Traumatic Subarachnoid Hemorrhage

KEY FACTS

TERMINOLOGY

• Blood within subarachnoid spaces

○ Contained between pia and arachnoid membranes

IMAGING

• High density on CT, hyperintensity on FLAIR

TOP DIFFERENTIAL DIAGNOSES

• Nontraumatic SAH

• Meningitis: Cellular and proteinaceous debris

• Carcinomatosis meningitis

• Pseudosubarachnoid hemorrhage

• Gadolinium administration

• High inspired oxygen

PATHOLOGY

• Associated with contusions, subdural or epidural

hematoma, diffuse axonal injury

CLINICAL ISSUES

• Headache, emesis, decreased consciousness

• Trauma is most common cause of subarachnoid

hemorrhage (SAH)

• Outcome is related in logistic regression analysis to

○ Admission Glasgow Coma Scale score

○ Amount of subarachnoid blood

• Isolated traumatic SAH, no other injuries usually benign

• Poor prognosis if associated with other intracranial injuries

• Vasospasm develops earlier than with aneurysmal SAH

• Associated with ↓ neuropsychologic profiles, worse

vocational outcomes in 1 year follow-up

DIAGNOSTIC CHECKLIST

• Isolated supratentorial sulcal blood common

• Hyperdense blood in interpeduncular cistern may be only

manifestation of subtle SAH

(Left) Coronal graphic depicts

findings in a severe traumatic

brain injury. Closed head

trauma has resulted in

multiple gyral contusions and

subarachnoid hemorrhage

(SAH). Most traumatic SAHs

(tSAHs) ﬈ occur adjacent to

parenchymal brain injuries and

are found centered around the

sylvian fissures, inferior

frontotemporal, and convexity

sulci. (Right) Axial NECT in a

patient with head trauma and

tSAH demonstrates focal

hyperdense collections in a

few left posterior frontal sulci

bordering the

interhemispheric fissure ſt.

(Left) Axial NECT scan in a 28-

year-old man with closed head

injury shows tSAH in the right

sylvian fissure ſt. Note the

absence of blood in the

adjacent suprasellar cistern, a

more common site for

aneurysmal SAH. A left

parietal epidural hematoma

﬇ is also present. tSAH often

occurs in combination with

other injuries. (Right) Axial

NECT scan in the same patient

shows the typical curvilinear

configuration of tSAH ſt in

the sulci of the right temporal

lobe.

Brain: Pathology-Based Diagnoses: Malformations,

Trauma, and Stroke

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