CHAPTER 16: PRINCIPLES OF MANAGEMENT & PREVENTION OF ODONTOGENIC INFECTIONS

ppt only / still need to get from book

odontogenic infections

infections that arise from teeth and is generally caused by bacteria

• 2 major origins:

  • periapical → from pulp necrosis (most common origin)

  • periodontal → from perio pocket

    
    

microbiology of odontogenic infections

polymicrobial

50% to 60% involves mixed bacteria

caused by normal oral bacterial flora (aerobic and anaerobic)

aerobic bacteria

gram-positive cocci → viridans-type Streptococci (45% occurrence)

anaerobic bacteria

• gram-positive cocci:

  • Streptococcus

  • Peptostreptococcus

• gram-negative rods:

  • Prevotella

  • Fusobacterium

  • Porphyromonas

pathophysiology of odontogenic infections

begins in periapical / periodontal area

↓

spreads in all directions favoring the path of least resistance

↓

gradually erodes cancellous bone toward facial or lingual cortices

↓

once through cortical bone, it spreads to fascial spaces (fascial spaces are not actual spaces but become created when invaded by infection)

fascia

thin casing of connective tissue beneath the skin

these are “potential” spaces, only existing when invaded by bacteria

surrounds and holds every organ, blood vessel, bone, nerve fiber, muscle in place

the deep spaces of the head and neck are fascia-lined spaces containing loose areolar connective tissue

primary spaces

infratemporal

vestibular, buccal

canine / infraorbital

submandibular, submental, sublingual

secondary spaces

parapharyngeal

retropharyngeal

pterygomandibular

submasseteric / masseteric

superficial / deep temporal (masticator space)

prevertebral (deep cervical fascial spaces of the neck)

periorbital (masticator space) (deep cervical fascial spaces of the neck

location of the involved potential space is determined by:

the thickness of the bone overlying the apex of tooth

the relationship of the site of perforation of bone to muscle attachments of maxilla and mandible

thickness of the bone overlying the apex of tooth

periapical infections arising from mx molars generally erode through the thin buccal cortex

periapical infections arising from mn molars generally erode through the lingual cortex

site of perforation of bone to muscle attachments of mx-mn

• if bone erosion is below buccinator muscle attachment:

  • mx → vestibular space

  • mn → buccal space

• if bone erosion is above buccinator muscle attachment:

  • mx → buccal space

  • mn → vestibular space

    
    

Lingual perforation

Lingual perforation superior to the mylohyoid attachment = sublingual space (shown in orange). Lingual perforation inferior to the mylohyoid attachment = submand

4 stages of odontogenic infections

edema or inoculation

cellulitis

abscess

resolution

resolution

spontaneously or surgically drainage of abscess destruction of bacteria by immune system-healing

edema

0-3 days

diffuse borders

variable size

normal color

jelly-like consistency

increasing progression

absence of pus

low degree of seriousness

aerobic bacteria

cellulitis

1-5 days

diffuse borders

larger size

red color

doughy or indurated consistency

increasing progression

absence of pus

greater degree of seriousness

mixed bacteria

abscess

4-10 days

localized borders

smaller size

shiny center color

fluctuant consistency

decreasing progression

presence of pus

less degree of seriousness

anaerobic bacteria

principles of management of odontogenic infections

principle 1: determine severity of infection

principle 2: evaluate state of a px host defense mechanism

principle 3: determine whether px should be treated by general dentist or oral & maxillofacial surgeon

principle 4: treat infection surgically

principle 5: support px medically

principle 6: choose & prescribe appropriate antibiotics

principle 7: administer antibiotic properly

principle 8: evaluate the px frequently

principle 1: determine severity of infection

most odontogenic infections are mild and require only minor surgical therapy

• severity can be determined by:

  • complete history taking

  • physical examination

• complete history taking:

  • how long the infection has been present?

    • time of onset, progression of infection, rapidity of progression

  • information on patient’s symptoms

    • cardinal signs of inflammation

  • determine the general health of patient

    • malaise. fatigue, feverish, weak & sick patients

• physical examination:

  • vital signs

    • pulse rate (increases with a rise in body temperature)

      • severe infection = >100 b/m

    • blood pressure

      • generally not altered by infection

      • pain and anxiety can cause an increase in BP

    • respiratory rate

      • normal: 12–20 b/m

      • mild-moderate infection: >20 b/m

    • temperature

      • normal: 36.5°C – 37.5°C (97.7°F – 99.5°F)

      • fever: more than 38°C (WHO)

      • [ergo, mild infection → vital signs normal, slight inc in temp

      • severe infection → vital signs abnormal, high inc in temp]

  • general appearance:

    • toxic appearance

      • suggests severe infection

      • elevated temperature, pulse, respiratory rate

    • head & neck examination

      • inspect cardinal signs of infection & inflammation

      • elevated temperature, pulse, respiratory rate

    • head & neck examination

      • assess tenderness, consistency of swelling

      • fleshy swelling → doughy swelling

      • firm or hard swelling → indurated swelling

      • fluctuant swelling → fluid-filled balloon (indicates liquid pus in the center)

• others:

  • perform intra oral examination

  • radiographic examination

  • staging of infection

  
  

principle 2: evaluate state of a px host defense mechanism

estimate the patient's ability to defend against infection

• can be reduced by:

  • medical conditions, such as:

    • uncontrolled diabetes mellitus

    • HIV, leukemia, malignancy,

    • congenital & acquired immunological disease

  • drugs, such as:

    • cancer chemotherapy

    • immunosuppressive drugs

citeria for referral to an OMFS

trismus

dehydration

need for GA

extra oral swelling

difficulty breathing

difficulty swallowing

temperature >101°F

failed previous treatment

compromised host defense

sever malaise / toxic appearance

criteria for immediate hospital emergency room admission

rapidly progressing infection

difficulty breathing (dyspnea)

temperature >101 °F (38.3 °C)

difficulty swallowing (dysphagia)

threat to airway or vital structures

trismus

results from involvement of the muscle of mastication by inflammatory process

medial pterygoid muscle

the most commonly affected muscles during an IAN block

mild trismus

maximum interincisal opening between 30-40 mm

moderate trismus

maximum interincisal opening between 15-30mm

severe trismus

maximum interincisal opening is <15mm

ways to anesthesize patients with trismus

• vazirani akinosi

  • lingual nerve

  • inferior alveolar nerve

  • mylohyoid nerve (often)

  • mental and incisive nerves

• gow-gates mandibular block

  • used if the patient has enough mouth opening

the principal managements of odontogenic infection

primary goal → remove the cause of infection

secondary goal → surgical drainage of pus

reasons for performing incision and drainage (I&D)

to decrease the load of bacteria and necrotic debris

to reduce hydrostatic pressure by decompressing tissues

to remove the accumulated pus and bacteria from the tissues

to prevent the spread of infection into deeper anatomic spaces

[ergo, decreases bacterial load and decreases pressure]

technique for I&D of a vestibular abscess or cellulitis

aka: Hilton’s Method

• anesthesia

  • preferred → regional nerve block

  • alternative → infiltration

• stab incision

  • at the site of maximum swelling

  • in mx: inferiorly for maximum gravity → dependent drainage

  • no more than 1cm in length

  • avoid frenum and mental nerve

• insertion of hemostat or sinus forceps

  • if pus is not encountered, deepen the surgical site carefully with sinus forceps to avoid damaging vital structures

  • steps:

    • closed forceps are pushed through the deep fascia towards the pus collection

    • once the abscess cavity is entered, the forceps are opened parallel to vital structures

    • pus drains along the sides of the forceps

    • entire cavity is explored for additional loculi

• placement of drain

  • a rubber drain is inserted into abscess cavity

  • external part is secured to the wound margin

  • drain is left for at least 2–5 days

  • purpose of drain:

    • allows continuous drainage of contents

    • maintains the opening for drainage

    • enables irrigation and debridement

  • commonly used drain:

    • ¼ inch sterile penrose drain

  • alternative:

    • sterile glove or rubber dam

• dressing

  • for extraoral incisions to protect the wound

principle 5: support patient medically

body's physiologic reserves are altered during infection

• children:

  • susceptible to dehydration and high fever during infection

• old patients:

  • less susceptible to fever, but in them dehydration occurs during infection

principle 6: choose & prescribe appropriate antibiotics

first, determine the NEED for antibiotic administration

• the need can be determined from following 3 factors:

  • seriousness of infection

  • state of patient's host defenses

  • whether adequate surgical treatment can be achieved

[antibiotics do not speed up the wound healing and do not provide any benefit for non-bacterial conditions]

conditions that antibiotics are necessary

trismus & swelling

severe pericoronitis

temperature >101°F

deep fascial space infection

immunocompromised patient

osteomyelitis & lymphadenopathy

swelling extending beyond the alveolar process

acute onset infection with diffuse swelling & moderate to severe pain (cellulitis)

conditions that antibiotics are not necessary

toothache

severe pain

patient demand

mild pericoronitis

drained alveolar abscess

alveolar osteitis (dry socket)

minor, chronic, well-localized dentoalveolar, periapical, periodontal abscess

multiple extraction in patient who is NOT immunocompromised

empirical therapy

refers to treatment initiated before a definitive diagnosis is made

use of antibiotics on the assumption that it is the appropriate drug

recommended oral antibiotics

• penicillin → first line (drug of choice)

  • penicillin G → original penicillin, IV route

  • penicillin V → oral route

• amoxicillin

  • preferred due to better absorption

• clindamycin

  • for penicillin allergy

• cephalexin, clarithromycin, azithromycin

  • for clindamycin allergy

compliance decreases as dosage frequency increases

• once daily → 80% compliance

• twice daily → 69% compliance

indications for culture & sensitivity testing

recurrent infection

compromised host defense

rapidly progressive infection

previous multiple antibiotic therapy

nonresponsive infection (after >48hrs)

routine testing is NOT recommended but should be done in cases like nonresponsive infections!

principle 7: administer antibiotic properly

follow proper dose and at the proper dose interval

kills not only oral bacteria but also beneficial flora in the gut, skin

use cost effective antibiotics (do not always need to be expensive!)

choose drug which could be given once a day for not more than 4-5 days to get more compliance

avoid broad spectrum unless necessary, prefer narrow spectrum antibiotics (targets a limited range of bacteria)

plasma level of drug should be high enough to kill the bacteria but not so high to cause toxicity (peak plasma: 4-5x the minimal inhibitory concentration of bacteria)

use bactericidal antibiotic, if possible bc:

• bactericidal

  • interferes with cell wall

• bacteriostatic

  • interferes bacterial reproduction

use the antibiotic with lowest incidence of toxicity & side effects:

• such as:

  • penicillin, clindamycin, macrolide, moxifloxacin

  • oral cephalosporins, tetracycline, metronidazole

narrow-spectrum antibiotics useful for treating simple odontogenic infections

penicillin

amoxicillin

clindamycin

metronidazole

[mnemonic: PACM]

broad-spectrum antibiotics useful for treating simple odontogenic infections

azithromycin

moxifloxacin

amoxi-clavulanic acid (for sinus infections)

[mnemonic: AMA]

penicillin

drug of choice

• major side effect:

  • allergic reactions (hives, itching)

• prophylactic dose:

  • 2g ; 60mins before operation

clindamycin

• advantages:

  • low incidence of toxicity & side effects

• side effect:

  • pseudomembranous colitis caused by Clostridium difficile

macrolides

no longer used due to drug reactions

best alternative: azithromycin due to low toxicity

moxifloxacin (fluoroquinolone class)

• advantages:

  • more effective than older fluoroquinolones

• toxicity:

  • mental clouding

  • drug interactions

  • muscle weakness

oral cephalosporins (cephalexin & cefadroxil)

mild toxicity

cross-allergenicity with penicillin allergy

not recommended for odontogenic infections

tetracycline

mechanism: chelation to calcium

not used for odontogenic infections

used topically in high concentrations (periodontal pockets)

tooth discoloration (pregnant women; children under 12 year)

metronidazole

for anaerobic bacteria ONLY!

avoided in patients who are taking lithium

• mild toxicity:

  • gastrointestinal disturbances

  • disulfiram-like reaction or antabuse effect

• interacts with alcohol leading to:

  • severe abdominal cramping

  • violent vomiting

• other side effects:

  • inhibits warfarin metabolism prolonging prothrombin time

principle 8: evaluate the patient frequently

• if therapy is successful:

  • assess the I&D site to determine whether the drain can be removed

  • evaluate other key parameters:

    • trismus (should be improving)

    • swelling (should be reducing)

    • temperature (should be returning to normal)

    • patient’s subjective feelings (should report overall improvement)

• if therapy is unsuccessful:

  • conduct a thorough examination to identify possible reasons for treatment failure such as:

    • inadequate drainage

    • persistent infection

    • antibiotic resistance

    • undiagnosed systemic conditions

prophylaxis of post-operative wound infection

antibiotics can reduce infection by up to 70% in OMFS

antibiotics DO NOT replace proper surgical technique

• infection rate:

  • 6–9% (clean-contaminated)

  • 40% (dirty wounds)

• prophylactic drug:

  • 2x the usual therapeutic dose:

  • penicillin or amoxicillin → 2g (1hr before)

  • clindamycin → 600 mg (1hr before)

surgical features that need prophylaxis

complex surgeries

presence of foreign bodies

increase size of inoculum

immunocompromised patients

metastatic infection

refers to infections that occur in distant sites, not directly connected to the site of origin

most commonly occur via hematogenous route

• sites most susceptible

  • heart valves = infective endocarditis

  • prosthetic joint replacements = prosthetic failure

prophylaxis against infective endocarditis

caused by bacteremia

an infection of the endocardial surface of the heart (heart valves)

• non-antibiotic prophylactic measures:

  • oral hygiene

  • chlorhexidine gluconate rinses

prophylaxis against prosthetic joint infection

for patients with recently placed prosthetic joints who are immunocompromised or have poor glycemic control

prophylaxis in px with other cardiovascular conditions

arterio-venous shunt (AV) shunts for dialysis

ventri-culo-atrial shunts (VA) shunts for hydrocephalus

antibiotic regimen for the prevention of infective endocarditis for adults

• drug of choice

  • amoxicillin 2g 1hr prior the procedure (four 500mg tablets)

• alternative if allergic to amox

  • clindamycin 600mg 1hr prior the procedure

antibiotic regimen for the prevention of infective endocarditis for children

• drug of choice:

  • Amoxicillin 50mg/kg 1hr prior the procedure

• alternative if allergic to amox:

  • Clindamycin 20mg/kg 1hr prior the procedure