Viral Arthritis

Common Causes

• High likelihood (Presenting with Arthritis):

  • Parvovirus B19

  • Ross River virus, Barmah Forest virus (endemic in Australia)

  • Dengue virus, yellow fever virus

  • Rubella

• Low likelihood:

  • Hepatitis A/B/C, HIV

  • Epstein–Barr virus (EBV)

  • Herpesviruses: CMV, VZV, HSV

  • Adenovirus, enteroviruses

• Zoonotic causes:

  • Arboviruses: Chikungunya virus (mosquito-borne), hantavirus (rodent exposure)

  • Bacterial zoonoses (may mimic viral arthritis):

    • Brucellosis (unpasteurised dairy, livestock exposure)

    • Leptospirosis (contaminated water, rodents)

Clinical Features

• Symmetrical Polyarthritis: Can resemble early rheumatoid arthritis (particularly with parvovirus B19, arboviruses such as Ross River).

• Constitutional Symptoms: Fatigue, fever, myalgia, malaise.

• Rash:

  • Parvovirus B19: Erythema infectiosum (“slapped cheek” in children, arthropathy in adults).

  • Rubella, dengue: Maculopapular exanthem.

• Exposure History: Recent viral-like illness, arthropod bites (mosquito), zoonotic exposures (livestock, rodent-infested environments).

• Duration: Usually self-limiting over 1–3 weeks, though some cases persist longer (especially in immunocompromised or certain viral strains).

Investigations

• Serology

  • IgM and IgG for suspected viruses (e.g., parvovirus B19, Ross River virus).

  • Hepatitis serology, HIV testing if risk factors or clinical suspicion.

• Inflammatory Markers: ESR/CRP may be mildly elevated.

• Full Blood Count: Possible lymphocytosis or mild thrombocytopenia in viral infections.

• Joint Aspirate

  • Mild WBC elevation typically <5–10 × 10^9/L (usually <2 × 10^9/L in purely viral).

  • Essential to exclude bacterial arthritis if uncertain.

When to Refer

• Severe or Prolonged Symptoms (>6 weeks): Exclude rheumatoid arthritis (RA) or connective tissue diseases (CTDs).

• Unclear Diagnosis: Atypical features, inconclusive serology, or suspicion of alternative diagnoses.

• Recurrent/Disabling Arthritis: Consider post-viral autoimmune phenomena or other underlying pathology (e.g., chronic inflammatory arthritides).

Management

• Symptomatic Relief

  • NSAIDs (e.g., ibuprofen) or paracetamol for joint pain and mild inflammation.

• Supportive Care

  • Rest, adequate hydration, manage fever if present.

• Avoid Antibiotics: Not indicated for viral aetiologies unless a bacterial superinfection is suspected.

• Arboviruses (Ross River, Barmah Forest, dengue, chikungunya)

  • Advise mosquito bite prevention (insect repellents, long clothing).

  • Encourage local public health measures (reduction of breeding sites).

Notes

• Most acute viral arthritides resolve spontaneously without long-term sequelae.

• Early distinction from autoimmune arthritis (e.g., RA, psoriatic arthritis) is crucial to avoid unnecessary treatment.

• Education on preventive measures (avoiding unpasteurised dairy for brucellosis, controlling rodent exposure for hantavirus, etc.) may reduce further infections.