An 81 yo M presents to the ED with his daughter for worsening confusion. There is no reported trauma, but the patient is on anticoagulation. His physical exam is significant for expressive aphasia. A CT scan is obtained. What's the diagnosis? (scroll down for answer)

Answer:  Acute on chronic subdural hematoma w/ mass effect 

• Intracranial hemorrhage caused by venous bleeding into the potential space between dura and brain parenchyma
• Acute SDH: occurs within 14 days of injury and patients typically present after significant head trauma. On CT, appears as a hyperdense crescent shaped lesion that crosses suture lines
• Chronic SDH: after 14 days, often without history of traumatic event. On CT, are isodense, therefore more difficult to identify
• Chronic SDH is commonly seen in elderly patients or alcoholics and presenting complaint may be altered MS
• Require prompt neurosurgical consult- definitive treatment is determined by type, size and effect on underlying brain parenchyma
• Patients on antiplatelets/anticoagulants are at increased risk for SDH and should have coagulopathy reversed upon diagnosis

References:

Wright DW, Merck LH. Head Trauma. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e New York, NY: McGraw-Hill; 2016.