5.3 Oral Infections & Orofacial Pain Management

5.3 Oral Infections & Orofacial Pain Management

Quick Reference: Management of oral infections and chronic orofacial pain requires precise diagnostic categorization and strict adherence to UK clinical prescribing standards (SDCEP and BNF guidelines). First-line therapies must target verified bacterial, fungal, viral, or neurogenic mechanisms.

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Fungal & Bacterial Infections of the Oral Mucosa

Oral Candidiasis

Candida albicans is a dimorphic commensal organism of the oral cavity. Pathogenic overgrowth occurs secondary to local factors (denture wearing, inhaled corticosteroid use, xerostomia) or systemic immunosuppression (broad-spectrum antibiotics, diabetes, HIV/AIDS, chemotherapy).

Safety Alert: Miconazole oral gel is absorbed systemically and potently inhibits CYP2C9 enzymes. It is strictly contraindicated in patients taking Warfarin because it dramatically elevates the International Normalized Ratio (INR), risking fatal hemorrhage.

Bacterial Infections

• Acute Necrotising Ulcerative Gingivitis (ANUG): Rapid-onset painful opportunistic infection caused by an anaerobic fusospirochetal complex (Treponema denticola, Fusobacterium nucleatum, Prevotella intermedia). Characterized by punched-out, crateriform ulceration of the interdental papillae, covered by a grayish pseudomembrane, marked spontaneous bleeding, and distinct fetor oris (halitosis). First-line UK treatment comprises ultrasonic ultrasonic debridement, 0.2% Chlorhexidine mouthwash, and oral Metronidazole 200 mg TDS for 3 days (or Amoxicillin 500 mg TDS if metronidazole is contraindicated).
• Syphilis (Treponema pallidum): Primary stage features a painless indurated ulcer (chancre) at the site of inoculation (lips/tongue). Secondary stage presents 2-10 weeks later with highly infectious mucosal 'snail-track' ulcers and maculopapular cutaneous eruptions. Tertiary stage causes destructive granulomatous gummas of the hard palate.
• Tuberculosis (Mycobacterium tuberculosis): Presents as a chronic, non-healing, painful oral ulceration with characteristic undercut borders and a indurated base, typically on the dorsum of the tongue. Histopathology reveals caseating granulomatous inflammation with Langhans giant cells.

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Viral Infections of the Orofacial Region

Herpesvirus Family

• Herpes Simplex Virus Type 1 (HSV-1):
  • Primary Herpetic Gingivostomatitis: Initial exposure usually in early childhood. Features high fever, cervical lymphadenopathy, irritability, and widespread crops of painful fluid-filled intraoral vesicles that rupture to form yellow-crusted ulcers across both keratinised and non-motile mucosa. Treatment is supportive (hydration, analgesia). Systemic Aciclovir 200 mg 5 times daily for 5 days (or pediatric suspension) is indicated if initiated within 72 hours of disease onset.
  • Recurrent Herpes Labialis (Cold Sores): Reactivation of latent HSV-1 within the trigeminal ganglion (CN V). Prodromal tingling/burning precedes localized crops of vesicles at the vermilion border of the lips. Treated with topical 5% Aciclovir cream applied during the prodrome.
• Varicella Zoster Virus (VZV):
  • Primary Chickenpox: Generalized pruritic vesicular skin rash.
  • Herpes Zoster (Shingles): Reactivation of latent VZV in sensory ganglia. Produces severe, unilateral, dermatomal neurogenic pain and vesicular eruptions strictly respecting the anatomic midline along the V1, V2, or V3 divisions of the trigeminal nerve.
  • Ramsay Hunt Syndrome: VZV reactivation within the geniculate ganglion of the facial nerve (CN VII). Features the triad of ipsilateral lower motor neuron facial nerve palsy, severe ear pain (otalgia), and vesicular eruptions in the external auditory meatus and anterior two-thirds of the tongue.
• Epstein-Barr Virus (EBV):
  • Oral Hairy Leukoplakia (OHL): Asymptomatic, non-wipeable, corrugated white vertical hyperkeratotic striations occurring on the bilateral lateral borders of the tongue in immunocompromised individuals (HIV/AIDS, organ transplant recipients). Histopathology displays hyperparakeratosis, acanthosis, and nuclear koilocytosis (ballooning cells carrying viral inclusions).

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Trigeminal Neuralgia & Neurogenic Orofacial Pain

Trigeminal Neuralgia (TN) is a severe neuropathic pain condition characterized by sudden, brief, electric-shock-like paroxysmal pain confined to one or more branches of the trigeminal nerve (most commonly V2 maxillary or V3 mandibular divisions).

Diagnostic Features of Trigeminal Neuralgia

• Paroxysmal severe, sharp, shooting, or lancinating pain lasting from a fraction of a second up to 2 minutes.
• Pain is provoked by non-painful light tactile stimuli (trigger zones) such as washing, shaving, brushing teeth, eating, or exposure to cold wind.
• Presence of a refractory period following a pain paroxysm during which a trigger stimulus cannot evoke a second attack.
• Absence of neurological deficits on clinical examination.
• Etiology: Primary TN is caused by neurovascular compression of the trigeminal nerve root entry zone in the posterior fossa by an aberrant arterial loop (typically the superior cerebellar artery). Secondary TN is caused by structural lesions (Multiple Sclerosis plaques or cerebellopontine angle tumors).

Pharmacological & Surgical Management

• First-Line Pharmacological Therapy: Carbamazepine (100 mg BD initially, gradually titrated up to 600-1200 mg daily). Acts as a voltage-gated sodium channel blocker. Requires baseline and periodic monitoring of Full Blood Count (risk of agranulocytosis) and Liver Function Tests (hepatotoxicity).
• Second-Line Pharmacological Therapy: Oxcarbazepine, Gabapentin, Pregabalin, or Baclofen.
• Surgical Interventions: Microvascular Decompression (Jannetta procedure to place a Teflon sponge between the artery and nerve root), Gamma Knife radiosurgery, or peripheral radiofrequency thermocoagulation.

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Burning Mouth Syndrome & Persistent Idiopathic Facial Pain

Primary Burning Mouth Syndrome (BMS / Glossodynia)

Primary Burning Mouth Syndrome is a chronic neuropathic pain disorder defined by an intraoral burning or dysesthetic sensation that recurs daily for more than 2 hours per day over a period >3 months, without clinically detectable mucosal lesions or laboratory abnormalities. It predominantly affects postmenopausal females.

Diagnostic Workup (Exclusion of Secondary Burning Mouth): Primary BMS is a diagnosis of exclusion. GDPs must order a comprehensive screening panel to rule out organic causes:

1. Full Blood Count (FBC) & Ferritin: Exclude microcytic/macrocytic anemia and subclinical iron deficiency.
2. Serum Vitamin B12 & Folate: Exclude hematinic deficiencies causing glossitis.
3. Fasting Blood Glucose / HbA1c: Rule out diabetic neuropathy.
4. Microbiological Swab: Exclude erythematous candidiasis.
5. Salivary Flow Measurement: Exclude medication-induced xerostomia or Sjögren syndrome.

Management of Primary BMS

Reassurance and patient education regarding the neuropathic origin of symptoms. Pharmacological management utilizes low-dose Tricyclic Antidepressants (Amitriptyline 10-25 mg nocte) or selective serotonin reuptake inhibitors (SSRIs), alongside Cognitive Behavioral Therapy (CBT).

Persistent Idiopathic Facial Pain (PIFP / Atypical Facial Pain)

Continuous, dull, aching or deep facial pain present daily throughout the day, poorly localized, not conforming to anatomical cranial nerve distributions, and lacking organic pathology. Managed with low-dose Amitriptyline and multidisciplinary pain clinic referral.

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Temporomandibular Disorders (TMDs)

Temporomandibular Disorders (TMDs) encompass a heterogeneous group of musculoskeletal conditions involving the temporomandibular joint (TMJ), masticatory muscles, and associated structures.

Major TMD Diagnostic Categories

1. Myofascial Pain / Myalgia: Masticatory muscle pain (temporalis and masseter), aggravated by jaw movement. Associated with muscular trigger points and diurnal/nocturnal bruxism.
2. Internal Derangement - Disc Displacement with Reduction: The articular disc is displaced anteriorly when the jaw is closed, but relocates (reduces) back over the condyle during mouth opening, producing a distinct clinical reciprocal clicking sound.
3. Internal Derangement - Disc Displacement without Reduction ('Closed Lock'): The articular disc remains permanently displaced anteriorly, preventing full condylar translation. Presents with sudden restricted mouth opening (<35 mm), absence of clicking, and unassisted mandibular deflection toward the affected side upon opening.
4. Degenerative Joint Disease (Osteoarthritis): Cartilage degradation and bony remodeling of the condyle/glenoid fossa. Characterized by continuous crepitus (grating joint sound) and radiographic subchondral sclerosis, flattening, and osteophyte formation.

Conservative Management Protocol

UK guidelines advocate a reversible, conservative management strategy:

• Patient education, reassurance, soft diet, thermal therapy (warm compresses).
• Physiotherapy exercises and masseteric muscle relaxation techniques.
• Occlusal Splint Therapy: Hard acrylic Stabilisation Splint (Michigan splint) or soft nocturnal bite guard to decrease parafunctional muscle activity.
• Short-course NSAIDs (Ibuprofen 400 mg TDS) for acute inflammatory flare-ups.