Challenges in Managing Newly Diagnosed Granulomatosis With Polyangiitis and Concurrent Respiratory Infections: A Retrospective Case Series

Introduction: Granulomatosis with polyangiitis (GPA), formerly termed Wegener's granulomatosis, is an autoimmune disease marked by necrotizing granulomatous inflammation and vasculitis affecting small-sized vessels. It commonly impacts the renal and respiratory systems.

Materials and methods: This retrospective case series sampling conducted in a tertiary care hospital between May 2023 and April 2024 examined six newly diagnosed GPA patients who were proteinase 3 cytoplasmic-antinuclear cytoplasmic antibody (PR3 c-ANCA) positive and had concurrent respiratory infections. None of them had any prior immunosuppressive conditions. The age range was 18-47 years with a mean of 35.0 (standard deviation: 11.83). All the patients had pneumonia (N=6, 100%). Out of all, five had bacterial pneumonia (N=5, 83.3%) and one had tuberculous pneumonia (N=1, 16.7%). A high level of PR3 c-ANCA (>150 RU/mL) was noted in four patients (N=4, 66.7%). Common symptoms included dry cough (N=5, 83.3%), loss of weight and appetite (N=2, 33.3%), and fever (N=2, 33.3%). Three patients had otitis media and/or nasal polyposis (N=3, 50%). Two patients (N=2, 33.3%) with life-threatening organ dysfunction were given concurrent antibiotics and steroids; the antibiotics were later modified based on culture and sensitivity results. One of these patients received antituberculosis therapy as Mycobacterium tuberculosis (MTB) was detected after 27 days of incubation in mycobacterial growth indicator tube broth. The remaining four patients (N=4, 66.7%) received antibiotics initially for 5-7 days until clinical resolution of pneumonia. Ultimately, they all showed clinical and radiological resolution (N=6, 100%) within 3-6 months of treatment.

Results: The patients exhibited constitutional symptoms such as fever and weight loss; lower airway disease symptoms including dry cough and hemoptysis; nasal and ear disease symptoms like epistaxis, ear pain, and ear discharge; and a renal disease symptom, hematuria. Computed tomography of the thorax revealed bilateral consolidations, most of which were cavitating. Bronchoalveolar lavage cultures grew Escherichia coli, Burkholderia cepacia, Pseudomonas aeruginosa, Klebsiella pneumoniae, and MTB, whereas pus swab cultures from otitis media grew Pseudomonas aeruginosa, Staphylococcus aureus, and coagulase-negative staphylococci.

Discussion: This study highlights the therapeutic challenges of GPA complicated by concurrent infections. Patients exhibited typical GPA signs, confirmed by PR3 c-ANCA levels. Concurrent infections require cautious antibiotic treatment before starting immunosuppressive therapy, except in life-threatening organ dysfunction. A unique case presented with both tuberculosis and GPA. Tailored treatment regimens combining antibiotics and immunosuppressives, including corticosteroids, methotrexate, and rituximab, resulted in clinical and radiological improvement in all the patients within 3-6 months. The addition of co-trimoxazole reduced the incidence of non-severe GPA relapses.

Conclusion: Tailored treatment plans addressing both infectious and autoimmune aspects are essential for optimal care in GPA complicated by concurrent infections. This study highlights the need for a multidisciplinary approach involving pulmonologist, rheumatologist, microbiologist, and pathologist in the diagnosis and treatment of GPA, emphasizing the importance of individualized treatment plans tailored to the specific clinical scenario.