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Host and Defense > Week 9 > Flashcards

Week 9 Flashcards

1
Q

Is the pia mater in the brain more associated with white or grey matter?

A

Grey matter

Note that the pia mater is a histological layer, not a separate layer like arachnoid or dura mater.

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2
Q

What cells in the CNS are most sensitive to injury?

A

Neurons

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3
Q

What cells in the brain are most metabolically active?

A

Astrocytes

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4
Q

How can you identify neurons histologically in the brain?

A

Defined cytoplasmic borders

Basophilic inclusions

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5
Q

What are the two most common types of infectious disease in the CNS? What are some other types?

A

Bacterial and fungal infections are the most common.

Viral and prion infections are also possible

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6
Q

Where do each of the types of CNS infections occur?

A

Abscess - located in parenchyma (functional tissue)

Empyema - occurs in potential space

Meningitis - involves the subarachnoid space and/or CSF

Encephalomyelitis - inflammation of the spinal cord or brain parenchyma (usually due to viral infection)

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7
Q

How are oral infections typically spread to the CNS?

A

Contiguously (direct extension), not hematogenously

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8
Q

What types of dental infections are most likely to cause direct extension to cause CNS infection?

A

Caries - pulpitis
Apical periodontitis
Abscess formation
NUG/NUP

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9
Q

True or fals , encephalomyelitis involves the parenchyma of the brain and will result in systemic symptoms

A

True

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10
Q

Oral infections are most likely to cause what kind of CNS infections? Describe these infections

A

CNS infections

Abscesses can have systemic effects (vomiting and fever) and changes in consciousness (associated with increased CSF pressure) but also have focal neurological effects for the parts of the CNS affected.

Abscesses in brochas area will result in speech impairment. Abscesses in the occipital lobe can cause visual defects.
Paresis is also a possible

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11
Q

What are the risk factors for developing CNS bacterial abscesses?

A

Oralpathology
Oral procedures

Immunocompromised patients

Chronic illness
Chronic heart diesease (bacteria can seed off of infected valves and reach true brain) 
Skull fractures 
Meningitis 
Sinus infections
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12
Q

How can you diagnose a CNS abscess?

A

Evaluate symptoms

Physical exam

Imaging (this is the most important diagnostic aid)

Laboratory work: peripheral blood culture (typically poor diagnostic aid), CSF evaluation, cultures

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13
Q

Why is it that peripheral blood culture is typically a poor diagnostic tool for diagnosing CNS abscesses?

A

CNS abscesses are typically spread directly (contiguously), not hematogenously

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14
Q

What is the treatment for bacterial abscesses in the CNS?

A

Antibiotics,suregery may be indicated

Surgery is required if the abscess is greater that 2.5 cm

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15
Q

What may a bacterial CNS abscess look like histologically?

A

Reactive brain parenchyma overlaying an area of fibrosis. Fibrosis overlays an area of liquefactive necrotic tissue. Liquefactive necrosis is a pattern of necrosis that involves proteolytic enzymes that forms a liquid like pus instead of in-tact necrosis

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16
Q

___% of CNS infections have an underlying intra-oral pathology. In ___% of these cases, dental symptoms precede neurological symptoms. ___% of the time, the oral pathology and CNS infection are ipsilateral

A

87

40

70

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17
Q

___% of dental CNS infections are preceded by a dental procedure. What is the most likely procedure to cause a dental CNS infection?

A

47

Extraction of molar teeth

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18
Q

CNS infections are most likely to affect the ___ lobe

A

Frontal

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19
Q

What type of bacteria are the most likely to be the cause of a CNS infection ?

A

Gram positive cocci

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20
Q

In regards to the microbiology of a CNS infection, ___% of the oral cultures matches CNS cultures.

A

61

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21
Q

Why is it that even though you may have a CNS infection, 89% of the time the blood culture is negative?

A

Infection is usually due to direct extension, not hematogenously.

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22
Q

What is the most common intervention for a CNS infection? About what percentage of CNS infection patients die?

A

Craniotomy

~10%

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23
Q

True or false… actinomyces can be a culprit of CNS infection. It is a branching filamentous bacteria that is gram positive. It is part of the normal oral flora

A

True

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24
Q

What is the most likely cause for a CNS fungal infection?

A

Mycoses in immunocompromised patients.

Aspergillus fumigatus is the most common pathogen (goes from oral to sinus to CNS)

(Caused by aspergillus and zygomycete, sometimes candida spp., cryptococcus neoformans, or dimorphic fungi)

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25
Q

True or false… an aspergillus CNS infection results in systemic symptoms

A

False… just focal symptoms

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26
Q

What is the treatment for a CNS aspergillus infection?

A

Aggressive surgical excision

Ampotericin B + flucytosine (toxic antifungal)

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27
Q

What are the risk factors and presentation of zygomycetes (mucormycosis)?

A

Diabetes and immunosuppression are risk factors

Presentation = rapidly progressive facial swelling

May extend from sinuses directly into brain

Note that this is a surgical emergency

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28
Q

What fungi cause mucormycosis?

A

Zygomycetes (aseptate molds) such as…

Mucor
Rhizomucor
Rhizopus

29
Q

True or false… candida infections are common causes of CNS infections due to dental pathogology

A

False.. oral etiology unproven.

Most likely to occur in immmunocompromised patients

30
Q

What are the three forms of CNS candidia infections?

A

Meningitis
Encephalitis
Abscess

Note that candida forms yeast in culture but pseudohypha in vivo

31
Q

Name two parasites that may cause CNS infections

A

Helminths such as the pork tapeworm (Taenia solum). This condition is called neurocystercerosis

Protozoa such as toxoplasma gondii. This condition is called toxoplasmosis

32
Q

True or false… spirochetes are uncommon neurosurgical specimens and their dental/oral CNS infection is not known

A

True

33
Q

What are two diseases that may result in CNS infection caused by spirochetes?

A

Neurosyphilis (caused by treponema pallidum)

Lyme disease (caused by borrelia burgdorferi or gumma-inflammatory pseudotumors)

34
Q

What are two viruses that may cause CNS infection? Which is more common and which is rare?

A

Herpetic gingivostomatitis caused by HSV1 or HSV2 (very common)

herpes simplex encephalitis (rare)

35
Q

True or false… herpes simplex encephalititis is rare, yet highly aggressive, and affects the middle temporal lobe

A

True

36
Q

Name four types of prion disease (slow viruses). What are prion diseases?

A

Creutzfledt-jakob disease

CJD new variant

Gerstmann-straussler syndrome

Kuru (canabalism)

Prions are misfolded proteins that can misfold other proteins in the brain

37
Q

Define nosocomial infection

A

Infection acquired during an acute care hospitalization

38
Q

Where are some other locations in which a patient can get a health care associated infection?

A

Home care
Long term care facility
Ambulatory facility

39
Q

Define colonization

A

Presence or carriage of microbes without causing disease ( MRSA in anterior nares)

40
Q

Define infection

A

Invasion of body tissues by microbes resulting in disease (MRSA blood stream infection)

41
Q

What is a common nosocomial infection after giving birth?

A

Clostridium difficile

42
Q

How common are health care associated infections?

A

About 4% of those admitted

43
Q

What are the three top locations for HAIs

A

Pneumonia

Surgical site infections from inpatient surgery

Gastrointestinal illness

44
Q

What is the difference between exogenous and endogenous sources of HAIs?

A

Exogenous - health care providers bring in the infection from outside sources

Endogenous - patient brings in the infection

45
Q

Name the top five leading organisms that cause HAIs in order

A

C. Difficile
S. Aureus
Klebsiella spp.
E. Coli

46
Q

What is the most common identified pathogen responsible for HAIs?

A

Clostridium difficile

47
Q

What type of bacteria are new and high concerns of HAIs?

A

Carbapenem resistant enterobacteriaceae

48
Q

Describe the chain of infection (6 things).

A

Each link must be present and in order for infection to occur

Organism to reservoir to portal of exit to transmission to portal of entry to vulnerable host

49
Q

What are the two stages of the chain of infection that healthcare providers may have control over?

A

Transmission and portal of entry

50
Q

Why are hospitalized patients at high risk for nosocomial infections?

A

Exposure to exogenous organisms from…

Healthcare worker behavior
Contaminated shared equipment

51
Q

What diseases can be spread through direct and indirect contact?

A 
MRSA
VRE
CRE 
c. Difficile 
Noravirus
52
Q

What diseases can be spread by droplets and splashes?

A 
Neisseria meningitidis 
Pertusssis 
Group A strep 
Haemophilus influenzae 
Influenza
Respiratory viruses (such as RSV)
53
Q

What diseases may be spread airborne?

A

Influenza?
TB
Chicken pox
Corona virus (SARS)

54
Q

True or false… gloves can be used as a substitute for hand washing

A

False

55
Q

Latex allergies are an immediate ___ response. It is a systemic and life threatening response

A

Hypersensitivity

56
Q

Why are hospitalized patients at risk for nosocomial infection?

A

Interventions give ENDOGENOUS organisms the opportunity to engage…

Surgery and invasive devices such as catheters and ventilators

57
Q

What is a CLABSI? What kind of organisms are likely to cause this?

A

Central line associated bloodstream infection

Coagulase negative staphylococcus, S. Aureus, enterococcus, candida

Not so much gram negative organisms

58
Q

What can you do to prevent CLABSI?

A

Make sure you NEED a catheter

Prep site with chlorhexidine
Hand hygiene
Use sterile barriers

Maintain the site with scrubbing, tube cleaning, use chlorhexidine, clean dressing, use hand hygiene

59
Q

True or false… saliva can harbor bloodborne pathgens

A

True because saliva contains blood.

60
Q

True or false… hep C is transmitted less efficiently than hep b

A

True

61
Q

If you get a needle stick while treating a patient with either HBV, HCV, or HIV. What are the chances you will get infected from each of these patients?

A

HBV - 30%

HCV - 3%

HIV - .3%

62
Q

True or false… it is ok to give a needle to the assistant to have them put it into the sharps container

A

False.. the person who uses the sharp puts it into the sharps container

63
Q

True or false… you should never recap, break or bend needles

A

True

64
Q

What are the three classification of instruments in regards to minimal post-treatment protocol? Is the minimal post-treatment for each?

A

Critical - penetrates tissue . Heat sterilize between use or use sterile single use

Semi-critical - contacts mucous membranes but does not penetrate soft tissue. Heat sterilize or high-level disinfect

Non-critical - contacts intact skin. Clean and disinfect using a low to intermediate level disinfectant

65
Q

It is important to physically or spatially divide instruments based upon what four things?

A

Receiving, cleaning, decontamination

Preparation and packaging

Sterilization

Storage

66
Q

What are the two methods for cleaning dental instruments

A

Automated

Manual

67
Q

What are the three heat-based sterilization techniques?

A

Steam under pressure (autoclaving)

Dry heat

Unsaturated chemical vapor

68
Q

What are the three types of sterilization monitoring methods?

A

Mechanical - measure time, tempatrue, pressure

Chemical - change in color when physical parameter reached

Biological (spore tests) - use biological spores to assess sterilization directly

69
Q

For routine dental treatment, the water must meet regulatory standards for drinking water which is….

A

< 50 CFU/cl of heterotrophic water bacteria

Host and Defense (17 decks)

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