Deep Neck Space Infections

Anatomy - Neck's Hidden Hubs

• Cervical Fascia:
  • Superficial: Encloses platysma.
  • Deep:
    • Investing: Surrounds SCM, trapezius.
    • Pretracheal: Forms visceral compartment.
    • Prevertebral: Covers vertebral column/muscles.
• Key Deep Neck Spaces:
  • Parapharyngeal (Lateral Pharyngeal): Lateral to pharynx.
  • Retropharyngeal: Post. to pharynx; btw buccopharyngeal & alar fascia.
  • Danger Space: Between alar & prevertebral fascia.

    ⭐ Extends skull base to diaphragm; "Highway for infection".

  • Prevertebral: Ant. to vertebrae, deep to prevertebral fascia.
  • Submandibular: Sublingual & submaxillary areas.
  • Carotid Sheath: Common/internal carotid a., IJV, CN X.
  • Pretracheal (Visceral): Surrounds trachea, esophagus, thyroid. oka

Etiology & Bugs - Infection Invasion

• Etiology (Sources):
  • Odontogenic (most common; mandibular molars)
  • Tonsillopharyngeal (e.g., peritonsillar abscess)
  • Salivary gland (sialadenitis)
  • Trauma, IV drug use
• Common Pathogens (Often Polymicrobial):
  • Aerobes: Streptococcus spp. (viridans, pyogenes), Staphylococcus aureus
  • Anaerobes: Peptostreptococcus, Bacteroides, Prevotella, Fusobacterium
• Invasion: Direct spread, lymphatic.

⭐ Fusobacterium necrophorum is classically associated with Lemierre's syndrome (postanginal sepsis, IJV thrombophlebitis).

Clinical Clues & Dx - Spotting the Sepsis

• General: Fever, neck pain/swelling, dysphagia, odynophagia, trismus.
• Airway: Stridor, dyspnea - ⚠️ EMERGENCY!
• Specific Signs: Vary by space (e.g., Ludwig's: woody submandibular swelling).
• Investigation:
  • CT with contrast: GOLD STANDARD. Defines extent, abscess.
  • Labs: ↑WBC, ↑CRP.

⭐ Ludwig's angina (bilateral submandibular, sublingual, submental space infection) can cause rapid airway obstruction.

Key Infections - Danger Deep Dive

• Ludwig's Angina:
  • Bilateral cellulitis: submandibular, sublingual, submental spaces.
  • Source: Odontogenic (mandibular molars).
  • Symptoms: "Woody" floor of mouth, tongue elevation, drooling, airway risk.
• Retropharyngeal Abscess (RPA):
  • Children (<5 yrs): Often after URI; midline swelling, fever, torticollis, dysphagia.
  • Adults: Trauma, foreign body; can be lateral.
  • Risk: Danger space spread → mediastinitis.
• Parapharyngeal Abscess (PPA):
  • Source: Tonsillar, pharyngeal, dental.
  • Symptoms: Trismus, medial pharyngeal wall bulge, fever, neck pain/swelling.
  • Compartments: Prestyloid (trismus prominent) vs. Poststyloid (cranial nerve palsies, vascular risk).

⭐ In children, retropharyngeal abscesses are typically midline due to infection of retropharyngeal lymph nodes (nodes of Rouviere), which atrophy by age 4-5 years old.

Management & Mayhem - Treatment & Threats

• Airway First! Secure immediately if compromised (stridor, dyspnea). Options: intubation, tracheostomy.

• IV Antibiotics: Empiric broad-spectrum (e.g., Ampicillin-Sulbactam, Clindamycin +/- Metronidazole). Tailor to culture results.

• Surgical Drainage Indications:

  • Airway compromise despite medical Rx
  • Definitive collection > 2-3 cm on CT scan
  • No clinical improvement in 24-48 hrs of IV antibiotics
  • Presence of complications (e.g., mediastinitis)
  • Specific spaces (e.g., Ludwig's angina often needs early drainage)

• Dreaded Complications (Mayhem):

  • Airway Obstruction (esp. Ludwig's Angina)
  • Descending Necrotizing Mediastinitis (DNM) - high mortality
  • Sepsis / Septic Shock
  • Lemierre’s Syndrome (IJV thrombophlebitis, often F. necrophorum)
  • Carotid artery rupture, cranial nerve (CN) palsies

⭐ Ludwig's angina involves bilateral submandibular, sublingual, and submental spaces, rapidly progressing to airway obstruction if not managed promptly; it's a surgical emergency if airway is threatened or significant cellulitis/collection exists despite antibiotics.

• Ludwig's angina: bilateral infection of submandibular, sublingual, submental spaces; odontogenic origin; high airway risk.
• Parapharyngeal space infection: presents with trismus, medial bulge of lateral pharyngeal wall.
• Retropharyngeal abscess: common in children <5 yrs; risk of mediastinitis, airway obstruction.
• Danger space (Space 4): infection rapidly spreads to posterior mediastinum.
• CT scan with contrast is key for diagnosis and extent.
• Core management: Secure airway, IV antibiotics, prompt surgical drainage.
• Predominant organisms: Aerobic Streptococci and anaerobes.