NEURO 3 Flashcards
what is the calvarium?
brain case & comprises the skull vault & skull base
where & what does optic canal transmits?
sphenoid bone (middle cranial fossa to orbital apex)- transmits optic nerves & opthalmic arteries
where & what does superior orbital fissure transmits?
sphenoid bone (from middle cranial fossa to orbital apex)- 1st (orbital) division of 5th, 3rd, 4th & 6th CN, superior orbital vein & branch of middle meningeal artery
where & what does inferior orbital fissure transmits?
between maxilla & sphenoid bones- infraorbital nerve, infraorbital artery & inferior ophthalmic veins
where & what does foramen rotundum transmits?
sphenoid bone- 2nd (maxillary) divisions of 5th CN
where & what does foramen ovale transmits?
sphenoid bone- 3rd (mandibular) divisions of 5th CN & accessory meningeal artery
where & what does foramen spinosum transmits?
sphenoid bone- middle meningeal artery
where & what does foramen lacerum transmits?
apex of temporal bone- carotid artery pass through its posterior wall (nothing go through it only over it)
where & what does inernal auditory meatus transmits?
petrous temporal bone- 7th & 8th CN & internal auditory artery
where & what does jugular foramen transmits?
junction of occipital & petrous temporal bone- internal jugular vein, 9th, 10th, 11th CN- inferior petrosal sinus & ascending occipital & pharyngeal arterial branches
where & what does hypoglossal canal transmits?
occipital bone- 12th CN
where & what does foramen magnum transmits?
occipital bone- medulla oblongata/spinal cord, along vertebral & spinal arteries & veins and spinal root of 11th CN
what are the layers of the meninges?
dura mater, arachnoid materm, pia mater
what is the function of the meninges?
protect the brain & spinal cord, support framework for arteries, veins & sinuses, enclose subarachnoid space (CSF)
what is the dura mater?
tough fibrous coat (fibroblasts & CT fibrils), adherent to inner surface of skull, seperated from vertebrae by epidural space, infoldings of dura seperate brain regions from each other e.g. falx cerebi & tentorium cerebelli
what is the arachnoid mater?
located internal to the dural border cell layer- regarded as having 2 parts= arachnoid barrier cell layer & arachnoid trabeculae
what is the subarachnoid space?
located between the arachnoid barrier cell layer and the pial cells- contains CSF, superficial vessels, roots of cranial and spinal nerves
what is the pia mater?
flattened cells with long flat processes & closely follow the surface features of brain & spinal cord
what is a stroke?
Focal neurological deficits due to vascular disturbance within the CNS that evolve over a short period of time (seconds to hours) and last more than 24 hours- (If less than 24 hrs -transient ischemic attack)- symptoms may indicate arterial supply involved
what is the difference between ischemic & hemorrhagic stroke?
ischemic= blockage of blood vessel, neurons deprived of oxygen/nutrients- hemorrhagic= rupture of blood vessel, bleed into brain
what is a lucunar infarcts?
Lacune refers to a small deep infarct attributable to a primary arterial disease that involves a penetrating branch of a large cerebral artery- effects= putamen, thalamus, internal capsule, pons, corona radiata- the very thin arteries off middle cerebral artery
what is the difference between atherosclerosis & arteriolosclerosis?
Atherosclerosis= focal narrowing of intracranial arterial lumen (blocks major artery e.g. basal artery)- Arteriolosclerosis= sclerosis of small sized arteries, common from chronic hypertension and/or DM
what is hydrocephalus?
disturbance of CSF formation, flow, or absorption, leading to an increase in volume occupied by this fluid in the CNS- can be congential or acquired
what are clinical features of hydrocephalus influenced by?
patients age, causes of hydrocephalus, location of obstruction, duration, rapidity of onset
what is congenital hydrocephalus influenced by?
present at birth and may be caused by either events or influences that occur during fetal development or genetic abnormalitie
what is acquired hydrocephalus?
develops at the time of birth or at some point afterward and can affect individuals of all ages and may be caused by injury or disease
what is communicating hydrocephalus?
flow of CSF is blocked after it exits the ventricles- problems with reabsorbing the CSF
what is non-communicating hydrocephalus?
also called “obstructive” hydrocephalus — flow of CSF is blocked along one or more of the narrow passages connecting the ventricles
what is Hydrocephalus ex-vacuo?
stroke or traumatic injury cause damage to and loss of brain tissue that expands the ventricles - primary affects adults
what is Normal Pressure Hydrocephalus?
abnormal increase of CSF in the ventricles that may result from a subarachnoid hemorrhage, head trauma, infection, tumor, or complications of surgery- occurs in adults
what is a brain aneurysms?
a bulge or sac that develops in an artery because the wall of the vessel is weak- may compress surrounding nerves and brain tissue resulting in nerve paralysis, headache, neck and upper back pain as well as nausea and vomiting- if it ruptures, resulting bleeding in head may cause stroke or death- skull does not move, but tissue does- brain has no pain receptors
what are arteriovenous malformation (AVM)?
abnormal connection or passageway between arteries & veins- prevents oxygenated blood from circulating throughout brain- can cause significant deficits e.g. cells can die
what are symptoms of AVM?
unusual sound in one ear, neurological symptoms, increased pressure in the eye, double vision, pain
what is a subarachnoid hemorrhage?
injury of small arteries or vein on brain surface- ruptured vessel blends into space between pia & arachnoid- due to trauma
how does a subarachnoid hemorrhage appear on CT?
subarachnoid hemorrhage appears as focal high density in sulci and fissures or linear hyperdensity in the cerebral sulci
what is acute subdural hematoma?
blood collects in space between arachnoid & dura mater
how does a subdural hematoma appear on CT?
crescent shaped, hyperdense (may contain hypodense foci- may indicate a continuing bleed)- does not cross dural reflections
what is a epidural hematoma?
associated with skull fracture- occurs when an impact fractures the calvarium- bone lacerates a dural artery or a venous sinus- blood collects between skull & dura
how does an epidural hematoma appear on CT?
forms a hyperdense biconvex mass- usually uniformly high density but may contain hypodense foci due to active bleeding- can cross dural reflections but does not cross suture lines when dura tightly adheres to adjacent skull
what are acute infections of the CNS?
categorised as meningitis, encephalities or mass lesions- differ significantly in clinical presentations, bacteriology & clinical & laboratory assessment
what are symptoms of acute infection of CNS?
hisotry of headaches & fever, nausea & vomiting- look at hisotry of presentation, acquisition & associated complaints- also pay attention to travel, animal & insect exposures, HIV risks, recent immunizations- also – Intrathecal contrast dyes, ibuprofen and antimicrobials such as trimethoprim-sulfamethoxazole (TMP-SMX) and isoniazid can cause acute meningeal reactions in the absence of infection
what is meningitis?
inflammation of lining around brain & spinal cord- septicaemia is blood poisoning form- usually bacterial (life threatening) or viral (not life threatening)
is imaging required for meningitis?
imaging performed to look for complications and assess safety of lumbar puncture - Imaging is not performed to diagnose meningitis because imaging studies are frequently normal despite the presence of the disease
what are complications of meningitis?
hydrocephalus, ventriculitis, Subdural effusion, Subdural empyema, Cerebritis / Abscess, Vasospasm / arterial infarcts, Venous thrombosis / venous infarcts
what is encephalitis?
irritation & swelling of brain, due to viral infection- caused by viruses, bacteria, fungi, parasites
what is the difference between primary & secondary encephalitis?
primary= virus or other infectious agent directly infects brain- secondary= post infectious, faulty immune system reaction in response to an infection elsewhere in body
what are tests & diagnoses of encephalitis?
questions about symptoms, risk factors and medical history are important- test including brain imaging, lumbar puncture, lab tests, EEG
what are brain abscess?
caused by infectious agents- result of direct skull trauma or following surgery, spread of infection from paranasal sinuses, the middle ear and the mastoid air cells, a tooth abscess, or by hematogenous spread from the lungs or heart
what is subdural empyema?
intracranial focal collection of purulent material located between the dura and arachnoid mater- causes clinical problems through extrinsic compression of the brain by an inflammatory mass and inflammation of the brain and meninges- an emergency & leads to rapid clinical deterioration, especially if it is due to sinusitis
what is subdural empyema due to?
meningitis, sinusitis, trauma or prior surgery
how does subdural empyema appear on CT?
appears as isodense or hypodense extra-axial mass
what are brain neoplasms?
Brain tumors may originate from neural elements within the brain, or they may represent spread of distant cancers- – Gliomas, metastases, meningiomas, pituitary adenomas and acoustic neuromas account for 95% of all brain tumors
what is the most common primary brain tumour & how many?
meningioma followed by glioma (glioblastoma multiforme)- more than 120 types of primary brain tumours- also astrocytomas (tumours caused by astrocytes), meningioma (tumour of meninges)- for tumours to grow, they take the blood from surrounding structures and destroy those structures as a result
what are symptoms of brain neoplams?
Headaches, Seizures or convulsions, Difficulty thinking, speaking, or finding words, Personality or behavior changes, Weakness or paralysis in one part or one side of the body, Loss of balance or dizziness, Loss of hearing, Vision changes, Confusion and disorientation, Memory loss
what symptoms require neuroimaging in patients with inracranial neoplasm?
Acute mental status changes, New-onset seizures, Focal motor or sensory deficits, including gait disturbance, Suspicious headache, Signs of elevated ICP (eg, papilledema), Generally, CT is the imaging modality of choice for the ED physician
what is the venous drainage of the brain?
superior sagittal sinus drains lateral aspect- takes it to confluence of sinus
what drains the medial part of brain?
internal sagittal sinus & great cerebral vein- travels via straight sinus to confluence of sinus- blood than travels to transverse sinus- to sigmoid- to internal jugular- to heart & oxygenated than sent to brain again
