Extradural haemorrhage

Overview

•Blood between inner skull and dura mater - arterial bleeding (middle meningeal artery) in most cases

•Pterion is thinnest skull bone - overlies middle meningeal artery; temporal blow → fracture → arterial laceration

•Dura tethered at suture lines → haematoma cannot cross sutures → biconvex (lentiform) shape on CT

•Peak incidence 20-30 year olds; males 3x more common

Presentation

•Lucid interval - brief recovery after initial concussion, then rapid deterioration as haematoma expands (minutes to hours)

•Headache - worsening, progressive

•Nausea and vomiting - rising ICP

•Decreasing GCS - progressive as haematoma expands

•Ipsilateral fixed dilated pupil - CN III compression from uncal herniation

•Contralateral hemiparesis - corticospinal tract compression; ipsilateral hemiparesis = Kernohan's notch (false localising sign)

•Cushing's triad - bradycardia, hypertension, irregular respirations; late sign of critically raised ICP

⚠️
The lucid interval is not universal - some patients have no initial loss of consciousness, others are unconscious from the outset. Do not exclude EDH if the classic triad is incomplete.

Investigations

🥇 First-line

•CT head (non-contrast) - biconvex hyperdense collection not crossing sutures; may show skull fracture, midline shift, herniation signs (NICE CG176)

•FBC, coagulation, group and save - pre-operative workup

🚨
Lumbar puncture is absolutely contraindicated in suspected EDH - raised ICP means LP risks catastrophic tonsillar herniation. Always exclude raised ICP with CT first.

Management

•EDH is a neurosurgical emergency - urgent neurosurgical referral must not be delayed by investigations

•Definitive treatment: emergency craniotomy with haematoma evacuation and ligation of the middle meningeal artery

•Avoid secondary brain injury - correct hypoxia, hypotension, hypoglycaemia

Prognosis

•Better than most intracranial haemorrhages if treated before herniation - underlying brain often structurally intact

•Mortality rises sharply once uncal herniation occurs; GCS 3-5 with bilaterally fixed dilated pupils = poor prognosis

CT Appearance

Intracranial haemorrhage CT comparison
FeatureExtraduralAcute subduralChronic subdural
ShapeBiconvex (lentiform)Crescent-shapedCrescent-shaped
Density on CTHyperdense (bright)Hyperdense (bright)Hypodense (dark)
Crosses sutures?No - limited by suture linesYesYes
Vessel sourceMiddle meningeal artery (arterial)Bridging veins (venous)Bridging veins (venous)

Feature	Extradural	Acute subdural	Chronic subdural
Shape	Biconvex (lentiform)	Crescent-shaped	Crescent-shaped
Density on CT	Hyperdense (bright)	Hyperdense (bright)	Hypodense (dark)
Crosses sutures?	No - limited by suture lines	Yes	Yes
Vessel source	Middle meningeal artery (arterial)	Bridging veins (venous)	Bridging veins (venous)

🎯
EDH = biconvex hyperdense collection that does NOT cross suture lines. Subdural = crescent-shaped; chronic subdural = hypodense (dark). This distinction is directly tested.