Management of Parapharyngeal Abscess

Block diagram of the deep spaces of the neck - Rosen's Emergency Medicine

Anatomy and Significance

• Anterior PPS (prestyloid): Contains fat - prone to liquefaction and abscess formation; requires aggressive surgical drainage
• Posterior PPS (poststyloid/retrostyloid): Contains the carotid sheath (carotid artery, internal jugular vein, sympathetic chain, CN IX-XII), lymph nodes; more often causes lymphadenitis and may be managed more conservatively

• Scott-Brown's Otorhinolaryngology, p. 671
• Rosen's Emergency Medicine, p. 965

Aetiology and Microbiology

• Peritonsillar or retropharyngeal abscess (direct spread)
• Dental infection / mandibular molar periapical abscess
• Suppurative cervical lymphadenitis
• Parotitis
• Penetrating trauma, nerve blocks, or surgical procedures (iatrogenic)
• IV drug abuse

Clinical Features

Complications (Life-threatening - must anticipate)

1. Airway obstruction - edema, abscess mass effect
2. Descending mediastinitis - via retropharyngeal/danger space communication (crude mortality up to 2%)
3. Lemierre syndrome - septic thrombophlebitis of the internal jugular vein; suspect when sore throat + sepsis + multisystem involvement
4. Carotid artery erosion, aneurysm, or rupture - any signs of bleeding warrant CT/MR angiography urgently
5. Horner syndrome - sympathetic chain involvement (CN IX-XII neuropathies)
6. Cavernous sinus thrombosis - proptosis, impaired EOM, pupillary changes
7. Aspiration pneumonia / lung abscess / empyema - from abscess rupture into airway
8. Retroperitoneal sepsis - rare but described

Investigations

• Contrast-enhanced CT of neck + chest - gold standard; demonstrates rim-enhancing abscess, extent of infection, and any mediastinal involvement. Always include the mediastinum in the scan field. Cellulitis appears as fat stranding along fascial planes; abscesses show characteristic ring enhancement
• MRI - comparable to CT for delineating extent; useful when radiation is to be minimized
• Ultrasound - may assess whether abscess has sufficiently liquefied and can guide needle aspiration, but limited in deep spaces
• CT or MR angiography - when vascular complications suspected
• Orthopantomogram (OPG) - if dental origin suspected
• Fibreoptic nasendoscopy - assess upper aerodigestive tract and airway patency simultaneously (performed cautiously to avoid triggering gag reflex)

Management: Step-by-Step

Step 1 - Airway Assessment and Securing (Priority Zero)

• Assess for: dyspnea, tachypnea, stridor, inability to manage secretions, agitation, drooling
• Conventional laryngoscopy is often impossible due to trismus, reduced neck extension, laryngopharyngeal edema, and friable mucosa
• Do NOT paralyze before securing airway
• Preferred method: awake fibreoptic nasotracheal or orotracheal intubation with adequate topicalization
• Have emergency tracheostomy prepared and set up before commencing anaesthesia; pre-infiltrate with 2% lignocaine + 1:80,000 adrenaline at tracheostomy site
• Transfer to operating theatre with anaesthetic and surgical teams experienced in difficult airway management
• Supine positioning for CT is only safe once airway is deemed stable

Step 2 - Intravenous Antibiotics (Immediate, Do Not Delay for Cultures)

• Alternatively: amoxicillin-clavulanate, or 2nd/3rd generation cephalosporins with metronidazole
• Review all antibiotic choices once culture and sensitivity results are available
• Note rising resistance: clindamycin 11-18%, erythromycin 14%, penicillins 7-8%
• In children under 2: clindamycin preferred as first line due to MRSA rates

Step 3 - Corticosteroids (Adjunctive)

• Dexamethasone 0.6 mg/kg IV/IM (maximum 10 mg) given with antibiotics
• Associated with decreased need for surgical drainage in select cases
• Reduces pharyngeal edema and systemic inflammation

Step 4 - Surgical Drainage (Decision)

• Confirmed abscess on CT with liquefaction
• Failure to respond to conservative treatment after 24-48 hours (persistent pyrexia, worsening pain)
• Airway compromise from the abscess
• Vascular complications

• Intranodal abscess or phlegmon (cellulitis without pus collection)
• Abscess size <2.5 cm contained within a single neck space
• Most pediatric cases (especially posterior PPS / phlegmon)
• Patient is responding clinically to antibiotics within 24-48 hours

Step 5 - Surgical Approach Options

• Incision anterior to SCM, dissecting along the great vessels
• Approach anterior and medial to the carotid sheath
• Curette abscess wall; break down loculations
• Insert drain (usually corrugated or suction drain)

• Blunt instrument drainage through the oropharynx (medial to the pterygomandibular raphe)
• Risk of inadequate drainage; limited visualization

• Shown in a prospective RCT to reduce hospital stay from 5.2 to 3.1 days and reduce cost by 41%, with no difference in efficacy or complications
• Better for microbiological sampling (increases anaerobe isolation)
• Useful when abscess is superficially accessible
• Scott-Brown's ORL, p. 672; Bailey & Love's Surgery, p. 480

Step 6 - ICU Admission and Monitoring

• Admit to ICU if airway or vascular compromise is present
• Monitor for septic complications, mediastinal spread, vascular involvement
• Patients with stable airways may be admitted to a high-dependency floor bed
• IV fluid resuscitation; nutritional support (NG or parenteral if swallowing compromised)
• Serial clinical and radiological reassessment

Special Considerations

Recent Evidence

Summary Algorithm

Parapharyngeal Abscess
        |
        v
Airway Compromise? ──YES──> Awake fiberoptic intubation
        |                   (+ prepare emergency tracheostomy)
        NO
        |
        v
Contrast-enhanced CT Neck + Chest
        |
   _____|_____
  |           |
Cellulitis/  Abscess
Phlegmon     confirmed
  |           |
IV Abx       IV Abx + Dexamethasone
+ Dex        + Otolaryngology consult
  |           |
Reassess     Failure to respond  ──> Surgical drainage
at 24-48h    at 24-48 hours         (transcervical / US-guided)

• Rosen's Emergency Medicine - Concepts and Clinical Practice, pp. 964-966
• Scott-Brown's Otorhinolaryngology Head & Neck Surgery (Vol 2), pp. 671-674
• Bailey & Love's Short Practice of Surgery (28th ed.), p. 480
• KJ Lee's Essential Otolaryngology, pp. 709-711
• Sheikh Z et al. (2023). Systematic review of deep neck space infections. Clin Otolaryngol. PMID 37147934

Management of Chronic Retropharyngeal Abscess (Prevertebral Abscess)

Definition and Key Distinction

A chronic retropharyngeal abscess must NEVER be opened into the mouth - unlike an acute abscess. Intraoral drainage risks secondary pyogenic contamination of a sterile tuberculous collection and aspiration.

• Bailey & Love's Surgery, 28th ed., p. 809

Aetiology

Haematogenous seeding of cervical vertebral body
           |
   Bone destruction + caseation
           |
Extension beneath the Anterior Longitudinal Ligament
           |
Spread into the Prevertebral Space (behind prevertebral muscles)
           |
Cold abscess tracks anteriorly → Retropharyngeal swelling
           |
Presents as bulge in posterior pharyngeal wall

• Spread to the posterior cervical triangle
• Bulge into the retropharyngeal space - visible as a posterior pharyngeal wall swelling
• Track down into the mediastinum (along prevertebral fascia)

• Firestein & Kelley's Textbook of Rheumatology, p. 2503
• Bailey & Love's Surgery, p. 808

Clinical Features

Investigations

Imaging

• Rim-enhancing low-density collection anterior to the prevertebral muscles (the abscess is posterior to pharyngeal mucosa and prevertebral muscles displace anteriorly - distinguishing it from a retropharyngeal space mass where the prevertebral muscles are displaced posteriorly)
• Vertebral body destruction - loss of vertebral height, osteolysis of anterior vertebral body
• Disc space narrowing and intervertebral disc involvement
• Loss of normal cervical lordosis / kyphotic deformity
• Gibbus deformity in advanced cases
• Occasional calcification within the abscess (pathognomonic of TB)
• Epidural extension and cord compression in severe cases

Axial CECT - prevertebral abscess at C5/C6 with pharyngeal displacement (arrowheads) - Cummings Otolaryngology

• Osteolysis of anterior vertebral bodies
• Disc involvement (unlike metastatic disease which spares disc)
• Retropharyngeal soft tissue shadow widening
• Gibbus / kyphotic deformity
• Partial calcification of paravertebral mass
• Loss of normal curvature

Microbiological / Histological Confirmation

• CT-guided / US-guided percutaneous needle aspiration of the abscess - send fluid for:
  • AFB smear (only 40% positive from psoas/paravertebral abscesses)
  • Mycobacterial culture (gold standard but takes 6-8 weeks; positive in 80-95% of biopsy specimens with TB histology)
  • GeneXpert/NAAT (Nucleic Acid Amplification Test) - sensitivity 85-95%, specificity 96-100%, result in 48 hours - now the preferred rapid test
  • Standard bacterial culture (to exclude pyogenic co-infection)
  • Drug sensitivity testing (DST) to exclude MDR-TB
• CT-guided needle biopsy of the vertebral body/disc - send for:
  • Histology: granulomatous inflammation with central caseation, Langhans giant cells
  • AFB culture
• Blood tests: ESR (elevated), CRP, FBC (anaemia of chronic disease), liver function (pre-ATT baseline), renal function
• Mantoux / tuberculin skin test - positive in >80%
• IGRA (Interferon-Gamma Release Assay) - QuantiFERON-TB Gold - more specific in BCG-vaccinated populations
• Chest X-ray - screen for concurrent pulmonary TB (present in 52% of cases)
• HIV testing (alters treatment regimen and duration)
• Firestein & Kelley's Rheumatology, pp. 2503-2504

Management

Step 1 - Cervical Spine Precautions (Immediate Priority)

• Avoid neck manipulation - the spine may be unstable; undue force can precipitate atlantoaxial dislocation, subluxation, or acute cord compression
• Cervical immobilization with a rigid collar if instability is demonstrated or suspected on imaging
• Senior clinician involvement essential for examination

Step 2 - Anti-Tubercular Therapy (ATT) - The Cornerstone of Treatment

• Baseline LFTs, uric acid, urea/creatinine, visual acuity (for ethambutol)
• Monthly clinical assessment
• Monitor for hepatotoxicity (commonest toxicity - isoniazid, rifampicin, pyrazinamide)
• Ethambutol optic neuritis - check visual acuity monthly
• Pyridoxine (vitamin B6) 10 mg/day with isoniazid to prevent peripheral neuropathy

Step 3 - Drainage of the Abscess (Surgical Decision)

• Large collection causing significant airway compromise or dysphagia
• Failure to respond to ATT after 6-8 weeks (persistent abscess, worsening symptoms)
• Need for microbiological confirmation if CT-guided aspiration is not feasible or has failed
• Neurological compromise (see Step 4 below)
• Abscess pointing superficially and at risk of spontaneous rupture

1. Incision anterior to the sternocleidomastoid muscle
2. Dissect medially, approaching anterior and medial to the carotid sheath
3. Enter the retropharyngeal/prevertebral space
4. Open the cavity, suction dry thoroughly
5. Send biopsy material for histology, AFB culture, and GeneXpert
6. Cavity not primarily closed - drain insertion if needed
7. No dependent drainage (unlike pyogenic abscess) - prevertebral abscesses are often under no tension

• Bailey & Love's Surgery, p. 809

Step 4 - Surgery for Spinal Decompression / Stabilization

• Progressive neurological deficit (myelopathy, cord compression, paraplegia / quadriplegia)
• Spinal instability with risk of cord injury
• Significant kyphotic deformity (gibbus) requiring correction
• Large epidural abscess compressing the cord
• Failure of conservative management with ATT

• Surgical intervention was performed in 71.9% of cervical spine TB patients
• Bone fusion was achieved at a mean of 4.1 months
• Surgery-related mortality: 1.0%
• A combination of medical and surgical treatment produces favorable neurological outcomes
• MRI findings showed epidural/paravertebral abscesses with cord involvement in 72.9% of cases

Step 5 - General Supportive Measures

• Nutritional support - TB is a catabolic disease; high-protein diet, nutritional supplementation
• Analgesia - NSAIDs (avoid if hepatotoxicity is a concern on ATT)
• Immobilization - cervical orthosis / collar for pain relief and stability during the healing phase
• Physiotherapy - after spinal fusion is achieved; graduated mobilization and strengthening
• Notification to public health authorities (TB is a notifiable disease)
• Contact tracing and screening of household contacts
• HIV management if co-infected (adjust ATT timing/regimen; avoid rifampicin interactions with some antiretrovirals)

Differential Diagnosis of Prevertebral/Retropharyngeal Mass

Summary Algorithm

Posterior pharyngeal wall swelling / prevertebral mass in an adult
                    |
          Cervical spine precautions
          (Rigid collar; avoid manipulation)
                    |
       MRI / Contrast-enhanced CT neck + cervical spine
                    |
   Vertebral destruction + paravertebral cold abscess?
                    |
         YES → Suspect TB spondylitis
                    |
    ┌───────────────┼──────────────────┐
    |               |                  |
 CT/US-guided    Chest X-ray      Blood tests:
 aspiration/    HIV testing    ESR, CRP, FBC,
  biopsy        Mantoux/IGRA   LFT, GeneXpert
    |
 Confirm Mycobacterium tuberculosis
    |
 Start ATT: 2HRZE + 10HR (12 months total)
    |
 Reassess at 6-8 weeks
    |
 Responding?                Not responding / Large collection /
    |                       Neurological deficit / Instability
    |                                  |
Continue ATT                   External cervical drainage
                               (anterior to SCM, medial to
                               carotid sheath) + Spinal surgery
                               (decompression/fusion) if needed

Key Teaching Points

1. Cold abscess = TB until proven otherwise - insidious onset, adults, no acute toxicity
2. Never drain intraorally - secondary infection risk; always external cervical approach
3. Drainage may not be needed - ATT alone can resolve the abscess in many cases
4. Always get histology + GeneXpert before starting ATT wherever possible
5. Cervical spine instability is a real danger - handle the neck with care
6. 12 months of ATT for spinal/osteoarticular TB (not 6 months as in pulmonary TB)
7. Neurological deficit = surgical emergency - do not delay decompression

• Bailey & Love's Short Practice of Surgery, 28th ed., pp. 808-809
• Firestein & Kelley's Textbook of Rheumatology, pp. 2502-2505
• Cummings Otolaryngology Head & Neck Surgery (imaging section)
• Scott-Brown's Otorhinolaryngology Head & Neck Surgery, p. 456
• Grainger & Allison's Diagnostic Radiology (perivertebral space section)
• Murhega RB et al. (2026). Cervical spine tuberculosis: systematic review and meta-analysis. World Neurosurg. PMID 41319734

Ludwig's Angina

Definition

"A rapidly progressive, bilateral, gangrenous cellulitis of all submandibular spaces that can rapidly lead to death within hours"

• Rosen's Emergency Medicine, p. 961

Anatomy of the Submandibular Space

• Sublingual space (above mylohyoid) - contains tongue, sublingual glands, deep lingual vessels
• Submylohyoid / submaxillary space (below mylohyoid) - contains submandibular gland, facial vessels

Aetiology and Predisposing Factors

• Dental origin (80-90%) - particularly mandibular molar periapical abscesses
  • The roots of mandibular 2nd and 3rd molars insert below the mylohyoid line on the mandible - when infected, pus naturally tracks into the submylohyoid space
  • The lingual cortex of the mandible at this level is very thin, facilitating spread
• Mandibular fracture
• Oral trauma: tongue piercing, lingual laceration, iatrogenic (intubation lacerations)
• Secondary infection of oral malignancy
• Suppurative parotitis
• Adjacent deep neck infections spreading in

• Diabetes mellitus (most important - commonest comorbidity)
• Immunocompromised states (HIV, malignancy, chemotherapy)
• Malnutrition
• IV drug abuse
• Poor dental hygiene / neglected dentition

Microbiology

• Streptococcus species (especially viridans group) - most common; virulent streptococcal infections are classic
• Gram-negative rods (Klebsiella, Escherichia coli, Haemophilus)
• Anaerobes (Bacteroides, Peptostreptococcus, Fusobacterium) - essential to cover
• Staphylococcus aureus including MRSA in at-risk populations
• Eikenella corrodens (bite-related cases)
• Putrid halitosis is characteristic of anaerobic infection

Clinical Features

Investigations

• Extent of infection - which spaces involved, bilateral vs unilateral
• Presence of gas (necrotizing infection / gas-forming organisms) - poor prognostic sign
• Presence of a drainable collection vs. pure cellulitis/phlegmon
• Assess airway caliber and degree of tongue/supraglottic displacement
• Detect spread to parapharyngeal space, retropharyngeal space, or mediastinum
• Does NOT delay airway management if the patient is deteriorating

Sagittal CT - soft tissue stranding and inflammation in the submandibular space in Ludwig's angina - Tintinalli's Emergency Medicine

Anterior neck swelling with surgical marking lines delineating the extent of Ludwig's angina - Rosen's EM

• FBC (leukocytosis), CRP, ESR, blood cultures (before antibiotics), procalcitonin
• Electrolytes, renal function, LFTs, glucose (check for undiagnosed DM)
• Coagulation (if necrotizing infection suspected)

Management

1. AIRWAY → 2. ANTIBIOTICS → 3. SURGERY (if needed) → 4. ICU

Step 1 - Airway Management (ABSOLUTE FIRST PRIORITY)

• Dyspnea / tachypnea
• Stridor (late and ominous)
• Inability to manage secretions / drooling
• Progressive agitation or altered mentation (hypoxia)
• Oxygen saturations falling
• Hoarse voice or voice change

• Do NOT paralyze before securing the airway - a paralyzed patient with Ludwig's angina can be impossible to intubate or ventilate conventionally
• Conventional direct laryngoscopy is difficult or impossible due to trismus, tongue displacement, and edema
• Abscess rupture during laryngoscopy can flood the airway with pus - catastrophic
• Supine positioning worsens obstruction (tongue falls back further)

Step 2 - Intravenous Antibiotics (Immediate, Broad-Spectrum)

Step 3 - Adjunctive Corticosteroids

• Dexamethasone 0.6 mg/kg IV (max 10 mg) - reduces pharyngeal and floor-of-mouth edema, may reduce the need for surgical intervention and tracheostomy
• Evidence supports use in deep neck space infections, though Ludwig's-specific RCTs are lacking

Step 4 - Surgical Treatment

• Failure to respond to IV antibiotics within 24-48 hours
• Evidence of a drainable pus collection on CT
• Necrotizing infection (gas on CT, skin necrosis, rapid progression)
• Extraction of the causative tooth (source control - always do this)
• Progressive infection spreading to parapharyngeal or retropharyngeal spaces

• Usually performed under general anaesthesia (preferred - more controlled; airway already secured)
• May be done under local in extremis
• Curved submental incision through skin and platysma below the mandible to access both submandibular triangles
• Multiple transcutaneous stab incisions may be needed bilaterally to adequately drain all spaces
• The mylohyoid muscle is incised to decompress the floor of mouth and drain the sublingual space
• Abscess wall is curetted; all loculations are broken down with digital dissection - break down any boundaries between retropharyngeal, parapharyngeal, and submandibular communicating spaces
• Soft, non-suction corrugated drains placed; wound lightly sutured around drains
• Drains removed gradually over days, monitored by number of dressing changes per 24 hours
• Deal with the causative tooth (extraction) at the same general anaesthetic

Step 5 - ICU Admission and Monitoring

• All patients with Ludwig's angina are admitted to the ICU without exception
• Post-intubation monitoring: continuous pulse oximetry, arterial line, regular airway assessment
• Serial CT if clinical deterioration or concern of spreading infection
• Nutritional support (NG tube or parenteral - patient cannot swallow)
• Strict glucose control in diabetics
• IV fluid resuscitation and electrolyte management
• Daily wound care and drain management

Complications

Differential Diagnosis

Summary Algorithm

Suspected Ludwig's Angina
          |
     Assess airway
          |
   ┌──────┴──────┐
Stable           Compromised / stridor / desaturating
   |                     |
CT scan          AWAKE FIBREOPTIC INTUBATION
(confirm extent)  (nasal approach preferred due to trismus)
   |             Prepare emergency tracheostomy
   |                     |
   └──────────┬──────────┘
              |
    Broad-spectrum IV antibiotics
    (Ampicillin-sulbactam ± vancomycin if MRSA risk)
    + Dexamethasone 0.6 mg/kg IV
              |
    Reassess at 24-48h
              |
    Responding?         Failure / collection / gas / necrotizing
         |                           |
    Continue IV Abx          Surgical I&D
    ICU monitoring           Curved submental incision
    Source control           Mylohyoid incision
    (tooth extraction)       Multiple stab incisions bilaterally
                             Corrugated drains
                             Tooth extraction same GA
                             ICU post-op

Key Teaching Points

1. Bilateral involvement of all submandibular spaces - the hallmark; not a simple dental abscess
2. Spread via fascial planes - NOT lymphatics; hence no palpable fluctuation and no cervical lymphadenopathy
3. Airway first, always - asphyxia is the #1 killer
4. Never paralyze before securing the airway - cannot ventilate or intubate once muscle tone is gone
5. Nasal fibreoptic intubation preferred - trismus prevents adequate mouth opening for oral approach
6. Most cases respond to antibiotics alone - surgery only for failure, collection, necrotizing infection
7. Extract the causative tooth - essential source control
8. Diabetics and immunocompromised are at highest risk and progress fastest

• Rosen's Emergency Medicine: Concepts and Clinical Practice, pp. 961-962
• Bailey & Love's Short Practice of Surgery, 28th ed., pp. 808-809
• Scott-Brown's Otorhinolaryngology Head & Neck Surgery, pp. 480, 671-673
• Scott-Brown's ORL Vol 2, p. 480
• Miller's Anesthesia, 10th ed., p. 9800
• Tintinalli's Emergency Medicine, p. 839
• KJ Lee's Essential Otolaryngology, pp. 712-713
• Bridwell R et al. (2021). Diagnosis and management of Ludwig's angina: an evidence-based review. Am J Emerg Med. PMID 33383265