eMedicine Specialties > Pediatrics: Surgery > Otolaryngology

Retropharyngeal Abscess

Author: Jason L Acevedo, MD, Resident Physician, Department of Otolaryngology-Head and Neck Surgery, Walter Reed Army Medical Center
Coauthor(s): Rahul K Shah, MD, FAAP, Assistant Professor of Otolaryngology and Pediatrics, George Washington University School of Medicine and Health Sciences; Attending Physician, Department of Otolaryngology, Children's National Medical Center
Contributor Information and Disclosures

Updated: Mar 16, 2009

Introduction

Background

Retropharyngeal abscesses are deep neck space infections that can pose an immediate life-threatening emergency, with potential for airway compromise and other catastrophic complications.

In order to best understand deep space infections, knowledge of the anatomy of the fascial planes of the neck is necessary. Superficial and deep fascia layers are found in the neck. Although fascia is typically adherent to adjacent structures, potential spaces can be created when an infection intercolates between the fascial layers and creates a real space, with rapid spread of inflammation and pus in the space between the fascial planes.

The retropharyngeal space is located immediately posterior to the pharynx (nasopharynx, oropharynx, hypopharynx), larynx, and trachea. The visceral (buccopharyngeal) fascia, which surrounds the pharynx, trachea, esophagus, and thyroid, forms the anterior border of the retropharyngeal space. Bounded posteriorly by the alar fascia, the retropharyngeal space is bounded laterally by the carotid sheaths and parapharyngeal spaces. It extends superiorly to the base of the skull and inferiorly to the mediastinum at the level of the tracheal bifurcation (see Media file 1).

Pathophysiology

The retropharyngeal space can become infected in two ways. Infection can either spread from a contiguous area or the space can be directly inoculated from penetrating trauma. The "classic" retropharyngeal abscess observed in pediatric patients occurs when an upper respiratory infection (URI) spreads to retropharyngeal lymph nodes, forming chains in the retropharyngeal space on either side of the superior constrictor muscle.

Sources of infection can include pharyngitis, tonsillitis, adenoiditis, adenitis, otitis, sinusitis, and other infections (ie, nasal, salivary, dental). Degeneration/suppuration of these nodes leads to abscess formation. Infectious sources (eg, osteomyelitis of the spine) also can spread directly anteriorly from the prevertebral space.

Of specific interest is the group of lateral retropharyngeal nodes at the base of the skull that bear the name of French anatomist Henri Rouviere. These Rouviere nodes are typically not of great clinical interest, but as the primary lymphatic drainage of the nasopharynx, they can become significant in cases of nasopharyngeal cancer. They are also pertinent to the discussion of retropharyngeal abscess, as they can suppurate and lead to a retropharyngeal abscess.

Penetrating trauma can also be involved in retropharyngeal space infection. Accidental lacerations are not uncommon in children who run and fall down after they have placed a sharp object in their mouths. Foreign bodies (for example, fishbones) have been implicated in penetrating trauma to the retropharyngeal space. Iatrogenic causes of inoculation to this space include instrumentation with laryngoscopy, endotracheal intubation, surgery, endoscopy, feeding tube placement, and dental injections and procedures.

Complications of retropharyngeal abscesses are secondary to mass effect, rupture of the abscess, or spread of infection. The most urgent complication involves the abscess expanding against the pharynx or trachea, causing airway compression. Rupture of the abscess can cause aspiration of pus, resulting in asphyxiation or pneumonia. The infection can spread, resulting in inflammation and destruction of adjacent tissues. Spread of the infection to the mediastinum can result in mediastinitis, purulent pericarditis and tamponade, pyopneumothorax, pleuritis, empyema, or bronchial erosion.

Spread of the infection laterally can involve the carotid sheath and cause jugular vein thrombosis or carotid artery rupture. Posterior spread of infection can result in osteomyelitis and erosion of the spinal column, causing vertebral subluxation and spinal cord injury. The infection itself can evolve into necrotizing fasciitis, sepsis, and death.

Hence, accurate and prompt treatment and intervention for presumed retropharyngeal abscess is crucial to prevent significant untoward sequelae.

Frequency

United States

Lander et al analyzed a large national database of pediatric admissions in the United States.¹ They found 1,321 cases of retropharyngeal abscess in 2003. A large retrospective review of pediatric head and neck infections at the University of Mississippi Medical Center was published in 2006.² Of the 1,010 documented pediatric head and neck infections, 26 were retropharyngeal abscesses.

International

With less access to health care and less availability of antibiotics, deep space infection is a more common complication of URI in developing nations. Pathogens not typically seen in the United States are also seen in this population (including tuberculosis) and should be considered. 

A tertiary hospital in Freiburg, Germany studied deep neck infections occurring over 8 years.³ Of the 234 documented deep neck infections, 15 (6.4%) were retropharyngeal abscesses. Although no subgroup analysis was specifically performed for retropharyngeal abscesses, one interesting finding was a higher than expected rate of Bartonella henselae infection (Catscratch Disease) and cervical tuberculosis. The treating physician should thus consider all infectious etiologies when treating and evaluating patients with a suspected infection.

A study from India also described a socioeconomic correlation with deep neck abscesses.⁴  Most patients with retropharyngeal abscesses were of low socioeconomic status, which was theorized to contribute to the incidence of abscesses due to poor oro-dental hygiene and a lack of access to health care.

Mortality/Morbidity

When assessing a patient with a potential deep neck space infection, airway compromise should immediately be identified and addressed. Evaluation by an otolaryngologist, if possible, should be obtained. Large abscesses can compress the pharynx or trachea, causing suffocation. The abscess also can rupture, causing asphyxiation or aspiration and pneumonia. Proper positioning and avoiding unnecessary manipulation is essential. Closely monitor patients with airway compromise and do not allow these patients to leave the acute care area until deemed sufficiently stable.

Sedation and paralytics should be avoided until an airway assessment is performed because they can relax airway muscles, leading to complete obstruction. Endotracheal intubation is dangerous unless performed under direct visualization. If direct visualization is not possible secondary to trismus or anatomic distortion, consider fiberoptic intubation or a surgical airway (eg, cricothyroidotomy, tracheotomy).

Spread of infection to adjacent structures in the neck can be lethal. Carotid artery rupture has a 20-40% mortality rate. Even if the artery is successfully ligated, long-term morbidity secondary to stroke is common. Jugular vein thrombosis had a mortality rate of 60% prior to the use of antibiotics. Identifying this complication is essential. Osteomyelitis and vertebral erosion can cause subluxation and subsequent spinal cord injury. Atlantooccipital separation secondary to erosion of the transverse ligament of the atlas has been reported. These complications are rare in children in the postantibiotic era. In older children and adults, the disease spreads directly into the fascial planes and is a more deadly disease that must receive immediate surgical treatment.

Spread of infection into the chest has significant complications. Mediastinitis has a 40-50% mortality rate secondary to sepsis. Acute necrotizing mediastinitis and purulent pericarditis with tamponade can also be fatal. Mediastinal abscess, bronchial erosion, pyopneumothorax, pleuritis, and empyema also have significant morbidity and mortality.

Race

No racial predilection has been described in the literature.

Sex

Although no sex predilection has been described in the literature, several studies have noted a higher incidence of deep neck infections in boys. In a large national database, 63% of patients were male.¹

Age

Retropharyngeal abscess is almost exclusively a pediatric diagnosis. Most incidents occur in children aged 6 months to 6 years, with a mean age of 3-5 years.^1,2 Other deep neck abscesses (eg, parapharyngeal, peritonsillar) are observed more frequently in adults and older children.

In children, a retropharyngeal abscess is usually caused by an infection that spreads to the retropharyngeal lymph nodes, with subsequent cellulitis and abscess formation. Fibrosis and atrophy start in these nodes at age 4 years, and, by the time the child is aged 6 years, the retropharyngeal nodes have typically regressed.

In older patients, infection of the retropharyngeal space usually occurs from penetrating trauma or direct spread from an adjacent space.

Clinical

History

• Patients with a retropharyngeal abscess present with constitutional complaints such as fever, chills, malaise, decreased appetite, and irritability.
• Patients may complain of a sore throat, difficulty swallowing (dysphagia), pain on swallowing (odynophagia), jaw stiffness (trismus), or neck stiffness (torticollis). Small children with torticollis tend to hold their neck in a non-neutral position and do not turn their head from side to side.
• Patients may also complain of muffled voice, the sensation of a lump in the throat, and/or pain in the back and shoulders upon swallowing.
• Difficulty breathing may be an ominous complaint that portends impending airway obstruction.
• Patient history is not always straightforward. Signs and symptoms can include fever (74%), sore throat (47%), dysphagia (38%), trismus (36%), decreased appetite (22%), voice change (18%), odynophagia (17%), neck pain (15%), irritability (11%), and difficulty breathing (8%).
• The course of pharyngeal abscess can be insidious.
  • Sometimes an upper respiratory illness can precede symptoms by weeks.
  • Many patients do not recall (or parents are not aware of) incidences of penetrating trauma.
  • Maintain a high index of suspicion, especially in patients with upper respiratory illnesses that do not appear to resolve in a normal course or with conventional therapy.

Physical

• Most patients with a retropharyngeal abscess are febrile. Some appear toxic and irritable.
• Cervical lymphadenopathy, usually unilateral, is the most common physical finding in these patients.
• Patients may have decreased or painful range of motion of their necks or jaws.
• A neck mass or tenderness may be appreciated.
• These patients may present with a muffled "hot potato" voice (dysphonia).
• Upon inspection of the oral cavity, the physician may be able to appreciate a bulge in the posterior pharyngeal wall. Trismus (inability to open the mouth >40 mm from maxillary to mandibular incisors) can be present.
  • As many as 30% of patients have a pharyngeal bulge. It is typically not midline due to the presence of the raphe in the retropharyngeal space caused by the superior constrictor muscle; midline masses are usually in the prevertebral space.
  • Although this mass has been described as fluctuant to palpation, deferring this part of the examination is probably best. This maneuver can lead to abscess rupture and subsequent aspiration.
  • The tracheal rock sign elicits pain while gently moving the larynx and trachea from side to side.
• Patients in respiratory distress or those who present with stridor or drooling have potential airway compromise and should be immediately triaged as such.
• Address vascular complications in the physical examination.
  • Jugular vein thrombophlebitis may manifest as tender induration at the anterior sternocleidomastoid border, vocal cord paralysis, or sepsis of an unknown source. It may also be asymptomatic.
  • Carotid artery rupture can be heralded by sentinel bleeding from the ear, nose, or mouth.
  • Ecchymosis may be detected in the lateral neck.

Causes

• Most retropharyngeal space infections are spread from various sources in the upper respiratory tract due to the retropharyngeal lymph nodes. The lymphadenitis can form a cellulitis, which suppurate and become an abscess.
  • Possible predisposing infections can include pharyngitis, tonsillitis, otitis, adenitis, adenoiditis, sinusitis, and nasal, salivary, and dental infections.
  • Retropharyngeal infections are also spread from contiguous spaces, such as the parapharyngeal space (eg, abscesses), submandibular space, or prevertebral space (eg, osteomyelitis).
• The retropharyngeal space can also be directly inoculated secondary to penetrating trauma.
  • Running and falling down with a sharp object in the mouth is not unusual in children. Because parents may be unaware of these predisposing events, diagnosis is even more elusive.
  • Foreign bodies (for example, fishbones) can become lodged in the posterior pharynx. Although this can happen in the pediatric age group, a foreign body lodged in the posterior pharynx is also a cause of abscess formation in adults.
• Deep space infections can be iatrogenic secondary to instrumentation of the upper respiratory tract. All of the following can predispose to abscess formation:
  • Laryngoscopy
  • Endoscopy
  • Esophagoscopy
  • Feeding tube insertion
  • Endotracheal intubation
  • Head and neck surgery
  • Dental procedures
  • Injections
• Risk factors may include low socioeconomic status, poor oral hygiene, immune disfunction (including HIV, diabetes, and immunosuppression)
• Bacteria are often polymicrobial, with gram-positive organisms and anaerobes predominating, but gram-negative bacteria have also been isolated. The source is usually oropharyngeal flora.
  • The most common cause is group A beta-hemolytic streptococci. Other nonhemolytic streptococci can be present. Staphylococcus aureus is also fairly common. The most common anaerobes are Bacteroides species.
  • Other causative agents include Haemophilus parainfluenzae and Veillonella, Peptostreptococcus, Fusobacterium, and Eikenella species.
  • The incidence of beta-lactamase production is high. One study noted 22% beta-lactam resistance.
  • Suspect mycobacterium tuberculosis, B henselae, and coccidiosis in patients who may be predisposed (immunosupression, recent immigrants), especially if they are not responding to more conventional therapy.
  • Another consideration when evaluating these patients is the possibility of Lemierre syndrome (septic thrombophlebitis of the internal jugular vein from a head and neck infection (eg, retropharyngeal abscess). This infection is classically associated with the Fusobacterium necrophorum, an anaerobic, gram-negative rod.⁵

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