Pretest_12_Neurosurgery Flashcards
In the Glasgow Coma Score, why is “T” used?
to indicate intubation
A score of ______ on the GCS is indicative of severe TBI
8 or less (minimal is 3)
What does the GCS assess?
eye opening (4), verbal response (5), motor response (6)
How do you calculate the cerebral perfusion pressure? What should the CPP be?
MAP - ICP. CPP should be greater than 70
What is a normal ICP?
5-15; need to keep it less than 20
Why is hyperventilation not a good idea to decrease ICP in the long run?
It decreases cerebral perfusion (2/2 to vasoconstriction) to an already ischemic brain
CT and MRI revealing an irregular brain lesion with hypodense central necrosis, peripheral ring enhancement of highly cellular tumor tissue, and surrounding edema nad mass effect:
glioblastoma multiforme (the most common primary intracranial neuroepithelial tumor)
From what are glial cell tumors derived?
malignant degeneration of an astrocytoma or anaplastic astrocytoma
Ring enhancing brain lesion in an immunocompetent patient:
metastatic tumor (lung, kidney, GI, melanoma)
T/F: All depressed skull fractures (when skull is displaced inward) should be surgically elevated.
True! Especially if it is deprssed more than 1 cm, if a fragment is over the motor strip, or if small sharp fragments are seen on x-ray
What are compound skull fractures?
Bone and overlying skin are broken and must be cleansed and debrided; wound must be closed
Persistent CSF from the nose or ear for more than ___ days after a skull fracture requires surgical repair of the torn dura.
14
The dumbbell shape of a pituitary macroadenoma (>1cm) results from impingement on the adenoma by the
diaphragm of the sella turcica
What is Cushing triad in relation to acutely increasing ICP?
irregular respirations, bradycardia, hypertension
Papilledema is a finding with (acute/chronic) increases in ICP
chronic
What tumors arise from perineural fibroblasts of the peripheral nervous system?
Schwannomas
T/F: Schwannomas do not involve motor nerves.
True
What are the most frequent sites of cerebral contusion?
orbital surfaces of the frontal lobe and the anterior surface of the temporal lobes
From where do meningiomas arise?
The arachnoid layer of the meninges
What are causes of infection that can lead to brain abscess?
paranasal sinus infection, dental caries, ear infection
The effects of these hematomas become apparent several days after the initial injury:
subdural hematoma
What is the most common area for intracerebral hemorrhage?
putamen
If intracranial hemorrhage is suspected and a patient has blown eye, what should you NOT!! do?
Lumbar puncture! This patient is herniating. In the presence of increased intracranial pressure, LP is contraindicated.
What is hte pathophysiology of SIADH following head trauma?
Rupture of the pituitary stalk and with it the blood supply to the adenohypophysis (anterior pituitary gland). SIADH lads to sodium wasting in the urine.
Neurogenic shock occurs in traumatic injuries when spinal cord damage disrupts sympathetic outflow, allowing parasympathetic dominance to dramatically decrease BP.
Lesions or trauma above ___ (this level) cause hypotension.
T5!!
Dermatomes below the knee include what nerve roots and below?
L3 and below
L1-L2 is groin, L2-L3 is above the knee, anteriorly and laterally
Anterior cord syndrome causes
loss of pain and temperature sensation (lateral spinothalamic tracts) and paraplegia (corticospinal tract)
Central cord syndrome causes
upper extremity weakness and a cape-like distribution of loss of pain and temp sensation
Posterior cord syndrome causes
loss of proprioception and vibratory sense distally (dorsal columns lost; ie tabes dorsalis)
What is the name given to the syndrome of hyperreflexia and weakness below the lesion ipsilaterally and contralateral loss of pain and temperature?
Brown Sequard (hemicord) syndrome contralateral loss begins 2 levels lower
What is the most likely diagnosis causing “tunnel vision”?
prolactinoma
There is an association between ADPKD and what neural pathology?
Berry aneurysms (risk of SAH!)
Subdural hematoma looks like what on CT?
Epidural looks like what?
Subdural = CONCAVE
Epidural = CONVEX, lens shaped
Which artery in the circle of Willis is most commonly affected by aneurysms?
anterior communicating artery
