Unintentional injection to the bone with a pediatric epinephrine auto-injector

Mariam Ibrahim, Harold Kim

Skin-to-bone distance (STBD) in children prescribed a pediatric epinephrine auto-injector (EAI) for anaphylaxis is not commonly measured in practice. Recent evidence suggests that children with STBD less than the exposed needle length of available pediatric EAIs (dose: 0.15 mg, needle length: 12.7 mm) are at risk for unintentional injections to the bone during their use for an allergic emergency. Described here is a case of a female child with multiple food allergies prescribed a pediatric EAI (0.15 mg EpiPen Jr®) who experienced an unintentional injection to her femur. The patient's STBD at the recommended injection site (vastus lateralis) was shorter than the needle length of her prescribed EAI (12.7 mm) at the time of the injury (age: 7, height: 122 cm; weight: 25 kg), even though her weight was within the indication for this EAI (15-30 kg). The patient and her family were made aware of the risk of unintentional bone injection at the time the EAI was prescribed. Some children, even those at an appropriate weight per the indication of available pediatric EAIs (0.15 mg), may be at risk for unintentional injections to the bone. The effects of an unintentional bone injection with an EAI can have lasting effects on a child, including pain. Healthcare providers who prescribe pediatric EAIs for any child should consider evaluating this risk, inform patients and parents of the risk, and take measures to potentially mitigate unintentional bone injections. For some children, an EAI with a shorter needle length may be a more appropriate choice of treatment for anaphylaxis.