Ultrasound examination of extensive limb swelling reactions after diphtheria-tetanus-acellular pertussis or reduced-antigen content diphtheria-tetanus-acellular pertussis immunization in preschool-aged children

Abstract

<h4>Objective</h4>The aim of this study was to determine the site, extent, and resolution of tissue involvement when extensive limb swelling occurred in the injected limb for children who received diphtheria-tetanus-acellular pertussis or reduced-antigen content diphtheria-tetanus-acellular pertussis vaccine at 4 to 6 years of age.<h4>Methods</h4>Children who had experienced an injection site reaction at 18 months of age were assigned randomly to receive an intramuscular injection of either reduced-antigen content diphtheria-tetanus-acellular pertussis vaccine or diphtheria-tetanus-acellular pertussis vaccine between 4 and 6 years of age. Children who developed extensive limb swelling were recruited for assessment by clinical examination; ultrasound studies of the affected and opposite (control) arms were performed 24 to 48 hours after immunization and 48 to 96 hours later.<h4>Results</h4>Twelve children with extensive limb swelling were enrolled in the study. Ultrasound examinations demonstrated swelling of both the subcutaneous and muscle layers of the vaccinated arm. Ultrasound assessment showed that the swelling exceeded the clinical measurements of skin redness and swelling. Subcutaneous and muscle tissues expanded to 281% and 111% of the tissue thicknesses of the control arm, respectively. Repeat ultrasound examinations after 48 to 96 hours showed considerable resolution of muscle swelling, compared with subcutaneous tissue swelling. There was no significant difference in the extent of swelling detected between children who received diphtheria-tetanus-acellular pertussis vaccine and those who received reduced-antigen content diphtheria-tetanus-acellular pertussis vaccine.<h4>Conclusion</h4>Extensive limb swelling reactions after diphtheria-tetanus-acellular pertussis or reduced-antigen content booster immunizations involved swelling of subcutaneous and muscle tissues with swelling and duration more marked in subcutaneous tissue.