Chapter 25. Peritonsillar and Retropharyngeal Abscess

Peritonsillar and retropharyngeal abscesses (PTA and RPA, respectively) are commonly seen in children. The intent of this chapter is to help the clinician establish an accurate diagnosis early and to achieve cure by the judicious and adjunctive use of antibiotics, radiography, and surgery.

Peritonsillar Abscess

The pharyngeal tonsils are paired organs, which serve as the lateral lymphoid guardians at the posterior aspect of the oropharynx. PTA is an infected collection in the potential space surrounding the palatine tonsils. PTA usually presents with a pointing collection at the superior tonsillar pole.1,2 The loose areolar tissue surrounding the tonsils provides a potential space into which infections may spread.

In 1995, Herzon and Hassis estimated that children accounted for approximately one-third of the 45,000 episodes of PTA that occur annually.3 Most children with PTA present in the early teen years.4 While group A beta-hemolytic Streptococcus (GABHS) is the most commonly cultured organism, isolated in approximately one-third of cases,5 it is not the only bacterial pathogen identified. Most PTAs are polymicrobial, with GABHS, Staphylococcus aureus and Haemophilus influenzae accounting for most of the aerobic organisms and Prevotella spp., Porphyromonas spp., Fusobacterium spp., and Peptostreptococcus spp. comprising the common anaerobes.2,4

Retropharyngeal Abscess

The retropharyngeal space is a potential space located between the visceral layer of deep cervical fascia anteriorly and the alar division of deep cervical fascia posteriorly.6

Suppuration of lymphoid tissue imbricated between these layers is responsible for retropharyngeal infections. The lateral retropharyngeal nodes traditionally associated with RPA are eponymously referred to as the nodes of Rouviere.7 Infections may spread readily from the oropharynx to mediastinum via this “highway” of the neck. The retropharyngeal nodes regress around the age of 3–5 years.6,8

Consistent with nodal regression by the age of 5 years, most children present before age of 6 years with RPA, with the median age of around 3 years.4,6,9 The prevalence is in general thought to be increasing and was 4.94 cases/10,000 population in the Wayne State experience.8 RPA accounted for approximately 5% of deep neck space infections in Papua, New Guinea.10

Acute upper respiratory infection is the usual antecedent cause of RPA in children, as opposed to adults in whom foreign bodies, trauma, and dental infections are considered etiologic. Microbiology of RPA demonstrates a mixture of aerobic and anaerobic organisms. Common aerobic organisms include alpha- and beta-hemolytic streptococcal species, S. aureus, Neisseria spp., Eikenella spp., and nontypable H. influenzae. Common anaerobes include Bacteroides spp., peptostreptococci, Fusobacterium spp., and Prevotella spp. An increase over the past decade in the prevalence of GABHS has been noted.8 Less common organisms responsible for RPA include Epstein–Barr virus and Mycobacterium tuberculosis.6,11

PTAs typically occur when infectious tonsillopharyngitis progresses from cellulitis to abscess. RPAs may also develop as a consequence of antecedent pharyngitis. The lymphatics drain the nasopharynx, posterior sinuses, and adenoids. Purulent infections in these regions spread to the retropharynx by lymphatic drainage. Retropharyngeal lymph node inflammation may be complicated by necrosis and abscess formation. Rarely, RPAs are caused by penetrating neck injury or by extension of cervical osteomyelitis. The retropharyngeal lymph nodes atrophy by 4–5 years of age, making RPAs less common in older children.

General Considerations

Relevant history includes review of prodromal symptoms, recent travel and ill contacts, immunization status, airway and swallowing concerns, ability to maintain hydration, and response to supportive and pharmacologic therapy.

Physical examination may show serous otitis media as part of a usually antecedent upper respiratory infection. Oral examination should note the degree of trismus, which may be measured roughly in finger breadths or centimeters; the color and hydrations status of mucosa; and tonsillar size, symmetry, color, and exudate. The neck should be assessed for fullness, tenderness, adenopathy, and range of motion. Skin examination should focus on stigmata of complicated GABHS infections such as the scarlet fever rash.

Examination of the oropharynx is best achieved by first asking the child to open his or her mouth without protruding the tongue. This permits for a measurement of trismus (difficult with opening the mouth, measured in fingerbreadths or in centimeters) and can allow for a view of the posterior pharynx. Gentle depression of the mid portion of the tongue with a tongue depressor allows for a better view of the tonsils and posterior pharynx while avoiding gagging and allows examination even in the setting of trismus (Figures 25–1 and 25–2).

Flexible nasopharyngolaryngoscopy is useful when oral opening is limited or when there is a concern over pharyngeal edema or airway stability. Should supraglottitis be a concern, physical examination must be handled very carefully, as supraglottic contact by a tongue depressor or nasopharyngolaryngoscopy against inflamed and protuberant tissues may trigger immediate and life-threatening laryngospasm. Agitating a marginally stable child should be avoided.

Adequate lighting is critical to good oropharyngeal examination. Most often, the most expedient lighting is provided by an otoscope, penlight, or small flashlight, held by the examiner. A separate person to hold the light is useful. Stronger illumination without a second set of hands may be provided by a headlamp such as that worn by hikers, a set of lenses that magnify and illuminate (LumiView™, Welch Allyn, Skaneateles Falls, NY), or a headlight or head mirror.

Peritonsillar Abscess

Children usually present with several days of fever, dysphagia, or odynophagia. Ipsilateral otalgia and neck pain may be present.2 A characteristic voice change, described as muffled or “hot potato voice,” is frequently noted. Trismus, reported in two-thirds of patients with PTA in one series, results from irritation and reflex spasm of the internal pterygoid muscle.12 Physical examination shows an erythematous bulging of the soft palate above the tonsil, possibly with medial displacement of the tonsil, and/or uvular deviation away from its usual midline position (Figure 25–3). Trismus may limit examination, and so the previously described technique for oral examination is recommended, rather than attempting to force the mandible down and compressing the entire anterior tongue. Ipsilateral cervical adenopathy is also common.

Retropharyngeal Abscess

Retropharyngeal infections present similarly to peritonsillar infections with fever, drooling, dysphagia, odynophagia, and tender neck adenopathy. Many children have pharyngitis or tonsillitis,12 although pain with neck extension is a key finding that should raise suspicion for RPA rather than streptococcal or viral pharyngitis; as a consequence, the head is generally maintained in a neutral position, although in some children torticollis may be evident. Meningismus or stridor occurs in fewer than 5% of children. Airway obstruction is a possible complication.9 Diagnosis is suspected by a bulging of the posterior pharyngeal wall and confirmed by radiography.

Laboratory Studies

Children in whom intravenous therapy or hospitalization is considered should have a baseline urinalysis, and blood should be checked for a serum metabolic panel and a complete blood count with differential and may also be tested for serum markers of inflammation such as C-reactive protein and/or an erythrocyte sedimentation rate. Laboratory evaluation shows a leukocytosis with a propensity to immature cells. Monospot, as well as a throat culture or rapid strep test, should also be performed.

Radiologic Studies

Peritonsillar Abscess

Plain radiography has a limited role in the initial assessment of cases of peritonsillar cellulitis or abscess and may be reserved for cases in which fiberoptic nasopharyngolaryngoscopy is not available or possible. Contrast-enhanced computed tomography (CT) or gadolinium-enhanced magnetic resonance imaging (MRI) is useful in assessing young children with suspected PTA who are not cooperative with examination. It is also helpful for persistent symptoms (after 24–48 hours of therapy), especially if needle aspiration or surgical drainage had been performed initially. Imaging may reveal an unusual manifestation such as an inferior pole PTA.1 CT has a high sensitivity (approximately 90%) but modest specificity (60%) in detecting abscesses (as opposed to cellulitis) compared with operative findings.12

Retropharyngeal Abscess

In contrast to peritonsillar infections, radiologic studies are usually required for precise anatomic diagnosis of RPA. Lateral neck radiography provides only limited information and may show bulging of the retropharyngeal soft tissues, with resultant airway narrowing, loss of cervical lordosis, and a wide retropharyngeal space. The width of an abnormal retropharynx was defined by Wholey et al. in a 1958 paper as >7 mm in children 15 years of age or younger at the anteroinferior aspect of C2 and a wide retrotracheal space measured forward from the anteroinferior aspect of C6 of >14 mm (Figure 25–4).8

Contrast-enhanced CT and MRI are most useful, as these permit differentiation of abscess from phlegmon and anatomically localize the process to facilitate aspiration and surgical treatment. An abscess is identified by a rim-enhancing fluid collection, while a hypolucent area without ring enhancement is defined as phlegmon (Figures 25–5 and 25–6). Radiography may also localize a collection and indicate other sites of abscess formation as well as provide a means for objectively measuring abscess size and for following the progress of infection when clinical complaints are difficult to elicit, such as for a child with developmental delays.

Repeat imaging is generally not necessary for children who demonstrate unequivocal clinical improvement. Sequential radiography may be useful in monitoring the efficacy of therapy, particularly when surgery is not used initially or the patient is difficult to assess clinically because of age or cognitive development. Interventional radiologic techniques may have a role in some cases, for either therapeutic drainage or to provide diagnostic material for microbial culture. Consideration of the long-term effects of low-dose diagnostic irradiation should be weighed when selecting which type of study (e.g., CT that requires diagnostic irradiation vs. MRI that does not administer irradiation).13

Peritonsillar Abscess

Treatment aims to resolve discomfort, maintain the airway, and prevent abscess rupture. A ruptured PTA may result in the aspiration of purulence and lead to bronchopneumonia.2 The sixth century Byzantine physician Aetius of Amida treated spontaneously draining abscesses with gargles of honey, milk, and herbs, or with rose extract.14 Today, oral antibiotics are recommended to begin with, such as penicillin, amoxicillin/clavulanic acid, cephalosporins, and clindamycin. Antibiotic selection should be culture directed when possible. Hospitalization may be necessary for rehydration, analgesia, intravenous antibiotics, and/or airway observation.

Intravenous corticosteroid therapy may be considered to reduce inflammation in children with airway compromise, administered at the dose of 0.5 mg/kg of dexamethasone intravenously up to a maximum single dose of 10 mg, every 8 hours, for up to three total doses.

Many PTAs require either needle aspiration or incision and drainage (I&D). Needle aspiration may be performed diagnostically to confirm abscess formation, to identify the best point at which to perform I&D, or as a therapeutic measure to relieve symptoms and provide material for microbial culture. Needle aspiration is a rapid means of relieving the painful bulging of the abscess and may speed the course of recovery. Bacterial culture results are not clinically useful in most cases, but the cultures are valuable when there is a concern over antibiotic resistance, such as for immunodeficient children or those who have been recently treated with broad-spectrum antibiotics.15 CT guidance of needle aspiration is indicated after an unsuccessful surgical attempt and for an abscess that is located in an atypical location or that may be difficult to reach with standard surgical approaches.

I&D permits a more complete evacuation than that allowed by needle aspiration. I&D is performed trans-orally and is indicated for the older, more cooperative patients who may more easily permit a longer procedure. I&D may be performed awake, with the aid of local and topical anesthetic, with conscious sedation protocols or under general anesthesia in the operating room, the latter usually caused by a child's inability to cooperate. Acute tonsillectomy (“quinsy” tonsillectomy) may be necessary for relief of obstructive symptoms, a history of recurrent streptococcal pharyngotonsillitis, or an exposure of the abscess. Quinsy tonsillectomy is necessary in approximately one out of three cases of PTA in children.2,16

For both PTA and RPA, a proactive and coordinated airway management plan is critical when considering sedation, imaging, and surgery. A plan should be communicated between all providers, including physicians, anesthesiologists, and nursing and support staff. Appropriate preparation should be made for a variety of intubating laryngoscopes as well as flexible fiberoptic bronchoscopes. A discussion should be considered with the family of potential airway risks as well as the option for tracheotomy in the most dire circumstances.

When treating PTA, attention should be paid to the tissue characteristics of tonsillar and peritonsillar tissues. Fleshy, granular, or pale tissue may indicate a neoplasm presenting as a PTA.17 In such cases, tissue should be sent for immunohistopathologic evaluation. Follow-up should confirm resolution of fullness in the peritonsillar region along with normalization of swallowing and airway status.

Retropharyngeal Abscess

Management of small collections—whether abscess or phlegmon—may be initiated with oral or intravenous antibiotics. Usually, children who present with RPA are dehydrated and receive intravenous fluid. Initial inpatient antimicrobial therapy via the intravenous route is therefore easily achieved and is advised until clinical improvement is clearly demonstrated by at least 24 hours without fever and the child is able to swallow secretions, liquids, and medications. Inpatient stay allows for rehydration and antimicrobial care while permitting for airway observation with expedient airway intervention, imaging, or surgical drainage if necessary. Length of stay is generally less than 2 weeks and is often shorter than 5 days.9

RPA may often be treated by antibiotics alone, particularly when the abscess is small and there is no airway compromise. Antibiotic therapy may empirically begin with clindamycin with or without cefuroxime or ceftriaxone, or ampicillin/sulbactam.8,9 Duration of therapy should be for 10–21 days and, in some cases, may require placement of an indwelling intravenous catheter for outpatient administration of antibiotics. As with PTA, antibiotic choice should be guided by microbiologic cultures when possible. Intravenous corticosteroid therapy may be considered for children with airway compromise, with the dosing detailed above for children with PTA.

RPAs that are extensive or refractory to antibiotics require surgical drainage, by the trans-oral route for RPA medial to the great vessels and/or transcervically for collections lateral to the great vessels. Airway considerations during surgical drainage include difficult laryngoscopy during intubation caused by neck stiffness and a limited view as a result of forward bulging of retropharyngeal tissues. Spontaneous or iatrogenic abscess rupture may permit foul secretions to pour into the tracheobronchial tree and lead to aspiration pneumonia.

PTA recurs in 10–15% of patients undergoing drainage by needle aspiration. Recurrence is more common in patients with a history of recurrent tonsillitis prior to developing PTA; among 290 patients, PTA recurrence occurred in 40% of those with a history of recurrent tonsillitis compared with 9.6% of those with no such history.18

Suppurative complications of RPA include rupture of the abscess with aspiration of purulent secretions into the tracheobronchial tree, extension of inflammation into the mediastinum, jugular vein thrombophlebitis, erosion of carotid or vertebral arteries, and sepsis.8,9