neurosurg Flashcards
Communicating hydrocephalus
All ventricles affected. Due to defect in absorption at the arachnoid granulations
Noncommunicating hydrocephalus
Obstructive; due to block in CSF proximal to arachnoid granulations. May not affect all ventricles dep on level of block (e.g. aqueductal stenosis spares the 4th ventricle)
Third type of hydrocephalus
ex vacuo
Indications for carotid endartectomy
Asymptomatic: > 70% Symptomatic: > 60% NB: pts should stay on aspirin leading up to the surgery. If post-CVA, wait 4-6 wks for procedure
Carotid dissection causes
Trauma, CT disease, iatrogenic (angiogram), vasculitis
Carotid dissection symptoms
May have neck pain, headache, ipsilateral Horner syndrome, sx of SAH or stroke; can be nonspecific.
Carotid dissection management
If extradural, use medical therapy (anticoagulation). If intradural, do endovascular stenting or surgical bypass of ECA to ICA. Follow for 3-6 mo for healing.
Carotid dissection epidemiology
Carotid artery dissection is a significant cause of ischemic stroke in all age groups, but it occurs most frequently in the 5th decade of life and accounts for a much larger percentage of strokes in young patients.
Carotid dissection pathophys
Begins as a tear in one of the carotid arteries of the neck, which allows blood under arterial pressure to enter the wall of the artery and split its layers. The result is either an intramural hematoma or an aneurysmal dilatation, either of which can be a source of microemboli, with the latter also causing a mass effect on surrounding structures.
Uncal herniation
CN 3 palsy (blown pupil, down and out). Hemiparesis: can cause contralateral (from ipsilateral peduncle pressure) or ipsilateral (from contralateral peduncle pressure due to midbrain shift, aka Kernohan’s phenomenon)
Herniation syndromes
Cingulate (subfalcine) can affect ACA -> abulia. Cerebellar (upward) can occlude superior cerebellar arteries -> ataxia. Tonsillar can be rapidly fatal. CEntral (transtentorial) causes decreased consciousness, occlusion of PCAs leading to cortical blindness, Cheyne-Stokes etc
Parinaud syndrome
Parinaud’s Syndrome, aka dorsal midbrain syndrome and vertical gaze palsy, is an inability to move the eyes up. It is caused by a tumor of the pineal gland which compresses the vertical gaze center at the rostral interstitial nucleus of medial longitudinal fasciculus (riMLF). The eyes lose the ability to move upward.
Low-grade astrocytoma
Cerebral hemispheres or cerebellum. Asx lesions should be followed. Surgery usu not curative but used if sx. Radiotherapy used. Chemo if surgery/rads fail
Malignant glioma includes..
Anaplastic astrocytoma, glioblastoma multiforme
Glioblastoma multiforme
Have necrotic center, enhancing rim. Very poor prognosis (pretty much 0% 5 yr survival) despite surgery and radiation. Chemo does not help
Meningioma
F > M. Arise from arachnoid region. Seen on superior convexities, orbital rim, cerebellar tentorium, intraventricular. Slowly progressive growth. Homogeneous enhancement on MRI/CT, may have dural tail. Tx: surgical resection if sx. If can’t resect, do external beam radiotherapy/gamma knife. 5 yr survival 90%, often recur.
How to treat acromegaly from pituitary adenoma?
Surgical resection is curative 50% of time. Medical tx: octreotide (somatostatin analogue)
How to treat TSH adenoma?
Octreotide
How to treat prolactinoma?
Dopamine agonists first; surgical excision if no response to med tx
How to treat Cushing syndrome from pituitary adenoma?
Surgery
Neuromas most commonly affect what CN?
CN 8 (acoustic neuroma)
Bilateral acoustic neuromas are pathognomic for what syndrome?
NF2
Ependymoma
Most often in children, usu a posterior fossa mass. Tx: surgical resection; rads if in 4th ventricle or spinal cord.
Oligodenroglioma
Predilection for frontal lobes. Histology: “fried egg” or “chicken wire” appearance. Slowly progressive; most often presents with seizure. Tx: surgery, post-op rad often, chemo somewhat helpful.
Craniopharyngioma
Most often in childhood. Benign but difficult to cure. Presents with HA, visual disturbance.
Pineal tumors
More often in children. Possibly can be germinoma or teratoma, so measure HCG and AFP; recall that germinomas are radiosensitive.
CNS lymphoma
Tend to melt away after one round of steroids but will come back. Radiation therapy is mainstay of tx. MTX and CHOP chemo
Epidermoid and dermoid tumors
Non-neoplastic masses, congenital or 2/2 trauma. Rare type of brain mass. Surgical excision if sx
What is the most common pediatric malignant brain tumor?
Primitive neuroectodermal tumors (PNET). Located on cerebellar vermis. Tx: surgery followed by XRT
Glomus tumors aka paraganglioma
Arise from paraganglion cells, rare. May secrete catecholamines. Location: carotid bulb, jugular glomus body. Can present similarly to acoustic neuromas but distinguish by angiogram: glomus tumors are highly vascular.
What types of metastasis to the brain are radiosensitive?
SCLC, lymphoma, MM, germ cell tumors
Tuberous sclerosis
Ash leaf spots. Supependymal hamartomas, calcific. Causes seizures
Spurling’s sign
Cervical spine finding- radicular pain produced with downward pressure on head when neck extended and tilted toward affected side
Herniated disc bulging vs protruding
Bulge is symmetric extension. Protrusion is asymmetric
Atlantoaxial (C1 = atlas) dislocation
RA underlies 1/4 of cases. Presents with local pain +/- hyperreflexia. If sx or atlantodental interval >6 mm, do C1-C2 fusion.
How to assess pathologic hyperreflexia vs benign normal variant?
In benign normal variant, jaw jerk reflex will also be hyperreflexic
Thoracic outlet syndrome
Thoracic outlet is the space defined by the clavicle and 1st rib- subclavian artery/vein and brachial plexus pass through. Vascular compromise > neurologic compromise. PE: rotating head away from affected side + elevation of arm reproducing sx, +/- reduction of radial pulse. Etiologies: fibrous band, elongated C7 transverse process. Tx: surgical.
Papilledema
see in CHRONIC increased ICP, not acute
