A 24-year-old man comes to the emergency department for evaluation of eye pain and swelling. He was involved in an altercation last night after significant alcohol use but does not remember any further details. The patient has double vision when he attempts to look up. On examination, the left side of the face is significantly swollen, tender, and ecchymotic. Visual acuity is normal. He is unable to look up with his left eye. CT scan is shown below: Which of the following is the most likely reason for this patient's diplopia?

Question

A 24-year-old man comes to the emergency department for evaluation of eye pain and swelling.  He was involved in an altercation last night after significant alcohol use but does not remember any further details.  The patient has double vision when he attempts to look up.  On examination, the left side of the face is significantly swollen, tender, and ecchymotic.  Visual acuity is normal.  He is unable to look up with his left eye.  CT scan is shown below:  Which of the following is the most likely reason for this patient's diplopia?

Quizplus · Accepted Answer

11ec25c8_d930_4979_bc81_bdee6bb548bd_MD0003_00 This patient sustained facial trauma and now is unable to look up with his left eye. Blunt trauma to the globe often causes a rapid increase in pressure that is transmitted posteriorly into the orbit, causing fracture of the weakest areas of the bony orbit (ie, orbital floor, medial orbital wall). This hydraulic transfer of force (ie, "blowout" fracture) protects the globe from rupture. All patients who sustain orbital trauma should undergo assessment of visual acuity and extraocular movements. CT scan is obtained if there is evidence of a fracture (eg, step-off on palpation), changes in vision or extraocular movements, or the examination is limited due to soft-tissue swelling or altered mental status. This patient's coronal CT scan shows a left orbital floor fracture with herniation of orbital fat into the maxillary sinus and entrapment of the inferior rectus muscle. An entrapped inferior rectus keeps the affected globe in a downward position, leading to diplopia on upward gaze despite normal visual acuity. Prolonged entrapment may cause ischemia, fibrosis, and permanent dysfunction. Therefore, if there is concern for muscle entrapment either on examination or CT scan, the patient should be seen by a surgical subspecialist (eg, plastic surgeon, ophthalmologist) within 24 hours. (Choice B) Open globe injury can also occur with facial trauma. However, patients with this injury have markedly decreased visual acuity, and CT scan would show a flattened appearance of the globe. flattened appearance of the globe (Choice C) Orbital cellulitis can present with swelling, pain, and impaired extraocular movements. However, patients also typically have fever and diffuse (rather than just upward gaze) restriction of ocular movement. Orbital cellulitis (Choice D) An orbital hematoma can occur after facial trauma and present with diplopia. However, patients with hematoma have markedly decreased visual acuity due to pressure-induced ischemia of the optic nerve, and CT scan would show intraorbital fluid rather than an orbital floor fracture. (Choice E) Trochlear nerve (CN IV) dysfunction can present with vertical diplopia after trauma. However, because CN IV innervates the superior oblique muscle, the vertical diplopia is present on downward (rather than upward) gaze, and examination shows hypertropia and extorsion of the eye. hypertropia and extorsion of the eye Educational objective: An orbital floor fracture can result in entrapment of the inferior rectus muscle, which presents with vertical diplopia and restriction of upward eye movement. References: Orbital fractures: a review (http://www.ncbi.nlm.nih.gov/pubmed/21339801)

A 24-Year-Old Man Comes to the Emergency Department for Evaluation