Imaging Case of the Week 521 Answer

The coronal CT image shows orbital blow out fracture. Floor of the right orbit is fractured with herniation of the inferior rectus (tear drop sign).

The key difference between adult and pediatric patients in the presence of an orbital blow out fracture are:

  • Presence of minimal signs: in children, only diplopia with upward gaze palsy may be present whereas in adults, one can find enophthalmos, subconjunctival bleed, diplopia, and subcutaneous emphysema over the affected cheek. These injuries are therefore called a ‘white orbital blowout fracture ‘ in children (WOBOF).
  • Higher incidence of oculocardiac reflex in children, leading to bradycardia and vomiting which can mislead the medical practitioner to believe that the affected child has a head injury.

The pediatric white orbital blowout fracture is a maxillofacial emergency as the herniated inferior rectus can quickly become ischaemic due to trapdoor mechanism of the injury.

Reference: Jae Hwan Kwon, MD; Jung Hwan Moon, MD; Min Sang Kwon, MD; Joong Hwan Cho, MD,The Differences of Blowout Fracture of the Inferior Orbital Wall Between Children and Adults,) ARCH OTOLARYNGOL HEAD NECK SURG/VOL 131, AUG 2005