Extradural subdural intracranial hemorrhage
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"intracranial hemorrhages"[MeSH Terms] AND hematoma
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Merck Manual epidural subdural hematoma intracranial hemorrhage
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diagram comparing extradural epidural hematoma and subdural hematoma CT appearances
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https://www.merckmanuals.com/professional/injuries-poisoning…
Extradural and subdural intracranial hemorrhage
Both are traumatic collections of blood around the brain and can cause raised intracranial pressure, brain herniation, and death. They require urgent assessment with non-contrast CT and neurosurgical input.
| Feature | Extradural hematoma (EDH), also called epidural | Subdural hematoma (SDH) |
|---|---|---|
| Location | Between skull and dura mater | Between dura mater and arachnoid mater |
| Usual vessel | Middle meningeal artery, usually arterial | Bridging veins, usually venous |
| Typical mechanism | Blow to temporal/temporoparietal region, often with temporal bone fracture | Acceleration-deceleration injury, falls, assault |
| Rate of bleeding | Rapid, high pressure | Often slower, but acute SDH can be severe |
| Typical patients | Younger patients after trauma | Elderly people, alcohol use disorder, anticoagulant use, infants |
| CT appearance | Biconvex/lens-shaped hyperdensity, usually does not cross sutures | Crescent-shaped collection that can spread widely over the hemisphere |
| Classic clinical pattern | Brief loss of consciousness, possible lucid interval, then rapid deterioration. The lucid interval occurs only in a minority. | Altered consciousness or focal deficits after trauma; chronic SDH may present later with headache, drowsiness, confusion, or personality change |
| Prognosis | Can be excellent if evacuated before neurological deficit/herniation | Depends heavily on accompanying brain contusion and injury; acute SDH is often more severe |
Extradural hemorrhage
A fracture may tear the middle meningeal artery. Blood then strips dura away from the inner skull, forming an expanding hematoma. As pressure rises, ipsilateral pupillary dilation, contralateral weakness, reduced consciousness, and herniation may occur rapidly.
- CT: focal, lens-shaped hyperdensity.
- Treatment: urgent neurosurgical evacuation when significant or causing deterioration, plus resuscitation and management of raised intracranial pressure.
Gray's Anatomy for Students, p. 1028: rupture of middle meningeal arterial branches after inner-table skull fracture produces extradural hematoma.
Tintinalli's Emergency Medicine, p. 1732: early recognition and evacuation before herniation reduces morbidity and mortality.
Tintinalli's Emergency Medicine, p. 1732: early recognition and evacuation before herniation reduces morbidity and mortality.
Subdural hemorrhage
Sudden movement of the brain relative to the skull tears bridging veins as they pass to dural venous sinuses. The bleeding lies beneath the dura. Cerebral atrophy increases traction on these veins, explaining the risk after apparently minor falls in older adults.
- Acute SDH: occurs within hours to days after major trauma and is frequently associated with cerebral contusions or edema.
- Chronic SDH: may evolve over weeks after minor or forgotten injury, particularly in older adults or those taking anticoagulants.
- CT: crescent-shaped collection with possible midline shift.
- Treatment: observation and repeat imaging for selected small stable lesions; urgent surgical drainage/evacuation for neurological deterioration, substantial clot, or mass effect. Anticoagulant-related coagulopathy should be promptly reversed where appropriate.
Tintinalli's Emergency Medicine, p. 1732: SDH is caused by acceleration-deceleration with tearing of bridging dural veins, and is more likely with cerebral atrophy.
Emergency warning signs after any head injury
Seek emergency care immediately for worsening headache, vomiting, confusion, unusual drowsiness, seizure, weakness/numbness, unequal pupils, loss of consciousness, or anticoagulant use. A normal period immediately after injury does not rule out a dangerous hemorrhage. The Merck TBI review likewise describes lentiform EDH and crescentic SDH appearances on CT.
Compare extradural and subdural hemorrhage on CT
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CT scan comparison epidural extradural biconvex lens shaped hematoma versus subdural crescent shaped hematoma
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"epidural hematoma" AND "subdural hematoma"
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epidural versus subdural hematoma CT appearance authoritative
CT comparison: extradural (epidural) vs subdural hemorrhage
| CT feature | Extradural / epidural hematoma (EDH) | Subdural hematoma (SDH) |
|---|---|---|
| Shape | Biconvex, lentiform, lens-shaped hyperdense collection | Crescent-shaped, concavo-convex extra-axial collection |
| Extent | Usually localized | Often spreads over a large part of a cerebral hemisphere |
| Relation to sutures | Usually does not cross cranial sutures, because the dura is tightly adherent there | Can cross sutures because blood lies beneath the dura |
| Relation to dural reflections | May cross the falx or tentorium if not limited by suture attachment | Usually does not cross dural reflections such as falx or tentorium |
| Usual density on acute CT | Hyperdense | Hyperdense when acute; becomes isodense in subacute phase and hypodense in chronic SDH |
| Typical associated finding | Skull fracture, especially temporal bone fracture | Cerebral contusions, edema, and possible diffuse brain injury |
| Mass effect | Can rapidly cause midline shift, ventricular compression, and herniation | May cause substantial midline shift, especially in acute large or chronic expanding SDH |
| Typical vessel | Middle meningeal artery | Bridging veins |
Memory aid:
- EDH = lens, restricted collection.
- SDH = crescent, spreads along the brain surface.
A subdural collection is characteristically concave toward the brain, whereas extradural hematoma is convex toward the brain. Bradley and Daroff's Neurology in Clinical Practice, CT figure description. Acute EDH is classically biconvex and often temporal; SDH results from bridging-vein injury and can spread more broadly. Tintinalli's Emergency Medicine, p. 1732.
CT is the first-line imaging study in acute traumatic head injury because it rapidly shows hemorrhage, skull fracture, mass effect, and midline shift, as summarized in this NCBI imaging comparison.
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