Retropharyngeal Abscess Clinical Overview
I. The "On-Call" Snapshot
Clinical Significance in Malaysia: This is a key "can't miss" diagnosis for a child presenting with fever, neck stiffness, and difficulty swallowing. While not as common as a simple tonsillitis, missing it can lead to airway obstruction and mediastinitis, especially in the paediatric population.
High-Yield Definition: A retropharyngeal abscess is a collection of pus in the potential space between the posterior pharyngeal wall (buccopharyngeal fascia) and the prevertebral fascia.
Clinical One-Liner: Basically, it's a pus pocket deep in the throat that can squeeze the airway shut.
II. Etiology & Risk Factors
Etiology: It's almost always a polymicrobial bacterial infection. Think of it as a complication of a preceding infection.
In children (<5 years old): Typically results from suppuration of the retropharyngeal lymph nodes (the nodes of Rouvière), which drain the nasopharynx, adenoids, and middle ear. These nodes atrophy with age, which is why this is more common in toddlers.
In adults: Usually due to direct trauma (e.g., fish bone), iatrogenic causes (e.g., endoscopy, intubation), or extension from an adjacent deep neck infection.
Risk Factors:
Non-Modifiable: Age < 5 years, congenital abnormalities.
Modifiable: Recent upper respiratory tract infection (URTI), pharyngitis, otitis media, poor dental hygiene, immunocompromised state (e.g., uncontrolled diabetes mellitus).
III. Quick Pathophysiology
An infection from the nasopharynx or sinuses seeds the retropharyngeal lymph nodes. This leads to suppurative lymphadenitis. The nodes eventually break down, forming a contained collection of pus. This abscess expands, pushing the posterior pharyngeal wall forward and compromising the airway. If it ruptures or extends, it can track down the 'danger space' directly into the mediastinum, causing mediastinitis.
IV. Clinical Assessment
Red Flags & Immediate Actions:
Stridor or Respiratory Distress: This is an airway emergency. → Action: Do NOT agitate the child. Keep them comfortable (often in a parent's lap). Alert your senior and the anaesthetics team immediately. Prepare for airway management in the operating theatre.
Drooling & Inability to Swallow Saliva: Signifies significant odynophagia and impending airway obstruction. → Action: Keep patient Nil By Mouth (NBM). Secure IV access. Alert seniors.
"Hot Potato" Voice (muffled voice): Indicates significant pharyngeal swelling. → Action: Escalate to your senior; this patient needs urgent ENT review.
Torticollis or Neck Hyperextension: Suggests irritation of the deep neck muscles. → Action: Maintain a position of comfort. Do not force neck movement.
History:
Common (>50%): Fever, sore throat (odynophagia), refusal to feed/eat, irritability.
Less Common (10-50%): Neck pain or stiffness, muffled voice, neck swelling/mass, snoring.
Pertinent Negatives: Ask about recent URTI, history of foreign body ingestion or throat injury. The absence of a cough in a child with stridor should make you worry more about an upper airway obstruction like this or epiglottitis.
Physical Examination:
General: The child often looks toxic, febrile, and anxious, holding their neck stiffly (torticollis) or in slight extension. Drooling may be present.
Oropharynx: Look for a unilateral bulge or swelling of the posterior pharyngeal wall. Be cautious; vigorous examination with a tongue depressor can cause abscess rupture or laryngospasm. If the patient is in distress, defer this until in a controlled setting (i.e., the OT).
Neck: Check for cervical lymphadenopathy and tenderness.
Auscultation: Listen for stridor (inspiratory noise indicating upper airway obstruction).
Clinical Pearl: The classic triad is fever, neck pain, and dysphagia. In a toddler, this should immediately bring retropharyngeal abscess to the top of your mind. They won't tell you their throat hurts; they'll just refuse to eat and drool.
V. Diagnostic Workflow
Differential Diagnosis:
Acute Epiglottitis:
Points For: Rapid onset, high fever, drooling, tripod position.
Points Against: Epiglottitis patients often prefer to sit up and lean forward; RPA may have neck extension. RPA usually has preceding URTI symptoms.
How to Differentiate: A lateral neck X-ray showing a "thumbprint sign" is classic for epiglottitis. Definitive diagnosis is by laryngoscopy in OT.
Peritonsillar Abscess (Quinsy):
Points For: Severe sore throat, fever, "hot potato" voice, trismus.
Points Against: Quinsy is rare in young children, more common in adolescents/adults. The swelling is unilateral peritonsillar, often displacing the uvula away from the affected side, not in the posterior pharyngeal wall.
How to Differentiate: Clinical examination clearly shows a bulging tonsil and soft palate.
Meningitis:
Points For: Fever, neck stiffness, irritability.
Points Against: Meningitis won't typically cause drooling, stridor, or a pharyngeal bulge.
How to Differentiate: Absence of throat signs. Presence of other neurological signs (e.g., photophobia, altered mental status). Diagnosis is via lumbar puncture.
Investigations Plan:
Bedside / Initial (First 15 Mins):
Vital signs monitoring, including oxygen saturation.
First-Line Labs & Imaging:
Lateral Neck X-ray (in extension, during inspiration): This is your first-line imaging. Look for widening of the prevertebral soft tissue. Rule of thumb: The prevertebral space should be no wider than the vertebral body of C2, or half the width of C4.
Bloods: FBC (leukocytosis), CRP (elevated), Blood C&S if septic.
Confirmatory / Gold Standard:
CT Scan of the Neck with IV Contrast: This is the gold standard. It differentiates between cellulitis (phlegmon) and a drainable abscess (a rim-enhancing fluid collection). It also defines the extent of the infection. Do this only in a stable patient who can lie flat safely.
VI. Staging & Severity Assessment
Severity is based on clinical and radiological findings.
Retropharyngeal Cellulitis/Phlegmon: Diffuse inflammation without a discrete, drainable fluid collection on CT. May be managed with IV antibiotics alone initially.
Retropharyngeal Abscess: A distinct collection of pus with peripheral rim enhancement on CT.
Small Abscess (<2 cm): May sometimes be trialed on IV antibiotics with very close observation.
Large Abscess (≥2 cm) or Any Abscess with Airway Compromise: Requires surgical drainage.
The presence of any red flag (stridor, respiratory distress) automatically classifies the patient as severe and requires immediate escalation for airway security and drainage.
VII. Management Plan
Immediate Stabilisation (The ABCDE Plan):
A (Airway): This is your priority. Maintain a position of comfort. Minimise distress. Have airway equipment ready. Involve anaesthetists and ENT early.
B (Breathing): Administer high-flow humidified oxygen.
C (Circulation): Secure IV access. Give a fluid bolus (e.g., Normal Saline 10-20 mL/kg) if tachycardic or hypotensive. Take bloods.
D (Disability): Assess GCS.
E (Exposure): Check for fever, assess for signs of sepsis.
Definitive Treatment (The Ward Round Plan): This is a combined medical and surgical issue. Refer to ENT urgently.
First-Line (Antibiotics): All patients need IV antibiotics. The choice must cover Gram-positives, Gram-negatives, and anaerobes.
As per the Malaysian National Antimicrobial Guideline (NAG) for deep neck infections:
Preferred: IV Ampicillin/Sulbactam OR IV Amoxicillin/Clavulanate (Augmentin).
Alternative (e.g., Penicillin Allergy): IV Clindamycin.
Start empirically after securing IV access. Do not wait for cultures.
Surgical Drainage:
Indicated for large abscesses, any airway compromise, or failure to improve after 24-48 hours of IV antibiotics.
This is done by the ENT team in the operating theatre, usually via a transoral approach.
Supportive Care: IV hydration, analgesia (paracetamol, consider opioids carefully due to risk of respiratory depression), antipyretics.
Long-Term & Discharge Plan:
Patient can be stepped down to oral antibiotics (e.g., Oral Co-amoxiclav) once afebrile and able to tolerate orally.
Complete a total of 10-14 days of antibiotics (IV + oral).
Ensure follow-up in the ENT clinic.
VIII. Complications
Immediate:
Airway Obstruction: Management: Intubation or emergency tracheostomy.
Abscess Rupture: Can lead to aspiration pneumonia. Management: Immediate suctioning, securing the airway.
Short-Term (Days to Weeks):
Mediastinitis: Spread of infection to the chest. High mortality. Management: Requires cardiothoracic surgery consultation for drainage.
Internal Jugular Vein Thrombophlebitis (Lemierre's syndrome): Management: Prolonged antibiotic course, anticoagulation.
Sepsis: Management: Fluid resuscitation, antibiotics, supportive care in ICU/HDW.
Long-Term:
Carotid artery erosion: A rare but catastrophic complication.
IX. Prognosis
With prompt diagnosis and treatment (antibiotics and drainage), the prognosis is excellent. The mortality rate is low (<1%) but increases significantly if complications like airway obstruction or mediastinitis occur. The most critical prognostic factor is the timely securing of the airway and drainage of pus.
X. How to Present to Your Senior
"Dr, for review please. This is [Patient's Name] in Paeds A&E, a 3-year-old boy with no past medical history, who presented with high-grade fever, refusal to eat, and drooling for one day. On examination, he is toxic-looking, holding his neck stiffly, and has a muffled cry. He has mild inspiratory stridor. My main differential is a retropharyngeal abscess. I have kept him NBM, secured an IV line, and am starting IV fluids. I am calling to inform you and to urgently get both ENT and anaesthetics involved for airway assessment. I will order a lateral neck X-ray while waiting for the teams."
XI. Summary & Further Reading
Top 3 Takeaways:
Suspect RPA in any young child with fever, neck stiffness, and dysphagia/drooling.
Airway compromise is the biggest threat. Stridor is a red flag requiring immediate escalation to seniors, ENT, and anaesthetics.
Diagnosis is confirmed with a contrast CT neck, but a lateral neck X-ray is a good first step. Management is urgent ENT referral for IV antibiotics and probable surgical drainage.
Key Resources:
Malaysian National Antimicrobial Guideline (NAG) 2019: Refer to the section on Otorhinolaryngology Infections for antibiotic choices. (Accessible on the MOH website).
UpToDate: Search for "Retropharyngeal infections in children".
StatPearls: Search for "Retropharyngeal Abscess".
