|
|
| Images
below require Macromedia's Flash Player to view |
 |
Neuroradiology Case of the Week
Case 400
April 2009
Bruce Chien, MSIII, Virendra Kumar, MD and PL Westesson, MD, PhD, DDS
Clinical
Presentation: Patient is a 19-year-old male who sustained trauma to the head after a skateboarding accident.
Imaging Findings: Imaging of the head revealed a large epidural hemorrhage over the frontoparietal lobe causing compression and displacement of dural venous sinuses. The epidural hemorrhage is seen to cross midline suggesting the possibility of damage to the dural venous sinuses. The brain parenchyma does not appear to have suffered any injury or hemorrhage. MRI of the head again revealed bilateral epidural hematomas over the frontoparietal lobes. The hematoma is slightly hyperintense on T1-weighted images and hyperintense on T2-weighted images, and is causing inferior displacement of the dura and superior sagittal sinus. Although the brain parenchyma is compressed by the hematoma, no signal changes is noted. MR venogram of the brain revealed displacement with distortion and compression of the superior sagittal sinus by the epidural hematoma. However, the superior sagittal sinus is patent. MR angiography of the brain revealed normal ICA's, ACA's, MCA's and PCA's. Vertebral and basilar arteries were also normal bilaterally.
| |
Figure 1: Coronal head CT demonstrates epidural hematoma at the vertex crossing the midline.
|
| |
| Figure 2: Sagittal head CT demonstrates epidural hematoma over the frontoparietal lobes of the brain parenchyma.
|
| |
| Figure 3: Axial head CT of the epidural hematoma.
|
| |
Figure 4: MR venogram demonstrates the patency of the inferiorly displaced superior sagittal sinus.
|
|
|
| Figure 5: Coronal SPGR with contrast shows the hematoma overlying the dura.
|
|
|
| Figure 6: T1-weighted image of the hematoma inferiorly shows displacing and distorting of the superior sagittal sinus.
|
Diagnosis: Bilateral epidural hematomas
Discussion: Epidural hematomas are blood clots that form between the skull and the dura. Majority of epidural hematomas results from high impact injuries that cause trauma to the skull and thus damage to the middle meningeal artery, middle meningeal vein or the venous sinuses. Arterial blood, most commonly from the middle meningeal artery, dissects the dura mater away from the skull thus forming a hematoma. Epidural hematomas are formed rapidly secondary to high pressure arterial flow and are usually located in the temporoparietal region, which allows for early detection. However, if epidural hematomas result from venous sinus tears, which are usually located in the parietal-occipital region or posterior fossa, hematoma formation is usually delayed.
Epidural hematomas account for about 1-2% of all head trauma cases and are usually unilateral. Patients younger than 20 years of age account for 60% of epidural hematomas. They are less common in the elderly and in children younger than 2 years of age as their dura is more closely attached to the skull. The most common cause in adults is traffic-related accidents (53%) and among children are falls (49%).
Patients with epidural hematomas classically present after sustaining trauma to the head with a subsequent decreased level of consciousness, which is then followed by a lucid interval. The patient then experiences a second episode of decreased level of consciousness. However, this pattern is not pathognomic for epidural hematomas as only 30% of patients have the "classic" presentation. Moreover, any expanding mass lesion could generate a similar presentation. Patients commonly report having a severe headache, sleepiness, dizziness, nausea and vomiting. The rapidity of symptoms usually depends on the speed with which the epidural is expanding.
CT of the head will reveal a hyperdense, biconvex, ovoid, and lenticular lesion with sharply defined margins. The hematoma usually bulges into the brain and does not extend beyond the dural attachments at the suture lines. The most common site is the temporal region, which consists mostly of the middle meningeal artery and its branches.
Mortality of all patients with epidural hematomas is approximately 10%. However, factors such as Glasgow Coma Scale, age, pupillary abnormalities, associated intracranial lesions, time between neurological deterioration and surgery, and intracranial pressure are important factors that influence patient outcome. Conservative, non-operative management of epidural hematomas is becoming more common through the use of serial CT imaging and close clinical follow-up. However, if the patient demonstrates neurologic deterioration (decreased level of consciousness, pupillary dilation, hemiparesis) operative intervention is usually required.
References:
- Bullock MR, Chesnut R, Ghajar J, et al. Surgical management of acute subdural hematomas. Neurosurgery. 2006 Mar;58(3 Suppl):S16-24. [PubMed]
- Heegaard WG, Biros MH. Chapter 38: Head. IN: Marx JA, Hockberger RS, Walls RM, et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice, 6th ed. Philadelphia: Mosby Elsevier, 2006. [MDConsult]
- Offner PJ, Pham B, Hawkes A. Nonoperative management of acute epidural hematomas: a "no-brainer". Am J Surg. 2006 Dec;192(6):801-5. [PubMed]
- Price DD, Wilson SR. Epidural hematoma. eMedicine, January 31, 2008. http://emedicine.medscape.com/article/824029-overview.
|
