Q8 - ICS III Final Study guide

What is bacteremia vs septicemia?

Bacteremia: transient load of bacteria in the blood stream

Septicemia: chronic load of bacteria in the blood

Why is antibiotic prophylaxis done?

Aimed to prevent bacteremia from reaching a site of compromised blood flow (artificial join or heart valve) to prevent infection

What does cellulitis indicate?

Infection that is not localized but is acute and spreading

What does an abscess indicate?

Infection that is localized, walled off, and filled with pus

T or F

Antibiotics are very effective against abscesses.

False; Due to poor blood supply antibiotics have minimal effect

What is the treatment for abscesses?

Incision and drainage

Remove source of infection

What is pathogenesis of a bacteria determined by?

- Quantity

- Virulence of bacteria

What percent of odontogenic infections are mixed anaerobic and aerobic?

60%

What aerobic bacteria make up the majority of infections?

- Streptococcus (90%)

- Staphylococcus (10%)

What anaerobic bacteria make up the majority of infections?

- Gram + peptostreptococci

- Gram - prevotella

Odontogenic infections are initiated by ________ bacteria.

aerobic

What is alveolar osteitis?

AKA dry socket

- Occurs when pathogens contribute to loss of clot

- Collagenase produced by bacteria destroy clot

What type of streptococcus causes endocarditis post dental treatment?

Alpha hemolytic Strep viridans

What is the problem with treating staphylococcus infections?

Most are resistant to penicillin due to penicillinase enzyme that breaks down antibiotic

What is prevotella buccae resistant to ?

Clindamycin

Describe bacterial exotoxins

- Easily destroyed at body temp

- High toxicity

- Mostly from gram + bacteria

Describe bacterial endotoxins

- Stable and can withstand autoclaving

- Low toxicity

- Mostly from gram - bacteria

How do wounds re-epithelialize?

The sides grow towards the middle like a volcano

How do you perform source control on an odontogenic infection?

- Extraction

- Decrease

- Release pus and bacterial byproducts (Incise and drain)

T or F

You should perform I&D during abscess stage ONLY, NOT cellulitis.

False; Perform I&D during either cellulitis or abscess stage to stop progression of infection

What should you keep in mind when doing I&D?

- Incise healthy skin

- Full thickness mucoperiosteal flap

- Explore entire infected space

When should you extract a tooth causing an odontogenic infection?

- If it is nonrestorable

- Remove ASAP to remove source

When do buccal space infections occur?

- Apices above/below buccinator muscle attachments

When do sublingual space infections occur?

- When infection drains above the mylohyoid muscle

- Usually mandibular teeth

What space communicate with sublingual space?

- Submandibular space

When do submandibular space infections occur?

- When infection drains below the mylohyoid muscle

Where do submandibular space infections tend to spread?

- Extend medially and posterior towards digastric muscle and hyoid

T or F

The Submental space is not commonly the solely infected space.

True

What is the canine space?

- Muscular space

- Bordered by Levator anguli oris and levator labii superioris

- Often invades orbit

Where do maxillary infections tend to drain?

- Posterior

- Superior

What is cavernous sinus thrombosis?

- Orbital cellulitis that travels through angular veins to cavernous sinus

Why does cavernous sinus thrombosis occur?

Veins of the face lack valves so retrograde infection is quite easy

What are signs and symptoms cavernous sinus thrombosis?

- Proptosis

- Fever

- Altered state of consciousness

- Orbital cellulitis

What are contents in the cavernous sinus?

- CN III

- CN IV

- CN V1 and V2

What space infections are often associated with trismus?

- Masticator space

- Temporal space

- Masseteric space

What defines the masticator space?

Split in deep cervical fascia at inferior of mandibular border

What are common symptoms for Masticator space infections?

- Trismus

- Pin

- Swelling

What space do we inject during an IA block?

Pterygomandibular space

T or F

Pterygomandibular space infections can present as trismus without swelling.

True

Where do mandibular infections tend to drain?

- Posterior

- Inferior

What is Ludwig's angina?

Bilateral cellulitis that has spread from submandibular, sublingual, and submental spaces

What is the main concern with Ludwig's angina?

Occlusion of airway

What are the clinical signs of Ludwig's angina?

- FOM hard and elevated

- Tongue filling mouth

- Difficulty breathing and swallowing

What is the old belief regarding extracting teeth that are acutely infected?

It used to be thought that extracting acutely infected teeth would lead to spread of infection

What should be done if a tooth is acutely infected and causing a space infection?

- Extract tooth as soon as possible

- I &D and Antibiotics if indicated

T or F

More than half of these severe odontogenic infections are caused by aerobic bacteria.

False; More than half of infections are caused by anaerobic bacteria

What are some life threatening complications from odontogenic infections?

- Airway obstruction

- Sepsis

- Mediastinitis

- Brain abscess

- Jugular vein thrombosis

What are the treatment options for deep neck infections?

- Immediate I&D

- Intervenous antibiotics

What was the old thought behind I&D for cellulitis and abscesses?

- Fluctuant abscess swelling would be I&D

- Cellulitis would receive antibiotics

How do you tell the difference between cellulitis vs abscess?

- Duration

- Pain

- Size

- Localization

- Pus is the main indicator

What are the two ways you can differentiate cellulitis and abscesses?

- Presence of pus upon I&D

- Contrast enhanced CT

What is the fear behind not treating cellulitis?

Further spread of infection

What was found during a study regarding accuracy to clinically determine abscess vs cellulitis?

Majority of odontogenic abscesses were underestimated to be cellulitis

What was found when reviewing the literature on whether or not to drain abscesses and cellulitis in odontogenic infection?

Differentiating between cellulitis and abscess is less important -> Immediate treatment (I&D) is most important

How can cellulitis be treated if it is correctly diagnosed in a stable patient?

IV antibiotics are sufficient

What antibiotic works against all oral pathogens?

No single antibiotic works for all pathogens due to the polymicrobial nature of odontogenic infections

When is penicillin not effective in odontogenic infections?

- 21% of the time

- Common in severe hospitalized cases

What are the first line antibiotics used for outpatient treatment of infections?

- Amoxicillin

What are the first line antibiotics used for outpatient treatment of infections if the patient is allergic to penicillin?

- Clindamycin

- Azithromycin

What are the first line antibiotics used for inpatient treatment of infections?

- Ampicillin/Sulbactam

- Clindamycin

- Penicillin + Metronidazole

What works better, short course or long course antibiotics?

It was shown there were no difference in cure rates as long as surgical treatment was done (so go with short term)

What are the advantages of short course antibiotic therapy?

- Fewer side effects

- Lower risk of resistance

- Higher compliance

What is the most cost effective antibiotic?

Amoxicillin

How should providers choose antibiotics?

- Bacteria susceptibility

- Cost

- Safety

What have laboratory studies shown in terms of bacteria susceptibility in odontogenic infections?

Newer and broader spectrum antibiotics are more effective

What was found comparing resistance of bacteria in outpatient infection vs inpatient infections?

Much higher rate of penicillin resistance in severe hospitalized cases

What is a biofilm?

community of bacteria embedded in a extracellular matrix

T or F

Most bacteria exist in a biofilm.

True

What percent of biofilm are actual bacteria?

15%

What are the benefits for bacteria being in a biofilm?

- Evade antibiotics

- Immune cells can't penetrate entire biofilm

- Quorum sensing allows entire biofilm to change gene expression depending on environment

Do antibiotics work against biofilms?

- May kill surface bacteria but unable to penetrate and kill deep bacteria

- Cause for recurrent infections

How do biofilms explain the need for I&D and source removal?

Antibiotics alone cant kill space infection biofilms, therefore debridement and drainage are NECESSARY

There are many diseases of the mouth that are caused by biofilms of bacteria. What is the common treatment for all these diseases? (ex. periodontitis, osteomyelitis, pulpitis, MRONJ)

Debridement! This is the only way to erradicate a biofilm since antibiotics won't work

What kind of bacteria do antibiotics help with?

Planktonic AKA free floating

What species tends to become virulent in post extraction sites?

Prevotella

What puts a patient at high risk for prevotella infection post-ext?

- Excessive plaque

- Nearby gingivitis

- Periodontitis

- Immunocompromised patients

What antibiotics resolves most post-extraction infections caused by prevotella species?

Metronidazole

What prevotella strain was found in odontogenic infections and pericoronitis that was resistant to empirical antibiotics?

Prevotella buccae

T or F

Prevotella bacteria are not common inhabitants of the oral cavity but are often introduced during extractions.

False; They are normal inhabitants of the periodontal sulcus

What is the most common facultative anaerobic species in odontogenic infections?

Viridans streptococci

What are the most common obligate anaerobic bacteria in odontogenic infections?

- Bacteriodes

- Prevotella

- Peptostreptococci

T or F

Deep space infections of the neck are most commonly from odontogenic origin.

True

What are the main principles of source control?

- Decreased bacterial load via I&D

- Drain swelling and pus to improve blood supply

- Irrigate to remove bacteria and toxins

- Extract tooth

What are the most common causes of odontogenic infections?

- Caries (65%)

- Pericoronitis

- Periodontitis

What was found regarding Prevotella intermedia and its effects on the immune system?

- inhibit proliferation of B-cells and T cells leading to immunosuppression

- Shields bacteria from humoral response

- Degrades antibodies

- Degrades compliment

Where is P. buccae normally found?

- Peri-implant bone

- Periodontitis

- Root canal infections

- Radicular cysts

What happens to opportunistic pathogens after a few days of antibiotic prophylaxis?

Resistance was observed along with ecological disturbance

T or F

Clindamycin is always effective against all prevotells species.

False

What is a good first line empiric antibiotic to prescribe if Prevotella is suspected?

Penicillin plus Flagyl (metronidazole)

What kind of antibiotic is metronidazole?

- Nitroimidazole

- Antibiotic and antiprotozoal

What is the first choice for treatment of C. difficile?

Metronidazole

How does Metronidazole work?

forms free radical toxic metabolites in bacterial cell that damage DNA

What is the risk of taking Metronidazole?

- Disulfiram-like reaction with alcohol

- Symptoms include nausea, vomiting, respiratory depression, death

What should be determined before prescribing B-lactam antibiotics?

Ability of bacteria to produce B-lactamase; this is to avoid potential antibiotic resistance

What bacteria species produce B-lactamase the most?

Prevotella

What kind of bacteria does Metronidazole work on?

Anaerobic bacteria only

What antibiotics are prevotella species most susceptible to?

- Amoxicillin + clavulanic acid

- Metronidazole

- Clindamycin

What should be done if a single opportunistic organism dominates a culture from an infection?

Suscpetibility testing should be performed and then the appropriate antibiotic prescribed

What should be used if Metronidazole does not cure a complicated anaerobic infection?

Meropenem

What antibiotics are Prevotella species resistant to?

Beta lactam antibiotics (-cillins) and Clindamycin