Week 9 Flashcards
Is the pia mater in the brain more associated with white or grey matter?
Grey matter
Note that the pia mater is a histological layer, not a separate layer like arachnoid or dura mater.
What cells in the CNS are most sensitive to injury?
Neurons
What cells in the brain are most metabolically active?
Astrocytes
How can you identify neurons histologically in the brain?
Defined cytoplasmic borders
Basophilic inclusions
What are the two most common types of infectious disease in the CNS? What are some other types?
Bacterial and fungal infections are the most common.
Viral and prion infections are also possible
Where do each of the types of CNS infections occur?
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)
How are oral infections typically spread to the CNS?
Contiguously (direct extension), not hematogenously
What types of dental infections are most likely to cause direct extension to cause CNS infection?
Caries - pulpitis
Apical periodontitis
Abscess formation
NUG/NUP
True or fals , encephalomyelitis involves the parenchyma of the brain and will result in systemic symptoms
True
Oral infections are most likely to cause what kind of CNS infections? Describe these infections
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
What are the risk factors for developing CNS bacterial abscesses?
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
How can you diagnose a CNS abscess?
Evaluate symptoms
Physical exam
Imaging (this is the most important diagnostic aid)
Laboratory work: peripheral blood culture (typically poor diagnostic aid), CSF evaluation, cultures
Why is it that peripheral blood culture is typically a poor diagnostic tool for diagnosing CNS abscesses?
CNS abscesses are typically spread directly (contiguously), not hematogenously
What is the treatment for bacterial abscesses in the CNS?
Antibiotics,suregery may be indicated
Surgery is required if the abscess is greater that 2.5 cm
What may a bacterial CNS abscess look like histologically?
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
___% 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
87
40
70
___% of dental CNS infections are preceded by a dental procedure. What is the most likely procedure to cause a dental CNS infection?
47
Extraction of molar teeth
CNS infections are most likely to affect the ___ lobe
Frontal
What type of bacteria are the most likely to be the cause of a CNS infection ?
Gram positive cocci
In regards to the microbiology of a CNS infection, ___% of the oral cultures matches CNS cultures.
61
Why is it that even though you may have a CNS infection, 89% of the time the blood culture is negative?
Infection is usually due to direct extension, not hematogenously.
What is the most common intervention for a CNS infection? About what percentage of CNS infection patients die?
Craniotomy
~10%
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
True
What is the most likely cause for a CNS fungal infection?
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)
True or false… an aspergillus CNS infection results in systemic symptoms
False… just focal symptoms
What is the treatment for a CNS aspergillus infection?
Aggressive surgical excision
Ampotericin B + flucytosine (toxic antifungal)
What are the risk factors and presentation of zygomycetes (mucormycosis)?
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
What fungi cause mucormycosis?
Zygomycetes (aseptate molds) such as…
Mucor
Rhizomucor
Rhizopus
True or false… candida infections are common causes of CNS infections due to dental pathogology
False.. oral etiology unproven.
Most likely to occur in immmunocompromised patients
What are the three forms of CNS candidia infections?
Meningitis
Encephalitis
Abscess
Note that candida forms yeast in culture but pseudohypha in vivo
Name two parasites that may cause CNS infections
Helminths such as the pork tapeworm (Taenia solum). This condition is called neurocystercerosis
Protozoa such as toxoplasma gondii. This condition is called toxoplasmosis
True or false… spirochetes are uncommon neurosurgical specimens and their dental/oral CNS infection is not known
True
What are two diseases that may result in CNS infection caused by spirochetes?
Neurosyphilis (caused by treponema pallidum)
Lyme disease (caused by borrelia burgdorferi or gumma-inflammatory pseudotumors)
What are two viruses that may cause CNS infection? Which is more common and which is rare?
Herpetic gingivostomatitis caused by HSV1 or HSV2 (very common)
herpes simplex encephalitis (rare)
True or false… herpes simplex encephalititis is rare, yet highly aggressive, and affects the middle temporal lobe
True
Name four types of prion disease (slow viruses). What are prion diseases?
Creutzfledt-jakob disease
CJD new variant
Gerstmann-straussler syndrome
Kuru (canabalism)
Prions are misfolded proteins that can misfold other proteins in the brain
Define nosocomial infection
Infection acquired during an acute care hospitalization
Where are some other locations in which a patient can get a health care associated infection?
Home care
Long term care facility
Ambulatory facility
Define colonization
Presence or carriage of microbes without causing disease ( MRSA in anterior nares)
Define infection
Invasion of body tissues by microbes resulting in disease (MRSA blood stream infection)
What is a common nosocomial infection after giving birth?
Clostridium difficile
How common are health care associated infections?
About 4% of those admitted
What are the three top locations for HAIs
Pneumonia
Surgical site infections from inpatient surgery
Gastrointestinal illness
What is the difference between exogenous and endogenous sources of HAIs?
Exogenous - health care providers bring in the infection from outside sources
Endogenous - patient brings in the infection
Name the top five leading organisms that cause HAIs in order
C. Difficile
S. Aureus
Klebsiella spp.
E. Coli
What is the most common identified pathogen responsible for HAIs?
Clostridium difficile
What type of bacteria are new and high concerns of HAIs?
Carbapenem resistant enterobacteriaceae
Describe the chain of infection (6 things).
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
What are the two stages of the chain of infection that healthcare providers may have control over?
Transmission and portal of entry
Why are hospitalized patients at high risk for nosocomial infections?
Exposure to exogenous organisms from…
Healthcare worker behavior
Contaminated shared equipment
What diseases can be spread through direct and indirect contact?
MRSA VRE CRE c. Difficile Noravirus
What diseases can be spread by droplets and splashes?
Neisseria meningitidis Pertusssis Group A strep Haemophilus influenzae Influenza Respiratory viruses (such as RSV)
What diseases may be spread airborne?
Influenza?
TB
Chicken pox
Corona virus (SARS)
True or false… gloves can be used as a substitute for hand washing
False
Latex allergies are an immediate ___ response. It is a systemic and life threatening response
Hypersensitivity
Why are hospitalized patients at risk for nosocomial infection?
Interventions give ENDOGENOUS organisms the opportunity to engage…
Surgery and invasive devices such as catheters and ventilators
What is a CLABSI? What kind of organisms are likely to cause this?
Central line associated bloodstream infection
Coagulase negative staphylococcus, S. Aureus, enterococcus, candida
Not so much gram negative organisms
What can you do to prevent CLABSI?
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
True or false… saliva can harbor bloodborne pathgens
True because saliva contains blood.
True or false… hep C is transmitted less efficiently than hep b
True
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?
HBV - 30%
HCV - 3%
HIV - .3%
True or false… it is ok to give a needle to the assistant to have them put it into the sharps container
False.. the person who uses the sharp puts it into the sharps container
True or false… you should never recap, break or bend needles
True
What are the three classification of instruments in regards to minimal post-treatment protocol? Is the minimal post-treatment for each?
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
It is important to physically or spatially divide instruments based upon what four things?
Receiving, cleaning, decontamination
Preparation and packaging
Sterilization
Storage
What are the two methods for cleaning dental instruments
Automated
Manual
What are the three heat-based sterilization techniques?
Steam under pressure (autoclaving)
Dry heat
Unsaturated chemical vapor
What are the three types of sterilization monitoring methods?
Mechanical - measure time, tempatrue, pressure
Chemical - change in color when physical parameter reached
Biological (spore tests) - use biological spores to assess sterilization directly
For routine dental treatment, the water must meet regulatory standards for drinking water which is….
< 50 CFU/cl of heterotrophic water bacteria
