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257 Cards in this Set

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SCALP

Skin - Connective Tissue - Aponeurotica - Loose Areolar CT - Pericranium (periosteum)

Anterior Fossa

Contains Frontal Lobe, divided from the middle fossa by the lesser wing of sphenoid bone

Middle Fossa

Contains Temporal lobe, divided from the posterior fossa by the petrous ridge of the temporal bone as well as by a sheet of meninges - Tentorium Cerebelli

Posterior Fossa

Contains the cerebellum and brainstem

Falx Cerebri

Flat sheet of Dura that is suspended from the roof of the cranium and separates the right and left cerebral hemispheres, running in the interhemispheric fissure

Tentorium Cerebelli

Tent like sheet of Dura that covers the upper surface of the cerebellum

Supratentorial

Above the Tentorium Cerebelli

Infratentorial

Below the Tentorium Cerebelli

Tentorial Notch

Also known as Tentorial Incisure, narrow opening in the tentorium cerebelli which the midbrain passes through. At the level of CNIII and the Interpeduncular fossa.

Virchow-Robin Space

where pia surrounds initial portion of each blood vessel as it penetrates the brain surface forming a perivascular space and then fuses with the blood vessel wall

Epidural Space

between dura and skull; contains the middle meningeal artery

Middle Meningeal Artery

Enters skull through the foramen spinosum and runs in the epidural space between the Dura and the skull

Subdural Space

Potential space between the inner layer of Dura and the loosely adherent arachnoid

Bridging Veins

Traverse the subdural space and drain the cerebral hemispheres and pass through the subdural space en route to several large Dural venous sinuses

Dural Sinuses

Large venous channels that lie enclosed within the two layers of Dura, Dural sinuses drain blood mainly via the sigmoid sinuses to reach the internal jugular vein.

Subarachnoid Space

CSF filled space between arachnoid and pia, also major arteries of the brain travel within the subarachnoid space and then send smaller penetrating branches inward through the pia

Epidural Fat

In spinal canal only layer between the Dura and the periosteum

Ependymal cells

line the ventricles

Choroid Epithelial Cells

Blood vessels of the choroid plexus are lined with ependymal like cuboidal cells called Choroid Epithelial Cells

Lateral ventricles

one in each cerebral hemisphere
Anterior (frontal) horn: anterior to foramen of Monro and extends to frontal hemisphere
Body: Posterior to foramen of Monro; within frontal and parietal lobe
Atrium (trigone): area of convergence of the occipital horn, and the body of the lateral ventricle
Occipital (posterior) horn: Extends from the atrium posteriorly into the occipital lobe
Temporal (inferior) horn: Extends from the atrium inferiorly into the temportal lboe

Third ventricle

within the thalamus and hypothalamus

Fourth ventricle

within the pons, medulla, and cerebellum

General Flow of CSF

Lateral Ventricles ---(foramen of monro)--> Third Ventricle ---(cerebral aqueduct/aqueduct of Sylvius)---> fourth ventricle ----(foramina of Lushka and foramen of Magendie) --> outsideeee world

Normal total CSF volume adults

150cc

Rate of CSF production

20cc/hour (500cc/day)

Cisterns

Areas where subarachnoid space widens in a few areas to form larger CSF collections called Cisterns

Ambient Cistern

located lateral to the midbrain

Quadrigeminal Cistern

posterior to the midbrain, beneath the posterior portion of the corpus callosum (quad bc four bumps of superior and inferior colliculi)

Interpenduncular Cistern (Interpeducular fossa)

located on the ventral surface of the midbrain between the cerebral peduncles

Prepontine Cistern

located just ventral to the pons, contains the basilar artery and the 6th nerves as they ascend from the pontomedullary junction along the cilvus

Cisterna Magna (cerebellomedullary cistern)

largest cistern; located beneath the cerebellum near the foramen magnum

Lumbar Cistern

located in the lumbar portions of the spinal column, contains the cauda equina and is the region from which CSF is obtained during a lumbar puncture or spinal tap

What substances permeate readily across the cell-membrane of the blood-brain and blood-CSF barriers

O2 and CO2

Arachnoid Villus Cells

Carries out one-way bulk flow of CSF from subarachnoid space to venous sinuses via giant vacuoles

Circumventricular Organs

Blood-brain barrier is interrupted allowing the brain to respond to changes in the chemical milieu of the remainder of the body 1. Organum Vasculosum 2. Median Eminence 3. Neurohypophysis 4. Area Postrema - also known as the chemotactic trigger zone, involved in detecting circulating toxins that cause vomiting 5. Subcommissural Organ 6. Pineal 7.Subfornical Organ

Area postrema

the only paired circumventricular organ; located on the caudal wall of 4th ventricle in the medulla
Also known as chemotactic trigger zone --> detects circulating toxins that cause vomiting

Cytotoxic Edema

Cellular damage that can cause excessive intracellular fluid accumulation within the brain cells

Vasogenic Edema

Disruption of the blood-brain barrier resulting in the extravasation of fluids into the interstitial space

Headache mechanism

Caused by mechanical traction, inflammation, or irritation of the structures in the head that are innervted (blood vessels, meninges, scalp, skull)

Innervation supratentorial dura

Trigeminal (CN V)

Innervation dura of posterior fossa

CN X (to a lesser extent CN IX and first 3 cervical nerves)

Vascular Headache

not fully understood, but thought to involve inflammatory, autonomic, serotonergic, neuroendocrine and other associated symptoms (migraine or cluster headache)

Migraine

75% of patients have a positive family history, suggesting a genetic basis, symptoms may be provoked by certain foods, stress, eye strain, menstrual cycle, changes in sleep pattern. Usually unilateral; presence of aura

Symptoms of Migraine

Often preceded by an aura or warning symptoms, classically involving visual blurring, shimmering, scintillating distortions or fortification scotoma, pain is often throbbing and may be exacerbated by light (photophobia) sound (phonophobia) or sudden head movement. Nausea and vomiting may occur. 30 minutes - 24 hours

Fortification Scotoma

Characteristic region of visual loss bordered by zigzagging lines resembling the walls of a fort

Complicated Migraine

May be accompanied by a variety of transient focal neurologic deficits including sensory phenomena motor deficits visual loss brainstem findings in basilar migraine and impaired eye movements in ophthalmoplegic migraine

Treatment of Migraines

Acute attacks usually respond well to nonsteroidal anti-inflammatory drugs, anti-emetics, triptans (seretonin agonists, or resting in a quiet dark room)

Migraine Prevention

prophylaxis with beta-blockers, topriamate, valproate, calcium channel blockers, tricyclic antidepressants, NSAIDS

Cluster Headache

Less than 1/10th as common as migraine. 5x more common in males than in females. Lasts 30-90 minutes usually felt behind eyes. Usually accompanied by unilateral autonomic symptoms

Tension Headache

(aka tension-type headache) steady dull ache sometimes described as a bandlike sensation

Tx Tension Headache

muscle relaxation techniques, NSAIDS, other analgesics, tricyclic antidepressants

Sudden "explosive" onset of severe headache differential dx

subarachnoid hemorrhage

Headache accompanied by fever, stiff neck, sensitivity to light

possible infectous meningitis

Idiopathic Intracranial Hypertension

(aka Pseudotumor cerebri) condition of unknown cause characterized by headache and elevated intracranial pressure with no mass lesion. More common in adolescent females, treated with ACETAZOLAMIDE (or with shunting procedures)

Temporal Arteritis (Giant Cell Arteritis)

Important treatable cause of headaches, this disorder seen most commonly in elderly individuals, vasculitis affects the temporal arteries and other vessels, including those supplying the eye. Temporal artery is characteristically enlarged and firm.

Diagnosis of Temporal Arteritis

Diagnosis by erythrocyte sedimentation rate (ESR) and temporal artery biopsy

Effects of Intracranial Mass Lesion

1. Compression and destruction of adjacent regions of the brain causing neurological abnormalities
2. Mass located within cranial vault can raise the intracranial pressure causing certain characteristic symptoms and signs
3. Mass lesions can displace nervous system structures so severely that they are shifted from one compartment into another situation called herniation

Mass Effect

Distortion of normal brain geometry due to a mass lesion - can be as subtle as a mild flattening or effacement of sulci next to a lesion.

Midline Shift

results from mass effect caused by large masses which dramatically shift brain structures away from the side of the lesion, can compression ventricular system and obstruct CSF flow producing hydrocephalus.

Landmark the measures midline shift

pineal calcification

Elevated Intracranial Pressure

Severely elevated intracranial pressure can cause decreased cerebral blood flow and brain ischemia, cerebral blood flow depends on cerebral perfusion pressure.

Cerebral Perfusion Pressure

Mean arterial pressure minus the infusion pressure (CPP = MAP - ICP)
As intracranial pressure increases, cerebral perfusion pressure decreases. Autoregulation of cerebral vessel caliber can compensate for modest reductions in cerebral perfusion pressure leading to relatively stable cerebral blood flow however large increases in intracranial pressure can exceed the capacity of autoregulation leading to reduced cerebral blood flow and brain ischemia

Symptoms of Elevated Intracranial Pressure

-Headache (often worse in morning due to brain edema increasing overnight from effects of gravity)
-Altered mental status (especially irritability and depressed level of alertness and attention)
-Nausea and vomiting (typically suddenly and without much nausea known as projectile vomiting)
-Papilledema (elevation of optic disc)
-Visual Loss
-Diplopia
-Cushing's Triad (Hypertension, Bradycardia, Irregular respirations)

Cushing's Triad

Hypertension, Bradycardia, and irregular respirations

Normal Intracranial Pressure

In adults is less than 20 cm H2O or less than 15 mm Hg (torr)

Contraindication of Lumbar Puncture

Severely increased intracranial pressure (can precipitate herniation)

Tx Intracranial Pressure: Elevation of head of bed to 30 degrees,maintaining head straight

Immediate effect; promotes venous drainage

Tx Intracranial Pressure: Hemicraniectomy

Immediate effect; decompresses intracranial cavity (experimental)

Tx Intracranial Pressure: intubation and hyperventilation to PCO2 of 25-30mmHg

Onset = 30 seconds; causes cerebral vasoconstriction

Tx Intracranial Pressure: IV mannitol and furosemide

Onset = 5 minutes; promotes removal edema and other fluids from CNS while maintaining cerebral perfusion

Tx Intracranial Pressure: Ventricular drainage

Onset = minutes; removal of CSF decreases intracranial pressure

Tx Intracranial Pressure: barbiturate-induced coma

Only if all other measures fail; onset = 1 hour; causes cerebral vasoconstriction and reduced metabolic demands

Tx: Intracranial Pressure: Steroids

Onset = hours; reduces cerebral edema, possibly by strengthening blood-brain barrier; may also work by other mechanisms

Herniation

Occurs when mass effect is severe enough to push intracranial structures from one compartment into another.

3 Most Clinically important Herniation Syndromes?

1. Herniation through tentorial notch (transtentorial herniation)
2. Herniation centrally and downward (central herniation)
3. Herniation under the falx cerebri (Subfalcine herniation)

Transtentorial Herniation

Herniation of medial temporal lobe, especially the uncus (uncal herniation) inferiorly through the tentorial notch.

Clinical Triad Uncal Herniation

Heralded by clinical triad of "blown" pupil, hemiplegia, and coma.
Compression of Oculomotor (CN III) ipsilateral (85% of time) to the lesion produces first a dilated unresponsive pupil (blown pupil)

Compression of the cerebral peduncles can cause

hemiplagia (often contralateral to lesion)

Kernohan's Phenomenon

Sometimes in uncal herniation the midbrain is pushed all the way over until it is compressed by the opposite side of the tentorial notch, in these cases the contralateral corticospinal tract is compressed producing hemiplegia that is ipsilateral to the lesion.

Distortion of the midbrain reticular formation leads to...

decreased level of consciousness and ultimately, coma

Central herniation

central downard displacement of the brainstem

Causes central herniation

any lesion associated with elevated intracranial pressure

Mild central herniation

Traction of the abducens nerve --> lateral rectus palsy

Tonsillar herniation

herniation of the cerebellar tonsils downward through the foramen magnum --> associated with compression of the medulla and usually leads to respiratory arrest, blood pressure instability, and death

Subfalcine herniation

Herniation under the falx cerebri from one side of the cranium to another; can lead to infarcts of the anterior cerebral artery

Concussion

reversible impairment of neurologic function for a period of minutes to hours following a head injury; mechanism unknown

Clinical features concussion

loss of consciousness, headache, dizziness, nausea, vomiting; anterograde or retrograde amnesia

postconcussive syndrome

headaches, lethary, mental dullness lasting severeal months after accident

Diffuse axonal shear injury

causes widespread or patchy damage to the white matter and cranial nerves

Petechial hemorrhages

small spots of blood in the white matter

Types of intracranial hemorage

1. Epidural Hematoma (EDH)
2. Subdural Hematoma (SDH)
3. Subarachnoid hemorrhage (SAH)
4. Intracerebral or intraparenchymal hemorrage (ICH)

Location EDH

in the tight potential space between the dura and the skill

Causes EDH

Rupture of the middle meningeal artery due to fracture of the temporal bone by head trauma

Clinical features and radiological appearance EDH

Rapidly expanding hemorrhage under arterial pressure peels dura away from the inner surface of the skull; LENS shaped
Sx: initially, none; elevated intracranial pressure and ultimately, herniation

Location SDH

In the potential space between the dura and arachnoid

Usual causes of SDH

Rupture of the bridging veins

Radiological appearance SDH

crescent-shaped hematoma

Chronic SDH

often seen in elderly patients; blood collects over long period of time; headache, cognitive impairment, unsteady gait, focal seizures

Acute SDH

high impact velocity; areas in imaging are hyperdense and bright (acute blood) --> clot in 1-2 weeks (isodense); 3-4 weeks (hypodense)
continuous bleeding = mixed density

hematocrit effect

With mixed-density hematomas, the denser acute blood settles to the bottom

Location SAH

In the CSF-filled space between the arachnoid and the pia, which contains the major blood vessels of the brain

Radiological appearance SAH

Blood can be seen on CT to track down into the sulci following the contours of the pia (blood EVERYWHERE)

Nontraumatic (Spontaneous) SAH

presents as "the worst headache of my life"
causes: arterial aneurysm (or less commonly an AV malformation)

Risk factors intracranial aneurysm

atherosclerotic disease, congenital anomalies in cerebral blood vessels, polycystic kidney disease, connective tissue disorders (Marfan's)

Berry aneurysms

usually arise from Circle of Willis; typically have a neck and dome that can rupture
over 85% occur in the anterior circulation (carotid artery and its branches)

Most common locations: Berry aneurysms

AComm (30%), PComm (25%), MCA (20%), vertebrobasilar system (15%)

Are fusiform or saccular aneurysms less prone to rupture?

fusiform

Consequences of PComm aneurysm

Third nerve palsy

Risk factors aneurysm rupture

hypertension, smoking, alcohol, situations with elevation of BP

Type of scan to run for suspected hemorrhaging

CT scan WITHOUT contrast; both subarachnoid blood and contrast material appear white on the scan

Triple H Therapy

treatment of vasospasm following hemorrhage--> Induced Hypertension, hypervolemia, and hemodilution

Traumatic Subarachnoid Hemorrhage

caused by bleeding into the CSF from damaged blood vessels associated with cerebral contusions and other traumatic injuries; more common than spontaneous; severe headache

Location ICH

Within the brain parenchyma in the cerebral hemisphere, brainstem, cerebellum or spinal cord

Traumatic ICH

Contusions which are common at the temportal and frontal poles
Contusions occur on the side of the impact (coup injury) as well as on the side opposite the impact (contrecoup injury) because of rebound of the brain against the skull

Nontraumatic ICH Causes

hypertension, brain tumors, secondary hemorrhage after ischemic infarction, vascular malformations, blood coag abnormalities, infections, vessel fragility caused by deposition of amyloid protein in the blood vessel wall (amyloid angiopathy), vasculitis, mycotic (infectious) aneurysms in the setting of endocarditis

Hypertensive hemorrhage

most common cause of nontraumatic ICH
often involves small, penetrating blood vessels
uncertain pathogenesis, but may be related to chronic pathologic effects of hypertension on the small vessels (lenticulostriate arteries, including lipohyalinosis and microaneurysms of Charcot-Bouchard)

Most common locations of hypertensive hemorrage

Basal ganglia (usually the putamen)
thalamus
cerebellum
pons

Intraventricular extension

aka intraventricular hemorrhage; hemorrhages that involve the ventricles

Lobar hemorrhage

bleeding involves the occipital, parietal, temporal, or frontal lobe

Common cause of lobar hemorrhage

amyloid (congopilic) angiopathy

Vascular Malformations

1. AV malformations
2. Cavernomas
3. Capillary telangiectasias (capillary angiomas)
4. Developmental venous anomalies (venous angiomas, venous malformations)

Ateriovenous malformations (AVMs)

congential abnormalities in which there are abnormal direct connections between arteries and veins, often forming a tangle of abnormal blood vessels visible as flow voids on MRI scan, but best seen on conventional angiography

Tx AVM

neurosurgical removal, intravascular embolization, sterotactic radiosurgery

Cavernomas

abnormally dilated vascular cavities lines by only one layer of vascular endothelium
not visible on conventional angiography
Have a characteristic MRI appearance (central 1-2cm core of increased signal on T1 or T2, surrounded by a dark rim on T2-weighted sequences because of hemosiderin)

Capillary telangiectasia

small regions of abnormally dilated capillaries; rarely give rise to intracranial hemorrhage

Developmental venous anomalies

dilated veins usually visible on MRI scans as a single flow void extending to the brain surface

Hemotympanum

hemorrage in the inner ear

Hemorrage in subcutaneous tissue

results in Battle's sign or "racoon eyes"

Subgaleal hemorrhage

hemorrage in the loose space between the external periosteum and galea aponeurotica; can produce a "goose egg"

cephalohematoma

bleeding during delvery of newborns that occurs between the skull and external periosteum (pericranium)

Causes of hydrocephalus(3)

1) excess CSF production 2) Obstriction in ventricles or subarachnoid space 3) decrease in reabsorption via arachnoid granulations

Excess CSF Production

rare, seen in choroid plexus papilloma

Obstruction of CSF flow

common cause, especially at narrow points-foramen of monro, cerebral aqueduct, 4th ventricle

Decreased CSF Resorption

difficult to distinguish from obstruction and often has similar causes.

Communication Hydrocephalus

impaired CSF resorption in arachnoid agranulation, obstricution of flow in the subarachnoid space, or (rarely) by excess CSF production

Noncommunication hydrocephalus

obstruction fo flow w/in the ventricular system

Symptoms of hydrocephalus

Headache, nausea, vomiting, coagnitive impairment, decreased level of consciousness, papilledema, decreased vision, 6th N palsies(incomplete or slow abduction of eye), magnetic gait[feet barely leave the floor](assc with frontal lobe) and incontinence

Parinaud's Syndrome

dilation of the suprapineal recess of the posterior 3rd ventricle pushing downward onto the collicular plate. Causes limited upward gaze.

"setting sun" sign

bilatreal deviaton of the eyes downward and inward. Most often in children with acute hydrocephalus

Ventriculoperitoneal shunt

shunt tubing from lateral ventricle tunneled under the skin into the peritoneal cavity of the abdomen. Valve prevents reverse fluid direction.

Endoscopic Neurosurgery

cannula introduced into the cranium through small incision and passing instruments through it

Normal Pressure Hydrocephalus

condidtion usually in elderly, chronically dilated ventricles. Present with clinical triad of gait difficulties, urinary incontinence, and mental decline. Thought to be form of communicating hydrocephalus with impaired CSF resorption at the arachnoid villi.

Hydrocephalus Ex Vacuo

Refers to excess CSF in a regionwhere brain tissue was lost as a result of stroke, surgery, atrophy, trauma or other insult.

2 broad categories of brain tumors

Primary CNS tumors and Metastatic Tumors

Primary CNS tumors

arose from abnormal proliferation of cells originating in the nervous system

Metastatic tumors

arise from neoplasms originating elsewhere in the body that spread to the brain

Most common brain tumors

gliomas and meningiomas

Supratentorial tumors are more common in

adults

Infratentorial tumors are more common in

children

Most common brain tumors in children

astrocytoma and medulloblastoma, followed by ependymoma

Various symptoms of brain tumors

headache and other signs of increased intracranial pressure, seizure and focal symptoms

Tumors that are more commonly associated with seizures

low-grade gliomas and meningiomas

Types of gliomas

Glioblastoma multiforme
Astrocytoma Grades I and II
Asytrocytoma Grade III
Oligodendriglioma
Ependymoma
Other

Meningiomas

arise from the arachnoid villus cells and occur, in order of decreasing frequency, over the lateral convexities, in the falx, and along the basal regions of the cranium
In female pts, there may be an association between meningiomas and breast cancer

Pituitary adenomas

Can cause endocrine disturbances or compress the optic chiasm

Tx pituitary adenoma

dopaminergic agonists or transsphenoidal resection

Prolactinomas

most common type of pituitary adenoma

Most common schwannoma location

CN VIII

Lymphoma

increased incidence attributable to increase in HIV
Arises from B cells
controlled by chemotherapy and radiation therapy

Pineal region tumor

Relatively uncommon
Includes pinealomas, germinomas, and rarely, teratomas or gliomas
Tumors in this region can obstruct cerebral aqueduct or compress the dorsal midbrain, causing Parinaud's syndrome

Most common cancers that spread to brain

lung, breast, melanoma

Cerebellar astrocytoma

Grade I astrocytoma; often cured by surgical ressection

Common age range medulloblastoma

before age 10

Common age range cerebellar astrocytoma

between 2 and 20

Paraneoplastic syndrome

Relatively rare neurologic disorder caused by remote effects of cancer in the body, leading to an abnormal autoimmune response
Examples: limbic or brainstem encephalitis, cerebellar Purkinje cell loss, spinal cord anterior horn cell loss, neuropathy, impaired neuromuscular junction (Lambert-Eaton syndrome), and opsoclonus myoclonus (characterized by irregular jerking movements of the eyes and limbs)

Infectious Meningitis

infection of the CSF in the subarachnoid space

Causes infectious meningitis

bacteria, viruses, fungi, or parasites

Sx infectious meningitis

Headache, lethargy, photophobia, phonophobia

Dx of meningitis

CT followed by lumbar puncture

CSF characteristics of Bacterial meningitis

CSF = high white blood cell count with polymorphonuclear predominance
High protein
Low glucose

Most common pathogens in bacterial meningitis

depends on age

Most common tx bacterial meningitis

depends on age

Most common pathogen bacterial meningitis for children <3 months

E Coli, Group B, D Streptococcus, Listeria

Most common pathogen bacterial meningitis 1 month-7 years

Haemophilus influenzae, Neisseria meningitidis, streptococcus pneumoniae

Most common pathogen bacterial meningitis ages 7 years-adult

Listeria, Neisseria meningitidis, Streptococcus pneumoniae

Most common tx bacterial meningitis ages 0-3 months

Ampicillin + ceftriaxone

Most common tx bacterial meningitis ages 3 months - 7 years

Ceftriaxone

Most common tx bacterial meningitis ages 7 years - adult

Ampicillin + ceftriaxone

Complications of bacterial meningitis

seizures, cranial neuropathies, cerebral edema, hydrocephalus, herniation, cerebral infarcts, and death

What do you do with children following recovery of bacterial meningitis?

screen for hearing loss

Brain abcess

bacterial infection of the nervous system; presents as an expanding intracranial mass, much like a brain tumor, but with a much more rapid course

presentation brain abcess

headache, lethargy, fever (60% of cases), nuchal rigidity, nausea, vomiting, seizures, focial signs

Common infecting organisms: brain abscess

streptococci, Bacteriodes, enterobacteriaeae, Staphylococcus aureus, toxoplasma gondii, Nocardia

Tx patients small brain abscess (<2.5 cm)

antibiotics and observation

Tx pts with large brain abscess (>2.5cm)

stereotactic needle aspiration or surgical removal + antibiotics

CSF of Viral Meningitis

increased WBC (10-300); increased protein (50-100); normal glucose (exception = herpes, mumps, lymphocytic choriomeningitis virus)

CSF of Herpes meningoencephalitis

0-500 lymphocytes (normal = <5-10); increased protein (5-100); Normal or reduced glucose; RBCs or xanthochromia may be present

CSF of tuberculous menigitis or cryptococal meningitis

increased lymphocytes (10-200); increased protein (100-200); reduced glucose (<50)

Most common location epidural abscess

spinal canal

Common presentation epidural abscess

back pain, fever, elevated peripheral white blood cell count, headache, signs of nerve root or spinal cord compression

Ex epidural abscess

surgical drainage and antibiotics (nafcillin and ceftriaxone)

Pathogen epidural abscess

Staphylococcus aureus, streptococci, Gram-negative bacilli, and aneorobes

Sudbdural empyema

collection of pus in the subdural space, usually resulting from direct extension from an infection of the nasal sinuses or inner ear

Tx subdural empeyma

ceftriaxone + metronidazole

Pott's disease

tuberculous involvement of the epidural space

Tx tuberculous meningitis

combination of isonizid, rifampicin, ethambutol, and pyrazinamide

Lymphocyte-Predominant Meningitis

"Aseptic meningitis"
most commonly viral in origin

2 most important spirochetal infections of the nervous system

neurosyphilis and Lyme disease

Syphilis pathogen

Treponema pallidum

Primary syphillis

painless skin lesions called chancres appear at the site of infection about 1 month after exposure

Secondary syphilis

more diffuse skin lesions appear ~ 6 months (palms and soles)

Tertiary syphilis

neurologic manifestations

meningovascular syphilis

chronic meningeal involvement causes arteritis, typically involving medium sized vessels, that results in diffuse white matter infarcts

What occurs if meningovascular syphilis goes untreated?

general paresis-- accumulation of lesions causes dementia, behavioral changes, delusions of grandeur, psychosis, and diffuse UMN-type weakness

Tabes dorsalis

syphilitic myelopathy with degeneration of spinal cord dorsal roots; sensory loss and high stepping gait pattern and incontinence; Argyll Robertson pupils and optic atrophy

Dx neurosyphilis

blood tests for treponems (FTA-ABS or MHA-TP) + CSF w/ lymphocyte-predominant meningitis

Tx neurosyphilis

IV penicillin G

Lyme disease pathogen

Borrelia burgdorferi carried by Ixodes species of deer tick

Sx Lyme Disease

erythema chronicum migrans (rash); some cases show neurologic manifestations (lymphocyte-predominant meningitis, mild meningoencephalitis, emotional changes, crainial neuropathies (most commonly CN VIII)); arthritis and cardiac conduction abnormalities

Tx Lyme Disease

IV ceftriaxone

Causes viral meningitis

enterocviruses such as echovirus, coxsackievirus, mumps virus

Viral encephalitis

viral infections that involve the brain parenchyma

Most common cause viral encephalitis

herpes simplex Type I

Herpes Simplex encephalitis

causes necrosis of unilateral or b/l temporal and frontal sutures; progresses within days to coma and death

Tx Herpes Simplex encephalitis

Acyclovir

Subacute sclerosing panencephalitis

A delayed, slowly progressive fatal encephalitis often associated with measles

Herpes Zoster

shingles; infection caused by the same virus as chickenpox
primary sx = painful rash conforming to nerve root distributions

HTVL-1 virus

causes chronic type of spinal cord disease called HTVL-1 associated myelopathy, or tropical spastic paraparesis

Causes of transverse myelitis

enteroviruses (coxsakie and poliomyelitis), varicella-zoster virus, HIV
less commonly, Epstein-Barr virus, cytomegalovirus, herpes simplex, rabies, Japanese B virus

HIV-associated neurocognitive disorder (HAND)

common neurologic manifstation of HIV, with increasd frequency late in the course of the illness; Tx with antiviral agents (highly active antiretrovial therapy, or HAART) can cause improvement in AIDS related dementia

Common viral infections in pts with HIV

encephalitis, herpes simplex virus, varicella-zoster virus, or cytomegalovirus

Progressive multifocal leukoencephalopathy (PML)

Disorder that can occur in patients w/ AIDS or immunodeficiency status; caused by papvavirus called the JC virus and results in gradual demyelination of the brain (death within 3-6 months)

Important bacterial infections in pts with AIDS

tuberculous meningitis and neurosyphilis

Cryptococcal meningitis

common fungal infection in AIDS pts; should be suspected in all HIV-positive pts with chronic headache; organism can be identified by India ink stain

Tx cyrptococal meningitis

IV amphotercin B followed by oral fluxonazole

Exposure to toxoplasma

undercooked meat or cysts in cat feces; initial exposure is usually asymptomatic

Toxoplasma and AIDS pts

infection becomes reactivated and spreads to the CNS, forming brain abscesses visible on MRI scans as ring-enhancing lesions

Most common cause of intracranial mass lesions in pts with HIV

toxoplasmosis (second = primary nervous system lymphoma)

Tx toxoplasmosis

pyrimethamine and sulfadiazine

Primary nervous system lymphoma

B cell lymphoma that can appear radiologically similar to toxoplasmosis

Tx primary nervous system lymphoma

steroids and radiation therapy

Pathogen African sleeping sickness

Trypanosoma brucei

Cysticerosis

caused by ingestion of the eggs of the pork tapework Taenua solium; organism migrates through the bloodstream to the whole body forming multiple cysts in the muscles, eyes, and CNS

Sx Cysticerosis

Seizures, headache, nausea, vomiting, lymphocytic meningitis, focal deficits, hydrocephalus

Tx Cysticerosis

albendazole

Mucormycosis

Potentially fatal fungal infection that occurs mainly in diabetics in the rhinocerebral form and involves the orbital apex

Rhinocerebral mucormycosis

causes opthalmoplegia, facial numbness, visual loss, facial weakness; typical violet coloration of the tips of the eyelids

Tx mucormycosis

Amphotercin C; steroids should be avoided

Prion related illnesses

infectious agents that are protein-based contains no DNA or RNA
Pathologically diffuse degeneration of the brain and spinal cord occurs, with multiple vaculoes results in a spongiform appearance

Examples prion related illness

Creutzfeldt-Jakob disease, Gerstmann-Strauessler-Scheinker disease, kuru, and fatal familial insomnia

Creutzfeldt-Jakob Disease

presents with rapidly progressive dementia, an exaggerated startle response, myoclonus, visual distortions or hallucinations, and ataxia; MRI shows periodic sharp wave complexes and CSF shows increased 14-3-3 protein; no treatment available; may have been caused by ingestion of cattle infected with bovine spongiform encephalopathy

What should you do before performing a lumbar puncture?

Perform head CT to avoid risk of herniation

Normal CSF pressure in adults

less than 20 cm H2O

Ending spinal cord in adults

L1/L2

Loation of Lumbar puncture

between L4/L5; posterior iliac crest = landmark

Indication of RBCs are present in CSF

hemorrhagic encephalitis

Traumatic tap

damage to blood vessels caused by spinal needle at the time of the lumbar puncture

Presence of xanthochromic supernatant in CSF

indication that the hemorrhage is older

Pterion

region over the temporal where the frontal, parietal, temporal and sphenoid bones meet

Pterional craniotomy

provides access to the inferiortemporal lobes; used for surgey on anterior circulation and basilar tip aneurysms, the cavernous sinus, and suprasellar tumors

Temporal craniotomy

a more lateral approach; used for operating on the temporal lobe to resect seizure foci and for decompression of most intracranial hematomas

Frontal craniotomy

used for frontal lobe lesions such as tumors

Suboccipital craniotomy

access to posterior fossa stuctures such as cerebellopontine angle, vertebral artery, brainstem, and lower cranial nerves

transspenoidal approach

pituitary region reached through nasal passages

sterotactic procedures

an instrument is introduced through a small burr hole and directed to a specific target within the deep brain

Sx: Lt hemiparesis and Lt Babinski sign, Visual and tactile extinction(form of hemineglect) on the Lt, Rt sided headaches, Generalized fatigue All gradually worsening following a car crash 3 mos ago

Right hemisphere cortical and or subcortical lesion affecting corticospinal and attentional pathways. Gradual worsening suggests chronic subdural hematoma(crescent shape on MRI) (2-3 weeks for hematoma to become hyp0dense, acute=hyperdense) midline shift seen with mild subfalcine herniation. Treated by surgical evacuation.

Sx: Unresponsiveness except to painful stimuli, Abscent Rt corneal reflex, and no Rt arm or leg movement in response to pain, with plantar response absent on the Rt and upgoing on the Lt. Drunk at the bottom of stairs

Alcohol can skew neuro exams but it should get better with time, if not imaging done immediately. Most likely epidural hematoma, acute subdural hematoma, cerebral contusion or cerebral edema. Coup Contrecoup-blow to one side of the head is accompanied by decelration ninjury on the opposite side of the brain as it bangs against the inner surface of the skull; frontal and temporal poles especially susceptible to contusion. Midline shift seen at the level of the pineal calcification(>10mm shift is usually assc with profound coma.) Also had early Lt uncal transtentorial herniation. basal cisterns at near complete effacement. Lt lat ventricle and culci completely obliterated. Lt hemispheres swollen and somewhat hypodense, consistent with diffuse cerebral edema.