Neurosurgery Flashcards
List the four major types of intracranial hemorrhage.
Subdural hematoma
Epidural hematoma
Subarachnoid hemorrhage
Intracerebral hemorrhage
What causes a subdural hematoma? How do you recognize and treat it?
Subdural hematomas are caused by bleeding from veins that bridge the cortex and dural sinuses.
On a computed tomography (CT) scan, the hematoma is crescent-shaped (Fig. 24-1). Subdural hematomas
are common in alcoholic patients and victims of head trauma. They may present immediately
after trauma or as long as 1 to 2 months later. If the patient has a history of head trauma, always
consider the diagnosis of subdural hematoma. If large, expanding, or accompanied by neurologic
deficits, treat with surgical evacuation
What causes an epidural hematoma? How do you recognize and treat it?
Epidural hematomas are caused by bleeding from meningeal arteries (classically, the middle meningeal
artery). On a CT scan, the hematoma is lenticular in shape (Fig. 24-2). At least 85% of epidural
hematomas are associated with a skull fracture (classically, a temporal bone fracture), and many
patients have an ipsilateral “blown” pupil (dilated, fixed, nonreactive pupil on the side of the hematoma).
The classic history includes head trauma with loss of consciousness, followed by a lucid interval
of minutes to hours, then neurologic deterioration. Treatment usually includes surgical evacuation
Define subarachnoid hemorrhage. What causes it? How is it treated?
A subarachnoid hemorrhage is bleeding between the arachnoid and pia mater. The most common cause is
trauma, followed by ruptured berry aneurysms. Blood can be seen in the cerebral ventricles and surrounding
the brain or brainstem on a CT scan. Classically, the patient describes the “worst headache of my life,”
although many die or are unconscious before they reach the hospital. Patients who are awake have signs
of meningitis (positive Kernig sign and Brudzinski sign). Remember the association between polycystic
kidney disease and berry aneurysms. CT is the test of choice and should be performed before performing
lumbar puncture (see question 12). A lumbar puncture shows grossly bloody cerebrospinal fluid (CSF).
Treat with support of vital functions, anticonvulsants, and observation. Once the patient is stable,
do a CT or magnetic resonance (MR) angiogram to look for aneurysms or arteriovenous malformations,
which may be treatable with surgical clipping or catheter-directed angiographic procedures
What causes an intracerebral hemorrhage? How do you recognize and treat it?
Intracerebral hemorrhage describes bleeding into the brain parenchyma (Fig. 24-3). The most common
cause is hypertension, but it may also be a result of other forms of stroke, trauma, arteriovenous
malformations, coagulopathies, or tumors. Two thirds of intracerebral hemorrhages occur in the basal
ganglia (especially with hypertension). The patient may come to the hospital with coma or, if awake,
contralateral hemiplegia and hemisensory deficits. Blood (which appears white on a CT scan) can
be seen in the brain parenchyma and may extend into the ventricles. Surgery is reserved for large,
accessible hemorrhages, although usually it is not helpful
After a history of head trauma, what does a dilated, unreactive pupil
on one side mean until proved otherwise?
In the setting of head trauma, a dilated, unreactive pupil on one side most likely represents impingement
of the ipsilateral third cranial nerve and impending uncal herniation caused by increased
intracranial pressure. Of the different intracranial hemorrhages, this scenario is seen most commonly
with epidural hemorrhages. Do not perform a lumbar puncture in any patient with a “blown” pupil
because you may precipitate uncal herniation and death. Instead, order a CT or magnetic resonance
imaging (MRI) scan of the head.
List the four classic signs of a basilar skull fracture.
- Periorbital ecchymosis (“raccoon eyes”)
- Postauricular ecchymosis (Battle sign)
- Hemotympanum (blood behind the eardrum)
- CSF otorrhea or rhinorrhea (leakage of CSF, which is clear in appearance, from the ears or nose)
What is the imaging test of choice for skull fractures of the calvarium?
How are they managed?
Skull fractures of the calvarium (roof of the skull) are best seen on a CT scan (preferred over plain
x-rays). Surgical indications include contamination (surgical cleaning and debridement), depression
with impingement on brain parenchyma, or open fracture with CSF leak. Otherwise, such fractures
can be observed and generally heal on their own
True or false: Severe, permanent neurologic deficits may occur after head
trauma, even with a negative CT or MR scan of the head.
True. Head trauma can cause cerebral contusion or shear injury of the brain parenchyma, both of which
may not show up on a CT or MR scan but may cause temporary or permanent neurologic deficits
What finding suggests increased intracranial pressure?
Increased intracranial pressure (intracranial hypertension) is highly suggested in the setting of
bilaterally dilated and fixed pupils. Normal intracranial pressure is between 5 and 15 mm Hg. Less
specific symptoms include headache, papilledema, nausea and vomiting, and mental status changes.
Look also for the classic Cushing triad, which consists of increasing blood pressure, bradycardia, and
respiratory irregularity.
How should increased intracranial pressure be managed?
The first step is to intubate the patient in reverse Trendelenburg position (head up). Once intubated,
the patient should be hyperventilated for rapid lowering of intracranial pressure through decreased
intracranial blood volume (caused by cerebral vasoconstriction). For longer term treatment, mannitol
diuresis may decrease cerebral edema. Furosemide is also used but is less effective. Ventriculostomy
should be performed if hydrocephalus is identified. Barbiturate coma and decompressive craniotomy
(burr holes) are last-ditch measures. Anticonvulsant therapy should be started if seizures are suspected;
prophylactic anticonvulsants are controversial but may be warranted in some cases.
Remember that cerebral perfusion pressure equals blood pressure minus intracranial pressure.
In other words, do not treat hypertension initially in a patient with increased intracranial pressure
because hypertension is the body’s way of trying to increase cerebral perfusion. Lowering blood
pressure in this setting may worsen symptoms or even cause a stroke.
True or false: Lumbar puncture is the first test that should be performed
in a patient with increased intracranial pressure.
False. Never do a lumbar puncture in any patient with signs of increased intracranial pressure until a
CT scan is done first. If the CT is totally negative, you can proceed to a lumbar puncture, if needed. If
you do a lumbar puncture first, you may precipitate uncal herniation and death.
How do patients with spinal cord trauma present? How are they managed?
Patients with spinal cord trauma often come to the hospital with “spinal shock” (loss of reflexes
and motor function, hypotension). Order standard trauma radiographs (cervical spine, chest, pelvis)
as well as additional spine radiographs or CT scans based on physical examination. Also give
corticosteroids (proven to improve outcome). Moderate hypothermia is increasingly being used in the
management of patients with spinal cord trauma. Surgery is performed for incomplete neurologic
injury (some residual function maintained) with external compression (e.g., subluxation, bone chip).
An MRI can show cord injury noninvasively
What causes spinal cord compression? How do patients present?
Spinal cord compression usually is defined as acute or subacute. Most cases of acute cord compression
result from trauma. Look for the appropriate history. Subacute compression is often caused
by metastatic cancer but may also result from a primary neoplasm, subdural or epidural abscess
(classically seen in diabetics and caused by Staphylococcus aureus), or hematoma (especially after
a lumbar tap or epidural/spinal anesthesia in a patient with a bleeding disorder or a patient taking
anticoagulation).
Patients present with local spinal pain (especially with bone metastases) and neurologic deficits
below the lesion (e.g., hyperreflexia, positive Babinski sign, weakness, sensory loss).
How should patients with subacute spinal cord compression be diagnosed
and treated?
The first step in the emergency department is to give high-dose corticosteroids and order an MRI
scan (preferred over CT; Fig. 24-4). If the cause is cancer or tumor, give local radiation if the metastases
are from a known primary tumor that is radiosensitive. Surgical decompression can be used if
the tumor is not radiosensitive. For a hematoma or subdural/epidural abscess, surgery is indicated
for decompression and drainage. Prognosis is related most closely to pretreatment function; the
longer you wait to treat, the worse the prognosis.
