2. Outline
Introduction
Microbiology of Odontogenic Infections
Laboratory Investigations in Odontogenic Infections
Diagnostic Imaging in Odontogenic Infections
Principles of Management of Odontogenic Infections
Use of Corticosteroids in Maxillofacial Infections
References
3. Introduction
In 1940 Ashbel Williams published a series of 37 cases of Ludwig’s angina in which
54% of the subjects died; 3 years later the mortality rate of Ludwig’s angina was
reduced to 10%.
The principles of the initial establishment of airway security, followed by early and
aggressive surgical drainage of all anatomic spaces affected by cellulitis or abscess.
Proper Airway Protection and Surgical Management with the use of antibiotics and
advanced medical supportive care, the mortality of Ludwig’s angina has been further
reduced to 4%
4. Microbiology of Odontogenic Infections
The Oral microflora is complex and fluctuates with age, disease conditions and
preferred site of residence
Streptococci represent almost half of the viable counts of saliva and dorsum of the
tongue.
Polymicrobial with a higher prevalence of gram-positive cocci and gram-negative rod,
being the streptococci the most prevalent.
There is a 3:1 ratio of anaerobic to aerobic bacteria.
6. Laboratory Investigations in Oral and Maxillofacial Infections
To estimate the clinical condition of the patient, laboratory tests, such as white blood
cell count, and inflammatory markers, such as erythrocyte sedimentation rate (ESR)
and C-reactive protein (CRP), are used.
Physical examination; In advanced stages of OI an alteration of vital signs along with
leukopenia are manifested as a
Systemic Inflammatory Response Syndrome:
Temperature is < 36° or > 38°
Heart rate > 90/min
Respiratory rate > 20/min
Neutrophils > 12,000 mm3
13. Principles of Management of Odontogenic Infections
The eight steps in the management of odontogenic infections are as follows:
1. Determine the severity of infection.
2. Evaluate host defenses.
3. Decide on the setting of care.
4. Treat surgically.
5. Support medically.
6. Choose and prescribe antibiotic therapy.
7. Administer the antibiotic properly.
8. Evaluate the patient frequently.
15. Determine Severity of Infection
Three major factors must be considered in determining the severity of an infection of
the head and neck:
Anatomic location
Rate of progression
The potential for airway compromise of a given infection.
16. Anatomic Location
Facial Spaces are graded upon the level to which they threaten the airway or vital
structures.
Low Severity; The buccal, infraorbital, vestibular, and subperiosteal spaces
Moderate Severity; the masticator space (sub-masseteric, pterygo-mandibular, and
superficial and deep temporal spaces) and the peri-mandibular spaces
(submandibular, submental, and sublingual).
High Severity; lateral pharyngeal and retropharyngeal, the danger space, and the
mediastinum.
Cavernous sinus thrombosis and other intracranial infections also have high severity
18. Rate of Progression
Onset of swelling and pain and comparing to the current signs and symptoms of
swelling, pain, trismus, and airway compromise.
Stage I: Inoculation Stage
Stage II: Cellulitis Stage
Stage III: Abscess Stage; Fluctuance
Stage IV: Healing Stage
19.
20. Airway Compromise
The most frequent cause of death in reported cases of odontogenic infection is airway
obstruction.
Endotracheal intubation may be made,
Cricothyroidotomy or tracheotomy is more predictably successful.
Infection in the region of surgical airway access is not a contraindication to an
emergency cricothyroidotomy or tracheotomy.
In partial airway obstruction, abnormal breath sounds will be evident, consisting of
stridor or coarse airway sounds suggestive of fluid in the upper airways.
The patient may assume a special posture that straightens the airway, such as the
“sniffing position; the head is inclined forward and the chin is elevated, as if one were
sniffing a rose.
21. Airway Compromise
Sitting patient with the hands or elbows on the knees and the chest inclined forward
with the head thrust anterior to the shoulders (tripod position), which also straightens
the airway and pulls the tongue forward
22. Airway Compromise
Trismus; A maximum Interincisal opening that has decreased to 20 mm or less in a
patient with acute pain should be considered an infection of the masticator space until
proved otherwise.
Infections of the pterygomandibular space are sometimes missed because trismus
hinders the examiner’s view of the oropharynx.
Pulse Oximetry
An oxygen saturation of below 94% in an otherwise healthy patient is indeed an
ominous sign, because it indicates insufficient oxygenation of the tissues due to
hypoperfusion or hypo-oxygenation.
Given the patient with clinically apparent partial airway obstruction, an abnormally low
oxygen saturation is an indication for immediate establishment of a secure airway.
23. Necrotizing Fasciitis
Necrotizing fasciitis is a rapidly spreading infection that follows the platysma muscle
down the neck and onto the anterior chest wall.
Type I, or polymicrobial
Type II, or group A streptococcal
Type III gas gangrene, or clostridial myonecrosis
Group A Streptococcus (group A strep) are the most common cause of necrotizing
fasciitis.
Diabetes and alcoholism have been shown to be significant predisposing factors.
Medical compromise, delay in surgery, and mediastinitis are associated with increased
mortality
24. Necrotizing Fasciitis Signs and Symptoms and Investigations
The earliest signs of necrotizing fasciitis are small vesicles and a dusky purple
discoloration of the involved skin, soon after the skin becomes anesthetic and frank
necrosis appears
Complete blood count with differential, Serum chemistry studies,
Arterial blood gas measurement
Urinalysis
Blood and tissue cultures
Sonography may reveal subcutaneous emphysema spreading along the deep fascia,
swelling.
Computed tomography (CT) scanning can pinpoint the anatomic site of involvement by
demonstrating necrosis with asymmetrical fascial thickening and the presence of gas
in the tissues.
27. Necrotizing Fasciitis
Management of Necrotizing Fasciitis:
Broad-spectrum antibiotics; To cover Aerobic and Anaerobic Bacteria
Repeated surgical drainage
Antiseptic wound packing
Intensive medical supportive care, including fluids, calcium, and possibly blood
transfusion.
Hyperbaric oxygen therapy may also be of benefit
32. Axial computed tomography image at the level of the hyoid bone, demonstrating a
cellulitis of the left lateral pharyngeal space that is deviating the airway to the
opposite side
35. Diabetes and Infections
In uncontrolled diabetes hyperglycemia occurs, affecting the defense cells, favoring
the persistence of an infectious process due to the following factors:
1. Decreased chemotaxis, adhesion, migration and phagocytosis of leukocytes. They
present less defensive capacity against bacteria and prolong the inflammatory state.
2. Decreased proliferation of fibroblasts, endothelial cells and collagen. Impairs tissue
repair.
3. Macrophages and monocytes evade apoptosis, thus increasing cytokine production
and prolonging the inflammatory process. Chronic inflammation increases insulin
resistance.
4. Microangiopathy decreases blood flow and consequently decreases oxygen and
nutrients to defensive and reparative cells. Also, it hinders the arrival of antibiotics to
the site of infection.
5. Decreased proliferative capacity of keratinocytes which delays re-epithelialization of
wounds
36. Immune System Compromise
Corticosteroids appear to stabilize the cell membranes of immunocompetent cells,
thereby decreasing the immune response.
Organ transplant; Corticosteroids and Immunosuppressive Medications
Cancer chemotherapy directly suppresses the immune system along with rapidly
dividing cancer cells.
The role of human immunodeficiency virus (HIV) infection in diminishing host
resistance to odontogenic infections is somewhat unclear and paradoxical.
HIV infection first and primarily damages the T cell.
Most odontogenic infections are due to extracellular bacteria, which are attacked by B
cells, the white blood cells that elaborate antibodies.
Although HIV infection may damage B cells early in the course of the disease, its most
devastating effects are seen on the T cells.
37. Systemic Reserve
Fever can increase sensible and insensible fluid losses and caloric requirements.
A prolonged fever may cause dehydration, which can decrease cardiovascular
reserves and deplete glycogen stores, shifting the body metabolism to a catabolic
state.
An elevated temperature at an advanced age is not only a sign of a particularly severe
infection, but also an omen of decreased cardiovascular and metabolic reserve, due to
the demands placed on the elderly patient’s physiology.
41. Decide on the Setting of Care
Dehydration can be assessed by clinical signs of dry skin, chapped lips, loss of skin
turgor, and dry mucous membranes.
It can also be assessed in the presence of normal serum creatinine by:
An elevated urine specific gravity (over 1.030)
An elevated blood urea nitrogen (BUN) which indicates prerenal azotemia.
An odontogenic infection involving the masticator space, the peri-mandibular spaces,
or the deep neck spaces indicates hospital admission.
General anesthesia is required for patient management due to:
Inability to achieve adequate local anesthesia
The need to secure the airway
The inability of the patient to cooperate, as in a young child.
44. Airway Security
An infrequently used surgical technique that may aid in protecting the airway during
intubation or tracheotomy is needle decompression.
Under local anesthesia an abscess of the pterygo-mandibular, lateral pharyngeal ,
submandibular, or sublingual space is aspirated with a large-bore needle in order to
decompress the surrounding tissues:
Decrease the risk of abscess rupture through taut
Distended oropharyngeal tissues during instrumentation of the airway.
The redirection of pus drainage into the oral cavity or onto the skin
Obtaining an excellent specimen for culture and sensitivity testing.
45. Use of drains that have a line that appears Radiopaque
46. A: Superficial and deep temporal, submasseteric
B: submandibular, submental, sublingual
53. Surgical Drains
The advantages of through-and-through drainage are:
The provision of two pathways for the egress of pus
Placement of the incisions in healthy tissue in cosmetically acceptable areas
The ability to irrigate the infected wound with unidirectional flow from one incision to
the other.
Recent evidence does not support increased effectiveness of irrigating drains
54. Surgical Drainage
Drains should be discontinued when the drainage ceases.
They may be advanced gradually or removed all at once.
Pus usually stops flowing from surgically drained abscesses in 24–72 h, but this
process may take somewhat longer when only cellulitis has been encountered.
Latex Penrose drains can be antigenic, and after several days they may cause
exudation due to foreign body reaction alone.
55. Barton dressing, which avoids taping of the skin.
It can occlude and absorb the drainage of a maxillofacial infection
56. Timing of Incision and Drainage
“Never let the sun set on an undrained abscess”
57. Timing of Incision and Drainage
Expectant approach to surgical drainage of deep neck infections.
Use of parenteral antibiotic therapy as a means of controlling, localizing, or even
eradicating the soft tissue infection; Only then is surgical drainage undertaken.
The immediate establishment of airway security as necessary, and aggressive early
surgical intervention [Williams and Guralnick]
Identification of an abscess is not required before surgical intervention.
Predicated on the concept that early incision and drainage aborts the spread of
infection into deeper and more critical anatomic spaces, even when it is in the cellulitis
stage.
Peptostreptococcus was associated with cellulitis more than abscess
60. Culture and Sensitivity
Routine culture and sensitivity testing for minor oral infections does not appear to be
justified.
Culture and sensitivity testing as early as possible in the course of infection is
important in:
An infection involves anatomic spaces of moderate or greater severity
There is significant medical or immune system compromise,
Multiple prior courses of antibiotic therapy or in chronic infections that are recalcitrant
to therapy.
The final result of antibiotic sensitivity testing can be delayed for as much as 2 weeks
when fastidious or antibiotic-resistant organisms are involved.
61. Culture and Sensitivity
Even though the surgeon may not encounter pus during aspiration attempts or surgical
drainage, fluid aspirates and swab cultures of infected sites do yield valid cultures with
readily interpretable results.
Specimens should be sent for culture and sensitivity testing even when pus is not
obtained.
63. Support Medically
Hydration
Nutrition
Control of fever in all patients.
Maintenance or reestablishment of electrolyte balance and the control of systemic
diseases may also be a crucial part of the necessary supportive medical care for some
cases.
Decreased prealbumin levels; acute malnutrition, has been correlated with an
increased length of hospital stay in severe odontogenic infections.
Prealbumin levels can be used in evaluating a patient’s systemic reserve at the time of
admission, and need for nutritional support in some cases
64. Support Medically
Initial temperature has been shown to be a significant predictor of the length of hospital
stay
Fever below 103 °F (39.4 °C) is probably beneficial; to promote phagocytosis, increase
blood flow to the affected area, raise the metabolic rate, and enhance antibody
function.
Above 103 °F, fever can become destructive by increasing metabolic and
cardiovascular demands beyond physiologic reserve capacity.
Adequate hydration is perhaps the best method for controlling fever.
Daily sensible fluid loss, consisting primarily of sweat, is increased by 250 mL per
degree of fever. [each degree above 98.6°F [37°C]
Insensible fluid loss, consisting mainly of evaporation from lungs and skin, is
increased by 50 to 75 mL per degree of fever per day. [each degree above 98.6°F
[37°C]
65. Support Medically
The administration of acetaminophen or aspirin.
Fevers are often exaggerated in children and decreased in the elderly.
Fever also increases metabolic demand by 5–8% per degree of fever per day.
Supplement the infected patient’s oral intake, which is likely to be significantly inhibited
by the local effects of the infection and surgery, by using supplementary feedings or
even enteral nutrition via a feeding tube
67. Eight Principles of Modern Antibiotic Therapy
1. Surgery to remove the cause and establish drainage is primary; antibiotics are adjunctive
treatment.
2. Use therapeutic antibiotics only when clinically indicated.
3. Use specific antibiotic therapy as soon as possible, based on culture and sensitivity
testing.
4. Use the narrowest spectrum empiric antibiotic effective against the most likely
pathogens.
5. Avoid the use of combination antibiotics, except in specific situations where they are
shown to be necessary.
6. Use the least toxic indicated antibiotic, considering interaction with concurrent
medications.
7. Minimize the duration of antibiotic therapy, as appropriate to the presenting type of
infection.
8. Use the most cost-effective appropriate antibiotic
68. Use of Therapeutic Antibiotics only when indicated
Significant evidence is now available that antibiotic resistance is increasing among the
oral pathogenic flora.
The presence of one or more penicillin-resistant organisms in culture specimens from
odontogenic infections has increased from 33% in 1991 to 63% in 2017.
Clindamycin resistance increased from 13.7% in 2006 to 32% in 2017.
69.
70. Use Specific Antibiotic Therapy as Soon as Possible, Based on
Culture and Sensitivity Testing
Empirical Antibiotics
Prophylactic Antibiotics
Therapeutic Antibiotics
Identification of the causative pathogens and their antibiotic sensitivities has become
even more important than previously.
The use of broad-spectrum antibiotics is appropriately shortened, thus reducing
selection of antibiotic resistant bacteria.
71.
72. Use the Narrowest Spectrum Empiric Antibiotic Effective
Against the Most Likely Pathogens
Antibiotic selection is based on the individual patient’s medical history, pharmacologic
safety, and of least importance, cost
Flynn et al. found a 21% clinical failure rate of intravenous penicillin G in severe
odontogenic infections.
All of the patients meeting the criteria for clinical antibiotic failure subsequently yielded
antibiotic-resistant organism(s) when culture results became available.
Ampicillin-sulbactam has thus become the intravenous antibiotic of choice for severe
odontogenic infections in many institutions.
The addition of sulbactam, a beta-lactamase inhibitor to ampicillin, significantly
increases its effectiveness against the penicillin-resistant aerobic and anaerobic oral
pathogens, most of which synthesize penicillinase.
73. In infections that threaten the intracranial contents, selection of an antibiotic that
crosses the blood-brain barrier is essential.
Clindamycin does not cross the blood-brain barrier well.
The penicillins cross the bloodbrain barrier when the meninges are inflamed.
Metronidazole, a few cephalosporins (such as ceftriaxone), the fluoroquinolones (such
as moxifloxacin), and linezolid cross the blood-brain barrier.
Use the Narrowest Spectrum Empiric Antibiotic Effective
Against the Most Likely Pathogens
74. Avoid Combination Antibiotics Except in Situations in which
They Are Necessary
Combined antibiotic therapy regimens significantly increase the cost of care, especially
when given intravenously, and by increasing their antimicrobial spectrum, can select
for the survival of antibiotic-resistant organisms.
Can Bacteriostatic and bactericidal antibiotics be combined together?
Increased nephrotoxicity of vancomycin and gentamicin when they are combined.
In Odontogenic Infections given appropriate surgical therapy, a single antibiotic is
effective; Polymicrobial
When Conventional Culture methods are used it would yield 4–6 species and as many
as 18 species per case when molecular methods are used.
75. Use the Least Toxic Indicated Antibiotic, Considering
Interaction with Concurrent Medications
76. The penicillins, especially amoxicillin, because of increased compliance due to a
longer dosage interval and due to its lower cost than penicillin V, are among the safest
antibiotics appropriate for odontogenic infection.
Allergy Risk; Approximately 10% of patients report an allergy to penicillin, up to 90% of
these patients do not have a true allergy.
The incidence of anaphylaxis to penicillin is 0.02% to 0.04% and is mediated by a type
1 hypersensitivity reaction. [Latest Update June 2022]
Use the Least Toxic Indicated Antibiotic, Considering
Interaction with Concurrent Medications
77. Clindamycin becomes the empiric antibiotic of choice in penicillin allergy; Antibiotic-
associated colitis due to intestinal overgrowth of Clostridium difficile remains a
concern.
Azithromycin has a significant safety advantage over the other macrolide antibiotics,
because it is not metabolized by the CYP3A4 microsomal enzyme,
Azithromycin also has a better safety rating in pregnancy than the other macrolides.
Metronidazole; generally used in combination with other antibiotics effective against
aerobes, such as the penicillins.
Fluoroquinolones; Moxifloxacin’s spectrum covers the odontogenic pathogens,
including anaerobes.
Eikenella corrodens; if isolated the fluoroquinolones become the antibiotic of choice.
Use the Least Toxic Indicated Antibiotic, Considering
Interaction with Concurrent Medications
78. Minimize the Duration of Antibiotics
Continue the course of Antibiotic?
Antibiotic resistance is often conferred in a single step, by transfer of antibiotic
resistance genes even among different species.
Limitation of the period of antibiotic exposure may allow the “wild” strains to gradually
outcompete the resistant strains and replace them, thus reducing antibiotic resistance
of the target bacterial species.
Lewis et al. compared two large doses of amoxicillin on the day of surgery with a 5 day
course of penicillin V
Chardin et al. compared 3 and 7 day courses of amoxicillin, combined with appropriate
surgical treatment.
These studies indicate that there is no difference in clinical cure at 7 days using either
a 1–3 day antibiotic course or a 5–7 day antibiotic course, given appropriate surgery.
80. Proper Adminstration Route
The tissue level of antibiotics determines their effectiveness.
Oral route requires that the drug successfully navigate Intestinal Absorption and First
Pass Metabolism.
Orally administered antibiotics achieve much lower serum level at a slower rate than
when they are injected directly into the vascular system intravenously.
Fluoroquinolones (Ciprofloxacin and Moxifloxacin) are equally well absorbed
intravenously and orally [ IV route is not needed unless oral route is contraindicated]
The minimum inhibitory concentration (MIC) is the concentration of an antibiotic that is
required to kill a given percentage of the strains of a particular species, reported as
50% or 90% of strains (MIC50 or MIC90, respectively).
81. Proper Adminstration Route
The effectiveness of some antibiotics is determined by the ratio of the serum
concentration of the antibiotic to the MIC required to kill a particular organism.
Fluoroquinolones and the aminoglycosides; concentration- dependent antibiotics.
Time-dependent antibiotics, such as the β-lactams and vancomycin, antibiotic
effectiveness is determined by the duration for which the serum concentration of the
antibiotic remains above the MIC.
Serum elimination half-life (t1/2) of the antibiotic in order to determine its proper
dosage interval.
The dosage interval can then be designed in order to maintain the serum
concentration above the MIC for at least 40% of the dosage interval.
82. Proper Adminstration Route
Penicillin G, two million units given intravenously every 4 h, should be highly effective
against the viridans group of streptococci, especially the abscess-forming S. milleri
group
Oral amoxicillin is less likely to be effective against the viridans streptococci than
intravenous penicillin G.
84. Outpatient Follow-up
The most appropriate initial follow-up appointment is usually at 2 days postoperatively
for the following reasons:
1. Usually the drainage has ceased and the drain can be discontinued at this time.
2. There is usually a discernible improvement or deterioration in signs and symptoms
allowing the next treatment decisions to be made.
85. Inpatient Follow-up
Daily
By 2 to 3 postoperative days the clinical signs of improvement should be apparent,
such as:
Decreasing swelling
Defervescence
Cessation of wound drainage
Declining white blood cell count
Decreased malaise
Decrease in airway swelling such that extubation can be considered.
86. Inpatient Follow-up
Preliminary Gram stains and/or culture reports should be available, which may provide
some guidance as to the appropriateness of the empiric antibiotic therapy.
If the signs of improvement are not apparent: A postoperative CT is indicated when
Continued airway swelling that may preclude extubation,
Further spread of the infection into previously undrained anatomic spaces
It may confirm adequate surgical drainage of all the involved anatomic spaces by the
visualization of radiopaque drains in all of the involved fascial spaces
87. Four-days postoperative computed tomography (CT) image of a
patient with a right pterygomandibular and lateral pharyngeal space
abscess
88. Five-days postoperative axial CT of a patient with a previously
placed drain in the left Pterygomandibular space (arrow)
89. Inpatient Follow-up
The best available clinical test for the ability to extubate in the case of upper airway
swelling is the air leak test
90. Air-Leak Test
1. The endotracheal tube and trachea are suctioned.
2. The oxygen supply is reconnected and any coughing that was stimulated by the
tracheal suctioning is allowed to subside.
3. The oropharynx and oral cavity are suctioned free of debris, hemorrhage, and
secretions.
4. The cuff of the endotracheal tube is deflated while the oxygen supply is maintained.
5. After waiting for any coughing to subside, the oxygen supply is disconnected and the
surgeon’s thumb is placed to occlude the opening of the endotracheal tube.
6. The patient is then instructed to breathe spontaneously around the endotracheal
tube, and if this can be done, a positive air leak test is obtained.
If the patient cannot breathe around the occluded endotracheal tube, then a negative
result is obtained, and extubation should be delayed
91. Extubation
Given a positive air leak test result, the best method for patient extubation involves
extubation over a stylet or preferably an endotracheal tube changer.
1. The patient is pre-oxygenated for 3–5 min.
2. The endotracheal tube and trachea are suctioned.
3. Five milliliters of 1% lidocaine without epinephrine is administered via the
endotracheal tube, followed by oxygenation and then repeated tracheal suctioning.
4. The oral cavity and oropharynx are suctioned free of debris, hemorrhage, and
secretions.
5. The oxygen supply is disconnected and a tube changer then is introduced into the
trachea via the endotracheal tube.
6. The cuff of the endotracheal tube is deflated and the endotracheal tube is withdrawn
over the tube changer until its tip is in the oropharynx
92. Extubation
7. If the patient is able to breathe around the tube changer as it remains in the trachea,
then extubation can be completed.
8. If the patient is not able to breathe around the tube changer, then the endotracheal
tube is re-inserted over the tube changer into the trachea.
9. The endotracheal tube cuff is re- inflated, the tube changer is withdrawn, and oxygen
is reconnected.
After extubation, the patient is closely monitored clinically and with pulse oximetry.
Arterial blood gases may be drawn 1 h after extubation in order to verify adequate
oxygenation and ventilation.
Occasionally, the infecting flora will change during the course of treatment; selection
pressure exerted by intensive antibiotic therapy, or due to the subsequent introduction
of hospital-acquired pathogens, resulting in a nosocomial infection.
93. Inpatient Follow-up
Mnemonic can be used to provide a differential diagnosis for the chronic drainage of
pus.
“FETID” stands for:
Foreign body; bone plates and screws, or dental or cosmetic facial implants
Epithelium; may cause chronic drainage simply because an epithelialized fistulous
tract has not been completely excised or because an epithelium-lined cyst has drained
externally.
Tumor; (especially malignant ones) that become infected do not heal, which may result
in chronic drainage.
Infection
Distal obstruction; classically refers to intestinal obstructions, but the concept can still
be applied to the salivary ducts and to the natural sinus drainage pathways.
96. Corticosteroids in Maxillofacial Infections
The mass effect produced by edema causing airway obstruction.
Surgical management of the infection also may result in increased swelling around the
airway, necessitating prolonged intubation or tracheostomy.
97. Corticosteroids in Maxillofacial Infections
The role of corticosteroids in the management of deep cervicofacial infections
continues to cause controversy
