Thanks to Dr. Szumowski for sending us the case of a middle aged man who presented with acute L knee swelling and pain one week after a viral URI syndrome, initially concerning for septic joint.  His clinical course was complicated by recurrent high daily fevers, a diffuse maculopapular rash, and knee arthrocenteses and joint washes that were clean leading to a diagnosis of Still’s disease!

Clinical Pearls

• Still’s disease is a diagnosis of exclusion! Yamaguchi criteria can help with ruling in the diagnosis.
• Still’s remains a multi-systemic disorder of unknown etiology because it’s difficult to diagnose and rare (0.16 cases per 100,000).
• RF and ANA are generally negative but can be positive in <10% of patients with Still’s in low titers.
• ~66% of patients present with sore throat secondary to cricothyroid perichondritis or aseptic nonexudative pharyngitis.
• The disease is often recurrent. Predictors of poor outcome include erosive polyarthritis on presentation and shoulder/hip involvement.

Still’s disease:

• Described in 1897 by George Still, it is a systemic inflammatory disorder of unknown etiology
• Some clarifications on nomenclature:
  • Systemic juvenile idiopathic arthritis (sJIA): first presentation <17 years old, previously referred to as Still’s disease
  • Adult onset Still’s disease (AOSD): first presentation  > 17 years old
• Epidemiology of AOSD:
  • 0.16 cases per 100,000
  • No sex predominance (F=M)
  • Bimodal age distribution with peak between 15-25 and another 36-46 years of age.  New diagnosis in patients >60 have been reported.
• Etiology:
  • Poorly understood but likely a combination of genetic predisposition, environmental triggers (viruses such as echo, coxsackievirus B4, mycoplasma, yernisnia, lyme, etc), activated innate immunity leading aberrant production of pro-inflammatory cytokines
• Diagnostics:
  • High ESR and CRP
  • Very high ferritin levels
  • Ultimately a clinical diagnosis so it’s important to exclude potential mimickers
    • Yamaguchi criteria are the most sensitivity (93.5%)
    • Fautrel’s Criteria are the most specific (98.5%)
• Treatment
  • Largely empirical since clinical trial data is lacking
  • High dose steroids are first line when systemic symptoms predominate
  • MTX is second line
  • NSAIDs are not good
  • Biologic agents for refractory cases (IL1 antagonist anakinra or canakinumab), IL6 antagonist tocilizumab, or TNF inhibitors.
• Course:
  • Monocyclic pattern (systemic single episode)
  • Polycyclic pattern (multiple episodes, usually <1 /year)
  • Chronic pattern (persistently active disease with poly arthritis)

    

• Prognosis:
  • Poor prognostic indicators:
    • Hip and shoulder involvement
    • Erosive polyarthritis at initial diagnosis