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Welcome back.
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Thanks for joining me on this discussion of
traumatic brain injury under the section of trauma.
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Let’s start with a clinical scenario.
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Take a look at this picture.
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The driver, a 25-year-old man, sustained a high-speed roll-over motor
vehicle accident who now arrives in your trauma bay, is not responsive.
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Do you know what to do next?
I’ll give you a second to think about it.
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Remember, back to our previous initial assessment and management discussion,
always begin with the ABCs.
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Now that you’ve ascertained an intact airway,
a breathing patient and a patient who has intact circulation,
we move to the D of disability where we ascertain a Glasgow Coma Scale.
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The Glasgow Coma Scale has three components.
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It’s a global assessment of the patient’s neurological status.
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Take a look at this table.
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You’ll notice that there are columns for eye, verbal, and motor examinations.
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The coordinated effort of the patient who is able to open their eyes,
speak to you, and move their extremities is one that is an oriented patient.
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Glasgow Coma Scales are scored from a minimum of 1 to a maximum of 6 points.
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We assign the best exam finding.
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Remember, the best exam finding.
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When presented on an examination of what is the GCS score,
always look for the best exam finding.
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The eye exam is listed from 1 to 4.
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The verbal examination is listed from 1 to 5.
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And the motor exam is listed from 1 to 6.
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There is no precedence or importance of one exam over another,
although it appears that motor is heavily weighted.
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Important to remember that you just have to spend a
few minutes looking at the slide and memorizing.
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Unfortunately, I don’t have any simple ways of memorizing the GCS EVM scoring.
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The patient does not open his eyes, respond verbally or move.
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My question to you is, “What is this patient’s Glasgow Coma Scale?”
Again, the patient doesn’t open eyes,
has absolutely no verbal and is not moving at all.
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This is a common trick question.
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The minimum GCS is 3 because the lowest score is 1 on a 1 to 6 scale.
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So, the minimum score GCS is 3 in this completely comatose patient.
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As a side note, the placement of the ET tube, if that’s the only
limiting factor for patient’s ability to speak,
we assign a T for endotracheal tube at the end of the GCS score.
02:44
Let’s transition to a discussion of traumatic
brain injury but first let’s discuss the anatomy.
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On this image, you see the first layer as the skull and right underneath it
is the superior sagittal sinus containing venous drainage blood.
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The yellow outline suggests a subarachnoid space between 2 arachnoid and pia maters.
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I’d like to start the discussion of specific traumatic
brain injuries with a discussion of subdural hematomas.
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Classically, subdural hematomas or any intracranial
bleeding is associated with high impact to the skull.
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They are traditionally associated with tearing of bridging
veins between the brain surface to the dura sinus.
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As you can see in this image,
bleeding in the subdural space results in a semilunar
or often called moon-shaped crescent hematoma.
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The reason is because the blood separates the arachnoid away from the dura.
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It is not, however, bound by the sagittal sinuses.
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There may or may not be medial deviation or elevation of the intracranial pressure.
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Remember, any space-occupying lesion in the brain
may lead to elevations of intracranial pressure.
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We will come back to this concept.
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How do we manage subdurals?
Based on the clinical status and the severity of the subdural,
management is guided by midline shift, intracranial hypertension,
clinical picture such as a comatose or worsening GCS patient
or particularly large subdural hematomas as defined by
bleeding hematomas greater than one centimeter in thickness.
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If these findings are present, consider calling a neurosurgical
colleague for surgical decompression of the hematoma.
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Of course if the patient doesn’t have any of these significant findings,
then our job as trauma surgeons is to prevent secondary injury.
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What does it mean to prevent secondary injury?
With any trauma, just like when you bang your knee, some swelling is bound to happen.
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We want to decrease swelling and also prevent ischemia or low perfusion of your brain.
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Let’s move on and discuss epidural hematomas.
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Once again, epidural hematomas are associated with high impact to the skull.
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Unlike subdurals which are associated with bridging veins,
the epidurals are associated with middle meningeal artery.
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In a clinical scenario, this often describe classic lucid interval
where the patient immediately following the trauma may actually be lucid
and after about 30 minutes to an hour has a second comatose episode.
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I caution the viewer though that the classic lucid
interval is much more discussed and seen in real life.
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And seen on this CAT scan, you notice that the lenticular
shape or biconvex shape which is limited by the suture line.
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How do we manage an epidural hematoma?
Most epidural hematomas, unlike subdural hematomas, require a surgical decompression.
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If a clinical scenario is presented to you where a
patient sustains high velocity or a high-impact
brain trauma and they demonstrate a lucid interval,
I encourage you to hold epidural hematomas high on your
differential list and a list of surgical decompression.
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Once again, like any traumatic brain injury,
we want to try to prevent secondary injury.
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Now, let's have a short view on tumor types bleeding in the brain.
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First, there's a traumatic subarachnoid hemorrhage.
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This is type, there is blood in the subarachoid space, so between the pia and the arachnoid mater.
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A head trauma is the most common cause.
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Possible symptoms are headache, nuchal rigidity, photophobia, focal neurologic deficits, and loss of consciousness.
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For a diagnosis, you can use a head CT without contrast.
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To treat such a hemorrhage, you can do a surgical clipping or an intravascular coiling.
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On this slide, you can see two types of intracranial hemorrhage.
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The CT scan on the left depects a case of intracerebral hemorrhage,
whereas the slide on the right, shows a case of intraventricular hemorrhage.
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Treatment is mainly supportive.
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In severe cases, an external ventricular drain maybe required to evacuate the blood or even craniotomy.
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Let’s discuss skull fractures.
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Once again, skull fractures are associated with
high-impact mechanisms such as an assault with a weapon.
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It’s a classic scenario to have a patient undergo assault
with a bat or a metal instrument direct blow to the head.
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Remember that skull fractures are often associated with cervical spine injuries.
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This likely has to be dissociation due to the high impact injury.
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Some very important classic signs include the
raccoon’s eyes which is a bruising around the eyes.
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Remember, raccoon eyes and battle’s signs are signs of a basilar skull fracture.
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Battle’s sign is bruising around the mastoid process.
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Just to review, raccoon’s eyes is bleeding or bruising around the eyes
and battle’s sign is bruising of the mastoid process just behind the ear.
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And depending on the severity, the patient can have a CSF, cerebrospinal fluid leak.
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Most skull fractures are largely managed
non-operatively unless couple of caveat exists.
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One, significant depression of the skull.
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This may require elevation of the skull.
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And most importantly, an open skull fracture
uniformly requires exploration and elevation.
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Earlier, I mentioned that one of the clinical signs to
evaluate the patient for is intracranial pressure monitoring
and to try to prevent intracranial hypertension for high ICPs.
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A very useful and practical equation to remember is the cerebral perfusion pressure.
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The cerebral perfusion pressure is a difference between the mean arterial pressure.
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That’s the systemic circulation minus the intracranial pressure.
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Again, the cerebral perfusion pressure is a
difference between your MAPs and your ICPs.
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In severe TBI patients where their GCS is less than 9 were considered comatose.
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Intracranial pressure monitoring may help with diagnosis of further deterioration.
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Remember, comatose patients will not likely
participate in your neurological examination.
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Patients in whom we cannot follow the examination,
for example, a comatose patient or one who is on severe sedation
or anesthesia may also require intracranial monitoring.