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Epidural and Subdural Hematomas

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Neuroradiology
Traumatic Hemorrhage
By: Luke Aldo, MSIV
LECOM
Erie, Pennsylvania
Layers of the Meninges
Epidural Hematoma
• Accumulation of blood in the potential
space between dura mater and bone
• EDH is considered to be the most serious
complication of head injury, requiring
immediate diagnosis and surgical
intervention (mortality rate associated
with epidural hematoma has been
estimated to be 5-50%)
Pathophysiology
• Usually results from a brief linear contact force
•
•
•
to the calvaria that causes separation of the
periosteal dura from bone and disruption of
interposed vessels due to shearing stress
Skull fractures occur in 85-95% of adult cases
Extension of the hematoma usually is limited by
suture lines owing to the tight attachment of the
dura at these locations.
The temporoparietal region and the middle
meningeal artery are involved most commonly
(66%)
Frequency
• Epidural hematoma complicates 2% of cases of head
•
•
trauma (approximately 40,000 cases per year)
Alcohol and other forms of intoxication have been
associated with a higher incidence of epidural hematoma
Sex
– more frequent in men, with a male-to-female ratio of 4:1
• Age
– rare in individuals younger than 2 years
– rare in individuals older than 60 years because the dura is tightly
adherent to the calvaria
History
• Head trauma
• Lucid interval between the initial loss of
•
•
•
•
consciousness at the time of impact and a
delayed decline in mental status (10-33% of
cases)
Headache
Nausea/vomiting
Seizures
Focal neurological deficits (eg, visual field cuts,
aphasia, weakness, numbness)
Diagnostic Imaging
• Noncontrast CT scanning of the head (imaging
•
•
study of choice for intracranial EDH) not only
visualizes skull fractures, but also directly images
an epidural hematoma
It appears as a hyperdense biconvex or
lenticular-shaped mass situated between the
brain and the skull, though regions of
hypodensity may be seen with serum or fresh
blood
MRI also demonstrates the evolution of an
epidural hematoma, though this imaging
modality may not be appropriate for patients in
unstable condition
Subdural Hematoma
• Rapidly clotting blood collection below the inner
•
•
layer of the dura but external to the brain and
arachnoid membrane
Typically, low-pressure venous bleeding of
bridging veins (between the cortex and venous
sinuses) dissects the arachnoid away from the
dura and layers out along the cerebral convexity
It conforms to the shape of the brain and the
cranial vault, exhibiting concave inner margins
and convex outer margins (crescent shape)
• Frequency is related directly to the incidence of
•
blunt head trauma
It’s the most common type of intracranial mass
lesion, occurring in about a third of those with
severe head injuries
Mortality/Age
• Mortality
– Simple SDH (no parenchymal injury) is associated with a
mortality rate of about 20%
– Complicated SDH (parenchymal injury) is associated with a
mortality rate of about 50%
• Age
– It’s associated with age factors related to the risk of blunt head
trauma
– More common in people older than 60 years (bridging veins are
more easily damaged/falls are more common)
– Bilateral SDHs are more common in infants since adhesions
existing in the subdural space are absent at birth
– Interhemispheric SDHs are often associate with child abuse
History
• Usually involves moderately severe to severe blunt head
trauma
• Acute deceleration injury from a fall or motor vehicle
•
•
•
•
accident, but rarely associated with skull fracture
Generally loss of consciousness
Any degree or type of coagulopathy should heighten
suspicion of SDH
Commonly seen in alcoholics because they’re prone to
thrombocytopenia, prolonged bleeding times, and blunt
head trauma
Patients on anticoagulants can develop SDH with
minimal trauma and warrant a lowered threshold for
obtaining a head CT scan
Diagnostic Imaging
• MRI is superior for demonstrating the size of an acute
•
SDH and its effect on the brain, however noncontrast
head CT is the primary means of making a diagnosis and
suffice for immediate management purposes
Noncontrast head CT scan (imaging study of choice for
acute SDH)
– The SDH appears as a hyperdense (white) crescentic mass along
the inner table of the skull, most commonly over the cerebral
convexity in the parietal region. The second most common area
is above the tentorium cerebelli
• Contrast-enhanced CT or MRI is widely recommended
•
for imaging 48-72 hours after head injury because the
lesion becomes isodense in the subacute phase
In the chronic phase, the lesion becomes hypodense and
is easy to appreciate on a noncontrast head CT scan
Summary
• Epidural Hematoma
– Potential space between
the dura in the inner table
of the skull
– Can’t cross sutures
– Skull fractures in
temporoparietal region
– Middle meningeal artery
– Lenticular or biconvex
shape
– Lucid interval
– Common in alcoholics
– Medical emergency
– CT without contrast
– Evacuate via burr holes
• Subdural Hematoma
– Between the dura mater
and the arachnoid mater
– Can cross sutures
– Cortical bridging veins
– Crescent shape
– Loss of consciousness
– Common in elderly
– Common in alcoholics
– Medical emergency
– CT without contrast
– Evacuate via burr holes
Bibliography
• Abramson, Nina, MD. Subdural Hematoma.
•
•
•
Brigham Radiology: 1994 Nov.
Azmoun, Leyla, MD. Epidural Hematoma.
Brigham Radiology: 1995 Nov.
Liebeskine, David, MD. Epidural Hematoma.
Emedicine.com: 2006 Apr; 1-10.
Scaletta, Tom, MD. Subdural Hematoma.
Emedicine.com: 2006 May; 1-10.
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