Subdural Hematoma and Epidural Hematoma are easy to mix up on the boards. Here's a side-by-side comparison — presentation, workup, imaging, and first-line treatment — drawn from our full outlines.
Subdural Hematoma vs Epidural Hematoma at a glance
Subdural Hematoma: Bleeding between dura and arachnoid from torn bridging veins; crescent-shaped on CT.
Epidural Hematoma: Arterial bleeding between skull and dura, classically from middle meningeal artery injury.
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Question 1NeurologyMedium
A 74-year-old man is brought in by his daughter for two weeks of worsening headache, mild confusion, and a new unsteady gait. He takes apixaban for atrial fibrillation and tripped on a rug about three weeks ago without striking his head, per the family. Vital signs are normal. Neurologic exam shows mild left-sided pronator drift and a wide-based gait but no other focal deficits. A non-contrast head CT is read as showing no acute hemorrhage, though the radiologist notes effacement of the right cortical sulci. Which of the following is the most appropriate next diagnostic test?
ALumbar puncture for CSF studies
BRepeat noncontrast head CT scan
CBrain MRI without IV contrast
DElectroencephalography study
Reveal answer & full explanation
Correct answer: C — Brain MRI without IV contrast
ALumbar puncture for CSF studies
BRepeat noncontrast head CT scan
CBrain MRI without IV contrast✓
DElectroencephalography study
Why Brain MRI without IV contrast is correct
The picture of an elderly anticoagulated patient with a remote minor fall and a subacute course of headache, cognitive decline, gait disturbance, and contralateral pronator drift is classic for a subacute-to-chronic subdural hematoma.
A subacute subdural hematoma (about 1 to 3 weeks old) becomes isodense to brain on noncontrast CT and is easily missed; the unilateral sulcal effacement is a subtle clue to a hidden isodense collection.
MRI is the most sensitive study for small, isodense, or chronic subdural hematoma and can also help date the bleed, making it the best next step when CT is nondiagnostic but suspicion remains high.
Why the others are wrong
Lumbar puncture for CSF studies — used for suspected meningitis or subarachnoid hemorrhage with a negative CT, and it is hazardous when a space-occupying collection with mass effect is suspected.
Repeat noncontrast head CT scan — reasonable only if the patient acutely deteriorates, but repeating the same modality that misses isodense collections will not reliably reveal a subacute subdural hematoma.
Electroencephalography study — nonconvulsive seizure activity can cause subacute confusion in an older adult, but the focal pronator drift, therapeutic anticoagulation, and unilateral sulcal effacement demand that a structural lesion be imaged before an electrographic cause is pursued.
Question 2NeurologyMedium
A 24-year-old man is brought to the emergency department after a baseball struck his left temple during a game. He briefly lost consciousness, then spoke normally to teammates for about an hour before becoming progressively drowsy and confused. On arrival his GCS is 11, the left pupil is dilated and sluggishly reactive, and he has right-sided weakness. A non-contrast head CT is obtained. Which of the following findings on CT best supports the diagnosis?
ABiconvex hyperdense collection limited by suture lines
BHyperdense blood layering within the sulci and cisterns
CCrescent-shaped hyperdense collection crossing the sutures
DPunctate hemorrhages at the gray-white matter junction
Reveal answer & full explanation
Correct answer: A — Biconvex hyperdense collection limited by suture lines
ABiconvex hyperdense collection limited by suture lines✓
BHyperdense blood layering within the sulci and cisterns
CCrescent-shaped hyperdense collection crossing the sutures
DPunctate hemorrhages at the gray-white matter junction
Why Biconvex hyperdense collection limited by suture lines is correct
An epidural hematoma is arterial blood, usually from a middle meningeal artery laceration at a temporal or pterion fracture, dissecting the tightly adherent dura off the inner skull.
Because the dura is firmly attached at suture lines, the collection cannot cross them, producing the classic lens-shaped (biconvex) hyperdensity, often with an adjacent skull fracture on bone windows.
The temporal blow, lucid interval, ipsilateral blown pupil, and contralateral hemiparesis are the textbook uncal-herniation picture of an expanding EDH, and non-contrast head CT with brain and bone windows is the confirmatory study.
Why the others are wrong
Crescent-shaped hyperdense collection crossing the sutures: this is an acute subdural hematoma from torn bridging veins; it follows the brain surface and does cross sutures.
Hyperdense blood layering within the sulci and cisterns: this describes subarachnoid hemorrhage, an intra-sulcal and cisternal pattern rather than a lens-shaped extra-axial collection.
Punctate hemorrhages at the gray-white matter junction: these suggest diffuse axonal injury, typically better seen on MRI and associated with coma out of proportion to CT, not a focal lucid-interval EDH.
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Bleeding between dura and arachnoid from torn bridging veins; crescent-shaped on CT.
Arterial bleeding between skull and dura, classically from middle meningeal artery injury.
Classic presentation
Crescentic (concave/'moon-shaped') extra-axial collection on CT that crosses suture lines. Acute = hyperdense (white), subacute = isodense (may be subtle), chronic = hypodense (dark).; Acute SDH: history of significant trauma, immediate decreased consciousness, headache, vomiting; Chronic SDH: insidious onset over weeks-months of…
Lucid interval after temporal trauma + ipsilateral blown pupil + contralateral hemiparesis = uncal herniation from expanding EDH.; Head trauma with brief loss of consciousness; Classic 'lucid interval' (minutes to hours of normal mentation) followed by rapid neurologic deterioration in ~20-50%; Headache, vomiting, confusion progressing…
Workup / key labs
CBC, platelets, PT/INR, PTT — anticoagulation common in this population; BMP, LFTs; Type and screen if surgical intervention likely
CBC, platelets, PT/INR, PTT (rule out coagulopathy); BMP, type and screen, alcohol/toxicology if indicated
Imaging
Non-contrast head CT — first-line, identifies acute SDH easily; Subacute (isodense) SDH may be missed on CT; contrast or MRI helpful; MRI — most sensitive for small or chronic SDH and dating the bleed; Repeat CT in 6-24 h if patient deteriorates or has progressive symptoms
Non-contrast head CT — biconvex (lens-shaped) hyperdense collection limited by suture lines, often with adjacent skull fracture; CT brain windows + bone windows mandatory (fracture identification); CT angiography if vascular injury suspected (e.g., carotid dissection from skull base fracture); Cervical spine imaging — significant head…
First-line treatment
ABCs; intubate if GCS ≤8; Reverse anticoagulation: warfarin → 4-factor PCC + vitamin K 10 mg IV; DOACs → idarucizumab (dabigatran) or 4-factor PCC (factor Xa inhibitors; andexanet alfa was withdrawn from the US market in 2025); aspirin/clopidogrel — platelet transfusion controversial; BP control (avoid hypotension; target SBP <160 in…
ABCs, cervical spine immobilization; Intubation if GCS ≤8 or airway compromise; Manage ICP: head of bed 30°, normocapnia (PaCO2 35-40), hypertonic saline (3%) or mannitol 1 g/kg if herniation signs; Reverse anticoagulation if present (warfarin → 4-factor PCC + IV vitamin K, FFP if PCC unavailable; factor Xa inhibitors → 4-factor PCC;…
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