Severe Odontogenic Infections: Causes of Spread and Their Management

Abstract

Background:

We conducted a study designed to investigate the clinical factors correlated with the spread of an odontogenic infection to the deep spaces of the head and neck. We also analyzed the treatment modalities for this and their outcomes.

Methods:

The study retrospectively examined all patients admitted in 2009 and 2010 to the General Hospital of Attica “KAT” with maxillofacial infections of odontogenic origin. The patients' case records were reviewed according to predefined inclusion and exclusion criteria and the relevant data were collected. The data were analyzed statistically.

Results:

The study involved 212 patients with a mean age of 40.8 y. Of these, 59.9% reported using oral antibiotics, usually (35.4%) without prescription. Moderate or poor oral hygiene was present in 78.3% of the study patients. The percentage of incompatible use of antibiotics due to non-compliance was 13.4%. Non-compliance indicates that these patients failed to follow the daily dosage or the dosing intervals of a prescribed antibiotic or they stopped an antibiotic due to an adverse reaction. Incision and drainage was required in 63.2% of the study patients, and 46.2% required extraction of the tooth responsible for their infection. A statistically significant association was documented between fever on admission and a prolonged hospital stay. No major complications were encountered among the study patients.

Conclusions:

Odontogenic infections remain a common cause of morbidity. Poor oral hygiene, self-medication, inadequate utilization of antibiotics, lack of treatment of the causative tooth, delayed presentation at the hospital, and bacterial resistance to empirically administered antibiotics appear to correlate with the spread of odontogenic infections. Incision and the evacuation of pus when indicated, intravenous antibiotic therapy, modification of the antibiotic regimen according to the results of sensitivity tests, and early treatment of the causative tooth constitute a successful management protocol for odontogenic infections.

Despite the widespread utilization of antibiotics and improvements in health-care services, odontogenic maxillofacial infections remain a common cause of morbidity and mortality [1,2]. These infections impose substantial financial costs and may result in severe, even life-threatening complications, such as necrotizing fasciitis, airway obstruction, thrombosis of the cavernous sinus, orbital abscess and loss of vision, descending mediastinitis, cardiac tamponade, and severe sepsis [3 –8].

It has been documented that most infections of the head and neck are of odontogenic origin [1,2,9]. The earliest stage of an odontogenic infection is the inoculation of bacteria into periapical tissues. The portal by which bacteria enter these tissues may be a carious or non-vital tooth, defective root canal treatment, or deep periodontal pocket. The periapical tissues are the initial site of bacterial growth, resulting in a focus of infection, which induces an immune response in the patient [10]. Occasionally, the immune system alone or together with a therapeutic intervention (e.g., dental treatment, antibiotics) suffices in combating the infection. At other times, however, the infection cannot be restrained and spreads along the path of the least resistance to affect the deep maxillofacial spaces.

We conducted a study to investigate factors that could correlate with the spread of odontogenic infections. In addition to our findings in this study, we also report our experience with the in-hospital treatment and outcome of the infections in the study.

Patients and Methods

The study comprised all patients admitted with a diagnosis of odontogenic infection or post-extractive infection over the 2-y period of 2009 and 2010. Cases of infection without an evident odontogenic cause were excluded, as also were cases of patients with odontogenic sinusitis, osteomyelitis, infected cystic lesions of the jaws, or a history of radiotherapy to the head or neck. All other cases were considered eligible for the study.

The case records of the patients were reviewed retrospectively for predetermined factors that could correlate with the clinical appearance and management of odontogenic infections. No institutional review board approval was required for the study because of its retrospective nature. For each case included in the study the following data were collected: 1) Demographics (age and gender); 2) preadmission course (duration of symptoms, antibiotic therapy per os and whether the patient was compliant with the appropriate dosage, and referral or not by the patient's dentist); 3) clinical presentation (signs and symptoms, involved space, causative tooth, oral hygiene); 4) medical history; 5) in-hospital course and management (incision and drainage or not, extraction of causative tooth or not, culture and sensitivity test results, change of the patient's empiric antibiotic regimen or not); and 6) duration of hospitalization.

All patients were subjected to the same treatment protocol including: 1) A standard intravenous antibiotic regimen of ampicillin-sulbactam plus metronidazole or clindamycin alone in case of allergy to β-lactam drugs. 2) Incision and drainage of the involved anatomic spaces, given clinical or radiologic evidence of pus or in cases of life-threatening abscesses. 3) Aerobic and anaerobic cultures of the harvested exudates, as well as sensitivity testing. 4) Appropriate modification of the patient's antibiotic regimen based on the result of sensitivity testing. In all cases dental surgery was done only after at least one dose of intravenous antibiotics and analgesics, and was done under local anesthesia. Extractions of responsible but non-salvageable teeth extractions were done as soon as possible, irrespective of drainage.

Statistical analysis of the study data was done with SPSS software version 17.0 (SPSS, Chicago, IL). Descriptive statistics were used to present the patient data (mean and standard deviation [SD]). Comparisons between different study groups was done with the Student t-test. Values of p<0.05 were considered significant.

Results

Over the 2-y period of 2009 and 2010, a total of 981 patients were admitted to our department. Among them, 305 (31.0%) were admitted with a diagnosis of infection, of whom 212 (21.6%) met the inclusion criteria and were enrolled in the study. Of these 212 patients, 103 were males (48.6%) and 109 females (51.4%), ranging in age from 14–82 y, with a mean age of 40.78 y (SD=16.4). The patients' mean length of hospitalization was 5.77 d (SD=3,08), with a minimum and maximum value of 1 d and 22 d, respectively. The mean interval from the onset of the patients' symptomatology to their presentation at the emergency department was 4.91 d (SD=3.9), with a minimum value of 1 d (22 cases) and a maximum of 21 d (one case).

Three categories of oral hygiene were constructed for the study. Of the 212 patients in the study, 44 (20.8%) had good, 112 had moderate (52.8%), and 54 (25.5%) had poor oral hygiene. In two cases data about oral hygiene were missing from the file, and these cases were excluded from the descriptive presentation of the oral hygiene results for the study.

As depicted in Table 1, the space affected most frequently by odontogenic infection was the submandibular space (42.0%), followed by the buccal space (29.7%) and the canine fossa (11.3%). Infection in other locations occurred in fewer than 5% of the study patients. In 12.3% of cases infection occurred post-extractively.

Table 1.

Affected Fascial Spaces of the Head and Neck

Affected space	Cases	%
Submandibular	89	42.0
Buccal	63	29.7
Canine fossa	24	11.3
Lateral pharyngeal	10	4.7
Palatal	10	4.7
Submental	7	3.3
Pterygomaxillary	5	2.4
Submasseteric	4	1.9

A high proportion of the subjects (59.9%) reported the use of oral antibiotics. Forty-five patients (35.4%) practiced self-medication and 80 (63%) took antibiotics prescribed by a dentist or a general practitioner. Of the 127 patients receiving antibiotics, 17 (13.4%) used them in an inadequate daily dosage or at inadequate dosing intervals. In the study, these patients were classified as non-compliant. The medication data for the study are analyzed in Table 2.

Table 2.

The Oral Antibiotics Received by the Study Patients before Admission and Cases of Non-Compliance and Self-Medication

Reported oral antibiotics	Cases	Non-compliant	Self-medication
AMX	43 (33.9%)	2	12
AMX+metronidazole	20 (15.7%)	5	3
AMX/CA	19 (15.0%)	1	8
AMX/CA+metronidazole	14 (11.0%)	4	4
Clindamycin	11 (8.7%)	3	3
Cefaclor	7 (5.5%)	0	3
Clarithromycin	5 (3.9%)	1	4
Metronidazole	4 (3.1%)	1	4
Other	4 (3.1%)	0	4
Total	127	17 (13.4%)	45 (35.4%)

AMX=amoxicillin; CA=clavulanic acid.

Among the total of 212 patients in the study, 100 had been evaluated by a dentist, but only 50 of them were referred to the hospital. The overall referral rate was therefore only 23.6%.

In 93.9% of cases the initial intravenous antibiotic regimen of patients in the study was ampicillin-sulbactam plus metronidazole. In the remaining 6.1% of cases the patients were given clindamycin because of a known allergy to β-lactam drugs. In all cases intravenous antibiotic treatment was continued for the full duration of a patient's hospitalization, with its mean duration coinciding with the study patients' mean hospital stay. After a patient's discharge the same antibiotics given in the hospital were continued orally, as follows: In cases of post-extractive infections, as well as in cases in which the responsible tooth had been extracted, a 4-d course of oral antibiotics was prescribed. In the remaining cases oral therapy was prolonged until definitive management of the responsible tooth by the patient's dentist. As shown in Table 3, five patients required vancomycin, one patient required amikacin, and one patient required ceftriaxone on the basis of sensitivity testing. The respective agents used to treat these five patients may be given entirely on a parenteral basis, and these patients therefore completed their course of antibiotic therapy with intravenous medication during their hospitalization.

Table 3.

Cases of Infection by Organisms That Required a Change in Antibiotic

	Vancomycin	Ciprofloxacin	Amikacin	Cefuroxime	Ceftriaxone
Staphylococcus epidermidis	1	1		2
MRSA	3	2
Enterococcus	1	1
Enterobacter cloacae		1		1	1
Escherichia coli		1
Acinetobacter baumanii			1
Citrobacter braakii		1
Klebsiella pneumoniae		2

MRSA=methicillin-resistant Staphylococcus aureus.

Of the 212 patients in the study, 134 (63.2%) underwent incision and drainage, followed by culture and analysis of a sample of the drainage fluid. Because of unsatisfactory improvement of infection, re-operation was done in nine of these 134 patients. A revision of the incision was done in three cases of lateral pharyngeal, two cases of pterygomaxillary, and one case of submandibular abscess. A second incision was done in three cases of submandibular abscesses. According to the results of culture, bacteria other than those of the normal oral flora were isolated from 23 of the 134 (17.1%) patients who underwent incision and drainage. In 19 of the 134 patients (14.1%), sensitivity testing showed resistance to the initial empiric antibiotic regimen and a new antibiotic was therefore administered (Table 3). In 78 (36.8%) of the 212 study patients no incision or drainage was done, and consequently no sample was sent for culture. All of these 78 patients responded well to their empiric medication. Interestingly, culture failed to grow any bacteria in 8.0% of cases, although a pus sample had been sent for microbiologic analysis. A decision to extract the responsible tooth was made for 98 (46.2%) of the study patients.

Of the 212 patients in the study, 5.7% (12 patients) reported having diabetes mellitus. These patients' mean hospital stay was longer, by a mean of 1.62 d, than that of the non-diabetic patients, but difference did not exceed the level of statistical significance. (t-test, t=1.80, df=208, p=0.072). With fever defined as an axillary temperature of 38.0°C or higher, the mean hospital stay of patients who were febrile at presentation (77 patients; 36.3%) was also longer, by 1.15 d, than that of patients who were non-febrile (135 patients; 63.7%). This difference was statistically significant (t-test, t=2.68, df=210, p=0.008).

The odontogenic infections in all of the study patients resolved finally. The evaluation of resolution was based mainly on clinical signs such as swelling, trismus, pus discharge, and fever. In reaching the conclusion of resolution of infection, the white blood cell count was also taken into consideration. No major or life-threatening complication related to the treatment protocol was recorded.

Discussion

That 31% of the admissions at the maxillofacial unit of a hospital were cases of infection shows that head and neck infections are a frequent cause of morbidity, at least for the population studied. In the series studied, 212 (69.5%) of the 305 patients with infections had odontogenic infections, which constitutes a fairly high percentage of patients with such infections presenting to a general hospital. The predominance of odontogenic cause over other types of infection has been documented by other studies [1,2,11]. A possible explanation for this is a constant flow of microbes of the oral flora toward the periapical tissues of the gum from a diseased tooth. Often, the immune system cannot eradicate such an infection because of the constant arrival, at the anatomic space involved in an odontogenic infection, of new microbes from the diseased tooth. By contrast, other causes of infection do not exert such a constant effect. The infection therefore resolves when the immune system curtails its initial focus of bacterial seeding.

Of the patients investigated in the study, 78.3% (166 patients) had oral hygiene of moderate or poor status. In these cases, the concentration of oral bacteria is increased and their virulence increases concomitantly [12,13], resulting in a greater risk of infection in the presence of an existing portal of bacterial entry into adjacent or nearby tissues. Moreover, it is a common practice of dentists to prescribe an antibiotic agent rather than treating the tooth that is the cause of an infection. As a consequence, a localized infection may spread because of persistence of the portal of bacterial entry to the site of infection. Moreover, the non-vital pulp of a tooth lacks a blood supply, and as a result, neither immune cells nor proteins nor any antibiotics can reach the root canal of the tooth. It has also been proved that bacteria attaching to surfaces, such as gram-positive cocci in the oral cavity, form biofilms that inhibit the interaction of antibiotics with their bacterial targets [14 –16]. Consequently, the only way to eradicate the bacterial focus in cases of such infection is to extract the tooth or use root canal therapy [17]. Given this, poor oral hygiene and lack of treatment of the tooth responsible for an odontogenic infection may increase the risk of its spread.

A percentage of patients with dental infections are noncompliant with oral antibiotic therapy (13.4% in our study). In these cases, the titer of the antimicrobial agent in the serum may be less than its minimum inhibitory concentration for a particular organism, rendering such treatment ineffective and increasing bacterial resistance [18]. The same is also true with self medication (35.4% in our sample), because the antimicrobial agent used in such cases often fails to cover the spectrum of resistance of the pathogens usually responsible for odontogenic infections.

Not uncommonly, the bacteria responsible for such infections are found to be resistant to empiric antibiotics, as suggested by the findings (14.1% resistant organisms) in our study. In their studies, Akinbami et al. [19] and Rao et al. [20] reported similar percentages, and Storoe et al. [21] reported percentages of resistance of as high as 81%. Because bacterial resistance to antibiotics can be regarded as another factor in the spread of maxillofacial infections, we advocate culture and sensitivity testing as both useful and inexpensive procedures that should be included in the management protocol for such infections.

Despite having experienced debilitating symptoms, such as dysphagia or trismus, the patients in our study presented at the hospital on an average of 4.91 d after the onset of their symptoms. The option for early intervention, disrupting the spread of infection, was therefore lost. Delayed presentation of odontogenic infections at a treatment facility, possibly contributing to the spread of such infections, has also been reported in other studies [1,22].

Our standard empiric antibiotic regimen of ampicillin-sulbactam coupled with metronidazole was curative of infection in the vast majority of cases in our study, and this particular regimen is supported widely in the literature [2,9,20,23].

The potency of clindamycin in treating maxillofacial infections has been documented by numerous studies [19,23 –27]. Thirteen patients (6.1%) in our study received clindamycin because of reported β-lactam allergy, and another two patients received it on the basis of the results of sensitivity testing. All 15 of these patients had clinical resolution of their infections. No incidence of pseudomembranous colitis, the most severe adverse effect of clindamycin, was recorded.

Incision and drainage was done in 134 (64.2%) of the 212 patients in our study. By contrast to other reports of the use of general anesthesia in high percentages of patients treated for odontogenic infections [19,22,28], we used local anesthesia in all of the patients in our study on whom we performed incision. The incision was undertaken immediately after fluid resuscitation, the administration of intravenous analgesic agents, and the administration of at least one dose of intravenous antibiotics. All of patients treated in this way cooperated well and none developed any complications. Trismus, encountered in 25.9% of the patients in our series, is a frequent sign of maxillofacial infection [1,22]. Trismus precludes the normal intubation of a patient, instead necessitating intubation under fiberoptic guidance [2,22]. We advocate the alternative of incision under local anesthesia for patients in whom general anesthesia is contraindicated or a fiberoptic laryngoscope is unavailable.

In the present study, diabetes mellitus was recorded for 12 patients (5.7%). Rao et al., in their comparison of maxillofacial infection in diabetic and non-diabetic patients, reported a significantly higher proportion of diabetic patients (31/111) than in our study, and found that these patients had a comparatively longer hospital stay than their non-diabetic patients, with the mean lengths of stay of the two groups being 9.51 d and 6.15 d, respectively [19]. The difference was statistically significant (p=0.003). On the contrary, the respective values for the diabetic and non-diabetic patients in our study were 7.33 d and 5.71 d, which was not statistically significant. This may be attributed to the small sample of diabetic patients in our study.

Conclusions

Minor infections of the mouth confined to the periodontal tissues occasionally spread to the deep fascial spaces of the head and neck, evolving into severe infections. Our results in the present study indicate that important contributions to the process of infectious spread are made by poor oral hygiene, self-medication, non-compliant utilization of antibiotics, lack of treatment of the causative tooth, delayed presentation at a hospital, and bacterial resistance. As a safe and effective management protocol in cases of maxillofacial infection, we propose early treatment of the causative tooth, with incision and drainage as indicated and as early as possible, as well as the use of intravenous antibiotics with aerobic and anaerobic coverage and the adaptation of these antibiotics on the basis of sensitivity testing.

Footnotes

Author Disclosure Statement

No competing financial interests exist

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