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January 17, 2007 Pipeline Neuroscience: EpiduralHemorrhage

An Epidural Hemorrhage

Anatomy and Key Concepts


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Anatomy of an Epidural Bleed


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Anatomy of an Epidural Bleed

The middle meningealarteryruns directly belowthe temporal boneof the

face If the temporal bone is

fractured by a blow to theface, the middlemeningeal may be

lacerated.

If this happens, the arterybleeds into what is calledthe epidural space.


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Anatomy of an Epidural Bleed:

The Meninges Three membranes (the meninges) envelop

the brain and spinal cord:pia, arachnoid,

anddura


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Meningeal Anatomy


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Anatomy of an Epidural Bleed:

Spaces and Potential Spaces in

the CNS The epidural space:

the space between the dura (the outermost membrane covering thebrain and spinal cord) and skull, or the bony vertebrae that form

the spinal canal. In the spine, the epidural space containslymphatics, small arteries, and the epidural venous plexus. In thebrain the epidural space is apotential space, meaning that thespace does not exist under normal conditions.

The subdural space:

The space between the dura mater and the arachnoid mater, this isa potential space in both the skull and the spine.

The subarachnoid space:

between the arachnoid mater and the pia mater, this space containsthe cerebrospinal fluid


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Concept: Bleeding Into a Closed

Space


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The Lucid Interval

An epidural hemorrhage is often characterized bythe following sequence of events:

Blunt trauma/ a blow to the head, followed by:

1) Initial confusion, decreased consciousness, or loss ofconsciousness

2) A lucid interval (20-50%):

a brief period of full conciousness/restored mental status. Thepatient seems back to his/her normal self.

3) Change in mental status +/- unstable vital signs (bloodpressure, heart rate):

the patient becomes confused, somnolent (sleepy), may haveneurologic signs such as hemiparesis, one dilated pupil, may

become comatose.


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Cushings Response

Bodys response to increased intracranialpressure (ICP):

Increase in blood pressure (Hypertension)

Decrease in heart rate (Bradycardia)

Altered respiratory rate

ICP can compress blood vessels in thebrain, block off oxygen delivery (ischemia),and put pressure on the brainstem.


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Cushings Response

Hypertension

Bradycardia

Respiratory Rate


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The Blown Pupil


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The Motor Homunculus


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