Supplementary Material for: A Rare Case of Concurrent Carotid Cavernous Fistula and Orbital Cellulitis: Challenging Diagnosis and Divergent Management

Purpose: Carotid cavernous fistula (CCF) is abnormal vascular connections between the cavernous sinus and the carotid artery or its branches, leading to orbital signs. This rare case report illustrates the diagnostic complexities posed by orbital cellulitis and concomitant CCF.
Case Presentation: A 52-year-old male with a recent trauma of dehiscent internal carotid artery (ICA) presented initially with bacteremia, fever, tachycardia, and leukocytosis. Based on the orbital symptoms, including proptosis, chemosis, and restricted extraocular in the right eye, the patient was diagnosed with orbital cellulitis. His ocular manifestations deteriorated despite the improvement of systemic symptoms, signs, and laboratory results during systemic antibiotic treatment. A faint bruit and pulsatile proptosis were found in the right eye; thus, neuroimaging was performed. Magnetic resonance venography and computed tomography angiogram demonstrated a direct CCF with arterialized flow in the cavernous sinus, and superior ophthalmic vein dilation. Endovascular coil embolization successfully resolved the CCF, yet the patient experienced permanent vision loss in the affected eye due to an afferent pupillary defect, a neurological sequelae attributed to either orbital cellulitis, CCF or both .
Conclusion: The significant overlap in symptoms of orbital cellulitis and CCF complicates diagnosis. When two diseases coexist, the diagnosis becomes more complex. This rare case report highlights that CCF should be considered a potential concurrent pathology in patients with head and neck trauma presenting with orbital cellulitis. In addition, CCF can be considered in trauma patients exhibiting dehiscent ICA, irrespective of orbital symptoms, and prior to performing neuroimaging.