CNS infections

Question 1

def. of empyema

Answer 1

accumulation of pus within a space of cavity (ie epidural space = epidural empyema)

Question 2

def. of abscess

Answer 2

localized collections of pus

Question 3

meningitis/leptomenigitis definition

Answer 3

inflammation of the pia and arachnoid in the subarachnoid space

Question 4

def. of encephalitis

Answer 4

inflammation of brain parenchyma

Question 5

def. of myelitis

Answer 5

inflammation of spinal cord parenchyma

Question 6

def. of radiculitis

Answer 6

inflamm. of nerve roots

Question 7

def. of neuritis

Answer 7

inflamm. of peripheral nerve

Question 8

def. of encephalomyeltitis

Answer 8

generalized inflammation of brain and spinal cord

Question 9

def. of ependymitis

Answer 9

inflamm. of ventricles

Question 10

reactive leptomeningitis

Answer 10

response in the leptomeninges (subarachnoid space) due to infection in OTHER location (ie epiduarl, subdural spaces)… thus you have the changes in cell count, protein level, and pressure but will NOT find any organisms

Question 11

CNS response to bacteria, fungi, and viruses

Answer 11

bacteria = purulent reactions with polymorphonuclear leukocytes and necrosis
fungi = granulomatous inflammation
viruses = lymphocytis response (and occasionally myelin breakdown via allergic response)

Question 12

E. Coli in meningitis (g stain and group effected)

Answer 12

neonates most vulnerable (G neg rods)

Question 13

Neisseria Meningitides in meningitis

Answer 13

adolescents and young adults (COLLEGE DORMS!)

(G neg diplococci)

Question 14

Strep. pneumoniae in meningitis

Answer 14

elderly, children, infants (G pos diplococci)

Question 15

group B strep (aka step. agalactiae) in meningitis

Answer 15

neonates (G pos cocci with Lancefield antigen B)

Question 16

Listeria monocytogenes in meningitis

Answer 16

elderly aka immunocompromised (G pos rods)

Question 17

What are the 3 main categories of meningitis?

Answer 17

1) acute pyogenic (usually bacterial)
2) acute lymphocytic aka aseptic meningitis (usually viral)
3) chronic (fungi, TB, and syphilis)

Question 18

Acute pyogenic meningitis characterisics

Answer 18

Purulent exudate in subarachnoid space and along vessels, includes neutrophils and bacteria

Question 19

acute lymphocytic meningitis

Answer 19

increase in lymphocytes (aka mononuclear cells aka B/T cells)

Question 20

Chronic meningitis causes

Answer 20

Caused by:
fungi (candidiasis, cryptococcosis)
tubercle bacillus (TB)
T. pallidum (syphilis)

Question 21

CSF changes characteristic of each of the 3 types of meningitis (pressure, glucose, and cells found)

Answer 21

Acute pyogenic = increased pressure, DECREASED glucose, and thousands of neutrophils ***CSF can actually appear cloudy, is normally clear

acute lymphocytic = normal/mild increase in pressure, NORMAL glucose, hundreds of mononuclear cells

chronic = increased pressure, sometimes decreased glucose, hundreds of mononuclear cells

Question 22

Most common form of virus causing encephalitis

Answer 22

herpes simplex virus 1.

acyclovir is the treatment!

unique among other viruses causing encephalitis because there are often RBCs in the CSF

Question 23

Rabies virus in CNS

Answer 23

enters peripheral nerve, goes retrograde to CNS

Negri bodies often found in hippocampal pyramidal neurons

Question 24

Varicella zoster virus (VZV) aka herpes zoster in CNS

Answer 24

causes chickenpox in primary infection and establishes a latent infection in DRG or trigeminal ganglia.

Manifests a 2nd infection in a dermatomal distribution

in immunosuppressed, can cause encephalitis or myelitis

Question 25

Cytomegalovirus in CNS

Answer 25

affects fetuses (part of TORCHES) or immunosuppressed. CMV is common opportunistic pathogen in AIDS patients*

Question 26

Fungal infection patterns in CNS (3 of em)

Answer 26

1) chronic meningitis
2) vasculitis
3) parenchymal invasion (most commonly via Candida and Cryptococus)

Question 27

Toxoplasma gondii in CNS

Answer 27

• from cat shit
• typically causes a ring-shaped lesion in brain
• common in patients who are immunocompromised

Question 28

intracerebral abscesses (commonly bugs and their effects)

Answer 28

strep and staph are most common (fungi in immunocompromised)

resulst in a zone of fibrous tissue

seizures occur in 50% of cases

Question 29

what are the 3 types of tertiary neurosyphilis?

Answer 29

1) meningovasculitis - mimics a stroke (via occlusion)
2) General paresis - spirochetes found in brain tissue… mental changes, progressing to dementia, headache
3) Tabes Dorsalis - Loss of axons/myelin in dorsal roots with wallerian degeneration of dorsal columns
- causes “lightning pains”, sensory deficits, argyll-robertson pupils (react to accomodation but not to light)

Question 30

HIV-related CNS probs

Answer 30

50-70% develop AIDS-related cognitive-motor complex

primary: HIV-associated dementia & vacuolar myelopathy (swelling of myelin sheaths in dorsal and lateral columns thus MVP, CST probs)
secondary: CMV, cryptococcus, and toxoplasma infection & Progressive multifocal leukoencephalopaty (PML)

Question 31

progressive multifocal leukoencephalopathy (PML)

Answer 31

• occurs in immunosuppressed
• slowly progressing encephalitis due to altered virus
• caused by JC polyomavirus
• intellectual decline and dementia, death within 2-6months
• inclusion bodies in oligodendroglia nuclei

Question 32

Subacute sclerosing panencephalitis

Answer 32

slowly (years) progressive encephalitis associated with altered measles virus

• onset between 5-20 years old
• personality changes, intellectual decline, seizures, limb spasticity
• elevated IgG, antibody titer against measles elevated!*

perivascular cuffing by lymphocytes and plasma cells

death usually within several years