Master the board step 3

Neurology
Diagnostic Testing
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Best initial test: A head CT without contrast is 95 percent sensitive. If this is
conclusive for an SAH, you do not need to do a lumbar puncture.
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Most accurate diagnostic test: Lumbar puncture. This is not necessary if the
head CT scan shows blood.
To tell if an increased number of white cells in CSF is caused by infection or
is just from blood, look for the ratio. A normal number of white cells is 1 for
every 500 red cells. An infection is considered to be present only if the number
of white cells is greater than the ratio of 1 to 500.
• Normal white cell
count = 1 WBC:500 RBC
Treatment
1. Perform angiography to determine the site of bleeding.
2. Embolize the site of the bleeding. This is superior to surgical clipping.
3. Insert a ventriculoperitoneal shunt if hydrocephalus develops.
4. Prescribe nimodipine orally; this is a calcium channel blocker that prevents
stroke.
When SAH occurs, an intense vasospasm can lead to a nonhemorrhagic stroke.
You must embolize (or clip) the source of bleeding in an SAH before it can
rebleed. If it rebleeds, there is a 50 percent chance that the patient will die.
Spine Disorders
The following table summarizes some spine disorders and their symptoms:
Lumbosacral Strain Cord Compression Epidural Abscess Spinal Stenosis
Nontender Tender Tender and fever Pain on walking downhill
Syringomyelia
This is a defective fluid cavity in the center of the cord caused by trauma,
tumors, or a congenital problem. It presents with loss of sensation of pain and
temperature in the upper extremities bilaterally in a capelike distribution over
the neck, shoulders, and down both arms.
Diagnose with an MRI. Treat surgically.
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