Neurosurgery Flashcards
How do brain tumors cause increased ICP?
occupying space
producing cerebral edema
interfering with normal CSF flow
impairing venous drainage
How do pts w brain tumors typically present?
progressive neuro defects dt rising ICP, tumor invasion, or brain compression
headaches
seizures
How are intracranial tumors classified?
Intracerebral
Extracerebral
What are the intracerebral tumors?
glial cell tumors
metastatic tumors
pineal gland tumors
papillomas of the choroid plexus
What are the glial cell tumors?
astrocytomas anaplastic astrocytomas GBM- glioblastoma multiforme oligodendrogliomas ependymomas primitive neuroectodermal tumors
Where do metastatic tumors typically come from?
Lung Breast Melanoma Kidney Colon
What are the extracerebral tumors?
These arise from extracerebral structures: meningiomas (from meninges) acoustic neuromas pituitary adenomas (from pit gland) craniopharyngiomas (from pit gland)
What are the most common CNS tumors seen in adults?
Glial cell tumors and mets tumors (both of which are intracerebral)
Glial cell tumors are 50% of adult CNS tumors!
T/F Children have more posterior fossa tumors
True
What does glioma usually refer to?
Astrocyte tumor.
Can actually refer to any glial tumor, but usu used for astrocytic tumors.
Grades/aggressiveness of astrocytic tumors
Slow-growing astrocytomas are least malignant- grades I and II
In kids, astrocytomas in the post fossa usu have cystic morphology- pilocystic astrocytoma
Anaplastic astrocytomas are more aggressive- grade III
Most common and most malignant is GBM- grade IV
What is a butterfly glioma?
GBM tumor which has tracked through the white matter and crossed the midline via the corpus callosum- looks like a butterfly on CT.
Very poor pgx.
What is an oligodendroglioma?
Slow-growing calcified tumor
Often in frontal lobes
Adults> kids
often a/w seizures
What are ependymomas?
Arise from cells that line the ventricular walls and central canal.
Px w elevated ICP
Mostly in children
Usually arise in 4th ventricle
What kinds of tumors to children usually have?
Infratentoral posterior fossa tumors-
cystic cerebellar astrocytomas
ependymomas
medulloblastomas- highly malignant ones are see in the vermis of young children, but in the cerebellar hemispheres of young adults
Where are most metastatic lesions to the brain located?
Supratentorial, at the cortical-white matter jn
Rx for metastatic braint tumors
If it’s a single, approachable lesion- surgical removal + radiation
If multiple lesions- stereotactic radiosurgery
What is a meningioma?
Slow-growing tumor that arises from meninges lining brain and SC.
Pt px for meningioma
neuro signs and sx from cerebral compression dt expanding tumor mass
seizures
headaches, nausea, vom, mental status chgs- dt elevated ICP
Diffuse headache that is worse in morning after laying down all night
Phys Ex for meningioma
Personality chgs (later to stupor, coma) Speech deficits, confusion Bilateral papilledema (optic disc swelling from increased ICP) Eye deviation (frontal lobe involved) Ataxia if cerebellar Motor or sensory defects if tumor is around central sulcus or deep structures
DD for pt w central neurologic deficits and sx
IC hemorrhage neurodegenerative dz abscess vascular malformation meningitis encephalitis communicating hydrocephalus toxic state (and of course, meningioma)
Dx eval for meningioma
CT or MRI- dx and localize tumor
MRI w gadolinium- visualize high grade gliomas, meningiomas, schwanomas, pit adenomas
T2 MRI for low-grade gliomas
Goal of rx for brain tumors
total tumor removal (when feasible)
but subtotal resection is nec if brain fn will be compromised by full resection
If subtotal resection is performed, what should follow?
post-op radiation therapy
also chemo for some cancer types
Rx for metastatic brain tumors
Whole-brain radiation
sometimes single lesions that are easy to remove are removed first
What kind of drugs are used for perioperative mgmt of increased ICP from cerebral edema?
Corticosteroids- dexamethasone
also may need shunting of CSF if there is hydrocephalus
What is an intracranial aneurysm?
Saccular, berry-shaped aneurysm found at branch points in circle of Willis
What happens when intracranial aneurysms rupture and bleed?
Subarachnoid hemorrhage (SAH) this is rare.
HPE of SAH
sudden onset of worst headache ever
ICP transiently rises w each contraction of the heart–> pulsating headache
Progressive neuro deficits dt blood clot mass effect, vasospasm, or hydrocephalus
Coma and death
How are SAH’s classified?
Hunt-Hess grade 1- (good) to 5 (almost dead)
Dx Eval for SAH
CT
If highly susp but CT is neg, do an LP
If SAH is found, do a four-vessel cerebral angiography to define aneurysm neck and relation w surrounding vessels.
Medical rx for SAH
control of HTN
phenytoin for prophylactic seizure control
mannitol for edema
nimodipine to reduce risk of delayed neuro deficits dt vasospasm
Non-medical rx for SAH
emergency external ventricular drainage- to lower ICP
if progressive deterioration- emergency craniotomy and evac blood clot
definitive Rx = obliteration by microsurgical clipping or endovascular coiling of the aneurysm.
In what pts do epidural hematomas occur?
Head trauma pts w a skull fracture across a MMA, causing arterial laceration (and expanding hematoma)
What is an epidural hematoma?
arterial bleeding from MMA which strips dura from inner skull and creates lens-shaped mass which causes brain compression and herniation
Hx of pt w epidural hematoma
head trauma w LOC, but no perisistent neuro deficit
after honeymoon, progressive deterioration of consciousness
Phys Ex for epidural hematoma
Assess consciousness! Use GCS
GCS <8 = severe head injury
8-12 - moderate
12+ - mild
If a pt has a GCS of <8, what should be done?
immediate intubation for airway protection
rapid neurosurgical eval
What does unilateral dilated pupil indicate in setting of head trauma?
Brainstem herniation
What does bilateral fixed and dilated pupils indicate in setting of head trauma?
impending respi failure and death
Dx eval for epidural hematoma
CT
Rx for epidural hematoma
airway control and emergency cranial decompression- Burr holes, turn a flap, decompress clot.
Control MMA bleed and fix dura to bone to prevent reaccumulation
What is a subdural hematoma?
hemorrhage dt ruptured bridging veins (they drain blood from the brain into the superior sagittal sinus)
T/F subdural hemotomas are high-pressure bleeds dt rupture of bridging veins
False
They are low-pressure. (But it’s true that they are secondary to venous hemorrhage).
They can be spontaneous or traumatic.
Which pts most often get spontaneous subdural hematomas?
Elderly pts w brain atrophy who are on anticoagulants
HPE of subdural hematoma
headache, drowsiness, hemiparesis
Rx for subdural hematoma
If significant neuro deficits dt mass effect, do urgent burr hole decompression or craniotomy
How are spinal tumors characterized?
By anatomic location-
extradural
intradural
intramedullary
What are the extradural spinal tumors?
Usu mets from lung, breast, prostate
Can also be multiple myeloma of the spine, lymphoma
What is the usual presenting complaint for extradural spinal tumors?
Back pain or neuro deficit from cord compression
What are the intradural spinal tumors?
meningioma schwannoma neurofibroma ependymoma dumbell tumor- nerve root tumor that transverses the intervertebral foramen.
Px for intradural spinal tumors
numbness progressing to weakness
What are the intermedullary tumors of the spine?
astrocytomas
ependymomas
cavernous malformations
How can you differentiate cystic spinal tumors from syringomyelia?
Gadolinium-enhanced MRI
both may px w sensory loss, so do MRI to differentiate them
DD for pts w spinal cord pathology
Tumor cervical spondylitic myelopathy acute cervical disc protrusion spinal angioma acute transverse myelits
Dx Eval for spinal tumors
Plain XR- show bony erosion
MRI- best. shows anatomy
CT myelogram if MRI unavailable
Goal of spinal tumor Rx
relieve cord compression
maintain spinal stability
What are the two columns of the spine?
Anterior- vertebral bodies, discs, ligaments
Posterior- facet joints, neural arch, ligaments
Rx for anterior spinal tumors
If they involve the vertebral body- remove tumor via anterolateral approach.
Resect vertebral body, repair w bone graft and metal plate.
Rx for posterior spinal tumors
Remove by laminectomy (which usu does not cause spinal instability)
Rx for mets to spine
If unresectable, palliate and pain control w radiation therapy.
What are the two parts of intervertebral discs?
central- nucleus pulposus (cushion bt vertebrae)
surrounding- dense annulus fibrosis
Why does disc space narrowing occur?
Nucleus pulposus dehydrates
Disc space narrowing causes abn vertebral stresses and mvmt, which causes….
osteogenesis, with formation of osteophytes and bone spurs- these can traumatize nerve roots
aka spondylosis
What happens when there is structural failure of the IV disc?
nucleus pulposus herniates into spinal canal or the neural foramina thru a defect in the circumferential disc annulus
What does lateral disc herniation cause?
nerve root compression adn radicular sx
What does central disc herniation cause?
myelopathy
Which parts of the spine are most commonly affected by spine dz?
the most mobile parts- cervical and lumbar
Pt px of cervical spondylosis and disc dz
over 50yo
pain, paresthesia, weakness
If cervical spondylotic myelopathy is secondary to repetitive SC dmg by osteophytes, what is the px?
progressive numbness, weakness, paresthesia of the hands and forearms in a glovelike distribution
If pts have pain secondary to disc dz, what is the px?
radiculopathy- pain radiating down the arm in a nerve root distribution, worse with next extension
Phys Ex for spondylosis
limited neck motion
straightening of the normal cervical lordosis
sensory and motor deficits in a radicular pattern
diminished reflexes
hyperreflexia and Hoffman or Babinski sign show myelopathy
DD for spondylosis
Rheum arthritis
Ankylosing spondylitis
Brachial plexus compression from a first or cervical rib (for nerve root compression sx)
scalenus anticus syndrome (thoracic outlet)
In pts w arm pain but no neck pain: peripheral nerve entrapment (carpal tunnel, ulnar nerve palsy); pancoast tumor of pulmonary apex
Dx eval for spondylosis/disc problems
CXR- shows straightening of cervical lordosis, disc space narrowing, osteophyte formation, spinal canal narrowing. (if diameter is <10mm, high risk for compression)
CT myelography and MRI- look at SC and nerve roots
MRI for herniated discs, CT for bony stuff
Rx for spondylosis
medical therapy first! usu improve w/o surgery
cervical traction, analgesics, muscle relaxants.
anterior cervical fusion- remv disc, bone graft replacement, internal fixation.
this and other spine stabilizing procedures stabilize the spine so that osteophytes get reabsorbed.
Decompression laminectomy- for narrow spinal canal.
Px for lumbar disc prolapse
Pain radiating down lower extremity (sciatica)
Parasthesias, numbness, weakness
Pos straight leg test
No ankle or knee reflex
Weakness of foot dorsiflexion or plantar flexion
Weakness of knee extension
Which discs most commonly prolapse?
L4-5 and L5-S1
so get L5 and S1 nerve sx
Dx eval for lumbar disc prolapse
MRI- shows disc herniation at suspected level
Rx for lumbar disc prolapse
Most pts improve w/o surgery
only do surg if chronic disabling pain
Open laminectomy
Urgent surgery if progressive neuro deficits (foot drop) or acute onset of cauda equina syndrome
What is cauda equina syndrome?
Massive midline disc protrusion that compresses cauda equina- neurosurg emergency.
Px in cauda equina syndrome
urinary retention or overflow incontinence
bilateral sciatica
perineal numbess/tingling (saddle anesthesia)
Rx for cauda equina syndrome
Urgent bilateral laminectomy decompression w disc removal
