29F with trauma and headache • Xray of the Week
Figure 1. What is the important finding on this CT scan.
A. Axial CT brain showing epidural hematoma in frontal region (yellow arrow).
B. Axial CT brain showing fracture of right frontal bone (red arrow)
C. Coronal CT brain showing right frontal epidural hematoma extending across the midline to the left frontal region (yellow arrows).
D. 3D CT showing linear fracture of linear fracture of right frontal bone (red arrow) and left parietal bone (green arrow).
Epidural hematomas (EDH) refer to bleeding between the skull and the dura mater (1). EDH can occur when skull fractures result in arterial or venous injuries, causing pooling of blood in the epidural space (1). The majority of EDH's are unilateral and supratentorial, and 20% are frontal (2). Damage to a branch of the middle meningeal artery is the most common source of bleeding, but some EDH's can be attributed to venous bleeding after laceration of a dural venous sinus (3). Patients with EDH may initially lose consciousness and then regain consciousness and appear normal during a “lucid interval” before losing consciousness again (4). This lucid interval is an important characteristic of EDH that may help in diagnosis.
On CT scan, EDH's present as a hyperdense, biconvex-shaped mass. Whereas subdural hematomas are not limited by the sutures, EDH's usually do not cross suture lines since blood cannot expand beyond the point where the dura attaches to the cranial sutures (1). However, the EDH in this case is unique because it does cross the sagittal suture. This can occur when diastatic fractures cause widening of sutures, allowing blood to cross the suture lines (3,10). In this case, the fracture crosses the sagittal suture (Fig. 2D) with resultant acute bifrontal EDH. Larger EDH's can also present with midline shift or compression of the ventricles due to mass effect (3). In acute bleeding, the non-clotted fresh blood appears as areas of low density on CT, also known as a swirl sign (5). Subacute EDH occurs between days 2-4 and appears solid while chronic EDH occurs between days 7-20 and appears as mixed or lucent with contrast enhancement (3). MRI can also be used to visualize EDH as it is more sensitive than CT. The presence of the displaced dura as a hypointense line on T1 and T2 on MRI is a key finding in EDH (6). MRI can also be used to differentiate between acute and chronic EDH. Acute EDH appears isointense on T1 with varying intensities on T2 while chronic EDH appears hyperintense on T1 and T2 (6). Angiography of EDH can show tears of the middle meningeal artery. In rare cases, EDH can appear with a “tram track sign” on angiography due to extravasation of contrast into the paired meningeal veins (7, 8).
Treatment for acute and symptomatic EDH is hematoma evacuation to reduce pressure on the brain (9). Burr hole evacuation can also be used, and craniotomy may be necessary in large hematomas (3, 9). Non-surgical treatment is rare, but can be appropriate if there is a midline shift less than 5 mm, an EDH volume less than 30 ml, clot diameter less than 15 mm, and Glasgow Coma Score greater than 8 with no focal neurological symptoms (3). Follow up includes neurological examinations and surveillance with brain imaging to ensure that the hematoma does not expand (3, 9).
1. Heit JJ, Iv M, Wintermark M. Imaging of Intracranial Hemorrhage. J Stroke. 2017;19(1):11-27. doi:10.5853/jos.2016.00563
2. Bonfante, Eliana, and Roy Riascos. “Imaging of Brain Concussion.” Neuroimaging Clinics of North America, vol. 28, no. 1, Feb. 2018, p. i. doi:10.1016/S1052-5149(17)30140-5.
3. Khairat A, Waseem M. Epidural Hematoma. [Updated 2020 Jul 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK518982/
4. Ganz JC. The lucid interval associated with epidural bleeding: evolving understanding. J Neurosurg. 2013;118(4):739-745. doi:10.3171/2012.12.JNS121264
5. Gupta VK, Seth A. "Swirl Sign" in Extradural Hematoma. World Neurosurg. 2019;121:95-96. doi:10.1016/j.wneu.2018.10.010
6. Marincek BF, Dondelinger RF. Emergency Radiology: Imaging and Intervention. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg; 2007:109-110. doi:10.1007/978-3-540-68908-9
7. Yu J, Guo Y, Xu B, Xu K. Clinical importance of the middle meningeal artery: A review of the literature. Int J Med Sci. 2016;13(10):790-799. Published 2016 Oct 17. doi:10.7150/ijms.16489
8. Paiva WS, Andrade AF, Amorim RL, et al. Computed tomography angiography for detection of middle meningeal artery lesions associated with acute epidural hematomas. Biomed Res Int. 2014;2014:413916. doi:10.1155/2014/413916
9. Ren H, Yin L, Ma L, Wei M, Ma X. Emergency bedside evacuation of a subset of large postoperative epidural hematomas after neurosurgical procedures. Medicine (Baltimore). 2018;97(30):e11475. doi:10.1097/MD.0000000000011475
10. Huisman TA, Tschirch FT. Epidural hematoma in children: do cranial sutures act as a barrier?. J Neuroradiol. 2009;36(2):93-97. doi:10.1016/j.neurad.2008.06.003
Amara Ahmed is a medical student at the Florida State University College of Medicine. She serves on the executive board of the American Medical Women’s Association and Humanities and Medicine. She is also an editor of HEAL: Humanism Evolving through Arts and Literature, a creative arts journal at the medical school. Prior to attending medical school, she graduated summa cum laude from the Honors Medical Scholars program at Florida State University where she completed her undergraduate studies in exercise physiology, biology, and chemistry. In her free time, she enjoys reading, writing, and spending time with family and friends.
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Kevin M. Rice, MD is the president of Global Radiology CME
Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015, Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" Award for the Most Effective Radiology Educator.
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