Bilateral Subacute Subdural Hematomas
Updated: Jul 23, 2021
63 year old male. Headache for 1 month and unsteady gait. What is the diagnosis? • Xray of the Week
Figure 1. Brain CT. Name the significant findings.
Figure 2. A, B, C: Non-contrast axial CT displaying subtle bilateral isodense subdural hematomas. There is medial displacement of gray matter with left (orange arrows) worse than right (red arrows). Shift of midline structures to the right is also a clue to the diagnosis. D: Non-contrast coronal CT indicating isodense subdural hematoma (orange arrows). Note again the midline shift to the right.
Figure 3. Post op CT brain on same patient. Note the lower attenuation fluid after treatment. Partial evacuation of hematoma with hypodense regions indicating residual fluid and blood products (red and orange arrows).
Subacute subdural hematomas (SDH) are usually due to clinically undetected acute SDH. Two leading causes are tearing of the bridging vessels due to abrupt acceleration-deceleration of the head or accumulation around a parenchymal laceration (1). This trauma leads to blood accumulation between the arachnoid and dura layers of the brain (2). Risk factors include cerebral atrophy (elderly patients or chronic alcoholics), anticoagulation use, or recent thrombolysis (3). The patient may or may not have a history of head trauma. Common presenting features include headache, decreased memory, confusion, and motor dysfunction (4).
SDH can cross suture lines since they occur deep to the dura mater; this differs from epidural hematomas which usually do not cross suture lines since blood cannot extend beyond the point where the dura attaches to the cranial sutures (5). Subacute subdural hematomas are categorized as isodense biconcavities on CT. When blood clots degrade, the density decreases and becomes more similar to the brain parenchyma. Furthermore, subacute (and chronic) SDHs may show septations within an iso/hypodense hematoma due to reactive granulation tissue formation (6). Subacute hemorrhages can be challenging to recognize because of the isodense characteristics. Therefore, one must also look for signs of mass effect such as asymmetry of the lateral ventricles, shifting of midline structures, sulcal effacement, and sulci that do not extend into the skull (Figs. 1-2) (7).
Management of subacute SDH is determined by whether a patient is symptomatic or exhibiting signs of mass effect; those who are asymptomatic may be candidates for conservative treatment (8). Mainstay surgery modalities include twist-drill craniostomy, burr-hole craniostomy, and craniotomy (8). Figure 2 shows this patient following bilateral craniotomy.
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Deven Champaneri is a medical student at Edward Via College Osteopathic Medicine (VCOM) – Carolinas and plans to pursue residency in diagnostic radiology. While he was rotating through various specialties, he realized his passion for DR and valued its role in all aspects of medicine. He graduated from the University of South Carolina in 2017 with a degree in Business Marketing. During his undergraduate studies, he was involved with multiple volunteer organizations, such as Camp Kemo a summer camp for children with cancer and Palmetto Richland Children’s Hospital. Currently, he mentors at-risk high-school students and tutors students for Step 1/COMLEX 1. In his spare time he enjoys, golfing, backpacking, cooking, and spending time with family.
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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