CNS Flashcards Preview

Micro > CNS > Flashcards

Flashcards in CNS Deck (195):
1

Bacterial causes of meningitis

Infants (2-4 mnths)

S. agalactiae,

E. coli,

L. monocytogenes,

S. pneumoniae,

N. meningitides,

H. influenzae

Pressing a PIN on a baby will give a MEAN cry

Pneumonae, INfluenza

Monocytogenes,Ecoli, aglactia, Nisseria meningitis

1

Viral meningitis also reffered to as 

Aspectic meningitis 

1

Venezuelan Equine Encephalitis Virus- type

Alphavirus

1

Non-polio Enteroviruses common types 

Enterovirus 71, Echovirus 18, Coxsackieviruses

2

Infants (2-4 mnths) Bacterial meningitis

S. agalactiae, E. coli, L. monocytogenes, S. pneumoniae, N. meningitides, H. influenzae*

2

Post splenectomy, complement deficiency

N. meningitides

2

This bacterial meningitis seen in

Infants -

– Adults >60y, alcoholics, cancer patients, renal transplant.

 

Listeria monocytogenes

2

Encephalitis CSF findings 

A image thumb
3

Rabies virus dx

– Skin biopsy: Immunohistochemical staining - Rabies Ag

– Negri bodies: Intracytoplamsic inclusions in neurons

– Corneal smears – Rabies Ag

– Rabies virus neutralizing Ab – CSF or serum (unimmunized) Direct Ab Test

3

African Sleeping Sickness

Protazoa 

African Trypanosomes

4

Vectors st. Louise vs. eastern equine

A image thumb
4

Schistosomiasis

Schistosoma species

 

Liver or bladder

brain or spinal cord vasculature

5

Haemophilus influenzae

• Clinical features

Slower onset (meningococcal meningitis), 3-4d – Follows: nasopharyngitis, sinusitis or otitis media – 1/3 survivors – neurologic sequelae

5

Predominant Demyelination imaging defect 

JC virus

6

Most common cause (Chronic meningitis)

Mycobacterium tuberculosis

6

CSF findings in Western Equine Encephalitis Virus

CSF: pleocytosis (lymphocytic), normal-↑ protein, normal glucose

6

Primary amebic memeningoencephalitis (PAM)

Ameoba implicated 

Naegleria fowleri

7

Underlying conditions related to Staphylococci

Diabetes mellitus

– Alcoholism

– Chronic renal failure (hemodialysis)

7

Dx of California Encephalitis Group

– IgM antibodies in CSF or serum

8

Listeria monocytogenes serotypes 

Serotypes: 1/2b & 4b (80% cases)

8

St. Louis Encephalitis Virus distribution 

Canada, US, Central & Southern America

8

GAE; skin or lung lesions

Amoeba implicated 

Balamuthia mandrillaris

8

Eosinophilic Meningitis

Angiostrongylus cantonensis (rat lung worm)

Gnathostoma spinigerum

9

Clinical features of Streptococcus pneumoniae

Rapid 1-2 days (or gradual)

– Impaired consciousness common

9

Subependymal enhancement imaging defect 

 CMV ventriculitis

10

Meningitis

inflammation of meninges

11

Vector-borne viruses

Togaviridae

– Flaviviridae

– Bunyaviridae

– Reoviridae

12

Multifocal haemorrhagic infarctions & demyelinating lesions imaging defect

Varicella zoster virus vasculopathy

13

Basilar skull fracture + CSF leak

Puts you at risk for this bacterial meningitis 

Streptococcus pneumoniae

13

 Diagnosis neoforms 

india ink (capsule)

14

CM1 defects (Hodgkin’s disease, steroid therapy), elderly

L. monocytogenes

14

Distribution of Venezuelan Equine Encephalitis Virus

Southern US, Central & S. America

15

Herpes simplex 1 & 2 connection to meningitis 

Post neonatal

• Important: differentiate encephalitis from meningitis

– Most common: HSV 2 • primary to genital infection

• 36% women, 13% men

16

Bacterial meningitis Neonates (0-2 mnths)

Group B Streptococci (S. agalactiae), E. coli (other Gram –ve enterics), L. monocytogenes

16

Spirocheteal meningitis... whats the bacterial cause 

Treponema pallidum

17

Slow onset (period of weeks) – ↓ Fever, lethargy – TB, Fungi & (Protozoa)

Chronic (RARE)

18

Brudzinski’s sign

Q image thumb

Look up pic Flex knees and neck

18

Sx of California Encephalitis Group

Focalneurologicdisease

– Hemiparesis, aphasia, dysarthria, chorea

19

Biology behind prions 

– Normal cellular glycoprotein: PrPc (↑ a helix, ↓ b helix)

– Infectious glycoprotein form: PrPsc (↓a helix, ↑ b helix)

21

Adults (Adolescents- >55y) Bacterial meningitis

N. meningitides, S. pneumoniae

22

Fontal, Temporal, Parietal, abscess 

Predisposing/ bacteria 

Trauma, Penetrating wound

S. aureus, Clostridia

23

Bacterial etiology of CSF shunts 

– Staphylococci (epidermidis & aureus)

– Gram negative bacteria (E. coli, Klebsiella, Proteus & Pseudomonas)

– Streptococci

– Diphtheroids (Propionibacterium acnes)

– Anaerobes

– Mixed culture

24

Temporal lobe abcess what predisposes you, what bacteria 

Otitis media, Mastoiditis

Streptococci, Bacteroides, Enterobacteriacea

26

HA-CNS infection: MRSA

• CSF shunts: S. epidermidis

• Mortality 14-77%

Staphylococci

26

Mycobacterium tuberculosis adult vs children

– Children (haematogenous disseminated tuberculosis) • Rapid

– Adults

• Indolent

27

Eastern Equine Encephalitis Virus distribution

US, Southern America, Caribbean

27

FOCAL CNS SYNDROMES

Brain Abscess

Subdural empyema

Epidural abscess

28

CSF findings in Colorado Tick Fever Virus

CSF: pleocytosis (mildly lymphocytic), normal-mildly↑ protein, normal glucose

29

Enterovirus Seasonality

Late Summer, fall

30

Yellow csf

Blood breakdown products Hyperbilirubinemia CSF protein ≥150mg/dL (1.5g/L), >100,000 RBC/mm3

30

St. Louis Encephalitis Virus- type 

Flavivirus

31

Listeria monocytogenes

• Biology:

Gram +ve rod – Virulence:

• Internalin A & B • Listeriolysin O

31

PRIONS

Infectious proteins

– No Nucleic acid genome

– Resistant: formaldehyde (3.7%), dry heat, boiling, ethanol (50%) & ionizing radiation

– Sensitive: phenol (90%), household bleach, ether, NaOH (2 N), strong detergents (10% sodium dodecyl sulfate) & autoclaving (1 hour, 121oC)

32

Alcoholism, skull fractures, myeloma, splenectomy

S. pneumoniae

32

Clinical feature of Mycobacterium tuberculosis

Rupture in subarachnoid space

33

Distribution of Japanese Encephalitis Virus

Asia, Western Pacific, Australia

34

Dx of fungal brain abscess 

CT scan

– Hypodense centre

– Peripheral uniform ring – Brain oedema

35

Fungal Meningitis lab values 

Opening pressure Variable WBC count Variable Cell differential lymphocytes Protein 50-100mg/dL Glucose

35

Comparing meningitis lab values by organism

A image thumb
35

Japanese Encephalitis Virus type

Flaviviridae

36

>50 years Bacterial meningitis

S. pneumoniae, N. meningitides, L. monocytogenes, Aerobic Gram –ves

36

Eastern Equine Encephalitis Virus- type 

 Alphavirus

37

Granulomatous Amebic Encephalitis (GAE); skin or lung lesions; amebic keratitis

Ameoba implicated 

Acanthamoeba species

38

Western Equine Encephalitis Virus- type

Alphavirus

39

Pathogenesis of CNS shunts 

– Retrograde infection

– Skin

– Haematogenous seeding

– Colonization at surgery

41

Neisseria meningitidis

• Clinical features

Distinguishing feature

Quick onset

– Acute photophobia

 

– Skin petechiae → ecchymoses/diffuse petechial rash -

DIC

42

Neisseria meningitidis

• Prevention

2005, Quadrivalent: A, C, Y & W135

– Protection: ~3y

– No protection from carriage (MPSV4-menomune)

meningococcal conjugate vaccine seen as better

43

CSF findings in Measles 

 CSF: usually normal (↑Ig level)

44

Exposure to bats, other wild animals, dog bites, developing countries

Rabies

46

Brown CSF

Meningeal melanomatosis (Metastatic Melanoma)

47

characteristics of Enteroviruses

Picornaviridae

– Naked, icosahedral, small (25-30nm), ss +ve RNA

 

Echoviruses 30, 18, 16, 11, 9, 6 & 7

• Coxsackieviruses B1, B2, B3, B4 & A9 • Enteroviruses 71 & 70

48

Meningoencephalomyelitis

infection of meninges+ brain parenchyma+spinal cord

49

Colorado Tick Fever Virus dx 

IgM by ELISA

50

Histoplasma capsulatum

• Geographic location

Ohio & Mississippi river valley, Central America

52

Distribution of Colorado Tick Fever Virus

WesternUS&Canada(Mountains)

53

NORMAL CSF VALUES

• WBC count: children & adults 0-5/mm3 (70% lymphocytes, 30% monocytes) neonates 32/mm3 • RBC count: None • [Glucose]: ratio to serum glucose ≥60% 40-70mg/dL not >300mg/dL • [Protein]: adults 18-58mg/dL (by 6-12 mnths old) newborn 150mg/dL

54

Brain abscess in the frontal lobe- what predisposes, and what organisms 

Sinusitis, Dental abscess

 

Streptococci, Bacteroides, S. aureus, Haemophilus spp.

55

Abscess

localised infection in spinal cord or brain – Acute/Chronic Brain Abscess – Empyema – epidural or subepidural abscess

55

Lymphocytic choriomeningitis virus

Rare

– Contact with rodents & excreta (hamsters, rats, mice)

• Lab workers, pet owners, unhygienic housing conditions

57

Encephalitis –

inflammation of the brain parenchyma

58

Herpes viruses implicated in meningitis 

HSV, VZV, CMV, EB virus & HHV -6, 7, 8

60

Most common fungal cause of meningitis 

Cryptococcus neoformans (Cryptococcus gattii)

62

Rickettsia (RMSF) Seasonality

Late Summer & Spring

63

Herpesviruses Clinical features

 

 Incubation period uncertain • Rapid onset – several days

– Fever (90-100%)

– Altered consciousness (97-100%) – Headache (70-81%)

64

CSF findings in California Encephalitis Group

CSF: pleocytosis (lymphocytic), ↑ protein, normal glucose

65

THis bacteria Uncommon, seen in Early postneurosurgical/post-trauma

Staphylococci

66

Eastern Equine Encephalitis Virus CSF/MRI findings

CSF: pleocytosis (neutrophil predominance (2/3)), ↑ protein, norm glucose, RBC’s common

– MRI: thalamus, basal ganglia, brain stem

67

THis bacteria 

 Group B Strep

• Most common: neonates (52% cases, US) • Mortalityrate:7-27%

Streptococcus agalactiae

69

Who is most at risk for encephalitis when infected with st. louise 

>60

71

Blastomyces mostly presents with

Brain abscess

72

Temporal lobe & limbic imaging problem

HSV & HHV-6 encephalitis

72

Difference between Subdural empyema and epidural abcess 

Epidural abcess- MRI pachymeningeal enhancement, superficial area of diminished intensity

 

73

Pink CSF

Blood breakdown products

73

Haemophilus influenzae

• Human carriage

80% children, 20-50% adults (URT) – Unencapsulated

73

Coccidioides dx 

Eosinophils (CSF) Wright-Giemsa Stain

– Complement fixation test

74

sub acute sclerosing panencephalitis seen in 

Measles 

75

Western Equine Encephalitis Virus dx 

 WEE IgM antibodies in CSF or serum

77

CSF/MRI findings in Japanese Encephalitis Virus

CSF: pleocytosis (lymphocytic), mildly↑ protein, normal glucose

– MRI: normal

78

California Encephalitis Group- type 

Bunyaviridae

80

Green CSF

Hyperbilirubinemia Purulent CSF

80

Colorado Tick Fever Virus type

Reoviridae

82

Rare cases protazoa affecting CNS 

Free-living ameba

84

Streptococcus pneumoniae characteristics 

Non-motile, Gram +ve diplococci – Virulence:

• Capsule

– (18 serogroups, 82% pneumonia = meningitis)

• IgA protease

• Pneumolysin (cytotoxin)

85

Tubercular Meningitis lab values 

Opening pressure Variable WBC count Variable Cell differential Mostly lymphocytes (10–500 cells/ml) Protein 10-500mg/dL Glucose 20-40mg/dL

86

Enteroviruses epidemiology

85-95% all cases

• Age: Infants & Young children

– no previous exposure & immunity

• Adults(common)

• Geographic consideration - Worldwide distribution

• Seasonal consideration:

– Temperate climate: summer/fall (water) – Tropical: year round (faecal-oral)

88

Associated with congenital defects and AIDS

Protazoa affecting CNS 

Toxoplasma gondii

89

Bacterial Meningitis Lab values 

Opening pressure Elevated WBC count ≥1,000/mm3 Cell differential Neutrophils 90% (>100cells/ml) Protein 100-500 mg/dL Glucose 0-10mg/dL

90

US: Most common epidemic

West Nile Virus

92

Rabies tx 

– Postexposure prophylaxis

– Wash wounds: soap & water + providone-iodine

– Vaccine

– Human rabies immunoglobulin (HRIG)

93

• Direct spread CNS

Trauma or injury

– Most common: Staphylococcus aureus

– Immunodeficient/HIV: Nocardia, Aspergillus, Candida

94

Orange CSF

Blood breakdown products Xanthochromia

95

Treponema pallidum known to cause 

Clinical neurosyphilis

 

 Syphilitic meningitis (0.3-2.4% untreated cases) – Meningovascular syphilis

– Parenchymatous neurosyphilis

– Gummatous neurosyphilis (rare)

96

CSF findings in Venezuelan Equine Encephalitis Virus

pleocytosis (lymphocytic), ↑ protein, normal-↑ glucose

97

Etiology of subdural empyema 

– Streptococci (25-45%)

– Staphylococci (10-15%)

– Enterobacteriacea (3-10%) – Anaerobic bacteria (33%) – Polymicrobial

99

Candida found in 

– Neonatal ICU (use of IV catheters)

Postneurosurgery

– Immunosuppressed

100

Haemophilus influenzae

• Biology characteristics 

Non-motile, Gram –ve rods – Fastidious

• NADP (V) & Haematin (X), (Chocolate agar) – Virulence:

• Capsule (polyribitol phosphate) • Pili

• LPS

102

Types of Facultative anerobe bacteria 

Klebsiella, E. coli, S. marcescens, P. aeruginosa

 

Neontates: E. coli K1

Pregnant women carry this in their rectum

103

West Nile Virus dx 

ELISA 

104

Cysticercosis

Taenia solium (pork tape worm)

Muscle and brain

106

West nile sx 

60 years of age) – Brain parenchymal involvement

– CSF: pleocytosis, ↑ protein, normal glucose

– MRI: thalamus, basal ganglia, brain stem

• Poliomyelitis-like (acute flaccid paralysis)

– Motor neuron injury (anterior horn of spinal cord) – Brain parenchymal involvement

108

Most common: sporadic encephalitis

Herpesviruses

109

Routes of infections CNS

Direct Heamatogenous Neural tissue

111

Arboviruses (Arthropod-borne)

– Mainly encephalitis

113

Cerebral Malaria

Protazoa 

Plasmodium falciparum

114

St. Louis Encephalitis Virus findings in csf/ mri

CSF: pleocytosis, ↑ protein, normal glucose

– MRI: normal, or substantia nigra

115

Neural tissue (rare)

Human Herpesvirus 1-3 – Rabies: peripheral→nerve axons→ganglia & spinal cord→brain

117

PRevention of polio

– 3 strains of Polio (1, 2 & 3)

– 4 Vaccines available

– Inactivated Polio Vaccine (IPV) - Salk

– Live Oral Polio Vaccine (OPV) - Sabin • Monovalent (mOPV1 & mOPV3)

• Bivalent (bOPV)

119

Most higher cortical function deficits.

• Progress over weeks-months: profound dementia (memory loss, impaired judgment, intellectual function

Creutzfeldt-Jakob disease

120

Immunocompromised (allogenic bone marrow transplants) herpes type 

HSV 6

122

Pathogenesis of rabies 

A image thumb
123

Multiple lobes brain abscess what predisposes you and organisms 

Infective endocarditis, Congenital Heart Disease, Lung abscess

S. aureus, Streptococci (viridans), Fusibacteria, Nocardia

125

TESTS FOR MENINGISM

Inability to flex neck (chin to chest) • Inability to oppose nose with knee • Tripod sign: Inability to sit up without using hands • Kernig’s sign • Brudzinski’s sign

126

Head trauma/neurosurgery put you at risk for these bacterial meningitis 

Facultative anerobe bacteria 

128

St. Louis Encephalitis Virus dx 

Anti-SLEV IgM antibodies in serum or CSF

129

What is the human carriage of strep pneumonia 

throat & nasopharynx

130

Primary amoeba affecting CNS 

Entamoeba histolytica

131

CSF normal pressure

Normal pressure: 70-180 mm H2O

132

Dx of Venezuelan Equine Encephalitis Virus

VEE IgM antibodies in CSF or serum

133

Bacterial causes of meningitis

Neonates (0-2 mnths)

Group B Streptococci (S. agalactiae),

E. coli (other Gram –ve enterics),

L. monocytogenes

 

ALE

134

Bacterial meningitis can be seen in Lyme

disease whats the bacteria

Borrelia burgdorferi

135

Polio virus transmission

Faecal-oral

136

Dx of Japanese Encephalitis Virus

– IgM antibodies in CSF by ELISA

– PCR

138

Eastern Equine Encephalitis Virus dx 

EEE IgM antibodies in CSF by ELISA

139

CSF shunts

S. aureus

140

Bacterial causes of meningitis 

Adults (Adolescents - >55y)

N. meningitides,

S. pneumoniae

141

Human carriage (5-30% healthy individuals, URT) 

Neisseria meningitidis

 Higher in military recruit camps, schools

142

Immunocompetent adults herpes type 

HSV 1

143

Onset: hours-several days • Life-threatening • Meningism: Fever, Headache, Nuchal rigidity, Nausea & Vomiting, Photophobia • Altered mental status

Acute

144

ENCEPHALITIS

Inflammation of the brain parenchyma

145

Haematogenous dissemination cns

Respiratory tract infection: N. meningitidis – Insect bite: West Nile Virus – Transplacental: Rubella

146

Listeria monocytogenes

• Clinical features:

Subclinical-gastrointestinal like

– Neonatal

– Immunocompromised

147

Routine Tests for CSF

WBC count with differential RBC count [Glucose] [Protein] Gram stain/ India stain Bacterial culture/ Fungal culture

148

Neisseria meningitidis

• Biology characteristics 

– Non-motile, Gram -ve diplococci

(kidney-bean shaped) – Fastidious

• 5-10% CO2, (Chocolate agar, Modified Martin-Thayer agar) – Virulence:

• Capsule (serogroups A, B, C, X, Y & W-135) • IgA protease

• Pili

• LOS

149

Increased Risk Factors csf shunt infections 

– Premature birth

– Previous shunt infection

– Cause of hydrocephalus

– Length of the shunt procedure

– Shunt revision

150

Bacterial causes of meningitis 

>50 years

S. pneumoniae,

N. meningitides,

L. monocytogenes, 

Falcultative anerobes 

152

Polio endemic 

Endemic: Afghanistan, Pakistan, & Nigeria (Somalia, Ethiopia, Kenya, South Sudan & Cameroon)

153

Haemophilus influenzae

why has its rates dropped compared to previous years 

Present: 7% cases (conjugate Hib vaccine @ 2 mnths/age)

155

Q image thumb

MRI Fungal abscess in brain 

Interhemispheric fissure 

156

Alcoholism, post splenectomy, hypogammaglobulinemia

H. influenzae

157

This bacteria 15-35%

asymptomatic pregnant women

Streptococcus agalactiae

158

Myelitis

infection of spinal cord

159

Tick bite

Lyme disease

161

Fungal causes CHRONIC MENINGITIS

Cryptococcus

Histoplasma

162

California Encephalitis Group distribution

CEV, La Crosse & Jamestown – US; Tahyna - Russia

La Crosse: Mississippi & Ohio river basins

164

DIAGNOSTIC TESTS for encephalitis 

Neuroimaging

– All patients MRI

– Distinctive patterns of abnormalities

 

165

Western Equine Encephalitis Virus distribution

Western US, Western Canada, S. America

166

Bacterial meningitis Most common: children & young adults

Neisseria meningitidis

168

Polio clinical features 

– Inapparent-mild 90% cases

– Non-paralytic: Meningitis 8% cases (self-limiting)

– Paralytic disease 1% cases

– Polio encephalitis: Rare

– Incubation 1-2 wks

– Infection & death anterior horn cells (grey matter)

169

CDC PEP Recommendations of rabies 

– Wash all wounds with soap and water

– 1 dose of HRIG & 4 doses of vaccine (Days 1, 3, 7 & 14 + 2 boosters on Day 0 and 3)

170

Bacterial causes of meningitis 

4-6 mnths

N. meningitides,

S. pneumoniae,

H. influenzae

171

OVerv view of sx for viral meningitis 

Usually acute benign, self-limiting, monophasic

– Symptoms: cranial neuropathy & raised intracranial pressure uncommon

172

Histoplasma capsulatum seen in 

Immunosuppressed

– AIDS

– Solid organ transplants

173

Monkey handlers or monkey bite

Herpes B encephalitis

174

West Nile Virus- what type of virus 

Flavivirus

175

Most frequently observed  cause of bacterial meningitis (61% total cases, US)

Streptococcus pneumoniae

176

Lymphocytic choriomeningitis Seasonality

Winter

177

Coccidioides spp

• Geographic location

Central & Southern Arizona + Central Valley of California

178

4-6 mnths Bacterial meningitis

N. meningitides, S. pneumoniae, H. influenzae*

179

– Increased lymphocytes – Self limiting – Viral or non infectious (Absence of cultivable bacteria or fungi)

Aseptic (acute)

180

Kernig’s sign

Look up pic Elevate legs

 

 

A image thumb
181

Cryptococcus neoformans seen in 

Immunosupressed & previously infected healthy

182

Overcrowding

Meningococcal meningitis

183

Rabies virus type 

Rhabdoviridae

184

Transmission of prion dz

– Sporadic: CJD (85% cases), 50-75 year olds

– Inherited: GSS, FFI (10-15%)

– Ingested: Kuru (mostly disappeared)

– Iatrogenic: corneal transplants, contaminated EEG implants, possibly contaminated human growth factor

185

AIDS, other CM1 defects

C. neoformans

186

Hydatid Disease

Echinococcus species

Liver (75%) and lungs (15%) brain parenchyma

187

Paragonimiasis

Paragonimus

Lungs

188

Coccidioides spp seen in

CA-pneumonia,

Immunosuppressed individuals (AIDS)

189

Dx of polio 

– CSF: PMN early→lymphocytes, ↑protein, normal

glucose

– CSF: RT-PCR

190

• Most common VIRAL CAUSES of meningitis 

: Enteroviruses

191

Haemophilus influenzae Prevention:

 Vaccine: Hiberix

Uncapsulated are becoming a problem... can not use current drugs against them 

192

Histoplasma capsulatum Dx

– Histoplasma antigen

(CSF) – Cultures -ve

193

Rare invasion of the brain

Protazoa implicated

Entamoeba histolytica

194

Nipah Virus encephalitis

Malaysia

195

Eastern equine virus transmission cycle

A image thumb