Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Head and Neck Microbiology > Neurological Infections > Flashcards

Neurological Infections Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Describe the characteristics of normal CSF?

A

> is a clear, colorless, and sterile fluid
volume ranges from 90 to 150 mL in adult
protein level 15 to 45 mg/dL and 15 to 150 mg/dL in neonates
glucose level is 40 to 80 mg/dL : (CSF glucose-to-serum glucose ratio = 0.6) and 30 to 120 mg/dL in neonates
CSF contains 0 to 7 leukocytes/μL, and 0 to 30 leukocytes/mL in neonates
Differential count of 60% to 80% lymphocytes, 10% to 40%
monocytes, and 0% to 15% neutrophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name the host factors that increase the chances of one getting meningitis?

A
  1. age, nutritional
  2. immunologic status
  3. alcoholism
  4. diabetes mellitus
  5. malignancy
  6. renal failure
  7. head trauma
  8. neurosurgical procedures
  9. IgA
  10. Complement
  11. Ig
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name the microbial factors that increase a pathogens virulence?

A
  1. Capsules
  2. Pili
  3. Fimbriae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name the organisms that cause bacterial meningitis in neonates?

A
  1. Streptococcus agalactiae (group B)
  2. Listeria monocytogenes
  3. GNBs (Escherichia coli, Klebsiella spp., Enterobacter spp)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Name the organisms that cause bacterial meningitis in infants?

A
  1. Streptococcus agalactiae (group B)
  2. Escherichia coli
  3. Haemophilus influenzae
  4. Streptococcus pneumoniae
  5. Neisseria meningitidis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Name the organisms that cause bacterial meningitis in Children (>2 Yr) and Adults?

A
  1. Streptococcus pneumoniae
  2. Neisseria meningitidis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name the organisms that cause bacterial meningitis in Older Adults (>65 Yr)?

A
  1. Streptococcus pneumoniae
  2. Neisseria meningitidis
  3. Listeria monocytogenes
  4. Aerobic gram-negative bacilli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the pathogenesis of bacterial meningitis?

A
  1. nasopharyngeal colonization by one of the meningeal pathogens
  2. local invasion across the mucosal barrier and entry into the
    bloodstream
  3. gain access to the meninges
  4. In the subarachnoid space, bacteria replicate, release bacterial components, and cause an inflammatory reaction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe hemophilus influenzae type b and what it can cause?

A

structure = gram-negative coccobacillus
> Can be encapsulated or non-encapsulated
can cause = otitis media, pneumonia, and epiglottitis
Note:
- previously the most common cause of bacterial meningitis, especially in young children.
- routine use of conjugate vaccines against H. influenzae type b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe neisseria meningitidis?

A

Structure = gram-negative diplococcus
Classification = into 12 serogroups based on antigenically distinct non–cross-reactive capsular polysaccharides
• Serogroups A, B, C, Y, and W135 account for most cases of
meningococcal disease throughout the world.
Note: Individuals deficient in terminal components of complement (C5-9)
or properdin are at a higher risk for meningococcal infections.
> A meningococcal polysaccharide vaccine containing polysaccharides A, C, Y, and W135 is available for use in individuals older than 2 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe streptococcus pneumoniae along with its risk factors?

A

Structure = gram-positive diplococcus,
Causes
In patients with a CSF leak resulting from a basilar skull fracture pneumococcus is the most likely causative agent
Risk factors
Patients with sickle cell anemia, splenectomy or asplenia,
malignancy, malnutrition, and chronic renal or liver disease are
more likely to develop serious pneumococcal disease
Vaccination
• Two vaccines widely available
• The 13-valent pneumococcal conjugate vaccine (PCV13)*
• The 23-valent vaccine (PS23), composed of 23 purified capsular
polysaccharide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe listeria monocytogenes and its risk factors?

A

gram-positive rod
• Alcoholics, neonates, older adults,
• DM, and malignancy risk factors in adults
• Vertical transmission in neonates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Name gram negative bacilli that cause meningitis?

A

E. coli
K. pneumoniae
Pseudomonas aeruginosa
Acinobacter baumannii,
Serratia spp and Salmonella spp.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What causes shunt infections?

A

In patients with hydrocephalus
• One end is in peritoneal, pleural or vascular space
• Staphylococci most common infections, followed by aerobic GNBs
Note: Candida species also implicated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe viral infections and meningitis?

A

Most common cause of aseptic meningitis
> Most common viruses are EVs and herpesviruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is viral meningitis characterised by?

A

lymphocytic pleocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe the pathogenesis of viral meningitis?

A

> Viruses colonise mucosal surfaces
replicate and invade to cause viremia.
This if followed by invasion of the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Name common enteroviruses?

A

polioviruses
coxsackieviruses A and B
echoviruses
and the newly numbered EVs
> Belong to family Picornaviridae

19
Q

How are enteroviruses acquired?

A

Acquired by fecal-oral route
> Resolve within 2-7 days

20
Q

Consequences of infection by polioviruses?

A

> Polioviruses cause aseptic meningitis but a small proportion > Patients develop destruction of motor neurons in the anterior spinal cord, resulting in paralysis

21
Q

Describe arboviruses and the consequences of its infection?

A
  • A grp of viruses transmitted by anthropod vectors such as ticks, sandflies and mosquitoes
  • these viruses cause encephalitis, but aseptic meningitis and
    meningoencephalitis can also occur
    e.g. St. Louis encephalitis (SLE) virus, La Crosse (LAC) virus, Eastern and Western equine encephalitis (WEE) virus, and West Nile virus (WNV)
    Note: Japanese encephalitis virus^ cause death in a third of patients
22
Q

Describe the mumps virus and the consequences of its infection?

A
  • a member of the Paramyxoviridae family
  • RNA virus that commonly causes parotitis
  • Aseptic meningitis is the most common neurologic complication
  • Occasionally, meningeal symptoms can precede parotitis by up to 7 days
  • Infection of the CNS is usually self-limited and associated with complete recovery
23
Q

Name the DNA viruses that cause aseptic meningitis?

A

herpes simplex viruses (HSV-1 and HSV-2),
Epstein-Barr virus (EBV),
cytomegalovirus (CMV),
varicella-zoster virus (VZV),
human herpesviruses 6, 7, and 8.

24
Q

Describe HIV and meningitis?

A

HIV = a member of the Retroviridae family
- Meningitis associated with HIV infection may occur as part of the primary infection
- Patients presenting with chronic meningitis often have other
associated symptoms, such as cranial neuropathies

25
Q

Name pathogens that cause mycobacterial infections?

A

Mycobacterium bovis
Mycobacterium avium,
Mycobacterium intracellulare
Mycobacterium kansasii
Mycobacterium fortuitum
Mycobacterium abscessus
Mycobacterium africanus

26
Q

What is the most common mycobacterial infection of the CNS and what does it cause?

A

Ttuberculous meningitis caused by Mycobacterium tuberculosis.
> The clinical presentation of tuberculous meningitis is subacute and includes fever, headache, meningismus, and mental changes

27
Q

Name the 2 spirochetes associated with CNS infection?

A

T. pallidum and B. burgdorferi

28
Q

Describe spirochetal infections?

A
  • Many cases of neurosyphilis are reported in patients with HIV
    infection
  • Manifestations of neurosyphilis can occur at any stage
    > four forms—syphilitic
    > meningitis, meningovascular syphilis, parenchymatous neurosyphilis, and
    gummatous neurosyphilis
  • Lyme meningitis may be preceded by erythema migrans rash
28
Q

Name the pathogens that cause fungal meningitis?

A

Cryptococcus neoformans
Coccidioides immitis
Histoplasma capsulatum
Blastomyces dermatitidis

29
Q

Describe fungal infections and chronic meningitis?

A
  • usually chronic meningitis
  • Immunocompromised patients
  • Organ transplantation
  • WCC is usually elevated
    Note: Candida species may occur is shunt patients
30
Q

Describe cryptococcus neoformans?

A
  • encapsulated basidiomycetous yeast.
  • spread hematogenously to the CNS from pulmonary foci and cause chronic meningitis
  • two varieties of C. neoformans: var. neoformans and Cryptococcus gattii
31
Q

Describe coccidoides immitis?

A
  • is a dimorphic fungus that causes chronic meningitis
  • Human infection occurs via inhalation of arthroconidia
  • Infections caused by C. immitis are limited
32
Q

Describe the 3 parasitic infections that cause meningitis?

A
  1. Naegleria fowleri- rapidly progressive fatal primary amebic
    meningoencephalitis
  2. Acanthamoeba spp-soil and water organisms causes granulomatous amebic encephalitis
  3. Balamuthia mandrillaris also causes granulomatous amebic encephalitis
    > Trophozoites of these organisms travel to the brain via the olfactory nerve
33
Q

Name other parasites that could cause meningitis?

A

Toxoplasmosis gondii
Angiostrongylus cantonensis
Taenia solium
Trapanosome spp
Echinococcus granulosus,
Paragonimus westermani
Shistosome spp.

34
Q

Describe meingoencephalitis and encephalitis and its consequences?

A

Involvement of the cerebral cortex
> patients with encephalitis, mental status changes and other focal or diffuse neurologic signs, such as seizures

35
Q

What are the causes of encephalitis?

A
  1. viruses > including herpes viruses, EVs and arboviruses
  2. Nonviral causes > include L. monocytogenes, Rickettsia, Bartonella, Mycoplasma, B. burgdorferi, and T. gondii.
    Note: viruses are the most common cause
36
Q

What are brain abscesses?

A
  • brain abscesses are circumscribed areas of tissue destruction containing organisms and inflammatory cells
  • development of a necrotic center and the presence of macrophages and fibroblasts in the periphery
  • diminution in the necrotic center and formation of a collagenous capsule
37
Q

How do brain abscesses develop?

A
  1. spread from a contiguous focus of infection in the middle ear, mastoid cells, or paranasal sinuses.
  2. Hematogenous spread from a distant focus of infection, such as lung abscess, bronchiectasis, empyema, infective endocarditis, and intra abdominal infections
  3. Brain abscesses can also develop secondary to trauma with dural breach or following neurosurgery
38
Q

Name the bacterial pathogens that cause brain abscesses?

A
  1. Streptococci > Streptococcus anginosus, Streptococcus
    intermedius, and Streptococcus constellatus are isolated in 50% to 70% of cases
  2. Anaerobes > Bacteroides spp. and Prevotella spp
  3. E. coli, Proteus spp., and Enterobacter spp.
  4. Actinomyces and Nocardia spp. may also be isolated from patients with brain abscess.
    Note: Mixed infections are common
39
Q

Fungal pathogens that cause brain abscesses?

A

Candida spp., Aspergillus and zygomycetes (Mucor, Rhizopus, and Absidia)
> Mucormycosis is more commonly seen in patients with diabetic ketoacidosis, a transplant, or a hematologic malignancy increasing use of immunosuppressive drugs and broad spectrum antimicrobials

40
Q

Describe the laboratory diagnosis of CNS?

A

The diagnosis of CNS infections is based on examination of CSF samples obtained by lumbar puncture
> In patients with brain abscess, aspirates and tissue samples are helpful because the CSF may be normal
> Blood cultures are often helpful

41
Q

Describe the CSF sample collection method?

A
  • CSF samples may be stored at 2° C to 8° C in the short term
  • samples should be transported to the laboratory without delay and processed as soon as possible
42
Q

What is CSF analyzed for?

A
  1. glucose and protein concentration,
  2. cell counts
  3. identification of causative agent by Gram stain, culture, antigen detection, and PCR assay
43
Q

Identification of parasitic causes is usually based on?

A

based on microscopic examination of Giemsa
calcofluorstained aspirate
biopsy samples

Head and Neck Microbiology (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions