CC | Epidural v Subdural Hematomas

An Epidural Hematoma (EDH) and a Subdural Hematoma (SDH) are two distinct forms of focal intracranial bleeding caused by head trauma[1][2]. They differ significantly in anatomical location, primary bleeding source, clinical progression, and at-risk populations[2][3].

1. Side-by-Side Comparison

FeatureEpidural Hematoma (EDH)Subdural Hematoma (SDH)Anatomical LocationBetween the dura mater and the inner surface of the skull[2][4].Between the dura mater and the arachnoid layer of the meninges[2][4].Primary Vessel InvolvedUsually arterial (most commonly a tear of the middle meningeal artery beneath the temporal bone)[2][5]. Can occasionally be venous from a dural venous sinus tear[2].Usually venous (tear of bridging veins draining from the brain surface into the sagittal sinus)[2]. Can occasionally be arterial[2].Rate of Bleeding & OnsetRapidly developing due to high-pressure arterial expansion; considered a critical neurologic emergency[2].Usually slower to develop due to lower-pressure venous bleeding[2]. Divided into acute, subacute, and chronic forms[2][3].Classic Clinical PresentationUnconsciousness at the scene → brief lucid interval → rapid neurologic deterioration and decreased level of consciousness (LOC)[2].Symptoms of progressive increased intracranial pressure (ICP) and brain compression: headache, drowsiness, confusion, decreasing LOC, and ipsilateral fixed/dilated pupil[2].Associated Etiology & Risk FactorsFrequently associated with linear skull fractures crossing major dural arteries (e.g., temporal bone fractures)[2][5].Older adults (due to brain atrophy stretching bridging veins), alcohol use (risk of falls), and anticoagulant therapy[2][3].Surgical TreatmentRapid surgical evacuation via craniotomy or burr-hole decompression to prevent brain herniation[2][6].Surgical evacuation, decompression, or membranectomy (craniotomy or burr holes) depending on size and impairment[2].

2. Key Clinical Nuances

• The EDH Lucid Interval: The hallmark of an arterial EDH is a patient who temporarily regains clarity after an initial knockout, only to rapidly deteriorate as arterial blood expands inside the closed skull[2]. Emergency surgical intervention is required before herniation occurs[2][6].
• Subdural Subtypes (Acute, Subacute, Chronic):
  • Acute SDH: Manifests within 24–48 hours of severe trauma with immediate deterioration[2].
  • Subacute SDH: Appears within 48 hours to 2 weeks post-injury; blood breakdown products draw fluid into the subdural space, causing late expansion[2][3].
  • Chronic SDH: Develops over weeks or months (often >20 days) after a seemingly minor or forgotten head injury[2][3].
• Diagnostic Pitfalls in Older Adults: Chronic SDH in older adults is frequently misdiagnosed as dementia, a transient ischemic attack (TIA), or a stroke because symptoms present as subtle confusion, memory loss, and lethargy rather than acute ICP spikes[3].