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94 Cards in this Set
- Front
- Back
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where spinal cord meets medulla
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cervicomedullary junction at foramen magnum
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name layers of protection for brain from skin to cerebral hemisphere
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Skin
Connective Tissue- subcutaneous Aponeurosis Loose Connective Tissue Pericranium Dura- Periosteal Layer Epidural space Dura- Meningeal Layer Subdural Space Arachnoid Matter Subarachnoid Space Pia Matter |
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Name structures in anterior cranial fossa- what is it demarcated by?
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Frontal lobe-
lesser wing of the sphenoid bone |
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Name structures in middle cranial fossa- what is it demarcated by?
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Temporal Lobe-
Petrous ridge of temporal bone |
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Is the periosteal layer of dura mater adherent to the meningeal layer?
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Yes, except in places where meningeal layer forms folds that descent into cranial cavity- such as
1) falx cerebri 2) tentorium cerebelli *note both are made of MENINGEAL dura |
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How is posterior fossa divded from the rest of the cranial vault?
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by tentorium cerebelli and petrous part of temporal bone
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What artery causes epidural bleeds? What foramen does it come through?
What is it a branch of? What does it supply? |
Middle Meningeal Artery***
Foramen Spinosum External Carotid Dura ***do not confuse with middle cerebral artery- branch of internal carotid, supplying brain |
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What is the subdural space?
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between arachnoid and inner dura- bridging veins en route to dural venous sinuses
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Where are the dural venous sinuses? What do they drain?
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between dura layers
drain sigmoid colon |
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What space is the CSF-filled space?
What layers is it between? |
subarachnoid space- between arachnoid and pia layers
also contains major arteries that branch to supply brain |
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Name the parts of the lateral ventricle
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Frontal/anterior horn begins anterior to Foramen of Monro
connected by trigone/atrium Posterior-Occipital horn Inferior-Temporal horn |
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How does CSF travel from its site of production in the choroid plexus of lateral ventricles all the way to dural venous sinuses/blood stream
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Lateral ventricles to Forament of Monroe to Third Ventricles through Sylvian Aqueduct to Fourth Ventricles through foramen of Luschka and Magenid around spinal cord and brain in arachnoid space, absorbed through arachnoid villi to venous sinuses between the dura, then to blood stream
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Lumbar cistern is a widened area of subarachnoid space that forms collection of CSF, where we do lumbar punctures. What are other cisterns?
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Perimesenphalic Cistern
Cisterna Magda- Largest Prepontine Cistern fig. 5.12 |
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What are circumventricular organs?
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specialized regions of brain where blood-brain barrier is interrupted, allowing brain to respond to changes in chemical milieu of the remainder of the body
pineal gland areana postrema- vomitting toxins |
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vasogenic edema
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fluid extravasation into interstitial space
e.g. brain tumors, infections |
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cytotoxic edema
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cellular damage cause excessive intracellular fluid accumulation within brain cells
e.g. infarction |
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What are common causes of headache?
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irritation, mechanical traction, inflammation or irritation of structures in head that are innervated
blood vessels meninges scalp skull |
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Two types of vascular headaches
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cluster headache
migraine headache |
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migraine headache
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75% genetic
symptoms provoked by certain foods, stress, eye strain, menstrual cycle, changes in sleep pattern preceded by aura/warning symptoms pain is often throbbing and exacerbated by light or sound or sudden head movement may have nausea or vomitting duration 30min to 24 hours relief with sleeping treat with NSAIDs, anti-emetics, triptans, rest in dark room |
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cluster headache
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less than 1/10 as common as migraine
5X more common in males several times per day every day over few weeks and vanishes for months boring sensation beind one eye with unilateral autonomic systems- tearing, eye redness, sweating, nasal congestion |
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tension headache
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dullache, bandlike sensation
common moderate headache some continuously everday for years |
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what kind of cause for headache worse when standing up
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low CSF
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what kind of cause for headache worse when lying down
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neoplasms
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what can raise intracranial pressure?
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hemmorrhage
edema hydrocephaly abcess tumor |
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How do intracranial masses cause neurologic symptoms?
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compression or destruction of adjacent brain structures
raise intracranial pressure herniation- displace NS structures |
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explain how elevated intracranial pressure can cause decreased cerebral blood flow and brain ischemia
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cerebral perfusion pressure= mean arterial pressure - intracranial pressure
as intracranial pressure rises, cerebral perfusion pressure decreases |
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Symptoms or signs of elevated ICP
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nausea and vommiting
altered mental status headache: worse in morning b/c edema overnight from effects of gravity papilledema- SEVERAL HOURS OR DAYS to develop visual loss diplopia- downward traction on CN VI Cushing's Triad |
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Cushing's Triad
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syndrome of increased ICP
hypertension-reflex to maintain cerebral perfusion pressure bradycardia- reflex to hypertension irregular respirations- impaired brainstem |
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What is notable in management of increased intracranial pressure?
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no LP- reduce risk of ppting herniation
normal ICP less than 15mm Hg keep cerebral perfusion pressure above 50 mm Hg |
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What are treatment measures for elevated ICP?
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mannitol IV
steroids- indicated for brain tumors; stengthens blood-brain barrier intubate and hyperventilate-cerebral vasocontriction induced elevate head of bed 30 degrees |
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What is a transtentorial herniation
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Herniation of the medial temporal lobe- uncus downward through the tentorial notch
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What is the clinical triad for a uncal herniation?
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Blown Pupil- ipsilateral (CNIII)
compression of nerve Coma- because compression of reticular formation Hemiplegia- contralateral b/c corticospinal tract crosses at medulla at pyramidal decussation |
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What is central herniation
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central downward displacement of brainstem; lesion associated with anything causing increased intracranial pressure
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What palsy may be produced by central herniation?
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Abducens Nerve Palsy-
traction on abducens nerve CN VI during its long course over the clivus- unilateral or bilateral |
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What is tonsillar herniation?
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Herniation of the cerebellar tonsils downward through foramen magnum; may compress medulla and lead to respiratory arrest, blood pressure instability, and death
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What is a subfalcine herniation?
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Herniation of cingulate gyrus (medial) under the falx cerebri- from one side of the cranium to the other
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Define Concussion
Can you tell from CT or MRI any neurological dysfunctions? |
REVERSIBLE impairment of neurologic function for minutes to hours following a head injury
Normal CTs and MRI |
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What are symptoms of concussion?
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dizziness
nausea, vomitting headache seeing stars |
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What is postconcussive syndrome?
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period after accident lasting up to several months after even relatively minor trauma with headaches, lethargy, mental dullness
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For head injuries, if you patient is unresponsive, what else needs to be imaged?
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Spine
injury may cause unnoticed unstable spinal ffracture |
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What are the different compartments in which intracranial hemorrhages can occur?
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Epidural hematoma
Subdural hematoma Subarachnoid hemorrhage Intracerebral or intraparenchymal hemorrhage |
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What type of intracranial hemorrhage?
Seen in elderly patients where atrophy allows brain to move freely within cranial vault, thus making bridging veins more susceptible to shear |
CHRONIC Subdural hematoma
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What type of intracranial hemorrhage?
Due to fracture of temporal bone |
Epidural bleed due to rupture of middle meningeal artery
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What type of intracranial hemorrhage?
lens-shaped biconvex |
epidural bleed
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What type of intracranial hemorrhage?
blood collecting over weeks to months without symptoms, brain accomdates and causes vague symptoms |
chronic subdural hematoma
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What type of intracranial hemorrhage?
usually associated with high velocity impact in serious injuries |
acute subdural hematoma
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What type of intracranial hemorrhage? B/w what two layers?
crescent-shaped and spread over a large area |
subdural hematoma
inner dura-meningeal and arachnoid |
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What type of intracranial hemorrhage?
blood tracks down into sulci following the contours of the pia |
subarachnoid hemorrhage
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What type of intracranial hemorrhage?
hematocrit effect |
subdural hematoma
mixed-density hematomas the densa acute blood settles to the bottom black on top, white on bottom |
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Reason for subarachnoid hemorrhages 80% of the time?
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rupture of arterial aneurysm in subarachnoid space
less often arteriovenous malformations |
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Risk factors for intracranial aneurysms
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marfan's syndrome
polycystic kidney disease atherosclerotic dise |
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Most common locations for saccular/ berry aneurysms, in descending order
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anterior communicating
psterior communicating MCA |
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Risk factors for aneurysmal rupture
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hypertension
cigarette smoking alcohol consumption and situations causing sudden elevation in bp |
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What is the prognosis for subarachnoid hemorrhage?
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25% die immediately
50% die overall |
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signs and symptoms of meningeal irritation
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nuchal rigidity
brudzinski's sign- flexion at hip when neck is flexed kernig's sign- pain in hamstrings when knees are straightened with hips flexed fever sensitivity to light lethargy headache |
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when is angiogram indicated?
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finding location and size of the aneurysm in subarachnoid space
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contusions
coup vs. contrecoup injuries |
occur in regions where cortical gyri about the ridges of bony skull- common at frontal and temporal lobes
contusions of same side- coup injury contrecoup injury- rebound of brani against the skull |
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causes of intraprenchymal hemorrhages
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hypertensive hemorrhage (most common)
lenticulostriate arteries |
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most common locations for hypertensive hemorrhage
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basal ganglia
thalamus cerebellum pons |
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Is rebleeding common in the following conditions:
subarachnoid hemorrhage hypertensive hemorrhage lobar hemorrhage |
subarachnoid-yes
hypertensive-no lobar- yes |
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what is lobar hemorrhage?
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bleeding involves occipital, parietal, temporal, or frontal lobe; most commonly caused by AMYLOID ANGIOGRAPHY; deposits in vessel walls of older patients >50 years old- recurrent or multiple; more superficial than hypertensive hemorrhages
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What are vascular malformations? Do they cause intracranial hemorrhages?
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arteriovenous malformations
cavernous malformations capillary telangiectasias venous angioma of these, only AV malformations and cavernous malformations |
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What do patients with cavernous malformations present with? What is wrong?
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abnormal dilation in vascular cavity, lined by only one layer of vascular endothelium
seizures; risk of hemorrhage increases after an intial bleed |
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What are AVMs and how do they present?
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Arteriovenous malformations are congenital abnormalities in which there are abnormal direct connections between arteries and veins, forming a tangle of abnormal blood vessels; seen via conventional angiography
present with seizures and migraine-like headaches without hemorrhage |
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Battle's sign
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type of extracranial hemmorhage in subcutaneous tissues
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what two causes for hydrocephaly?
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obstruction of flow at any point in ventricles or subarachnoid space
decrease in absorption via arachnoid granulations or rarely, excessive CSF formation |
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Two clinical categorization of hydrocephaly
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Communicating- impaired CSF reabsorption, XS production (rare), or obstruction of flow in subarachnoid space
Noncommunicating- obstruction of flow within the ventricular system **note obstruction of flow outside ventricular system is still considered COMMUNICATING |
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Symptoms and signs of hydrocephaly?
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correlates with that of elevated intracranial pressure
headache, nausea, vomitting, papilledema, decreased vision, six-nerve palsy |
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Sunsetting sign
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eyes downward and inward
inward due to sixth-nerve palsy caused by elevated intracranial pressure downward due to limited vertical gaze due to Parinaud's syndrome- dilation of suprapineal recess of posterior 3rd ventricle can push downward onto the collicular plate of midbrain |
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Normal-pressure hydrocephalus
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in elderly individuals- chronically dilated ventricles
gait difficulties, urinary incontinence, and mental decline (frontal lobe like abnormalities) |
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what is lobar hemorrhage?
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bleeding involves occipital, parietal, temporal, or frontal lobe; most commonly caused by AMYLOID ANGIOGRAPHY; deposits in vessel walls of older patients >50 years old- recurrent or multiple; more superficial than hypertensive hemorrhages
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What are vascular malformations? Do they cause intracranial hemorrhages?
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arteriovenous malformations
cavernous malformations capillary telangiectasias venous angioma of these, only AV malformations and cavernous malformations |
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What do patients with cavernous malformations present with? What is wrong?
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abnormal dilation in vascular cavity, lined by only one layer of vascular endothelium
seizures; risk of hemorrhage increases after an intial bleed |
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What are AVMs and how do they present?
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Arteriovenous malformations are congenital abnormalities in which there are abnormal direct connections between arteries and veins, forming a tangle of abnormal blood vessels; seen via conventional angiography
present with seizures and migraine-like headaches without hemorrhage |
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Battle's sign
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type of extracranial hemmorhage in subcutaneous tissues
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what two causes for hydrocephaly?
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obstruction of flow at any point in ventricles or subarachnoid space
decrease in absorption via arachnoid granulations or rarely, excessive CSF formation |
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Two clinical categorization of hydrocephaly
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Communicating- impaired CSF reabsorption, XS production (rare), or obstruction of flow in subarachnoid space
Noncommunicating- obstruction of flow within the ventricular system **note obstruction of flow outside ventricular system is still considered COMMUNICATING |
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Symptoms and signs of hydrocephaly?
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correlates with that of elevated intracranial pressure
headache, nausea, vomitting, papilledema, decreased vision, six-nerve palsy |
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Sunsetting sign
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eyes downward and inward
inward due to sixth-nerve palsy caused by elevated intracranial pressure downward due to limited vertical gaze due to Parinaud's syndrome- dilation of suprapineal recess of posterior 3rd ventricle can push downward onto the collicular plate of midbrain |
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Normal-pressure hydrocephalus
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in elderly individuals- chronically dilated ventricles
gait difficulties, urinary incontinence, and mental decline (frontal lobe like abnormalities) |
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most common brain tumors in adults
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glioblastoma and brain metastases
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most common pediatric brain tumors
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medulloblastoma and astrocytoma and ependymoma
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pediatric brain tumors tend to be where?
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posterior fossa
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adult brain tumors tend to be where?
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70-supratentorial
30-infratentorial |
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most common brain metastases
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lung, breast, kidneys, GI, and melanoma
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What are paraneoplastic syndromes
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rare neurologic disorders caused by remote effects of cancer in the body- thought to result from autoimmune
tumors that cause paraneoplastic syndromes: small cell lung carcinoma breast cancer ovarian cancer |
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Pituitary adenomas
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cause endocrine disturbances or compress the optic chiasm, resulting in bitemporal visual field defect
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What is the characteristic CSF sample in patients with bacterial meningitis?
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Low glucose, high protein, and high white blood cell count with PMN predominance
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Treatment of bacterial meningitis
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CT
lumbar puncture antibiotic treatment- constantly evolving |
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Two most important spirochetal infections of the nervous system
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neurosyphilis and lyme disease
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Where is the needle typically inserted for a LP?
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L4 or L5 interspace
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What is found CSF of patients with in viral meningitis
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elevated WBC with lyphocyte predominance, normal or mildly elevated protein, and normal glucose
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common parasitic infection of the nervous system in patients with HIV
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toxoplasmosis
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who is at risk for pirmary central nervous system lymphoma?
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AIDS pateients
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