Intracranial Haematomas — EDH, SDH & SAH

🩸 Intracranial Haematomas

EDH, SDH and SAH — vessels, mechanisms, CT appearances, the four killers of SAH, and everything that will save a life in the trauma bay.

At a Glance — The Three Haemorrhages

Intracranial haemorrhages differ in where the blood collects, what vessel ruptures, and how fast the patient deteriorates. Knowing the space tells you the mechanism; knowing the mechanism tells you the patient and presentation. Three spaces, three completely different emergencies.

🔴

Extradural Haematoma

EDH — Between skull & dura

VesselMiddle Meningeal Artery (MMA)

PressureHIGH — arterial, fast accumulation

MechanismPterion fracture → MMA rupture

PatientYoung adults, significant trauma

History“Talk and Die” — lucid interval then rapid decline

CT Shape🍋 Biconvex / Lemon — bounded by sutures

Suture LinesCANNOT cross — dura is tacked to sutures

PrognosisExcellent if operated promptly — no underlying brain injury

🟠

Subdural Haematoma

SDH — Between dura & arachnoid

VesselBridging Veins (cortical → dural sinus)

PressureLOW — venous, can ooze for weeks

MechanismShear forces on stretched bridging veins

PatientElderly, alcoholics, anticoagulated

HistoryInsidious decline — often trivial or forgotten trauma

CT Shape🍌 Crescentic / Banana — follows brain surface

Suture LinesCAN cross — not bounded by dura attachments

PrognosisWorse — underlying brain injury often co-exists

🟣

Subarachnoid Haemorrhage

SAH — Into the subarachnoid space (CSF)

Vessel (85%)Berry (saccular) aneurysm of the Circle of Willis

Classic siteAnterior Communicating Artery (A-Comm) most common

MechanismSpontaneous aneurysm rupture — not traumatic

PatientAny age — peak 40–60s; associated with hypertension, smoking, PCKD

Headache⚡ Thunderclap — “worst of life,” instantaneous maximum intensity

CT signBright white “star” in basal cisterns — 95% sensitivity early

LP if CT −veXanthochromia or uniformly bloody 3 tubes (≥6–12 h after onset)

4 KillersRebleeding · Vasospasm · Hyponatraemia (CSW) · Hydrocephalus

The Anatomical Distinction — Where Is the Blood?

The meninges have three layers: dura mater (outer), arachnoid mater (middle), pia mater (inner, tightly adherent to brain).

🔴 Extradural = blood between the skull bone and the outer surface of the dura. A virtual space created by arterial pressure stripping the dura from the bone.

🟠 Subdural = blood between the inner surface of the dura and the outer surface of the arachnoid. The potential subdural space, traversed by the bridging veins.

🟣 Subarachnoid = blood directly into the CSF space between the arachnoid and pia mater. This is where the cerebral arteries run — a ruptured aneurysm floods the CSF with arterial blood, causing meningeal irritation (meningism), raised ICP, and the four delayed killers.

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