Cavernous Sinus Syndrome and Traumatic Carotid-Cavernous Fistula Attributable to a

Self-Inflicted BB Gunshot Injury

Marcellino CR, Graffeo CS, Perry A, Wetjen NM, Link MJ

Chris Marcellino, MDMayo Clinic, Department of Neurologic SurgeryRochester, MinnesotaEmail: marcellino.christopher@mayo.edu

ContactKumar, Ravi, et al. "Penetrating head injuries in children due to BB and pellet guns: a poorly recognized public health risk." Journal of Neurosurgery: Pediatrics 17.2 (2016): 215-221.

Keane, James R. "Cavernous sinus syndrome: analysis of 151 cases." Archives of neurology 53.10 (1996): 967-971.

Keltner, John L., et al. "Dural and carotid cavernous sinus fistulas: diagnosis, management, and complications." Ophthalmology 94.12 (1987): 1585-1600.

References

BB guns are a class of gas- or spring-powered projectile

weapons whose power and muzzle velocity are often

underestimated by casual users and children. Present

technology has advanced such that modern BB guns produce

high velocity but small caliber ballistic injuries which can

penetrate the intracranial space and cause focal central

neurologic deficits.

The small size of the projectile simultaneously complicates

diagnosis and treatment, particularly if the entry wound is not

appreciated by the layperson, resulting in delayed care.

We report a unique case of cavernous sinus syndrome

precipitated by a self-inflicted facial BB gunshot injury in a child.

Background

Modern BB guns can penetrate the cranium and injure skull base

structures such as the cavernous sinus, potentially producing severe

and highly focal neurological injuries, depending on the trajectory of the

pellet. Traumatic vascular injuries causes by BB guns are managed

similarly to other missile or penetrating trauma, although little is known

about their specific natural history. Other specific management

considerations are MRI safety and lead content, which vary significantly

from other types of retained projectile injuries, due to differences in

composition.

A 9-year-old boy was playing with a BB gun when he accidentally suffered a self-inflicted

BB gunshot injury to the face. Family believed that a superficial injury only had been

sustained, and medical evaluation was correspondingly delayed more than 5 days. During

that time, the patient was unable to completely open his eye and complained of diplopia,

eventually prompting ED presentation. At that time, he had progressed to malaise,

nausea and vomiting, and a right complete CN III and partial IV nerve palsy, with intact

vision, and functioning CN V and VI. The diplopia was secondary to the CN III palsy.

Diagnostic angiography revealed a BB retained in the medial cavernous sinus, as well as

a small carotid cavernous fistula probably from disruption of small branches of the

inferolateral trunk, which drained into the inferior petrosal sinus and did not require

treatment. The BB was in contact with the cavernous segment of the ICA, inducing

minimal arterial stenosis. The projectile was confirmed to be ferromagnetic, and so MRI

was deferred.

Figure 1 (a-e). AP and lateral direct and digital subtraction angiography of the right ICA the week following injurywith 3-D reconstruction demonstrates localization of the retained BB within the right cavernous sinus, intimatelyrelated with the intracavernous segment of the right ICA. DSA images show a small C-C fistula probably fromdisruption of small branches of the inferolateral trunk

Mayo Clinic, Department of Neurologic Surgery, Rochester, Minnesota

Discussion

Results

The patient was managed expectantly. One-month follow-up angiography was

arranged to rule out migration of the retained BB and reevaluate the status of the

carotid-cavernous fistula, which showed resolution of both the minimal ICA

stenosis and the fistula. CN IV nerve function improved but a complete CN III

nerve palsy persisted. His serum lead level was followed periodically in

consideration of medical management and was negative, although as this was a

spherical BB and not a pellet, the lead content is believed to be low. He is

currently undergoing evaluation for surgical correction of his persistent diplopia,

six months after his injury.

Results (cont.)

Figure 2. Lateral digital subtraction angiography of theright internal carotid artery 5 weeks after injury showingresolution of carotid-cavernous fistula.

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