A 20 year old man injured by an improvised explosive device (IED).
On physical exam the patient had a Glasgow Coma Score (GCS) of 12 with signs of penetrating injury to his neck.
Contrast enhanced CT angiogram of the head was performed which demonstrated a radiopaque foreign body in the expected location of the basilar artery with satisfactory collateral filling of the posterior cerebral arteries (Fig. 1). A subsequent non-contrast CT of the head was performed following onset of further neurological symptoms, which revealed interval displacement of the radiopaque foreign body to the left posterior cerebral artery (PCA) with loss of gray white matter differentiation consistent with left PCA territorial infarction from embolized IED fragment (Fig. 2).
Metal fragment embolism
Subarachnoid CSF metal fragments
Dx: IED Fragment Embolism to Left Posterior Cerebral Artery
Dx Confirmed by: Imaging alone
CT angiogram of the head and neck vessels was obtained (fig. 1). The next day, the patientâ€™s neurological status deteriorated and a non-contrast head CT was obtained (fig. 2).
Vascular embolism of a metal (missile) fragment or bullet is a rare occurrance with fewer than 200 cases reported in the literature since 1900 (1). Migration of missile fragments to the cerebral circulation is an even rarer occurance, with the majority involving the anterior circulation (2).
Missile fragment embolization usually occurs rapidly after entrance of the missile fragments into the vascular circulation (3). Embolizations are characterized as either arterial or venous, with a few reported cases of paradoxical embolus via a patent foramen ovale (4). Attention to missile fragment embolization phenomenon is particularly important in the combat setting. Once a patient has been stabilized according to Advanced Trauma Life Support protocols, all missile entrance and exit sites should be identified. If no obvious exit site is identified, and no missile fragment is visualized on initial imaging studies, fragment embolization should be considered (5).
The majority of arterial embolizations will be symptomatic. Complications of fragment embolization include vascular occlusion (with consequent organ or limb infarction), thrombus formation, vascular perforation, cardiac arrythmia, valvular dysfunction, septicemia, and lead toxicity.
When an embolized missile fragment is identified, the risks and benefits of retrieval vs. conservative management are considered. Typically the treatment of arterial missile embolization has been via direct surgical extraction (6).
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