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Deep Neck Space Infections

Overview
Deep neck space infections occur across all age groups with various etiologies. Mostly commonly caused by an infection of the upper aerodigestive tract (e.g., odontogenic, oropharyngeal, sinonasal), additional causes include foreign body, malignancy with secondary infection, necrotic lymphadenitis or infection of a congenital tract or fistula (i.e. branchial cleft and thyroglossal duct cysts). The location of the causative infection typically determines the presentation as well as the offending flora, which is polymicrobial in most cases. Knowledge of the anatomical layers of the cervical fascia is important for understanding tracts of spread and the presenting symptoms. Symptoms primarily depend on the involved space(s) such as dysphagia/odynophagia (e.g., parapharyngeal, retropharyngeal), nuchal rigidity (e.g., prevertebral), trismus (e.g., masticator space with pterygoid involvement), otalgia, dysphonia, and neck pain. The acute concern when evaluating a patient with a potential deep neck space infection is ensuring/establishing a safe airway followed by prevention of disease progression with secondary complications such as Lemierre’s syndrome (septic thrombophlebitis of the internal jugular vein with septic pulmonary emboli), mediastinitis, cavernous sinus thrombosis, or Ludwig’s angina (firm floor of mouth cellulitis/edema involving the submandibular and sublingual spaces), among others. Mainstays of treatment include securing a safe airway, broad antibiotic coverage (which may be narrowed based on culture data), potential surgical drainage and wound care, and serial examination to ensure improvement. In addition, it is crucial to distinguish these conditions from necrotizing fasciitis – a life-threating, rapidly progressive soft tissue infection that results in progressive destruction of the muscle, fascia, and overlying subcutaneous fat, as well as thrombosis of associated vasculature. Findings concerning for necrotizing fasciitis include, but are not limited to, overlying rapidly progressing erythema and edema, severe pain, fever, crepitus, skin bullae or ecchymosis. In some cases symptoms of sepsis including tachycardia, fever, and hypotension may develop. Necrotizing fasciitis will be discussed further in a separate section.


Layers of Cervical Fascia

  • Superficial Layer of the Cervical Fascia

    • Extends from top of head to thorax

    • Continuous with platysma, superficial musculoaponeurotic system (SMAS), and temporoparietal fascia superiorly

  • Deep Cervical Fascia (comprised of 3 layers)   

    • Superficial Layer of Deep Cervical Fascia – surrounds neck from nuchal line posteriorly, envelops sternocleidomastoid and trapezius muscles, muscles of mastication, and the submandibular and parotid glands

    • Middle Layer of Deep Cervical Fascia (comprised of 2 divisions)

      • Muscular division – envelopes strap muscles (omohyoid, sternohyoid, thyrohyoid, sternothyroid)

      • Visceral division – envelopes thyroid, trachea, esophagus, and pharyngeal constrictor muscles. Creates buccopharyngeal fascia

    • Deep Layer of deep cervical fascia (comprised of 2 layers)

      • Alar fascia – starts at cranial base and fuses with middle layer of deep cervical fascia in the upper mediastinum

      • Prevertebral fascia – starts at cranial base and extends to coccyx

      • Both laters are anterior the vertebral bodies, and envelope the paraspinous muscles

    • Carotid sheath fascia is created by all 3 layers of the deep cervical fascia

Key Supplies for Deep Neck Space Infection Consult

  • Appropriate PPE including mask, eye protection, gloves, and gown

  • Headlight

  • Tongue depressor

  • Flexible laryngoscope (with monitor & tower, if possible for recording)

  • If planning bedside needle aspiration or incision & drainage:

    • Alcohol pads and/or betadine swabs

    • 18-gauge needle and 10 cc control syringe

    • +/- use of portable ultrasound for image guided needle aspiration

    • 15-blade

    • Mosquito or Carmalt

    • Culture trap or swab

    • Saline irrigation & syringe for irrigation

    • Suction

    • Cotton tip applicators

    • Strip gauze

    • 4x4 gauze

    • Paper tape

 

Deep Neck Spaces

  • Parapharyngeal Space

    • The parapharyngeal space is shaped as an inverted pyramid with base of the pyramid at the skull base and apex at the hyoid bone. The space is divided into pre- and post-styloid compartments and can be thought of as a central space in the neck as it directly abuts the peritonsillar, masticator, parotid, retropharyngeal, and submandibular space with the carotid sheath running through it. Parapharyngeal space infections can both originate from and spread to any of these bordering spaces. An infection in the oropharynx, particularly the tonsil, is one of the most common sources of parapharyngeal space infection. Symptoms reflect this and can be nonspecific (most commonly throat pain, trismus, malaise, fevers) but may also present with neurovascular complications especially with post-styloid involvement such as mycotic aneurysm, cranial nerve neuropathy or Horner’s syndrome.

  • Carotid Sheath Space

    • The carotid sheath, comprised of all three layers of deep cervical fascia, runs the length of the neck and contains the carotid, internal jugular, vagus nerve, and sympathetic nerve plexus. Infections in this space are most commonly caused by spread from the parapharyngeal space, although rarely IV drug use can lead to an isolated carotid space infection. Involvement of the carotid sheath can present with insidious development of systemic symptoms or fevers weeks after the suspected causative infection and without trismus or other common deep neck space infection symptoms or obvious abnormalities on physical exam making the diagnosis a challenge. Sentinel bleeding from the oropharynx, nasopharynx, or even ear is thought to occur before many cases of carotid aneurysm rupture and any history of bleeding or neck hematoma on exam should prompt immediate evaluation for this rare but devastating complication.

  • Retropharyngeal Space

    • The retropharyngeal space, bounded by the buccopharyngeal fascia anteriorly and the alar fascia posteriorly, extends the length of the neck from skull base to tracheal bifurcation. Its contents include lateral fat pads and lymph nodes which receive drainage from the posterior pharyngeal wall, nasopharynx, middle ear and nasal cavity. Infections of the retropharyngeal space can be caused by spread from the aforementioned drainage pathways, parapharyngeal space, trauma, foreign bodies (e.g. fish bone, barbecue brush wire), suppurative retropharyngeal lymph nodes , or spread from a pharyngeal infection. Any patient with fluid/abscess in the retropharyngeal space deserves immediate evaluation, IV antibiotics, and observation in the hospital with possible surgical drainage depending on the clinical picture.      

  • Prevertebral and Danger Space

    • Directly posterior to the retropharyngeal space and separated by the alar fascia is the danger space. Bounded by the alar fascia and prevertebral fascia, the danger space receives its name because infections in this neck space have no barrier of spread to the chest and can rapidly lead to mediastinitis or acute necrotizing mediastinitis which carries a high mortality rate even with appropriate antibiotic coverage and treatment. The prevertebral space is directly posterior to the danger space and extends the length of the spine from skull base to cocyx. The prevertebral space is unique in that most infections occur secondary to vertebral body infections commonly from spinal hardware, trauma, or tumors.  
        

  •  Submandibular and Sublingual Spaces

    • These spaces, partially separated by the mylohyoid muscles (with communication around the posterior muscle edge), are commonly involved with periodontal infections while sialadenitis is a less common etiology. Ludwig’s angina, a bilateral submandibular space infection usually due to 2nd or 3rd mandibular molar infections, can rapidly progress to fatal airway obstruction secondary to posterior and superior tongue displacement. Anatomically, infection can spread from the submandibular space to nearby deep neck spaces through the buccopharyngeal gap, created by the styloglossus muscle traversing the pharyngeal constrictors. Oral exam frequently reveals an odontogenic source, oral airway obstruction, and a “woody” induration of the floor of mouth. Airway exam should include nasopharyngoscopy to evaluate the base of tongue, oropharynx, supraglottis and larynx. A definitive airway should be secured if Ludwig’s angina is suspected as cases can progress to complete airway obstruction rapidly. Adjuncts until a definitive airway is secured/needed include nasal or oral airways, supplemental oxygen, and Heliox (recommended by some sources though rarely used in the authors experience). Most often, fiberoptic nasal intubation is the preferred method for definitive airway though this should only be attempted with a team and equipment ready for an emergent surgical airway. In patients with advanced infection and impending airway distress, awake tracheostomy can be considered. Incision and drainage of any abscess (intraorally for mild disease and transcervical for more severe), drain placement, extraction of the offending tooth (if odontogenic), and broad-spectrum antibiotics are the mainstays of treatment.

  • Masticator Space

    • This space contains the muscles of mastication as well as the mandible, inferior alveolar nerve and internal maxillary artery. Infections of the masticator space predominantly originate from 3rd molar infections. Exam findings are non-specific, most commonly posterolateral oral swelling and tenderness with trismus (involvement of pterygoid. Amalgam artifact can inhibit CT visualization of this space making MRI necessary at times. Drainage may be performed intraorally or externally.

  • Pretracheal space infection

    • The pretracheal space extends from the thyroid cartilage to the mediastinum. Infection of this space is most commonly iatrogenic following surgical perforation of the anterior esophageal wall but may also be caused by foreign bodies, intubation trauma, or more rarely thyroid abscess or suppurative thyroiditis. Due to its location, airway edema or compression is possible.     

  • Parotid Space

    • The parotid space is formed by the superficial layer of the deep cervical fascia wrapping around the parotid gland. This fascia is deficient at the stylomandibular tunnel allowing communication between the parapharyngeal space and the parotid space. This communication more commonly allows spread of parotid tumors into the parapharyngeal space but may also allow infection to spread between these spaces. Primary infections of this space are most commonly related to sialadenitis and may require drainage in addition to the conservative treatments of parotid massage, warm compress, sialogogues, hydration, and antibiotics.    

 

Management    

  • Begin with basic airway evaluation and if signs of impending airway compromise: stay with patient, activate OR, notify senior resident/faculty, anesthesia, and mobilize help in obtaining airway adjuncts, supplies for intubation and emergent surgical airway if needed. If possible, an immediate nasopharyngeal scope is helpful in determining airway status (and whether intubation would be possible), but airway securement should not be delayed for this in emergent situations

  • If the patient is stable, obtain comprehensive history including symptom progression, surgical history especially recent procedures to airway or esophagus, dental pain or recent dental work, drug use, any infection of head or neck (sinusitis, otitis media, cellulitis, etc.), past medical history especially HIV or immunosuppression, TB, diabetes, and any steroid use

  • Complete head and neck physical exam with attention to oral exam including Stenson’s ducts, Wharton’s ducts, dental exam, detailed cranial nerve exam, and fiberoptic nasopharyngeal airway exam is required in most cases and certainly if any dyspnea/stridor or dysphonia

  • Labs including CBC and CMP with consideration for blood cultures and specific infectious etiologies (e.g., HIV) depending on clinical context

  • Imaging:

    • CT Neck with contrast is preferred in most cases; but do not delay securing an airway for imaging if impending or active airway distress

    • Plain films of neck can be considered in an unstable patient with suspected retropharyngeal abscess or supraglottitis

    • Chest radiograph for patients with dyspnea

    • Ultrasound can be helpful for some neck space infections and may assist in needle aspiration

    • MRI is uncommonly used due to the length of the scan and the need for extended supine positioning in patients that may have airway compromise but can be helpful in stable patients with contrast allergies or if dental artifact obscures the CT

  • Low threshold for securing an airway with intubation (either oral or nasal fiberoptic depending on clinical scenario), or awake tracheostomy if intubation is not possible

  • Some patients may be observed with medical trial before airway intervention but should be in a closely monitored environment, including consideration of continuous pulse oximetry, with airway equipment ready in case of decompensation

  • At minimum, admission with close airway observation is indicated in most cases, typically ICU or step-down unit depending on institutional capabilities and the patient’s situation

  • Patients are often managed primarily by an ICU team or Medicine team with Otolaryngology and Infectious Disease consultations

  • Antibiotics:

    • Initiate empiric broad spectrum antibiotics at maximum weight and age-based dosages

    • For adults without severe complications or disease, consider ampicillin-sulbactam or clindamycin

    • If severe disease, can consider ceftriaxone with clindamycin with metronidazole

    • Consider MRSA coverage for at risk patients with options of clindamycin or vancomycin (dosage dependent on weight and renal function with serum trough levels drawn per local protocol)

    • Consider antipseudomonal coverage for nosocomial infections with piperacillin-tazobactam or ciprofloxacin

  • Consider scheduled steroids if airway concerns, most commonly dexamethasone

  • Keep all patients NPO during medical trials and have a low threshold to repeat CT neck with contrast if the patient is clinically not responding or deteriorating to assess for the development or progression of a drainable abscess  

  • General Indications for Surgical Drainage:

    • abscess, particularly when discrete and > 2-3cm

    • airway compromise

    • failure to respond to medical therapy after 48 hour

    • concern for developing complications (Lemierre’s, Mediastinitus etc) from disease progression

  • Surgical drainage is most commonly performed in the OR depending on the clinical scenario and location of the abscess. Typically a drain or strip gauze packing is placed to allow continued egress of purulence from the wound and facilitate healing. Discussion of specific surgical approaches for drainage are beyond the scope of this review, but more information can be found in the included references

  • Convalescence

  • With improving clinical course, patients may be transitioned from IV to oral antibiotics, typically guided by susceptibility data from cultures; the Infectious Disease team may assist with determining the course of outpatient antibiotic therapy

  • Close follow up with Otolaryngology after discharge

  • Consider repeat imaging once the infection has resolved if suspicion for underlying predisposing pathology such as neoplasm or congenital cyst or tract. For patients with poor dental hygiene, consider dental follow-up to prevent further infections

 

References

  1. Aynehchi, B.B., Har-El, G. (2013). Deep Neck Infections. In J.J. Johnson, C.A. Rosen. (Eds.), Bailey’s Head and Neck Surgery-Otolaryngology 5e (pp. 794-814). Baltimore, MD: Lippincott Williams & Wilkins.

  2. Christian, J.M., et al (2020). Deep Neck and Odontogenic Infections. In P.W. Flint, et al (Eds.), Cummings Otolaryngology Head and Neck Surgery 7e (pp. 141-154). Philadelphia, PA: Elsevier.

  3. Vieira, F., Allen, S. M., Stocks, R. M., & Thompson, J. W. (2008). Deep neck infection. Otolaryngologic clinics of North America, 41(3), 459–vii. https://doi.org/10.1016/j.otc.2008.01.002