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Orofacial Infection

Orofacial infection

• 3 phases
  • inoculation and induration
  • cellulitis
  • abscess
• cause
  • mixed oral flora
  • usually dominated by gram positive aerobic and facultative streptococci
• pathology
  • aerobic early coloniser, cause local hypoxia and acidosis
  • creates ideal environment for anaerobes
  • anaerobes develop over 3-5 days
  • anaerobes cause tissue destruction and pus formation
• mortality rate of deep neck infections is 7.65%
  

Infection spread

• facial spaces exist between fascial planes of soft tissue, with muscle attachments determining whether vestibular or fascial space infection will result
• initially
  • caries -> pulp -> periodontium -> alveolar bone
• primary neck spaces
  • vestibular
  • buccal
  • submandibular
  • sublingual
  • canine
  • submental
• secondary spaces
  • masticatory
    • pterygoid
    • sub masseteric
    • pterygomandibular
    • temporal
  • infratemporal fossa
  • lateral pharyngeal
  • retropharyngeal
  • prevertebral space
  • danger space

Danger space

• space between alar and prevertebral fascia, extending from base of skull to diaphragm
• retropharyngeal space infection that perforates alar fascia into danger space can spread into mediastinum

Definition

• pus
  • avascular soup of debris/necrotic by-products and dead microorganisms
• abscess
  • localised collection of pus within a cavity, formed by disintegration of tissue
  • capsule of pseudo connective tissue
  • less aggressive than cellulitis, localised and well circumscribed
  • fluctuant with pus present
• cellulitis
  • diffuse swelling of inflammatory exudate within soft tissue
  • aggressive, diffuse, doughy feel, no pus, painful, spreading erythema

• not mutually exclusive, both can occur at the same time

Assessment

clinical exam

• history
• intra extra
• appropriate tests
• determine severity

Assessment

• clinical
  • systemic
    • do they look sick/well?
    • febrile/dehydrated/pain
    • bp, pulse rate, respiration rate
  • local
    • swelling, trismus, caries, deviation of uvula, elevation of tongue
• radiological
  • plain XR, opg
  • CT scan (gold standard Yonetsu et al 1998)

Diagnosis

• odontogenic cause
• concept of facial space

Systemic signs of infection

• 
  • hypotensive septicaemia

Airway and breathing assessment

• signs
  • dyspnoea - abnormal/shortness of breath
  • orthopnoea
  • tachypnoea
  • stridor - harsh high pitched wheezing sound
  • dysphagia
  • trismus
  • reduced tongue mobility
  • elevation of floor of the mouth
  • lateral pharyngeal oedema
  • deviation of uvula

• dehydrated in cases where standard measures do not improve condition
• patients with systemic diseases who need multidisciplinary team
  • uncontrolled diabetes
  • immunocompromised

Key features of hospitalised patients Hwang et al 2010

• trismus
• floor of mouth oedema
• decreased tongue mobility
• elevated temperature
  

Elevated tongue

Complications

Surgery vs antibiotic therapy

• removal of source of infection is superior treatment to antibiotics
  • where there is pus let there be steel
  • don't let the sun set on undrained pus

Follow up and review

• re evaluate whether patients have responded to treatment
• most respond well
• drains removed 1-2 days post op

Signs of treatment failure

• persistently raised temperature and WBCs
• persistent induration
• constant discharge of pus
• continued airway distress
• re-evaluation and re-treatment prudent

causes of failed treatment

• inadequate surgery
• depressed immune status
• foreign body retention
• wrong diagnosis
• failed antibiotic treatment

Cavernous sinus thrombosis

• uncommon but potentially lethal
  • occurs particularly in individual with thrombophilic disorders
• direct spread of infection from infratemporal fossa
• indirect spread from upper lip via superior labial vascular plexus
• indirect spread from canine fossa via inferior ophthalmic and facial vasculature
• facial vasculature have no valves
• clinical signs (usually result of cranial nerve involvement)
  • pressure headaches
  • periorbital oedema
  • proptosis
  • dilated pupils
  • limited range of eye movement
  • absent corneal reflex
  • supraorbital sensory deficits
  • generalised malaise, sepsis, meningitis
    
    
    Lateral pharyngeal space infection
• infection of contents
  • thrombosis within internal jugular
  • carotid erosion
  • cranial nerve compression
• spread to mediastinum via spread to retropharyngeal space: mediastinitis
• 

Ludwigs angina

• rare ish
• potentially life threatening cellulitis
• must involve bilateral submental, sublingual, submandibular spaces
• can close airway within hours, airway distress
• in reality:
• though uncommon, any sublingual or submandibular space infection is potentially life threatening if causing:
• elevation and displacement of tongue
• potential airway obstruction from cellulitic oedema or tongue obstruction
• inability to control secretions
• 

Advanced airway management

• fibreoptic assisted intubation or blind nasal intubation on awake patient Preferred
• orotracheal intubation is precarious given trismus and rupture of pharyngeal wall infection risk
• consider emergency cricothyrotomy followed by definitive tracheostomy if awake intubation not possible

Management

Treatment

• surgical
  • treat cause and establish drainage for infection
• medical
  • antibiotic therapy
• supportive
  • hydration
  • nutrition
  • antimicrobial
  • rest
  • pain management

Radiographs

• opg
• periapical xrays
• CT scan
  • gold standard for facial space spread
• lateral neck soft tissue view
  • historical, no longer performed

Laboratory tests

• FBC, UE, blood films
• most critical
  • WBC
  • electrolyte
  • ESR (sed rate)
  • CRP
• blood cultures if patient is septic or develops sudden pyrexia
• direct specimens by needle aspiration or swabbing

Indications for antibiotics

• rapidly progressive swelling
• diffuse swelling
• compromised host defences
• involvement of fascial spaces
• severe pericoronitis
• osteomyelitis

useful antibiotics

• mild moderate infection
  • amoxicillin - broad spectrum, gram+ve cocci and most oral anaerobes
• moderate severe infections
  • amox metronidazole
  • augmentin
  • clindamyacin
  • all broad spectrum with more aggressive anaerobic bacteria cover
  • consider flucloxacillin also as 7% of odontogenic infections include staph

Principles of treatment

• obtain drainage
• maintain drainage
• remove source of infection
• medical support

Clinical considerations

• do not introduce local anaesthetic into area of infection
• use blocks whenever possible
• change needle if possible contaminated
• may require more local than usual
• LA may still not work
• consider regional block or general anaesthetic

Incision and drainage