Slide 1: Question 1. Where are these two hematomas located and how can you tell them apart? Two CT scans showing hematomas.

Slide 2: Both hematomas are located outside the brain, they push the gray white junction medially, (blue arrows) but have different shapes and relations to skull sutures. The epidural hematoma shape is lentiform and doesn’t cross sutures. The subdural hematoma shape is crescenteric and crosses sutures.

Question 2. How are these hematomas typically causes and which blood vessels are involved?

Slide 3: Epidural hematomas are characteristically caused by a direct blow and often have associated fractures. The source of the hemorrhage is usually a tear of the middle meningeal artery. The middle meningeal artery is a branch of the external carotid. Graphic with arrows pointing to lenticular hematoma and dura.

Slide 4: Subdural hematomas are characteristically caused by shaking and rarely have associated fractures. The source of hemorrhage is usually a tear of a bridging cerebral vein. Graphic with arrows pointing to crescenteric hematoma and dura.

Slide 5: Cerebral atrophy is a large risk factor for subdural hematoma due to increased stretch on veins connecting the cortex with dural sinuses (bridging veins). Patients with cerebral atrophy can have subdural hematoma even with trivial head trauma. Common causes of cerebral atrophy include age-related cerebral atrophy, history of traumatic brain injury, and chronic alcohol use. Risk of medications associated with development of subdural hematoma. Aspirin has an odds ratio of 1.24 with confidence interval of 1.15 to 1.33. Clopidogrel has an odds ratio of 1.87 with a confidence interval of 1.57 to 2.24. DOAC has an odds ratio of 1.73 with a confidence interval of 1.31 to 2.28. Warfarin (any dose) has an odds ratio of 3.69 with a confidence interval of 3.38 to 4.03.

References

  • Gaist D, García Rodríguez LA, Hellfritzsch M, Poulsen FR, Halle B, Hallas J, Pottegård A. Association of Antithrombotic Drug Use With Subdural Hematoma Risk. JAMA. 2017 Feb 28;317(8):836-846. PMID 28245322.

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