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Flashcards in CNS Deck (56):
1

Pseudotumor cerebri

• Increased intracranial pressure due to decreased CSF reabsorption

• Papilledema, headache, vision change

• Risk factors: hypothyroidism, Cushing's, OCPs, isotretinoin, tamoxifen

• Flattening of posterior globe on MRI

2

Subfalcine cerebral herniation

• Cingulate gyrus herniates under falx cerebri

• Confusion and drowsiness; possible contralateral LE weakness and urinary incontinence w/ ACA compression

3

Uncal cerebral herniation

• Medial temporal lobe herniates thru tentorium cerebelli

• Midbrain compression (Duret hemorrhages)

• CN 3 compression (down-and-out eye deviation), pupil dilation

• PCA compression (occipital lobe infarct, visual disturbance)

• Hemiparesis ipsilateral to mass

4

Tonsillar cerebral herniation

• Cerebellar tonsils herniate into foramen magnum ("coning")

• Cardiorespiratory arrest

5

Hydrocephalus

• Increased CSF volume —> ventricular enlargement

• Noncommunicating hydrocephalus may be caused by pineal gland tumor or aqueduct of Sylvius (b/w 3rd and 4th ventricles) blockage

• Communicating hydrocephalus: can result from dural venous sinus thrombosis

• Increased head circumference in newborns

• Hydrocephalus ex vacuo: ventricular enlargement w/ Alzheimer's-related cerebral atrophy

• Normal pressure hydrocephalus: wide-based gait, urinary incontinence, dementia

• Causes: prior trauma/surgery, prior subarachnoid hemorrhage

6

Arnold-Chiari malformation

• Caudal extension of medulla and cerebellar vermis thru foramen magnum

• Noncommunicating hydrocephalus

• Platybasia (flattened base of skull)

• Associated w/ meningomyelocele, syringomyelia

7

Dandy-Walker malformation

• Partial or complete absence of cerebellar vermis

• Cystic dilation of 4th ventricle '

• Noncommunicating hydrocephalus

8

Syringomyelia

• Sx starting in 20s-30s

• Syrinx (fluid-filled cavity) w/in cervical spinal cord expands and causes degeneration of spinal tracts

• Associated w/ Arnold-Chiari malformation

• Disruption of spinothalamic tracts (pain and temp loss in "cape-like" distribution)

• Disruption of anterior horn cells (atrophy of intrinsic muscles of hand)

• Disruption of ANS

• Charcot joint

9

Neurofibromatosis

• Autosomal dominant

• Mutation on chr 17 (neurofibromin) or 22 (merlin), both tumor suppressors

• Both types: café-au-lait spots, pigmented cutaneous/subQ neurofibromas (except palms and soles)

• Type 1: Lisch nodules (pigmented hamartoma of iris), axillary/inguinal freckling, pigmented plexiform neurofibromas, pheochromocytoma, Wilms tumor (both w/ HTN), CML

• Type 2: bilateral acoustic neuromas, meningiomas, spinal schwannomas, juvenile cataracts

10

Tuberous sclerosis

• Autosomal dominant

• Mental retardation, seizures in infancy

• Angiofibromas on face, shagreen patches/ash leaf spots (Wood lamp), nail fibromas

• Neuroectoderm abnormalities —> "tubers" in cerebral CTX

• Subependymal giant cell astrocytomas ("candlestick drippings" in ventricles), angiomyolipoma of kidney, rhabdomyoma of heart

11

Sturge-Weber syndrome

• Vascular malformation of face (trigeminal nerve distribution)

• Ipsilateral AV malformation in meninges

• Unilateral "port wine stain" on face

12

Acute epidural hematoma

• Middle meningeal artery bleed creates blood-filled space b/w bone and dura

• Temporoparietal bone Fx

• May have period of lucidity before neuro degeneration

• Often fatal

13

Subdural hematoma

• Bridging veins b/w brain and dural sinus bleed b/w dura and arachnoid membrane

• Slowly enlarging blood clot covers brain

• Sx may emerge over months: HA, contralateral weakness, seizures, etc.

14

Atherosclerotic stroke

• Majority preceded by TIA

• Pale infarct (no reperfusion)

• Edema, loss of gray-white differentiation, myelin breakdown

• 3-10 day: liquefactive necrosis —> cystic change

• MCA: contralateral hemiparesis and sensory loss in face and upper extremity; expressive aphasia; visual field defect

• ACA: contralateral hemiparesis and sensory loss in lower extremity

• Vertebrobasilar arterial system: deafness, vertigo, ataxia, ipsilateral sensory loss in face, contralateral in trunk and limbs

15

Embolic stroke

• Most emboli from L heart (mural thrombus, A fib)

• MCA

• Hemorrhagic infarct (reperfusion)

16

Intracerebral hemorrhage

• HTN

• Abrupt Sx onset

• Lenticulostriate branches develop Charcot-Bouchard microaneurysms that rupture

• Basal ganglia/thalamus, pons, cerebellum

• Slit hemorrhages (resorbed blood from small vessels)

• Lobar ICH: white matter hemorrhage suggestive of amyloid angiopathy, vascular malformation, coagulopathy, or bleeding from tumor

17

Subarachnoid hemorrhage

• Berry aneurysm or AV malformation

• Thunderclap headache w/ nuchal rigidity

• Risk factors: epithelial stressors

• Communicating branches, most often anterior + ACA

• Blood covers surface of brain

• Xanthochromia (bilirubin makes CSF yellow)

• In survivors, rebleeding is frequent

18

Lacunar infarct

• Small cystic infarcts of parenchymal arteries or arterioles

• Risk factors: HTN, atherosclerosis

19

Meningitis

• Inflammation of pia mater

• Usu. hematogenous spread

• Seizures, focal neuro deficits, CN palsies, hearing loss, hydrocephalus

20

Multiple sclerosis

• Females 20-40 y/o

• HLA-DR2 (or others) and microbial triggers

• Type 2 and 4 hypersensitivity: TH1, TH17, CD8 T cells, and Abs vs myelin sheath and oligodendrocytes

• Episodic course

• Often begins with visual complains

• Paresthesias; loss of pain, temp, vibratory sense

• Spasticity; increased DTRs; muscle weakness; urinary incontinence

• Optic neuritis (blurry/lost vision); cerebellar ataxia; "drunken" speech; intention tremor; nystagmus; ophthalmoplegia

• Increased CSF WBCs, protein

21

Arbovirus

• Encephalitis

• Mosquitos all over US

22

Coxsackievirus

• Meningitis

• Enterovirus

23

CMV

• Encephalitis

• Neonates (vertical transmission) or AIDS patients

• Eosinophilic inclusions

24

HSV1

• Meningitis and encephalitis

• Hemorrhagic temporal lobe necrosis

25

HIV

• Encephalitis

• Slowness of thought and bradykinesis

• Microglial cells fuse to form multinucleated cells

 

26

Lymphocytic choriomeningitis

• Meningitis and encephalitis

• Mouse transmission

27

Poliovirus

• Encephalitis and spinal cord inflammation

• Destroys upper and lower motor neurons

• Muscle paralysis

28

Rabies virus

 

• ACh receptor; moves to CNS, then saliva

• Incubation period 10-90 days

• Prodrome: fever, paresthesias at wound site

• Hydrophobia

• Encephalitis: seizures, coma, death

• Eosinophilic inclusions called Negri bodies

29

Progressive multifocal leukoencephalopathy

• Slow encephalitis

• AIDS patients

• Papovavirus (JC virus)

• Scattered demyelination foci

• "Ground-glass" inclusions in oligodendrocytes

30

Subacute sclerosing panencephalitis

• Slow, fatal encephalitis

• Rubeola (measles) virus

• Inclusions in neurons and oligodendrocytes

31

Bacteria that cause neonatal meningitis

• Group B strep (Gram+ coccus)

• E. coli (Gram- rod)

• Listeria monocytogenes (Gram+ rod with tumbling motility; cheese and hot dogs)

32

Bacteria that cause meningitis

• Neisseria meningitidis (Gram- diplococcus); children; may show petechial rash

• Strep pneumoniae (Gram+ diplococcus); high incidence w/ basilar skull Fx

• Mycobacterium tuberculosis (complication of primary tuberculosis); involves base of brain; tuberculomas w/ caseous necrosis; may also cause Pott disease (in spine)

• T. pallidum (Gram- spirochete); multiple small infarcts; may also cause tabes dorsalis (loss of joint position sense and fine touch); late recurrence may cause dementia with "wind-blown appearance" of cortical neurons and "rod cells" (iron-encrusted microglia)

33

Fungi that cause meningitis

• Cryptococcus neoformans (immunocompromised; budding yeasts visible w/ India ink)

• Mucor species (frontal lobe abscess; diabetic ketoacidosis)

• Coccidiodes immitis (Southwest US; refractile endosporulating spherule)

34

Parasites that cause CNS infections

• Naegleria fowleri (amoeba from freshwater lakes; frontal lobes)

• Trypanosoma brucei (hemoflagellate from tsetse fly; Winterbottom sign [post cerv lymph]; somnolence, cyclical fever)

• Taenia solium (helminth; pigs; eggs invade brain)

• Toxoplasma gondii (sporozoan; AIDS pts; ring-enhancing lesions on CT; congenital —> basal ganglia calcification)

• Acanthamoeba: granulomatous encephalitis; usu. fatal

• P. falciparum: diffuse swelling, microinfarcts w/ gliosis (Dürck granulomata) or many small hemorrhages

35

Central pontine myelinolysis

• Alcoholics w/ hyponatremia

• Rapid salt correction CAUSES demyelination in basilar pons

36

Adrenoleukodystrophy

• Boys 3-10 yrs old, progresses to coma

• XLR

• Deficiency in beta-oxidation of FAs

• Cortex-sparing loss of brain myelin, adrenal insufficiency

37

Krabbe disease

• Autosomal recessive lysosomal storage disease

• Deficiency in galactocerebroside beta-galactocerebroside; accumulation of galactocerebroside

• Small brain w/ widespread myelin loss

• Large, multinucleated, histiocytic globoid cells

• Death w/in 1-2 yrs

38

Friedreich ataxia

• Autosomal recessive, Sx appear before age 25

• Frataxin deficiency (iron transport into mitochondria)

• Degeneration of dorsal root ganglia, posterior columns, sensory peripheral neurons

• Hypertrophic cardiomyopathy

• Gait ataxia, DTR loss, vibratory/proprioception loss, BLE weakness

39

Astrocytoma

• Diffuse tumors

• Adults: frontal lobe, children: cerebellum

• Diffuse pontine astrocytoma: lethal pontine tumor in young children

• Pilocytic astrocytoma: does not infiltrate; well-circumscribed; Rosenthal fibers

• Pleomorphic xanthoastrocytoma: Hx of seizures; BRAF mutation; very pleomorphic but low mitotic activity

• Subependymal giant cell astrocytoma: associated w/ tuberous sclerosis; low-grade tumor in lateral ventricle causing hydrocephalus

40

Glioblastoma

• Astrocytoma

• Hemorrhagic tumor

• Ring-enhancing areas of necrosis and cystic degradation

• Commonly cross corpus callosum ("butterfly" glioblastoma)

41

Meningioma

• Benign tumor of meningothelial cell of arachnoid membrane

• Female predominance (progesterone receptors)

• Parasagittal MC location; may appear in dural venous sinuses

• Risk factors: NF2, Hx of radiation

• Well-circumscribed, firm, tan tumor that may infiltrate bone

• Swirling mass of meningothelial cells encompass psammoma (calcified) bodies

• Common cause of new-onset focal seizures

42

Ependymoma

• Benign tumor of ependymal cells, usually in children and young adults

• Children: 4th ventricle, may produce hydrocephalus

• Adults: cauda equina

• Well-circumscribed with (pseudo-)rosettes

• Myxopapillary ependymoma: low SC of adults

• Subependymoma: adults, usu. asymptomatic but may block foramen of Monro or 4th ventricle outlet

43

Medulloblastoma

• Malignant small cell tumor of children; occasionally adults 20-45 y/o

• Cerebellum; often seeds neuraxis and invades 4th ventricle

• Desmoplastic/nodular variants: common in adults or infants, resembles lymph nodes; SHH gene

• Anaplastic/large cell variants: Wnt gene

44

Oligodendroglioma

• Benign tumor of oligodendrocytes

• Frontal lobe tumor that frequently calcifies

• Highly infiltrative but responsive to therapy

• Chromosome 1:19 translocation

• "Fried egg" appearance of cells, blood vessels in "chicken wire" pattern

• Cells cluster around neuron cell bodies or blood vessels

45

CNS lymphoma

• Majority are metastatic high-grade B-cell non-Hodgkin lymphomas

• Often AIDS and/or EBV-associated

46

Schwannoma

• Benign tumor of Schwann cells

• Acoustic neuroma: CN 8; cerebellopontine angle; NF2 association; may impinge on CN 5

47

Metachromatic leukodystrophy

• Accumulation of cerebroside in white matter and peripheral nerves

• Rusty-brown coloring with violet or blue stains

• Disease of infancy, lethal w/in several years

48

Tay-Sachs disease

• Hexosaminidase A deficiency w/ accumulation of ganglioside

• Cherry-red spot in macula, lipid droplets distent neurons

• Delayed motor development by 6 mos., death w/in 2 yrs

49

Subacute combined degeneration

• B12 deficiency (pernicious anemia)

• Degeneration of thoracic posterior spinal cord

• Burning in soles of feet, other paresthesias

• Limb weakness, defective postural sensibility, incoordination

50

Huntington's disease

• Involuntary movements, deteriorating cognitive fxn, emotional disturbances

• Frontal CTX and caudate/putamen atrophy, lateral ventricle enlargement

51

Holoprosencephaly

• Telencephalon (CTX and basal ganglia) fails to divide

• Single large ventricle

• Mildest form: arrhinencephaly (failure of olfactory nerves)

52

Choroid plexus papilloma

• Children: lateral ventricle, adults: 4th ventricle

• May disseminate via CSF

53

Atypical teratoid/rhabdoid tumor (ATRT)

• Malignant tumor of early childhood

• Differentiation along multiple different cell lines

• Often posterior fossa (cerebellum, brainstem)

• Inactivation of INI-1

54

Craniopharyngioma

• Often children

• Sella turcica region, causing endocrine and visual disturbances

• Heterogeneous tumor

• Adamantinomatous type: sheets of squamous epithelium with palisading, "stellate reticulum," "wet keratin," possible Rosenthal fibers

• Papillary: exclusively squamous epithelium

55

Germinoma

• Often involve pineal gland

• Large malignant cells + small reactive lymphocytes, may have granulomatous response

56

Hemangioblastoma

• Mainly cerebellum, can be seen in SC and brainstem

• Risk factors: von Hippel-Lindau disease

• Cystic w/ enhancing mural nodules