A migrating bullet – about an embolism after a gunfight

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Although an embolism brought by the migration of shells from a firearm in blood vessels sounds unbelievable but you will see that is absolutely possible.

The embolic material may be a thrombus (e.g. from a blood clot in the veins of the lower extremities, the fragments of which break off and travel further), fat droplets (e.g. from bone marrow in bone fractures), and even gas bubbles (e.g. in decompression sickness in divers ) or amniotic fluid. However, it turns out that also bullets that enter the body through the wound they create can enter the circulation, migrate and, in vessels with a diameter too small to pass them on, close the flow. العاب تجني منها المال The first case described was recorded as early as 1834, in a child with a wooden bullet in the right ventricle.

Usually, when a bullet sticks into a vessel, it pierces both of its walls. However, when it has too little kinetic energy, it can get trapped inside the vessel. Then there are two options for its path: it can move further with the blood flow (more possible scenario) or, due to the force of gravity, it moves backwards, against the direction of blood flow inside the vessel. Depending on where the bullet “flies”, we distinguish three groups of embolisms: arterial, venous and crossed (“paradoxical”), which occurs in patients who have a direct connection between the right and left atrium of the heart.

About 80% of patients with bullet embolism in the large (arterial) circulation, and only 30% (!) in the small (venous) circulation have symptoms. Victims without symptoms may develop them later, sometimes even months or years after the shooting, after which the blockage was in their circulation. For example, in one of the patients, arrhythmia caused by the presence of a cartridge in the right ventricle of the heart was revealed 4 years after the shot. Possible symptoms include limb ischemia, sepsis, endocarditis, heart valve failure, pulmonary embolism, stroke and even death.

Embolism caused by a migrating bullet is more common during accidental (“civilian”) shootings, not during hostilities. Weapons used in war have more power and cartridges have fired more kinetic energy, which makes them less likely to stop inside the body. Usually, they just pierce them through. In contrast, the arsenal used in “ordinary” shootings, often has a smaller caliber (which makes the bullets fit even in smaller vessels) and less power, such as a shotgun, which has a relatively large spread, but a small range. Nevertheless, this phenomenon also occurs in war: Americans estimated that during the Vietnam War, the incidence of such embolism in survivors was 0.3% (on over 7,000 cases analyzed), and more recently during military operations in Afghanistan and Iraq 1.1% (in over 300 cases). From another barrel, Canadians described a case of a failed suicide attempt with a 0.22 caliber weapon, where a fired bullet led to embolism. I would add that the patient survived and returned home after a psychiatric consultation.

You may ask: which persons injured in the shootings should be suspected of bullet embolism? The following tips may help:

1. uneven number of inlet and outlet holes in the body;

2. there is an unusual place considering its trajectory;

3. “wandering” sphere on various X-ray images.

An interesting case of this embolism was described in the Journal of Emergencies, Trauma, and Shock. A 25-year-old unconscious man was found on the side of the road. His left eyeball was torn, which was caused by a gunshot. There was no outlet. The bullet was visualized in the CT of the head made in the hospital – it was located in the right transverse sinus (i.e. in the venous vessel). Then the patient went to the operating room to decompress intracranial haemorrhage. The CT scan of the head after the ball procedure was no longer visible.

After imaging examinations, the gunshot turned out to have moved to the left lung cavity and then to its lower lobe, causing infarction of this area. The bullet probably travelled from the transverse sinus to the right jugular vein and right ventricle, and from there to the branches of the pulmonary artery. The starting point was, therefore, the head, and the embolism ended in the lung.

Regarding the treatment of such patients, unfortunately, the same problem arises as in all rare diseases and cases: no hospital has the opportunity to gain experience with such cases. Hence, there are no specific guidelines on how to deal with such patients. It is generally accepted that all patients with arterial congestion and all symptomatic patients should undergo bullet removal. This can be done with both “open” surgery and endovascular with the help of a catheter. However, if the presence of the bullet in the venous circulation does not cause any symptoms in some cases, doctors decide not to move it. Symptoms may be absent or very scanty if the projectile “gets tangled” between the layers of cardiomyocytes in the right ventricle. When such a cartridge is less than 5 mm, firmly seated, without signs of arrhythmia or valve dysfunction – then the patient can simply be observed.

(a) Admission head computed tomography demonstrates a metallic foreign body projecting in the region of the right transverse sinus (arrow) (b) the bullet previously seen in the right transverse sinus is no longer evident on the follow-up head computed tomography angiography
Chest radiograph obtained at admission (a) demonstrates no cardiopulmonary abnormality. A follow-up chest radiograph (b) shows a 5 mm round metallic foreign body projecting over the left hilum (open arrow) with interval development of a wedge-shaped pulmonary opacity in the left lung base (arrowhead)
Lung and bone windows (3a and 3b respectively) again show the 5 mm rounded metallic foreign body in the left lower lobe with an associated pulmonary infarct. A small left anterior pneumothorax and pneumomediastinum are also visible

References:

  1. Duke E, Peterson AA, Erly WK. Migrating bullet: A case of a bullet embolism to the pulmonary artery with secondary pulmonary infarction after gunshot wound to the left globe. Journal of Emergencies, Trauma, and Shock. 2014;7(1):38-40
  2. Carter CO, Havens JM, Robinson WP, Menard MT, Gates JD. Venous bullet embolism and subsequent endovascular retrieval – A case report and review of the literature. International Journal of Surgery Case Reports. 2012;3(12):581-583.
  3. Jaha L, Ademi B, Ismaili-Jaha V, Andreevska T. Bullet embolization to the external iliac artery after gunshot injury to the abdominal aorta: a case report.Journal of Medical Case Reports. 2011;5:354
  4. Hussein N, Rigby J, Abid Q. Bullet embolus to the right ventricle following shotgun wound to the leg. BMJ Case Reports. 2012;2012:bcr2012007471.

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