ICA (petrous) injury with its sequele

Case contributed by Talal F M Abdullah
Diagnosis certain

Presentation

Fight with left orbital stab wound by a screwdriver, facial trauma and bleeding per nose and mouth. Patient is dizzy and vomiting blood. No neurological defecit.

Patient Data

Age: 25 years
Gender: Male

CT paranasal sinus in bone window demonstrates air pockets along the medial aspect of the left orbit traversing the left lamina papyracea/vertical plate of left ethmoid, bilateral ethmoid air cells, nasal septum, left side of sphenoid sinus, left pterygoid fossa and the bony canal of the horizontal left petrous temporal bone with involvement of the right petrous canal roof. 
Hemosinus noted within the left maxillary, ethmoids, and right sphenoid sinuses.
The globes and conal compartments were intact.

Identification of the "track" and asymmetry of both petrous carotid canals lead to the identification of "raised" bony chip off the right carotid canal warranting further assessment wiht contrast.

Irregularity of the arterial wall of the horizontal petrous part of the right internal carotid artery with small hypoattenuating foci within corresponds to tiny air locules in the right petrous canal.
Otherwise, bilateral ACAs, MCAs, ACom are normal.
Vertebrobasilar arteries are normal as well.
No significant brain parenchyma abnormalities noted.

yellow arrow: irregularity of the opacified arterial lumen. tiny air locules noted nearby.
red arrow: raised fracture bony chip.

The case was managed conservatively. A follow-up non-contrast CT brain done on the next day showed a right MCA territory infarct. This is can be caused by arterial spasm/dissection secondary to trauma.

Case Discussion

An uncommon mechanism of internal carotid artery injury, while the direct trauma was through the left orbital socket and injured the right ICA. Amazingly it did miss the left orbit.

The fracture tract raised bony chip of the petrous canal, irregular wall of the petrous ICA and suspected minimal contrast extravasation; all raised the potential of arterial injury.  Being a tiny bony canal rendered a full assessment of the vessel hard by CT; though the aforementioned findings highly raised the possibility.

Again being in a bony canal mostly saved the patient from a catastrophic bleed, as it was "contained" by the tamponade effect.

Secondary spasm of the right ICA due to the direct trauma could have caused the right MCA infarct within less than 24 hours. Another theory is dissection extending into the right MCA.

The patient shifted to a neuroradiology center where carotid angiogram showed pseudoaneurysm formation.

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