Could a patient with a history of infectious mononucleosis (mono) who recently underwent a dental root canal procedure and now presents with a swollen left lymph node, swollen temporal area, and odynophagia (painful swallowing) be experiencing a recurrence of mono?

Clinical Assessment: Unlikely Mono Recurrence, Probable Dental Infection

This presentation is most consistent with a dental infection (odontogenic infection) following the root canal procedure, not a recurrence of infectious mononucleosis. 1

Why This Is Not Mono Recurrence

True recurrence of infectious mononucleosis after prior infection is extremely rare in immunocompetent adults. 2 The key diagnostic considerations that argue against mono include:

• Temporal relationship to dental procedure: The swelling and symptoms appearing weeks after a root canal strongly suggests an odontogenic source rather than viral reactivation 3
• Localized presentation: Unilateral lymph node swelling (left side only) and temporal area swelling adjacent to the dental work site points to a local infectious process, not systemic viral illness 3
• EBV serology pattern: A patient with prior mono history would have positive VCA IgG and positive EBNA antibodies from past infection, but would lack VCA IgM unless this represents true reactivation (which is exceedingly rare in immunocompetent hosts) 1, 4

Most Likely Diagnosis: Odontogenic Infection

The clinical picture strongly suggests a dental abscess or post-procedural infection with the following features:

• Cervical lymphadenitis: Reactive lymph node enlargement from dental infection commonly affects ipsilateral cervical nodes 3
• Temporal space involvement: Infections from maxillary teeth (common root canal sites) can spread to the temporal and masticator spaces, causing temporal area swelling 3
• Odynophagia: Pain with swallowing occurs when dental infections spread to involve the pharyngeal spaces or cause significant cervical lymphadenopathy 3

Recommended Diagnostic Approach

Immediate evaluation should focus on identifying and treating the odontogenic source:

• Dental examination: Assess the root canal site for signs of failure, periapical abscess, or periodontal infection 3
• Imaging: Panoramic radiograph or dental cone-beam CT to evaluate for periapical pathology, bone involvement, or abscess formation 3
• Complete blood count: Elevated WBC with neutrophil predominance suggests bacterial infection, whereas lymphocytosis with >50% lymphocytes and >10% atypical lymphocytes would suggest mono 1, 5

If mono is still suspected despite the clinical picture, obtain:

• Heterophile antibody test (Monospot): Should be negative in someone with remote mono history; a positive result would be unexpected 1
• EBV serology panel: VCA IgM (should be negative), VCA IgG (should be positive from past infection), and EBNA (should be positive from past infection) 1, 4

Critical Pitfall to Avoid

Do not delay treatment of a potential dental infection while pursuing mono workup. 3 Odontogenic infections can progress rapidly to involve deep neck spaces, causing:

• Airway compromise from retropharyngeal or parapharyngeal space involvement 3
• Descending necrotizing mediastinitis (rare but life-threatening) 3
• Cavernous sinus thrombosis from maxillary infections 3

Recommended Management

Empiric antibiotic therapy should be initiated if dental infection is suspected:

• First-line: Amoxicillin-clavulanate to cover oral flora including anaerobes 3
• Penicillin allergy: Clindamycin provides excellent coverage for oral anaerobes 3
• Severe infection: Consider hospitalization for IV antibiotics (ampicillin-sulbactam or clindamycin) if there is significant facial swelling, trismus, or systemic toxicity 3

Definitive dental treatment (drainage, extraction, or endodontic revision) should be coordinated urgently with a dentist or oral surgeon 3

When to Reconsider Mono

Reconsider EBV reactivation only if:

• Dental source is definitively excluded 1
• Patient is immunocompromised (on immunosuppressants, HIV-positive, or has underlying immunodeficiency) 1
• Blood work shows lymphocytosis with >50% lymphocytes and >10% atypical lymphocytes 1, 5
• Monospot or VCA IgM returns positive (highly unusual in someone with prior mono) 1

Even in confirmed EBV reactivation, treatment remains supportive as antivirals like acyclovir have no proven benefit in immunocompetent patients 3, 1