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Characteristics and patterns of adult and pediatric deep neck space infection in a tertiary care institute

Background: Deep neck space infections are a serious but treatable group of infections affecting the fascial planes of the neck. The objective of this study is to determine various etiological causes, common sites, bacteriology, and complications in adult and pediatric patients suffering from deep neck space infections. Results: We studied 80 patients retrospectively who were admitted and treated for deep neck space infections in the otolaryngology department in a tertiary care institute over 2 years between March 2019 and March 2021. The study cohort was divided into two major age groups; 20 patients belonged to the pediatric group, while 60 patients belonged to the adult group. In this study, odontogenic infection was the most common etiological factor, Ludwig’s angina and submandibular space abscess were the common sites of presentation. Methicillin-resistant Staphylococcus aureus was the most common isolated microorganism. Septicemia was the most common complication developed after drainage of deep neck space infections. Conclusion: In the wake of an increase in the prevalence of deep neck space infections, close attention must be paid to the management of patients with deep neck space infections to prevent the complications.


Background
Deep neck space infections (DNSI) are a serious but treatable group of infections affecting the potential spaces and fascial planes of the neck, either with abscess formation or cellulitis [1][2][3].
Deep neck spaces are divided into primary and secondary fascial spaces by Holmes and Pellecchia. Buccal, canine, sublingual, submandibular, submental, and vestibular spaces are primary spaces. A secondary space infection can occur after direct primary space infection. Pterygomandibular, masseteric, temporal, parapharyngeal, infratemporal, and retropharyngeal spaces are among these spaces [4].
Odontogenic and periodontal infections are among the most common leading risk factors of deep neck space infections. The second most common source is tonsillopharyngitis [5]. DNSIs are almost typically polymicrobial in nature, reflecting the normal resident upper aerodigestive tract flora [6,7].
Streptococcus viridans, Peptostreptococcus species, Staphylococcus aureus, Klebsiella, and anaerobes are the most encountered microorganisms from DNSI that represent pathological overgrowth of the endogenous flora of the mouth and upper respiratory tract [8].
DNSIs usually present with systemic upset, fever, neck pain with limitation in range of motion, with or without trismus, and neck swelling, but importantly can progress to serious and life-threatening complications in about 10-20% of cases such as airway obstructions, sepsis, descending mediastinitis, endocarditis, acute respiratory distress syndrome and pleura-pulmonary suppuration [4,

Open Access
The Egyptian Journal of Otolaryngology  [11]. Immediate surgical drainage has been the traditional mainstay of the management, but directed antimicrobial coverage and vigorous supportive care are important adjuvants in achieving successful outcomes [12].
The aim of this research is to study various etiological causes, common sites, bacteriology, and complications in adult and pediatric patients suffering from DNSI.

Methods
The medical records of eighty patients diagnosed with DNSI treated at tertiary care institutes between March 2019 and March 2021 were retrospectively reviewed.
This study was approved by the ethical committee for scientific research at the Otolaryngology Department, Cairo University, and the approval carries the number: 32-2020-11201.
DNSIs were always diagnosed solely from the history along with clinical, laboratory, and radiographic examination. The study cohort was divided into two groups; the pediatric group included patients aged 0-18 years and the adult group included patients older than 18 years old.
Patients of all age groups and both genders with clinically confirmed cases of abscesses were included. Patients with unavailable medical records, patients with cellulitis, infected traumatic wound, infected head, and neck tumors, and patients with associated medical co-morbidities were excluded from this study.
The epidemiological distribution of the study cohort, i.e., the age group and gender, was discussed. All the following parameters (site of neck spaces involved, etiology, culture growth, treatment methods, morbidities, and mortalities) were incorporated into the analysis. According to The Third International Consensus Definitions for Sepsis and Septic Shock, sepsis can be rapidly identified in non-intensive care settings using a quick SOFA (Sequential Organ Failure Assessment), when at least two of the following clinical criteria were met: • Respiratory rate of 22/min or greater • Altered mentation • Systolic blood pressure of 100 mmHg or less Septic shock is defined as a subset of sepsis in which a vasopressor is required to maintain a mean arterial pressure of 65 mmHg or greater and serum lactate level greater than 18 mg/dL in the absence of hypovolemia.
All patients underwent immediate surgical incision and drainage to drain pus according to the affected fascial space either via external cervical approach or trans-oral approach whenever possible. Needle aspiration from loculated pus in the affected space was done to obtain an appropriate culture specimen using extra-oral approach to exclude sample contamination with normal oropharyngeal flora. After obtaining an appropriate sample for culture and sensitivity, all patients were started on treatment with ambicillin/sulbactam and metronidazole [7] which was later modified based on a culture and sensitivity result. The patients were followed up for 6 months.

Statistical methods
Data were coded and entered using the statistical package SPSS version 25. Data was summarized using mean and standard deviation for quantitative variables and frequencies (number of cases) and relative frequencies (percentages) for categorical variables. Comparisons between groups were done using unpaired t test. For comparing categorical data, chi-square (χ 2 ) test was performed. Exact test was used instead when the expected frequency is less than 5. P values less than 0.05 were considered as statistically significant.

Results
This study comprised 80 patients who presented to our institution with DNSI with a mean age of 31.45 years. The study cohort was divided into two major age groups; 20 patients with a mean age of 7.53 years belonged to the pediatric group, while 60 patients with a mean age of 40.22 years belonged to the adult group. Regarding the adult group, 27 patients (45%) were male, and 33 patients (55%) were female. In the pediatric group, 16 patients (80%) were male, and 4 patients (20%) were female.

Etiological factors
In the pediatric age group, the odontogenic source is the most common etiological factor (50%). In 6 patients (30%) , the source of infection was unrecognizable. Each of tonsillo-pharyngitis and infected neck cysts was identified as an etiological factor in 2 patients (10%).
Contrast-enhanced CT scan of the neck (CECT) was performed in 32 patients (40%) upon admission. CECT was performed at admission to confirm the diagnosis. The mean size of the abscess in the CT scan, considering the greater axis, was (58.47 ± 18.45) mm (Fig. 1).
All patients underwent immediate surgical incision, drainage, and debridement to drain the pus according to the affected fascial space either via external cervical approach (73 patients) or via trans-oral approach (7 patients).

Microbiology
Among 80 patients included in this study, pathogens were isolated in all cases.
In the pediatric age group, methicillin-resistant Staphylococcus aureus (MRSA) was the most predominant encountered organism with a prevalence of 35%  Similarly, in the adult age group, methicillin-resistant Staphylococcus aureus and mixed organisms were the most cultured organism among 14 cases (23%) each, followed by Klebsiella pneumoniae in 11 cases (18%), Pseudomonas aeruginosa in 7 cases (12%), Proteus mirabilis in 6 cases (10%), and alpha-hemolytic streptococci and Enterococcus in 4 cases (7%) each ( Table 3).
The distribution of patients according to microbiology in the adult and pediatric group is significant (p=0.04).

Morbidity and mortality
Out of 80 patients with DNSI, 36 patients (45%) experienced postoperative complication; 27 cases were adults and 9 cases belonged to the pediatric group.
In the pediatric group, septicemia was the most common complication in 5 cases (25%) followed by airway obstruction and pneumonia in 2 cases (10%) each.
All patients survived without sequelae except 5 cases (8%) in the adult groups and 1 case (5%) in the pediatric group. The most common cause of death in this study was septic shock (4 cases) and airway obstruction (2 cases) ( Table 5).
It was worth noting that all fatality cases were diagnosed as Ludwig's angina.
The distribution of patients according to Morbidity and mortality in the adult and pediatric age group is statistically insignificant (p = 0.7).

Discussion
In this study, most of the adult patients belonged to the age group of third and fourth decades. This is in agreement with the studies done by Singhal et al. and Meher et al. [13,14].
Unlike the results of this study that showed female predominance in the adult group, Rega et al. and Jevon et al. showed male predominance in patients presented with DNSI [15,16]. This may be attributed to the lack of access to qualified health care among the female population in low resource environment.
Odontogenic source was the most common etiological factor in the pediatric and adult groups, 50% and    [4,[17][18][19]. In this study, Ludwig's angina was the most common site for abscess formation in the adult group followed by a submandibular abscess. Our study results go in accordance with studies by Kataria et al., Maharaj et al., and Khode et al. [20][21][22].
Both our results and Singhal results agreed that the most commonly affected site in the pediatric population was the submandibular space [13]. Our research team believes that the relative ease of breakdown of submandibular lympodenopathy, the relatively wide loose areolar tissue spaces, and the relatively weak response of the developing immune system make the submandibular space more prone to suppuration and abscess formation among the pediatric population.
Regarding microbiology, MRSA was the most common isolated organism in both pediatric and adult groups. Naidu et al. and Tan et al. studied reinforced our results [23,24]. The abuse of empirical antibiotic therapy at the ambulatory setting might be contributing to the predominance of this virulent organism.
Complications like septicemia, airway obstruction, cervical skin loss, and empyema were reported in this study. Septicemia was the most common complication in both groups in this study. Jundt and Gutta showed similar results [25].
All patients survived without fatality except 5 cases of the adult group and 1 case of the pediatric group. All mortalities are diagnosed as Ludwig's angina. The most common cause of death was septic shock. These results are in agreement with studies made by Bali et al. and Gorjon et al. [11,26]. Ludwig's angina is known to be associated with the highest rate of incidence of fatal complications [27,28]. For this, aggressive wound debridement with adequate drainage and postoperative aggressive anti-microbial therapy should be instituted early upon diagnosis.
The main limitation of the present analysis is that this study was conducted retrospectively so, we were unable to obtain data regarding antibiotic susceptibility and resistance of fascial space microbiological spectrum. Another important factor is the small sample size due to the strict exclusion criteria.
The main strength of this study is that it reports an appropriate number of patients in a limited resource environment. The relatively small sample size in our study is attributed to the strict exclusion criteria.

Conclusion
DNSIs are potentially fatal processes and susceptible to morbidities and mortalities. Odontogenic source is still the commonest cause leading to DNSI and hence proper dental hygiene is essential for prevention. Close attention must be paid to the management of patients with deep neck space infections to prevent complications.