Overview
Definition:
A peritonsillar abscess (PTA) is a collection of pus located between the tonsillar capsule and the superior constrictor muscle of the pharynx
A retropharyngeal abscess (RPA) is a collection of pus in the space behind the pharynx, between the prevertebral fascia and the buccopharyngeal fascia.
Epidemiology:
PTA is more common than RPA in children, typically occurring in older children and adolescents (5-15 years), often as a complication of acute tonsillitis
RPA is more common in infants and younger children (under 5 years), often secondary to pharyngeal infections, trauma, or foreign body ingestion
Incidence varies but is significant in pediatric emergency departments.
Clinical Significance:
Both conditions are potentially life-threatening due to airway compromise and spread of infection
Prompt diagnosis and management are crucial to prevent severe complications such as airway obstruction, mediastinitis, sepsis, and necrotizing fasciitis
Understanding the differences is key for effective pediatric care and board examination success.
Clinical Presentation
Symptoms:
PTA: Severe sore throat, typically unilateral
Trismus (difficulty opening mouth)
Muffled voice ("hot potato" voice)
Drooling
Fever
Headache
Ear pain (otalgia) due to shared nerve pathways
RPA: Sore throat
Difficulty swallowing (dysphagia)
Stridor (high-pitched noisy breathing)
Muffled voice
Fever
Neck pain and stiffness
Snoring
Poor feeding in infants
Possible sudden collapse.
Signs:
PTA: Uvular deviation away from the affected side
"Fluctuant" bulging of the tonsillar area
Erythema and swelling of the tonsil and surrounding pharyngeal mucosa
Trismus on examination
Muffled voice
Signs of dehydration
RPA: Posterior pharyngeal wall bulging, often visible with a tongue depressor or laryngoscope
Neck mass or swelling
Limited neck extension
Respiratory distress (stridor, retractions).
Diagnostic Criteria:
Diagnosis is primarily clinical, based on characteristic symptoms and physical findings
While specific criteria are not formally established, suspicion arises with unilateral tonsillar swelling, uvular deviation, trismus (PTA), or posterior pharyngeal bulge and stridor (RPA)
Imaging confirms the diagnosis when clinical suspicion is high but findings are equivocal.
Diagnostic Approach
History Taking:
Detailed history of sore throat onset and progression, particularly unilateral nature
Any recent upper respiratory infection or tonsillitis
Fever
Difficulty opening mouth
Voice changes
Drooling
Neck pain or stiffness
Stridor or breathing difficulties
Any history of trauma or foreign body ingestion
Feeding difficulties in infants.
Physical Examination:
Complete head and neck examination focusing on the oral cavity, pharynx, and neck
Assess mouth opening (trismus)
Inspect tonsils for asymmetry, erythema, and bulging
Palpate for neck masses or tenderness
Assess airway patency carefully, noting stridor or retractions
Assess for meningeal signs if RPA is suspected
Use extreme caution with direct pharyngeal palpation in suspected RPA.
Investigations:
PTA: Ultrasound of the neck can be useful for fluid collection confirmation and guiding drainage
CT scan of the neck with contrast is indicated if diagnosis is uncertain or to rule out other deep neck infections
RPA: Lateral neck X-ray may show widening of the retropharyngeal space (prevertebral soft tissue thickening > 7 mm in infants, >14 mm in older children)
CT scan of the neck with contrast is the investigation of choice for diagnosis and assessing extent, showing abscess cavity and potential spread
Laboratory tests: Complete blood count (leukocytosis), C-reactive protein (elevated)
Blood cultures if sepsis is suspected.
Differential Diagnosis:
PTA: Peritonsillar cellulitis, other deep neck infections (e.g., parapharyngeal abscess), tonsillitis, foreign body
RPA: Cervical lymphadenitis, epiglottitis, guttate psoriasis, foreign body, vertebral osteomyelitis, thyroiditis, lymphadenopathy, other deeper neck space infections.
Management
Initial Management:
Airway assessment and management are paramount
If airway compromise is present, immediate surgical airway (intubation or tracheostomy) may be required
IV fluids for hydration
Analgesia and antipyretics
IV antibiotics to cover aerobic and anaerobic bacteria (e.g., Clindamycin or Amoxicillin-clavulanate).
Medical Management:
Antibiotic therapy is essential
For PTA, common oral pathogens include Streptococcus pyogenes and anaerobes
For RPA, common pathogens include Streptococcus pyogenes, Staphylococcus aureus, and anaerobes
IV antibiotics typically include a beta-lactam with a beta-lactamase inhibitor (e.g., Amoxicillin-clavulanate) or Clindamycin
Duration of IV therapy depends on clinical response, usually followed by oral antibiotics for a total course of 7-10 days.
Surgical Management:
PTA: Needle aspiration or incision and drainage of the abscess is the mainstay of treatment
This should be performed by an experienced clinician, often with local anesthesia and sedation
RPA: Surgical drainage is indicated for larger abscesses, those causing significant airway compromise, or if there is no improvement with medical management
Drainage is typically performed by otolaryngology specialists via an anterior approach through the pharynx or a posterior approach through the neck.
Supportive Care:
Close monitoring of airway status, vital signs, and fluid balance
Pain management is crucial
Nutritional support, often via nasogastric tube if oral intake is significantly impaired
Isolation precautions if specific pathogens are identified.
Complications
Early Complications:
Airway obstruction leading to respiratory arrest
Extension of infection to adjacent spaces (parapharyngeal, pterygoid, masticator spaces)
Mediastinitis (life-threatening infection of the mediastinum)
Sepsis
Thrombosis of the internal jugular vein (Lemierre's syndrome).
Late Complications:
Recurrent peritonsillar abscess
Chronic neck pain
Trismus
Scarring and adhesions
Esophageal stricture (rare)..
Prevention Strategies:
Prompt and adequate treatment of underlying tonsillitis or pharyngitis
Good oral hygiene
Avoiding penetrating pharyngeal trauma
Prompt medical attention for any suspected deep neck infection symptoms.
Prognosis
Factors Affecting Prognosis:
Promptness of diagnosis and treatment
Adequacy of airway management
Presence of complications like mediastinitis or sepsis
Virulence of the infecting organism
Host immune status.
Outcomes:
With prompt diagnosis and appropriate management (drainage and antibiotics), the prognosis for both PTA and RPA is generally good, with most children recovering fully
Airway compromise and advanced infections significantly worsen the prognosis.
Follow Up:
Regular follow-up with the treating physician or ENT specialist is recommended to ensure complete resolution, monitor for recurrence, and address any long-term sequelae
Follow-up may include a repeat examination or imaging if indicated.
Key Points
Exam Focus:
Differentiate PTA (uvular deviation, trismus, unilateral tonsillar bulge) from RPA (posterior pharyngeal bulge, stridor, neck stiffness)
Recognize airway compromise as the most critical immediate threat
Know primary imaging modalities (Ultrasound/CT) and typical antibiotic regimens
Understand the need for drainage in both conditions.
Clinical Pearls:
Always consider airway first in a child with sore throat and stridor or severe dysphagia
Uvular deviation is a classic sign of PTA
A lateral neck X-ray can be a useful screening tool for RPA, but CT scan is more definitive
Never palpate a bulging posterior pharynx aggressively if RPA is suspected, as it can lead to airway collapse.
Common Mistakes:
Delaying definitive management due to diagnostic uncertainty
Underestimating the severity of airway compromise
Inadequate antibiotic coverage (especially for anaerobes)
Performing needle aspiration on a non-fluctuant collection or in a case of RPA without adequate airway preparedness.