Anti-neutrophil Cytoplasmic Antibody-Associated Vasculitis Presenting With Disseminated Streptococcus constellatus...

Area of Science:

• Infectious Diseases
• Rheumatology
• Immunology

Background:

• Infections and autoimmune diseases share a complex bidirectional relationship.
• Early diagnosis of autoimmune conditions can be challenging, especially when presenting with infectious symptoms.

Observation:

• A 49-year-old male presented with severe disseminated sepsis, including fever, anemia, septic polyarthritis, ARDS, DVT, and acute renal failure.
• Blood and joint cultures identified *Streptococcus constellatus*, but treatment yielded marginal improvement, with worsening respiratory symptoms.
• Further investigation revealed high positivity for proteinase 3 cytoplasmic-ANCAs, indicating autoimmune dysregulation.

Findings:

• The patient was diagnosed with antineutrophil cytoplasmic antibody (ANCA)-positive granulomatosis with polyangiitis, likely triggered by a preceding infection.
• Treatment with corticosteroids and rituximab resulted in a significant clinical response.
• The persistence of symptoms despite infection control suggested an underlying autoimmune disease.

Implications:

• This case underscores the importance of considering autoimmune diseases in patients with severe infections that do not fully resolve with targeted antimicrobial therapy.
• Accurate differential diagnosis between infection and autoimmune vasculitis is crucial for appropriate patient management.
• Understanding the interplay between infection and autoimmunity can improve diagnostic strategies and therapeutic outcomes in ANCA-associated vasculitis.