Continuing Education Activity

Neck abscesses in the deep neck tissues are challenging to diagnose and manage due to the complex anatomy of the neck, which contains vital vessels, nerves, and structures essential to the airway and gastrointestinal system. These abscesses often develop deep within tissues, making external visualization or palpation difficult. If left untreated, nearby structures may become involved, leading to complications such as neurovascular damage, bone involvement, or airway obstruction. Prompt recognition and proper management are crucial to prevent serious complications, as these abscesses can cause life-threatening issues if not handled appropriately.

In this course, participants learn how to identify and evaluate neck abscesses, understanding their variable presentations based on location and depth. The importance of imaging, surgical drainage, appropriate antibiotic therapy, and interprofessional team collaboration is emphasized. This team-based approach allows for accurate diagnosis, timely intervention, and effective management of potential complications, ensuring comprehensive care for patients with deep neck abscesses.

Objectives:

• Differentiate deep neck abscesses from other neck masses or infections using clinical evaluation and imaging techniques.

• Screen high-risk patients for early signs of deep neck abscesses, particularly those with recent head and neck infections or trauma.

• Implement appropriate imaging techniques, such as computed tomography scans or magnetic resonance images, to localize deep neck abscesses accurately.

• Communicate interprofessional team strategies for improving care coordination to enhance outcomes for patients affected by neck abscesses.

Introduction

Infections of the deep neck tissues are complicated in diagnosis, localization, access, and management. The anatomy of the neck is complex, with critical structures of the airway, gastrointestinal system, and major vessels and nerves. The affected tissues may be deep and impossible to palpate or visualize externally. Nearby structures can become involved in the inflammation and lead to neurovascular, bony, or airway issues. Understanding different neck abscesses, how they may present, and the best ways to treat them is crucial.[1][2][3]

Etiology

Historically, before antibiotics, tonsillitis and pharyngitis were the most frequent causes of deep neck space infections. Tonsillitis remains the most common cause of deep neck space infection in children, but in adults, an odontogenic origin is the most common. Other causes include oral surgical procedures, salivary gland infection or obstruction, trauma to the oral cavity or pharynx, instrumentation, foreign body aspiration, intravenous drug use, cervical lymphadenitis/suppuration of malignant lymph node or mass, branchial cleft anomalies, thyroglossal duct cyst, and others. There may be no clear source for 20% to 50% of deep neck infections. Considering a suppressed immune system due to human immunodeficiency virus/acquired immunodeficiency virus, chemotherapy, or immunosuppressant medications in these infections is important.[4]

Epidemiology

Deep neck infections are common. As they comprise many discrete entities, it is difficult to accurately estimate the number of deep neck space infections in the United States (US) or worldwide. It would be reasonable to assume that the incidence in the US is lower than in countries where immunizations and/or early medical intervention for more superficial infections are unavailable. Results from a 2009 study by Adeil et al estimated more than 3400 US pediatric hospital admissions per year for deep neck space infections.

Peritonsillar abscess is most common in those aged between 20 and 40. Children are not often affected by a peritonsillar abscess but can be if they are immunocompromised and all sexes are equally affected. Chronic tonsillitis or multiple rounds of oral antibiotics may predispose a person to the formation of a peritonsillar abscess. Parapharyngeal abscesses can develop in patients of any age but are most common in children and adolescents. Immunocompromised adults are also at increased risk.[5]

Pathophysiology

There are different potential paths of infection in the neck. Oral cavity/face/superficial neck infection can spread via the lymphatic system to the deep tissues of the neck. Lymphadenopathy may cause suppuration and then focal abscess formation. Direct communication between tissues in the neck may occur. Finally, penetrating trauma can introduce infection to the deep tissues. 

After the spread of infection, local inflammation or phlegmon may develop, or a fulminant abscess may form with a purulent fluid collection. Signs of neck abscess in the deep tissues may result from either the mass effect of inflamed tissue or abscess on the surrounding structures or from direct involvement of those structures with the infection. Examples of different types of spread include the following:

1. A lateral pharyngeal space infection can spread to the carotid sheath, causing internal jugular vein thrombosis, leading to subacute bacterial endocarditis or other thromboembolic diseases.
2. Lateral pharyngeal space infection can lead to extensive edema, causing respiratory compromise.
3. Tonsillitis may lead to a peritonsillar abscess and a lateral/posterior pharyngeal infection that can spread to the chest if untreated.

This condition can lead to mediastinitis or empyema. Neck abscesses can include peritonsillar infections, retropharyngeal infections, submandibular infections, buccal infections, parapharyngeal space infections, and canine space infections. The retropharyngeal, retroesophageal, and posterior mediastinum are all continuous spaces for the spread of infection. Organisms involved in deep neck infections include aerobes and anaerobes, frequently with a predominance of oral flora. Organisms frequently cultured include species of Streptococcus, Bacteroides, Staphylococcus, Peptostreptococcis, Pseudomonas, Escherichia coli, and Haemophilus influenzae.

Histopathology

Causative organisms for deep neck infections include gram-positive organisms, including but not limited to Streptococcus viridans, Staphylococcus epidermidis, and Staphylococcus aureus; and gram-negative organisms, including but not exclusively Escherichia coli, Klebsiella oxytoca, and Haemophilus influenza. In studies of retropharyngeal abscesses, polymicrobial results were found in almost 90% of patients. Aerobes were found in all patients, and anaerobes in more than half. Anaerobes may include Peptostreptococcus, Fusobacterium, Prevotella, and Actinomyces. Other bacteria may include Lactobacillus, Bacteroides, and Propionibacterium, among others. Some studies show cultures with an average of at least 5 isolates. There have been studies showing an association between the presence of biofilm and abscess development.[6]

Toxicokinetics

Within the neck are 11 zones created by planes of lesser and greater resistance between the fascial layers. These potential spaces can expand, communicate with each other, and permit the infection to spread. The spaces include the parapharyngeal or lateral pharyngeal space, which is superior to the hyoid bone. The skull base is the superior margin, and the medial boundary is the middle layer of the deep cervical fascia.

History and Physical

Deep neck space abscess should be considered when patients describe any or many of the following:

• Severe pain
• Recent dental procedures
• Upper respiratory infection
• Neck or mouth trauma
• Respiratory distress
• Dysphagia or dysphonia
• Immunosuppression
• The rapid rate of onset
• Prolonged duration of symptoms

Particular red flags include neck asymmetry, neck masses, lymphadenopathy, trismus, medial displacement of the lateral pharyngeal wall and tonsil, torticollis, cranial nerve involvement, spiking fevers, and tachypnea/shortness of breath.

Evaluation

Computed tomography (CT) imaging of the neck can help confirm and localize a deep neck infection. However, patients are often too unstable for CT imaging or unable to lie flat on the CT table to perform the CT. There may be situations where only a portable lateral soft tissue neck x-ray can be obtained, which can help support the diagnosis of neck abscess without much help in localization. In cases where an early neck abscess is suspected, an otolaryngologist may be called upon to perform direct laryngoscopy to ascertain the presence of swelling.[7] If a dental source is suspected, then a panoramic view is necessary. Blood work, including electrolytes, clotting profiles, blood cultures, and abscess cultures, should be obtained.

Treatment / Management

Treatment involves adequate drainage of the abscess in the operating room. Also, antibiotic therapy is paramount. Because cultures are unavailable during presentation, empiric antibiotics are started at presentation. Results from a study in 2008 by Yang et al found 3 comparable antibiotic regimens: (1) ceftriaxone and clindamycin, (2) ceftriaxone and metronidazole, or (3) penicillin G and gentamicin and clindamycin.

Results from a 2015 Iranian study by Motahari et al showed that 428 of 815 cases were managed surgically, while the rest were managed medically. Tracheostomy was performed in 5 cases. One 15-year-old with symptoms suggestive of mediastinitis died of airway compromise a day after undergoing surgical management of a parapharyngeal abscess. The study concluded that prompt surgical management is indicated if medical management fails after 24 to 48 hours or if fluctuance or any complications are present.

Determining the problem's underlying cause and addressing that specifically is essential. For example, with odontogenic infections, early dental extraction is crucial. Airway management must always be a consideration, as there is often swelling and distortion of anatomy; the surgical airway may be preferable. In cases of deep neck infection, early notification of otolaryngology and anesthesia for airway backup is wise. Prompt transfer to the operating room for simultaneous evaluation, airway management, and treatment may be life-saving for patients with compromised lungs.[8][9]

Differential Diagnosis

The differential diagnoses for neck abscesses include the following:

• Epiglottis
• Esophagitis
• Gastrointestinal foreign bodies
• Infectious mononucleosis
• Kawasaki disease
• Mediastinitis
• Meningitis
• Pharyngitis
• Sinusitis imaging
• Trachea foreign bodies

Pearls and Other Issues

The anatomy of the neck is quite complex. The 2 main fascial planes are (1) superficial cervical fascia and (2) deep cervical fascia. The deep neck spaces include the following:

• Parapharyngeal space (ie, lateral pharyngeal space/pharyngomaxillary space/pterygomaxillary space/pterygoid-pharyngeal space)
• Retropharyngeal space
• Prevertebral space
• Danger space
• Masticator space
• Submandibular space
• Carotid space, pretracheal space
• Peritonsillar space
• Parotid space
• Temporal space

Enhancing Healthcare Team Outcomes

Deep neck infections are not uncommon in clinical practice.  Sometimes, these infections are missed, which can place enormous morbidity on the patient. Deep neck infections compromise the airways and spread vertically to the brain, spinal cord, and mediastinum. Because most patients initially present to the primary care clinician, it is important to have a streamlined process to ensure that the diagnosis is made promptly and the condition treated. Data from infections in the pediatric population reveal that one can achieve very low morbidity by following clinical guidelines.[10] While there are no universal guidelines for managing deep neck infections, current expert opinion reveals that an interprofessional group of healthcare professionals can help achieve excellent outcomes.[11] Once a deep neck infection is suspected, the following healthcare professionals need to be involved:

• Radiologist to help determine the location and extent of the infection and even help with drainage
• Ear, nose, and throat clinician and/or thoracic surgeon to help with debridement
• Laboratory technologist to identify the organisms involved
• An anesthesiologist in case an airway is required
• Infectious disease expert on determining the choice of antibiotics
• Clinicians to help monitor the patient’s vital signs, educate the family, and ensure infection precautions
• Pharmacists help follow the different types of medications and prevent drug interactions
• Dietitian consult as the patient may not be able to eat and may require tube feedings

Outcomes

Since most deep neck infections are considered surgical emergencies, there are no randomized trials to determine the best procedure, antibiotic, or duration of treatment. The only definitive data is that surgery is recommended in almost all patients with neck abscesses. The earlier the surgery, the better the outcomes.[12]