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I'd like to review some information about

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epidural hematomas.

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Before then,

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I just want to make sure that we are all on the same page

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with respect to the etiology of epidural hematomas.

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As you can see,

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epidural hematomas are usually due to

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a defect in the arterial supply,

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usually the middle meningeal artery

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which leads to the lentiform shape

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of the epidural hematoma

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overlying the temporal lobe.

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However,

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the alternative etiology is a tear in the

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venous sinus where blood collects

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outside the dura.

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Contrast that with the subdural hematoma,

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where one has a collection

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which is deep to the dura

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from small veins that are torn.

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For those of you who like a little bit more

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of an anatomic explanation,

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here, we have a description of the anatomy.

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You see that we have the skin surface and then the skull

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and we have the meningeal artery,

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which is outside of the dura here.

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In this situation,

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a collection outside of the dura

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would lead to an epidural hematoma.

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Here we have a collection which is superficial,

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again, to the dural margin here in the epidural space

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and you would contrast that to the one that is deep to the

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dural space with these bridging veins,

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which would be in the subdural space.

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The indications for intervention for acute epidural

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hematomas are similar to that for subdural

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hematoma with a few exceptions.

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We note, as in this example,

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that an epidural hematoma that is greater than 30 CCs,

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would be an indication for surgical intervention.

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So once again, we would have to give our best guess

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as far as the three dimensions in AP right-left

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and superior-inferior dimension

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and divide that by two.

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However,

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an epidural hematoma that in one cross section is 15 mm

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thick or more, or one that leads to

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greater than 5 mm of midline shift,

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usually at the level of the septum pellucidum,

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would be an indication for surgical intervention, as well.

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Just want to remind you that when I spoke about subdural

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hematomas, the thickness was only 10 mm,

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whereas, for epidural hematomas, it's 15 mm.

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Again, this suggests that the prognosis for those

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patients who have subdural hematomas is worse than those

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with epidural hematoma, in that the surgeons are going to

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operate earlier on subdural hematomas

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than epidural hematomas.

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Remember also that there is the typical shape

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and location for an epidural hematoma.

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This is showing that biconvex appearance to an epidural

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hematoma, typically over the temporal bone,

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because that's along where the middle meningeal artery runs,

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and that's to be contrasted with the crescentic appearance

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of a subdural hematoma.

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In this case,

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the patient has an intraparenchymal hematoma as well,

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and likely has another collection outside

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the brain on the right side.

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These are two examples of epidural hematomas.

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One arterial. Which one do you expect?

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The A is actually not for arterial.

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The A represents an arachnoid cyst.

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This unfortunate individual had a traumatic epidural

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hematoma over the left hemisphere,

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as well as an arachnoid cyst.

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Crescentic in shape, over the temporal bone,

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unrelated to the patient's arachnoid cyst.

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This swirling nature of the blood products

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suggests active bleeding.

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So when you see heterogeneous density to the collection

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and a kind of a swirling pattern,

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that suggests active bleeding and it may encourage

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the surgeons to go in to evacuate it.

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Patient also has subarachnoid hemorrhage.

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This patient on the left-hand side of the slide,

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you can see has a collection which is crossing the midline.

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Well, we know that the falx normally would

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separate midline structures,

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so this collection must have dissected across

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the falx and crossing from right to left.

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Therefore, this is an epidural hematoma,

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not a subdural hematoma,

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which would be defined and cannot cross the falx.

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And this is one due to trauma to the venous sinus.

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So, I want to make sure I make this clear

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that venous sinus is epidural hematoma,

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yet bridging veins is subdural hematoma.

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Non-surgical management would be epidural hematomas who

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have a volume of less than 30 CCs,

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or less than 50 mm thick

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and with less than 5 midline shift

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and are stable clinically.

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This is another example of a patient who has an epidural hematoma,

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demonstrated as a biconvex collection,

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in this case, mixed collection in

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the posterior fossa.

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As you can see in this situation with this collection,

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we're going to look and see where there's mass effect on

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the fourth ventricle, effacement of sulci,

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displacement of the basal cisterns,

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and that may be an indication from posterior

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fossa lesion of any type,

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be it a parenchymal hematoma or a subdural hematoma,

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or an epidural hematoma.

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This epidural hematoma was secondary to

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transverse sinus disruption.