Kaplan et al. International Journal of Emergency Medicine 2012, 5:10 http://www.intjem.com/content/5/1/10 rising pressure within the cavernous sinus and compres- sion of its contents, including cranial nerves (CN) III, IV, V, and VI. Involvement of these nerves results in ophthal- moplegia, facial sensory deficits, ptosis, and photophobia. Mounting venous hypertension causes engorgement of the ophthalmic vessels leading to the classic triad of CCFs: orbital bruit, chemosis, and pulsating exophthalmos [4-7]. Pressure can also be transmitted to the contralateral caver- nous sinus via the presence of intercavernous bridging ves- sels [8], resulting in bilateral CN deficits and ocular findings, as is seen in this case report. The vast majority of CCFs follow blunt or penetrating trauma to the head [7,9,10], with only one quarter occurring spontaneously (often from ruptured aneur- ysms) [11]. Most cases described in the literature are secondary to closed head injuries related to motor vehi- cle accidents [7,12], but as seen in this case, any type of closed head injury can result in a CCF. Symptom onset is typically delayed until venous hypertension reaches a critical level, often days to weeks following the initial insult. CCFs can be categorized using the Barrow Classifica- tion System. Type A fistulas involve a direct communi- cation between the intercavernous portion of the internal carotid artery (ICA) and the cavernous sinus, whereas types B, C, and D are indirect communications between either dural branches of the ICA or external carotid artery (ECA) and the cavernous sinus [7,13]. Type A CCFs are common in young males, as this demographic has a higher incidence of closed head inju- ries, whereas indirect CCFs occur more often in the elderly [13]. It is important to distinguish between direct (type A) and indirect (types B-D) fistulas because of the prognos- tic implications. Direct CCFs are typically high flow and result in significant venous hypertension, while indirect fistulas tend to be low flow [7,14]. These low-flow lesions generally have fewer and less severe symptoms [7], they improve with time, and often can be medically managed [1,15]. In contrast, it is recommended that all high-flow lesions receive surgical treatment as these can progress to intracranial hemorrhage [1], vision loss [2,3], and even life-threatening epistaxis [16]. The diagnosis of CCFs is based on clinical presenta- tion as well as neuroimaging. A CT scan of the head without contrast may show proptosis, engorgement, and tortuosity of the superior ophthalmic vein, and enlarge- ment of the affected cavernous sinus. MRI images will typically show similar but more pronounced findings compared to CT, and are particularly useful in classify- ing CCFs [7,13]. If a direct, high-flow CCF is identified, the treatment of choice is endovascular embolization [13,14]. Once the lesion has been embolized, pressure Page 4 of 5 within the cavernous sinus will normalize and symptoms will begin to resolve. Consent The patient has given consent to present the case and for the use of images of diagnostic procedures. Abbreviations CCF: Carotid-cavernous sinus fistula; ED: emergency department; DTR: deep tendon reflexes; CBC: complete blood count; BMP: basic metabolic panel; PT: prothrombin time; PTT: partial thromboplastin time; INR: international normalized ratio; CT: computed tomography; MRI: magnetic resonance imaging; CN: cranial nerves; ICA: internal carotid artery; ECA: external carotid artery. Authors’ contributions JBK and MLF did the clinical examination and clinically managed the patient. JBK drafted the case report manuscript. ANB edited and formatted the manuscript and drafted the abstract for the case report, and prepared the final draft for submission. All authors read and approved the final manuscript. Authors’ information JBK is the Chief Resident Physician in the Department of Emergency Medicine, University of Florida College of Medicine at Gainesville, FL. ANB is the Research Fellow/Coordinator in the Department of Emergency Medicine, University of Florida. MLF is the Clinical Assistant Professor at the Department of Emergency Medicine, University of Florida College of Medicine, Gainesville, Florida. Competing interests The authors declare that they have no competing interests. Received: 22 July 2011 Accepted: 13 February 2012 Published: 13 February 2012 References 1. Halbach VV, Higashida RT, Hieshima GB, et al: Dural fistulas involving the cavernous sinus: results of treatment in 30 patients. Radiology 1987, 163:437-442. 2. 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