Master the board step 3

Surgery
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Diagnosis: CT scan shows semilunar, crescent-shaped hematoma with or
without midline deviation.
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Management: Emergency craniotomy is done only if there are lateralizing
signs and midline displacement.
Basic Science Correlate
Bridging veins drain the neural tissue and puncture through the dura mater
to empty into the dural sinuses.
To rule out bleeds in the
brain, order CT scans
without contrast. Blood
and contrast look the
same on CTs, giving a false
positive.
Diffuse Axonal Injury
Diffuse axonal injury results from acceleration-deceleration injuries to the
head. The patient will be deeply unconscious.
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Prognosis is terrible, and surgery cannot help.
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Therapy is directed at preventing further injury from increased intracranial
pressure (ICP).
Elevated Intracranial Pressure (ICP)
The classic history proceeds as follows:
1. Briefly depressed consciousness after head trauma
2. Improvement
3. Progressive drowsiness
Elevated intracranial pressure is a medical emergency.
Diagnostic Testing
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Gradual dilatation of one pupil and a decreasing responsiveness to light is
an important sign, as it indicates clot expansion on the ipsilateral hemisphere.
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Get a head CT and look for midline shift or dilated ventricles.
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Do not think about performing a lumbar tap in anyone without first getting
a head CT. If you perform a lumbar puncture on a person with increased
intracranial pressure, you will herniate the brain, kill the patient, and fail
the exam.
Basic Science Correlate
Hyperventilation causes vasoconstriction and decreased blood volume in the
brain, lowering ICP.
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