DIFFERENTIAL DIAGNOSIS: The patient arrived at the emergency department with an acutely proptotic eye with a questionable  history of trauma. What is the differential diagnosis?

• Traumatic retro-orbital hemorrhage
• Infectious orbital cellulitis (with or without subperiosteal ABCs): bacterial, fungal
• Carotid-cavernous fistula (CC fistula)
• Cavernous sinus thrombosis
• Orbital inflammatory pseudotumor
• Posterior scleritis
• Myositis
• Hemangioma of the orbit with hemorrhage
• Metastatic orbital tumor with hemorrhage
• Lymphoma
• Expanding varix
• Expanding mucocele
• Atypical thyroid eye disease (less likely to present acutely)
• Orbital vasculitis (Wegner disease)

 We felt our patient was less likely at risk for CC fistula on initial examination. In a CC fistula, more typical signs and symptoms  might include a subjective or audible bruit; headaches; dilated conjunctival, episcleral, and retinal vessels; choroidal effusion,  narrowed anterior chamber, ophthalmoplegia associated with other cavernous sinus cranial neuropathy; damage to the trigeminal  nerve; an enlarged superior ophthalmic vein, or diffuse cortical dysfunction.

 COMMON POTENTIAL SOURCES FOR ORBITAL CELLULITIS (1):

• Sinusitis
• Septicemia
• Infectious endocarditis
• Dental abscess
• Nasopharyngeal infections in debilitated patients
• Maxillary osteomyelitis
• Orbital cellulitis after surgery
• Trauma
• Panophthalmitis

 USE OF ANTIBIOTICS IN ORBITAL FRACTURES: The use of antibiotics for orbital fractures is controversial, as antibiotics are  associated with potential risks (eg, allergic or idiosyncratic reactions, development of resistant bacterial strains). However, this case  demonstrates that in the presence of underlying sinus disease, antibiotics may be appropriate.

 Normal sinuses are considered sterile (2). A fracture into a normal sinus could therefore be classified as a clean wound. If a patient  has maxillary, ethmoidal, or frontal sinusitis, the wound might be considered a dirty wound, with an associated rate of infection as  high as 40%, according to the surgical literature (3-5). (Dirty facial wounds may carry a lower risk of infection due to the excellent  blood supply of the face.) Therefore, when underlying sinusitis is present, it might be reasonable to treat the patient with prophylactic  antibiotics. Similarly, immunologic insults such as ethanol abuse, diabetes mellitus, or underlying immunosuppression/dysfunction  might compound this risk and should be taken into account. (Note: A foreign body also must be ruled out since orbital fractures are  most often associated with trauma.)