Critical Care Medicine-Neurologic Disorders>>>>>Neurotrauma
Question 4#

A 21-year-old male with no past medical history is brought in via emergency medical services (EMS) for evaluation of a gunshot wound to the head. Police and EMS were called, and he was found at the scene awake, interactive but confused. There appeared to be a left frontotemporal entry site without an exit site. His initial vital signs were heart rate 136, BP 95/54, and SpO2 98% on 2 L nasal cannula (NC). His initial examination demonstrated an uncomfortable young man oriented to person only, following simple commands with antigravity movements throughout his extremities with some decreased movement on the right homebody. A head CT was completed (see figures below).

Which of these statements is most correct regarding penetrating head trauma?

a. Prognosis is better for penetrating head trauma than blunt head trauma
b. Extensive debridement of the scalp and bony wound should be undertaken, and accessible intraparenchymal bone and bullet fragments should be removed
c. Antibiotic prophylaxis with vancomycin should be started
d. Retained fragments in eloquent cortex increase the risk of epilepsy following penetrating head
e. The SAH demonstrated on the CT commonly leads to vasospasm and worse outcome

Correct Answer is D

Comment:

Correct Answer: D

Penetrating head trauma has limited data compared to nonpenetrating head trauma with much of the literature and treatment paradigms extrapolated from military interventions. The head CT in this case demonstrates a number of findings: retained bullet fragments in eloquent cortex, intraparenchymal bone fragments, crossing of the midline with involvement of the bilateral hemispheres, and small epidural and SAH. The prognosis from penetrating head trauma is worse than nonpenetrating head trauma. Initial evaluation of penetrating head trauma is similar to other trauma with evaluation of airway, breathing, and circulation (ABC), then a trauma assessment. There is need for careful evaluation of the entry and potential exit wound. Specific evaluation of any CSF leakage, brain parenchymal, and ongoing bleeding at these sites is crucial. A detailed neurologic examination should be completed as well. Following this neuroimaging will assist with determination of surgical planning if needed. Imaging can reveal intracranial fragments, missile tract and relationship to blood vessels, intracranial air, ventricular injury, basal ganglia and brain stem injury, basal cistern effacement, herniation, and mass effect. CT and CTA are the standard imaging modalities for penetrating brain imaging. There are high-risk vascular areas including near the Sylvian fissure, supraclinoid carotid artery, vertebrobasilar vessel, aversions signs, and major dural venous sinuses. Other common findings on imaging are the presence of blood product including within the subarachnoid space. This type of hemorrhage is due to vascular injury and although there is risk of cerebral vasospasm similar to the typical aneurysmal SAH. As is in this case, there are retained fragments, and this places the patient at higher risk for intracranial infection. There are varying treatment paradigms for prophylactic antibiotic use, but it is recommended. The common infections are skin flora including Staphylococcus aureus, but also gram-negative organisms can cause infection. Therefore, broad-spectrum antibiotic therapy with a cephalosporin, vancomycin, and aerobic coverage (metronidazole) is considered mainstay therapy, but the duration of therapy is quite variable from 7 to 14 days up to 6 weeks. Lastly, following penetrating head injury, it is common to have epilepsy. About 50% of penetrating TBI patients may develop epilepsy in during the 15 years post injury.

References:

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