Infect Disease CNS

Question 1

What are the mechanisms by which infectious diseases enter the CNS?

Answer 1

Hematogenous

Direct implantation

Local extension from adjacent site of infections

Axoplasmic transport along peripheral nerve axons

Question 2

What causes pyogenic or granulamatous meningitis?

Answer 2

Most yeast forms and bacteria

Question 3

What causes abscess formaotin in the brain?

Answer 3

Bacteria and hyphal forms

Question 4

What causes cerebritis?

Answer 4

Hyphal forms

Question 5

What causes aseptic meningitis?

Answer 5

Viruses

Question 6

What causes aseptic meningitis?

Answer 6

Viruses

Question 7

What is the most common form of infection in the CNS?

Answer 7

Bacterial

Question 8

What types of mycoses and parasites hits immunocompromised patients?

Answer 8

Fungal: Asperigillus, Cryptococcus, Candida
Parasiteic: Toxoplasma

Question 9

What are parenchymal infections?

Answer 9

Cerebritis
Abscess
Encephalitis
Myelitis(meninges)

Question 10

What are peripheral nerve disease?

Answer 10

Radiculitis/neuritis

Question 11

What are findings of pyogenic meningitis?

Answer 11

CSF:
High PMN
High Protein
Low glucose

Clinical symptoms:
HA
Alter Mental Status
Increased ICP
Seizures

Question 12

What is the most common cause of meningitis in NEONATES, YOUNG CHILDREN, Older children

Answer 12

Neonates:
Group B Strep
E. coli
Listeria

Young children:
N. Meningitis
Strep Pneumo
Haemophilus influ

Adults:
Strep pneumo
Neisseeria mening

Question 13

What is seen grossly with meningitis?

Answer 13

Cloudy meninges

Question 14

Where is the exudate located in meningitis?

Answer 14

Leptomeninges

Question 15

What are some complications of meningitsi?

Answer 15

Infarcts

Chronic hydrocephalus

Question 16

What is lymphocytic meningitis?

Answer 16

Aseptic meningitis

• Self limited usually
• Viral

CSF:

• Lymphocytes
• Moderately high Protein
• Normal glucose

Etiology:

• Echovirus
• Coxsackie virus

Question 17

What is chronic meningitis?

Answer 17

Granulomatous

Question 18

What is the etiology of chronic meningitis?

Answer 18

Mycobac

Yeast forms of fungi

• Crypto (little inflammation)
• Coccidio, blastomycoses

Base of Brain

Can cause OBLITERATIVE ENDARTERITIS, infarct on underside of brain

Question 19

What is a problem with cerebritis and abscess?

Answer 19

Infection/abscess leads to liquefactive necrosis

-Ring enhancing lesion

Granulation tissue that has fibroblasts and collagen deposition

Question 20

What are common fungi and bacterial that cause cerebritis and abscess?

Answer 20

Bac: anaerobic strep, strep pneumo, Staph

Fungal: asperigillus, mucor, candida

Less common are protozola: Toxoplasma

Question 21

What is the etiology of direct spread cerebritis?

Answer 21

50%

Strep, Staph, bacterioides, actinomyces, gram neg bacilli

Question 22

What is the etiology of cerebritis from hematogenous spread?

Answer 22

25%

Congenital heart disease, immunodef, iatrogenic

Question 23

Where are the locations for abscess/cerebritis?

Answer 23

Frontal»»parietal>cerebelum

Question 24

What is often associated with aspergillus cerebritis?

Answer 24

Hemorrhagic infarcts

Question 25

What is seen in a chronic abscess?

Answer 25

A ring of collagen in granulation tissue at border of trichrome stain

Question 26

What can be seen with candida septicemia in the brain?

Answer 26

Many many little abscess throughout brain

Question 27

What is the most common cause of encephalitis?

Answer 27

Viruses Inflammation of brain parenchyma Arthropod born (mos or tick) Epidemic viral Nonspeecfici path findings (viral inclusions?) Associated with viral meningitis

Question 28

What is seen in vrial encephalitis?

Answer 28

Perivascular inflammation Microglial nodules Neurophagia

Question 29

What are some specific types of encephalitis?

Answer 29

Poliomyelitis Rabies: Negri inclusion bodies Herpes Group: HSV, CMV, ZOSTER -HSV 1 is most cocmmon HIV Encephalitis Progressive multifocal Leukoencephalopathy JC virus

Question 30

What is seen in HSV 1 encephalitis?

Answer 30

Most often hits temporal lobe Hemorrhagic, necrotizing INCLUSIONS: COWDRY type A (also CMV)

Question 31

What is HIV encephalitis?

Answer 31

Microglial nodules and multinucleated giant cells around vessels Chronic patchy inflammation

Question 32

What is seen in PML?

Answer 32

Loss of myelin LFB shows areas of myelin that are lost See bizaare atypical astrocytes Intranuclear inclusion in oligos

Question 33

What is seen in PML?

Answer 33

Loss of myelin LFB shows areas of myelin that are lost See bizaare atypical astrocytes Intranuclear inclusion in oligos

Question 34

What is seen in toxoplasma?

Answer 34

Enhancing lesion Bradyzoite (encysted form of parasite)

Question 35

What is spongiform encephalopathy?

Answer 35

It is transmitted by prions (little proteins) CJD, Mad cow, Gerstmann-Straussler-Scheinker Fatal familial insomnia Kuru Scrapie Characterized by vacuoles in the gray matter

Question 36

What is the triad of symptoms for spongiform encephalopathy?

Answer 36

Rapid dementia Myoclonus Periodic short wave activity on EEG Subtle motor and cerebellar signs followed by death within 1 year

Question 37

What is the triad of symptoms for spongiform encephalopathy?

Answer 37

Rapid dementia Myoclonus Periodic short wave activity on EEG Subtle motor and cerebellar signs followed by death within 1 year

Question 38

What is creuztfeldt-jacob disease?

Answer 38

Spongiform encephalopathy Rapid dementia death within a year 1/1000000/year Majority are sporadic Rare is iatrogenic (cornea transplant, graft, eeg electrodes, HGH extracts) Transmissable agent: Protease resistant prion Normal gene on CHR 20

Question 39

What is the pathogenesis of CJD?

Answer 39

Conformational change of PrP 3D structure into B-pleated sheet Gene mutations may play a role in conversion SIngle pathogenic PrP can cause conversion of wild type proteins Homozygosity for Met or Val on codon 129 increases risk of CJD

Question 40

What are microscopic features of CJD?

Answer 40

Looks normal grossly or may have atrophy Microscopic: -Neuronal loss, gliosis, sponigform change Defined by small punched out vacuoles in gray matter