Deep neck infections: a study of 365 cases highlighting recommendations for management and treatment
The aims of this investigation were to review the clinical behavior of deep neck infections (DNIs) treated in our institution in order to identify the predisposing factors of life-threatening complications and propose valuable recommendations for management and treatment. A total of 365 adult patients with DNIs were retrospectively identified. One-hundred and thirty-nine patients (38.1%) underwent surgical drainage. Overall, 226 patients (61.9%) responded effectively to intravenous antimicrobial therapy only. There were 67 patients (18.4%) developing life-threatening complications. Diabetes mellitus (odd ratio 5.43; P < 0.001) and multiple deep neck spaces involvement (odd ratio 4.92; P < 0.001) were the strongest independent predictors of complications. The mortality rate was 0.3%. Airway obstruction and descending mediastinitis are the most troublesome complications of DNIs. In selected patients, a trial of intravenous antibiotic therapy associated with an intensive computed tomography-based wait-and-watch policy may avoid an unnecessary surgical procedure. However, about one-fourth of patients present significant comorbidities, which may negatively affect the course of the infection. In these cases and in patients with large or multiple spaces infections, a more aggressive surgical strategy is mandatory.
KeywordsAbscessComplicationsComputed tomographyDeep neck infectionsDiagnosisTreatment
The deep neck spaces are regions of loose connective tissue filling the areas between the three layers of deep cervical fascia. Deep neck infections (DNIs) are suppurative infections that develop within deep neck spaces.
Deep neck infections usually starts as cellulitis in the soft tissues adjacent to the source of upper aero-digestive tract infection: if left untreated and depending on the virulence of the causative pathogen, the infection will eventually lead to an abscess and spread along cervical into to the mediastinum .
The insidious evolution of this pathology still represents an open problem. An unsuspecting physician may underestimate an initially localized infection, which could shortly present as airway collapse or descending mediastinitis.
In most of cases, the source of the infection is a periapical infection, involving the mandibular second or third molar teeth, or an acute follicular tonsillitis [2, 3]. The microbiology of DNIs reflects the normal endogenous upper aerodigestive tract flora and includes both aerobic and anaerobic microorganisms. As a consequence, the microbiology of DNIs is similar and no correlation usually exists between the anatomical region and microbiology of the infection .
The management of DNIs requires a multidisciplinary approach including head and neck surgeon, thoracic surgeon, infectious disease specialist, and radiologist.
The aims of this investigation were to review the clinical behavior of DNIs treated in our institution in order to propose valuable recommendations for management and identify the predisposing factors of life-threatening complications.
Patients and methods
This is an observational descriptive retrospective study of all cases of DNIs treated at the Department of Surgery, Treviso Regional Hospital over a period of 15 years (between May 1995 and November 2010).
Clinical charts, imaging and bacteriologic studies were reviewed. Patients with head and neck cancer, peritonsillar cellulitis or abscess, and post-traumatic infections were not included in the study. The following variables were reviewed: demographic and clinical data, associated systemic diseases, bacteriology, imaging studies, source, site, and character of the infections, medical and surgical treatment, complications, and outcome.
The infection was categorized according to the character of infections (cellulitis vs. abscess) and to the involved spaces (submandibular space, lateral pharyngeal space, retropharyngeal space, prevertebral space, parotid space, masticatory space, temporal space, visceral vascular space, anterior visceral space) according to Levitt . Patients with involvement of two or more spaces were classified as having multiple spaces infection.
The reference ranges for standard values at our laboratory were 4 × 103–11 × 103/mm3 for white blood cell count (WBC), 1.8 × 103–8 × 103/mm3 for neutrophil count, 1 × 103–4.5 × 103/mm3 for lymphocytic count, 0–10 mm/h for erythrosedimentation rate (ESR), and less than 0.5 mg/dL for C-reactive protein (CRP).
Descriptive data are reported as median, range, and percentages, as appropriate. Data were recorded from all patients unless otherwise specified. Following parameters were analyzed in order to identify potential risk factors for life-threatening complications: gender, age, body temperature, WBC, diabetes mellitus, character of infection, multiple space involvement. A multivariate logistic regression analysis was undertaken using a forward stepwise technique, in which including significant risk factors in univariate analysis, in order to identify independent risk factors for complications. Statistical analysis was performed using the SPSS/PC software package (SPSS Inc., Chicago, IL, USA).
Demographic and clinical data
A total of 365 adult patients with DNI were identified for this evaluation. The 365 patients consisted of 205 males (56.2%) and 160 females (43.8%) ranging in age from 18 to 96 years (median 52).
Patients were symptomatic for a median of 5.5 days prior to admission to our institution ranged from 1 to 22 days.
On admission neck swelling (n = 340; 93.2%), throat pain (n = 205; 56.2%), and dysphagia (n = 201; 55.1%) were the most common symptoms. Other symptoms and signs included fever (n = 257; 70.4%), swelling of the upper aero-digestive tract (n = 218; 59.7%), dyspnea (n = 54; 14.8%), neck stiffness (n = 54; 14.8%), trismus (n = 51; 14.0%), dysphonia (n = 50; 13.7%), and otalgia (n = 19; 5.2%).
The total WBC count (median 11.8 × 103/mm3; range 2.5–33.6 × 103/mm3) was increased above the upper limit of normal in 171 cases (46.8%), normal in 192 cases (52.6%), and under the lower limit of normal in two cases. Neutrophil count (median 8.7 × 103/mm3, range 1.1–26.9 × 103/mm3, rate of unknown data 16.4%) was increased above the upper limit of normal in 172 cases (56.4%), normal in 129 cases (42.3%), and under the lower limit of normal in 4 cases. Lymphocytic count (median 1.4 × 103/mm3, range 0.1–6.2 × 103/mm3, rate of unknown data 16.4%) was decreased under the lower limit of normal in 76 cases (24.9%), normal in 224 cases (73.4%), and above the upper limit of normal in 5 cases. ESR (median 50 mm/h, range 2–140 mm/h, rate of unknown data 26.8%) and CRP concentration (median 17.5 mg/dL, range 2–45 mg/dL, rate of unknown data 56.2%) were elevated above the upper limit of normal in 260 cases (97.4%) and in all cases, respectively.
Eighty-two patients (22.5%) had relevant associated systemic disorders including cardiovascular diseases (n = 53), diabetes mellitus (n = 52), pulmonary diseases (n = 14), liver diseases (n = 13), hematological diseases (n = 13), renal diseases (n = 5), connective tissue diseases (n = 3).
All patients underwent otolaryngological examination with fiber-optic, b-mode ultrasonography of the neck and/or contrast-enhanced computed tomography (CECT)/magnetic resonance imaging (MRI) of the neck. CECT and MRI were performed in 321 (87.9%) and 23 (6.3%) patients, respectively. 3-mm slides from skull base to the superior mediastinum were obtained before and after contrast injection using either the spiral or multi-slice technique. The CECT scan was interpreted as demonstrating an abscess in presence of the enhancing rim around non-enhancing central density consistent with fluid. The initial CECT scan was extended to include the chest in cases of suspected descending infection. Acquisition of high-resolution axial scans of the jaw together with curved and orthoradial multiplanar reconstructions was performed in patients with submandibular space infections and/or suspected odontogenic infection. Follow-up CECT was the diagnostic procedure of choice to evaluate response to medical and/or surgical treatment and was performed in 286 cases (78.3%). Overall, the median number of imaging examinations was two per patient (range 1–9). No significant differences were found in number of imaging procedures between patients who were immediately operated and in patients selected for observation (P = 0.670). On the other hand, a higher number of imaging procedures, particularly CECT, was performed in patients developing complications (median 4, range 3–9).
Source, site, and character of DNIs
The source of infection was identified in 297 patients (81.4%): the most common cause was a pharyngitis (n = 119; 32.6%), followed by dental infection (n = 102; 27.9%), submandibular sialadenitis (n = 39; 10.7%), parotitis (n = 23; 6.3%), cervical lymphadenitis (n = 7; 1.9%), otitis (n = 4; 1.1%), epiglottitis (n = 2; 0.5%). One patient developed deep neck abscess with descending mediastinitis secondary to cervical intravenous drug abuse. The pathogenesis of DNI was not determined in 69 patients (18.9%).
Site and character of deep neck infections
No. of patients (%) (N = 365)
Isolated pathogens from 177 patients with deep neck infections
Streptococcus viridans not typed
Streptococcus, β-hemolytic, group A
Streptococcus group F
All patients received empirical broad-spectrum intravenous antimicrobial therapy on admission in order to eradicate both aerobic and anaerobic microorganisms. The first-line therapy was later modified according to microbiological findings if the isolated microorganisms revealed resistance towards the empiric therapy. The most frequently provided treatment regimens, alone or in combination, were amoxicillin/clavulanate potassium (58.9%), second- and third-generation cephalosporins (37.3%), ampicilline/sulbactam (12.9%), clindamicyn (11.4%), metronidazole (3.6%), and vancomycin (2.4%).
Patients who were clinically unstable (airway obstruction, signs and symptoms of sepsis); patients with descending infection; patients with anterior visceral space involvement, with abscess involving more than two deep neck spaces; and patients with abscess larger than 3.0 cm, underwent immediate surgical drainage. Gas-forming infections were not in itself an absolute indication for immediate surgery unless large amount of tissue were involved. In all the other cases, patients were observed for 48 h. If the patient’s symptoms and signs worsened or if no clinical improvement was noted after 48 h, surgical drainage was performed. On the other hand, if clinical response was seen, a radiographic study was repeated to confirm clinical judgment. If the repeat imaging did not confirm a regression of collection of pus, surgical intervention was anyway considered. In selected cases, therapeutic needle aspiration of abscess was considered an alternative to conventional open surgery.
One-hundred and thirty-nine patients (38.1%) underwent surgical drainage. Of the abscess group (n = 213), 111 patients (52.1%) underwent surgical drainage. Of the cellulitis group (n = 152), 28 patients (18.4%) underwent surgical drainage.
In 112 cases (30.7%), an open surgical drainage was performed under general anesthesia. An exclusively transoral approach was used in 21 cases. An external or combined approach was necessary in 91 patients. In all cases, a wide exposure of the abscess cavity was performed including blunt avulsion of any loculations, the devitalized tissue was débrided, and the wound was irrigated with half-strength hydrogen peroxide. In patients with extensive tissue necrosis, the cervical incision was packed with plain gauze and left open to allow oxygenation of the tissue and daily irrigations with antiseptic solutions. In other cases, wounds were closed after placement of large-bore drains for irrigation. Twenty-seven patients (7.4%) underwent needle aspiration of abscess, with CT-scan guidance in five cases. Intraoperative findings confirmed the CECT diagnosis of abscess in 87.1%. Duration of symptoms (<5 days vs. ≥5 days) was not found to be predictive of necessity of surgical drainage (P = 0.566).
Overall, 226 patients (61.9%) responded effectively to intravenous antimicrobial therapy only.
Sixty-five patients (17.8%) underwent tooth extraction. On discharge, tonsillectomy was proposed to all patients treated for DNI secondary to pharyngotonsillitis.
No. of patients (%) (N = 365)
Jugular vein thrombosis ± septic embolism
Disseminated intravascular coagulation
Sixteen patients (4.4%) developed descending necrotizing mediastinitis with a median of 6 days (range 3–12 days) after onset of first symptoms of cervical infection. Most common symptoms and signs included neck and/or upper aero-digestive tract swelling (n = 16), dysphagia (n = 10), throat pain (n = 11), neck stiffness (n = 5). Acute onset of dyspnea and thoracic pain were seen in three and four patients, respectively. Neck swelling was the only clinical finding in five patients. In most cases (n = 10), the diagnosis of mediastinitis was made on the basis of CECT findings in absence of clinical signs of mediastinum involvement. Twelve patients underwent external drainage of the cervical abscess in conjunction with posterolateral thoracotomy, four patients with infection limited to the upper mediastinal spaces above the tracheal carina underwent transcervical thoracic drainage. Among patients with descending mediastinitis, a microbiological diagnosis was obtained from 10 patients (62.5%). A polymicrobial infection was identified in six patients. The isolated aerobic bacteria were Streptococcus spp (n = 5), Coagulase-negative staphylococcus (n = 3), Acinectobacter baumanii (n = 1), Gemella morbillorum (n = 2), Stenotrophomonas maltophilia (n = 1), and Klebsiella pneumoniae (n = 1). Bacteroides spp (n = 3), Fusobacterium spp (n = 2), Peptostreptococcus spp (n = 2), and Veillonella spp (n = 1) were detected in anaerobic cultures.
Among patients with critical airway narrowing, 15 patients (48.4%) had a bilateral diffuse gangrenous cellulitis of the submandibular and sublingual spaces (“Ludwig’s angina”) with or without extension to the visceral anterior space. In order to resolve airway obstruction, 8 patients underwent emergency tracheostomy, 17 patients underwent fiberoptic guided awake endotracheal intubation, and 6 patients achieve relief after successful treatment by intravenous corticosteroids.
Eleven patients developing visceral vascular space infection with jugular vein thrombosis secondary to oropharyngeal infection, underwent long-term antibiotic therapy in association with anticoagulant therapy (enoxaparin 100 IU/kg twice daily for 3 months). All patients with jugular vein thrombosis complained of neck stiffness. Positive blood cultures for Fusobacterium spp. and Streptococcus constellatus were documented in four and one patient, respectively. Septic embolization to multiple sites (lung, liver, spleen, and joints) was observed in five cases (Lemierre’s syndrome). Two patients with associated parapharyngeal abscess—one of those with concomitant descending mediastinitis—underwent surgical drainage of the pus collection. No patients underwent ligation of the internal jugular vein. Less severe complications account for osteomyelitis (n = 2) and vocal cord palsy (n = 2).
Predictors of complications
Univariate associations with life-threatening complications
Odds ratio (95% CI)
Sex: male vs. Female
Age: per 10-year increase
Body temperature: per increase of 1°C
White blood cell count: per increase of 1 × 103/mm3
Evidence of colliquation
Multiple space involvement
Factors associated with life-threatening complications in the stepwise multivariate model
Odds ratio (95% CI)
Body temperature: per increase of 1°C
White blood cell count: per increase of 1 × 103/mm3
Evidence of colliquation
Multiple space involvement
One patient with diabetes mellitus and liver dysfunction who have developed sepsis and disseminated intravascular coagulation died from severe hepatic insufficiency 16 days after successful drainage of bilateral submandibular abscess with extension to the anterior visceral space. All other patients were discharged in stable condition after a median length of inpatient stay of 11 days (range 6–73 days).
This is the largest series of DNIs reported in Western literature. Although DNIs can affect all age-group, most of cases in the present series were concentrated between the fifth and seventh decade of life. About one-fourth of patients have relevant associated comorbidities with diabetes mellitus being the most frequent. Diabetes mellitus is commonly reported in patients with DNIs . Several authors have identified diabetes mellitus as a significant risk factor for infection-related morbidity and mortality [5, 6]. The results of our study confirmed diabetes mellitus as the strongest independent predictors of complications. Peripheral vascular disease in diabetics may predispose patients to anaerobic infection . Furthermore, patients with a hyperglycemic state have functional leukocyte, macrophage, and fibroblast impairments that increase their susceptibility to serious infections [8, 9]. Therefore, optimal control of diabetes mellitus play a critical role in DNIs management: insulin use is the best option due to flexibility of timing and dose.
Most DNIs are mixed polymicrobial infections including aerobes and anaerobes. Bacteroides fragilis, Prevotella, Porphyromonas, and Fusobacterium spp resist penicillin through the production of beta-lactamase. Overall, more than two thirds of DNIs contain beta-lactamase-producing microorganisms. The low tissue oxygen tension in the loose areolar tissue of the cervical spaces favor the synergistic growth of aerobic and anaerobic bacteria. Streptococcus spp and Bacteroides spp were the most prevalent microorganism in aerobic and anaerobic bacterial cultures, respectively, reflecting the predominant pharyngeal source of DNIs in the present series. No bacterial growth was recorded in 188 patients and anaerobes were isolated in minority of cases. Use of antibiotics before admission, high-dosage intravenous empiric antibiotic therapy prior to surgical drainage, improper collection of specimen, no routine use of anaerobic cultures, and difficult in culturing anaerobes may affect and may have affected the result of microbiological tests in this series. Increase in the incidence of anaerobic bacteremias with multiple-drug-resistant organisms is emerging as a significant health problem as there is an increasing population with multiple comorbidities and compromised immune system . Anaerobes express significant virulence factors including adherence and spreading factors as hyaluronidase, collagenase, and fibrolysin that may promote the dissemination of a localized infection . Anaerobes also have the ability to produce the enzyme beta-lactamase protecting themselves and other penicillin-susceptible organisms from the activity of penicillins .
Therefore, all efforts should be directed to maximize successful isolation of anaerobes. In order to increase the chances of effective microbiological diagnosis, the specimen for anaerobic cultures should be an aspirate obtained by needle and syringe, transferred into anaerobic culturette, avoiding exposure to oxygen, and transported to the laboratory within 2–3 h . Tissue samples and biopsies placed in a sterile container are also adequate specimens for anaerobic cultures. The high rate of coagulase-negative Staphylococcus positive culture may reflect the collection of contaminated specimens. In this sense, when the material for microbiological cultures is transmucosally collected, it is essential to decontaminate the mucous membrane. Although no methicillin-resistant strains were identified, as community-associated methicillin-resistant Staphylococcus aureus (MRSA) isolation is increasingly common among out- and inpatients with suppurative infections, MRSA may play an increasing role in DNIs in the next future [12, 13].
The mainstay of treatment of DNIs consists of airway control, effective antibiotic therapy, and, when appropriate, surgical incision and drainage of the pus collection.
On the basis of the above considerations, empirical antibiotic therapy with a combination of a penicillin plus a beta-lactamase inhibitor (amoxicillin/clavulanate, ticarcillin/clavulanate, piperacillin/tazobactam), cefoxitin, carbapenem, or clindamycin should provide sufficient coverage for both anaerobic and aerobic bacteria. Metronidazole has excellent activity only against strict anaerobic bacteria and therefore is poorly effective as a single-agent in DNIs . Macrolides or ketolides plus metronidazole should be considered in patients with a penicillin allergy. Clindamycin resistance among strains of Bacteroides fragilis has increased over 10 years, and current resistance rates reach 20–50% or more worldwide . Take into account that in the present and other series  Bacteroides spp were among the most frequently isolated anaerobic pathogens both in uncomplicated and complicated DNIs, clindamycin may no longer be considered a first-line antibiotic in DNIs. First intention antibiotic therapy should be reviewed 48 h later and potentially adjusted according to the microbiological- and drug-resistance patterns. A prolonged antibiotic therapy should be advisable as anaerobic infections are frequently chronic. After resolution of clinical signs of DNIs, oral therapy can replace parenteral one.
Open surgical incision and drainage are considered the mainstay of treatment for deep neck abscesses. Almost two-third of the patients responded satisfactorily to medical therapy only. We and several authors have demonstrated previously that a trial of intravenous antibiotic treatment associated with an aggressive CECT-based wait-and-watch policy may result in a significant number of selected patients (patients with cellulitis, abscesses <3 cm not involving “danger spaces” or more than one space, stable general condition) avoiding an unnecessary surgical drainage [15, 17, 25].
This policy did not result in significantly higher number of imaging procedures in patients selected for observations mainly because imaging investigations were routinely performed also after surgical drainage of deep neck abscess in order to confirm the resolution of the infections.
In the present series, about one-fourth of patients required an extensive external cervical approach. This approach is mandatory for drainage of large abscesses, multiple space abscesses, and impending complications. In patients with Ludwig’s angina, an external surgical approach is justified, even if areas of colliquation are not usually evident .
No correlation was found between duration of symptoms and the necessity of surgical drainage. Considering that a short duration of symptoms may correlate with a more aggressive infection, one should have expected a higher prevalence of surgical drainage in these patients. On the other hand, an inappropriate antibiotic therapy and anaerobic infections may be responsible for a slow course of disease and longer duration of symptoms in patients who finally develop complications requiring surgical procedures.
About 7.5% of patients were successfully drained by needle aspiration. Minimally invasive techniques are attractive options in patients with well-defined, unilocular abscess without airway compromise. Draining an abscess by needle aspiration reduces the morbidity of open surgery by limiting surgical trauma, reducing healing time, minimizing the risk of contaminating the surrounding healthy tissue. CT or ultrasound guidance may improve the efficacy and safety of percutaneous abscess drainage. In selected retro- and parapharyngeal abscesses without involvement of visceral vascular space, endo-oral aspiration and/or incision should be considered in order to reduce patient morbidity, economic burden and avoid aesthetic complications.
About 18% of patients developed life-threatening complications. Diabetes mellitus was confirmed to be the strongest predictor of life-threatening complications . Airway obstruction and spread of infection to the mediastinum are the most troublesome complications in patients with deep neck space infections. In our study population, most patients with mediastinitis had not shown any symptoms and signs of mediastinum involvement with symptoms of neck infection being common. Therefore, prompt diagnosis of descending mediastinitis may be missed in the absence of a high index of suspicion and routine CECT through the mediastinum. On the basis of our multivariate analysis, patients with diabetes mellitus, multiple space involvement, evidence of colliquation, high WBC, or high body temperature should be considered to potentially have a descending mediastinitis until proven otherwise. Descending necrotizing mediastinitis requires an aggressive multidisciplinary management. Delay in diagnosis as well as inadequate drainage of the mediastinum are considered to be the most significant factors responsible for mortality . Transcervical drainage of the mediastinum should be reserved for patients with infection limited to the upper mediastinal spaces above the tracheal carina. On the other hand, cervicotomy along with posterolateral thoracotomy incision is the standard of care in patients with inferior mediastinum involvement.
Lemierre’s syndrome is an uncommon seen and often forgotten complication of acute oropharyngitis affecting healthy adolescents and young adults. Central to the pathogenesis of this disease is the internal jugular vein thrombophlebitis. Septic metastases may occur and frequently affect the lungs. Clinically, the onset of septic symptoms often coincides with the end of oropharyngeal symptoms. Septic fever, tension of the sternocleidomastoid muscle and a stiff neck are the most frequent symptoms plus those connected with the site of the secondary localizations (chest pain, dyspnea, hemoptysis, and more uncommonly joint pains, abdominal pain with possible acute abdomen) . Broad-spectrum therapy should be given for more than 3 weeks. On the other hand, the role of anticoagulation has remained controversial . Ligation and resection of the internal jugular vein, which was frequent in the pre-antibiotic era, is now recommended by some authors only in the case of persistent sepsis with embolism.
The availability of effective antibiotics and improved oral hygiene have dramatically modified the epidemiology of DNIs making them less common today than in the past. However, even in this era of antibiotic therapy and modern imaging techniques, DNIs remain a constant challenge. Airway obstruction and descending mediastinitis are the most troublesome complications of DNIs. In selected patients, a trial of intravenous targeted or broad-spectrum empiric antibiotic therapy associated with an intensive CECT-based wait-and-watch policy may avoid an unnecessary surgical procedure. However, about one-fourth of patients present significant comorbidities, which may negatively affect the course of the infection. In these cases and in patients with large or multiple spaces infections, a more aggressive surgical strategy is mandatory.
Conflict of interest
There are no potential conflicts of interest.