likely to interfere with ability to fully complete study or have protocol-specified assessments * Medical history, screening examination finding or historical clinical laboratory result precluding safe participation in study or which might adversely effect interpretation of study results * Participated in study of any investigational drug or device within 30 days prior to this study