Epidural hematoma vs Subdural and subarachnoid hemorrhage
How to tell Epidural hematoma and Subdural and subarachnoid hemorrhage apart when a board question makes them look alike.
Epidural is a lens that does not cross sutures but can cross midline; subdural is a crescent that crosses sutures but not the falx; subarachnoid is thunderclap blood in CSF spaces.
Side by side
Epidural hematoma follows trauma, often temporal bone fracture with middle meningeal artery injury, lucid interval, rapid deterioration, and biconvex lens-shaped CT bleed that does not cross suture lines but can cross midline.
Subdural hemorrhage is bridging-vein bleeding with crescent CT collection that can cross sutures but is limited by falx at midline; subarachnoid hemorrhage causes thunderclap headache with blood in sulci/cisterns, often from ruptured berry aneurysm.
Arterial bleeding dissects between skull and dura, creating a rapidly expanding extra-axial collection.
Subdural bleeding tears bridging veins between dura and arachnoid; subarachnoid bleeding enters the CSF-filled subarachnoid space.
Lens-shaped hyperdensity after head trauma and neurologic decline support epidural hematoma.
Crescent extra-axial blood supports subdural; CT/LP evidence of subarachnoid blood or xanthochromia supports subarachnoid hemorrhage.
The trap
All are intracranial bleeds, so CT shape, vessel source, and story tempo separate them.
Watch it explained
Test it nowThe repair move
For any brain bleed on noncontrast CT, translate shape and pattern into the vessel and the anatomic space in three steps: (1) lens-shaped (biconvex) hyperdensity that does not cross suture lines equals epidural hematoma from middle meningeal artery rupture, often with skull fracture and a classic lucid interval, needing urgent surgical evacuation; (2) crescent-shaped hyperdensity that crosses suture lines but not the falx equals subdural hematoma from torn bridging veins, classically in elderly, alcoholic, or shaken-infant patients with slower onset; (3) blood in sulci, basal cisterns, or sylvian fissure equals subarachnoid hemorrhage from a ruptured berry aneurysm (thunderclap headache, neck stiffness), with CT-negative cases needing LP for xanthochromia.
Try a free question
CoreA patient has temporal head trauma, brief loss of consciousness, a lucid interval, then rapid neurologic decline. CT shows a biconvex lens-shaped extra-axial hyperdensity. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Epidural hematoma. Lucid interval after trauma with lens-shaped CT blood points to epidural hematoma.
Why the other choices are tempting
- B. Subdural hemorrhage is crescent-shaped and usually venous.
- C. Subarachnoid hemorrhage causes blood in CSF spaces with thunderclap headache.
- D. Intracerebral hemorrhage is intraparenchymal blood.
- E. Ischemic stroke is vascular occlusion rather than lens-shaped extra-axial blood.
Flashcards
Tap a card to flip it.
What CT shape points to epidural hematoma?
A biconvex lens-shaped extra-axial bleed that does not cross sutures points to epidural hematoma.
What vessel is classically injured in epidural hematoma?
The middle meningeal artery is classically injured in epidural hematoma.
Quick answers
What is the fastest way to tell Epidural hematoma from Subdural and subarachnoid hemorrhage?
Epidural is a lens that does not cross sutures but can cross midline; subdural is a crescent that crosses sutures but not the falx; subarachnoid is thunderclap blood in CSF spaces.
What is the key clue for Epidural hematoma?
Epidural hematoma follows trauma, often temporal bone fracture with middle meningeal artery injury, lucid interval, rapid deterioration, and biconvex lens-shaped CT bleed that does not cross suture lines but can cross midline.
What is the key clue for Subdural and subarachnoid hemorrhage?
Subdural hemorrhage is bridging-vein bleeding with crescent CT collection that can cross sutures but is limited by falx at midline; subarachnoid hemorrhage causes thunderclap headache with blood in sulci/cisterns, often from ruptured berry aneurysm.
What is the common trap with Epidural hematoma vs Subdural and subarachnoid hemorrhage?
All are intracranial bleeds, so CT shape, vessel source, and story tempo separate them.