Case Presentation: A 23-year-old male with history of exercise- and allergy-induced asthma, sinusitis, repaired deviated septum, intermittent hematuria and proteinuria, allergies, occasional dysphagia, and nephrolithiasis presented with sudden-onset dyspnea, throat tightness, and cough while exercising. This episode differed from prior asthma exacerbations and was unresponsive to albuterol or montelukast. He reported recent sick contacts, chills, and sore throat without fever. Family history included maternal rheumatoid arthritis, inflammatory bowel disease, and Hashimoto’s thyroiditis.In the ED, he had stridor, coarse breath sounds, and dysphonia that improved with racemic epinephrine and dexamethasone. He was discharged with azithromycin, dexamethasone, and ENT referral. Outpatient laryngoscopy revealed subglottic stenosis, prompting re-admission with concern for croup. Hospital infectious workup was negative. Exam showed stridor and dysphonia. CXR was unremarkable. CT neck showed circumferential thickening of the proximal subglottic airway with luminal narrowing consistent with subglottic stenosis. Repeat laryngoscopy showed nasal crusting, sharp epiglottis, and subglottic edema. Due to ENT concern for infection vs. granulomatosis with polyangiitis (GPA), treatment included ampicillin-sulbactam for MSSA and Klebsiella aerogenes from nasal cultures, dexamethasone, fluticasone, racemic epinephrine, and azelastine with improvement by day 3. He was discharged with TMP-SMX and prednisone.Repeat laryngoscopy showed decreased edema but persistent subglottic stenosis with a 5-6 mm opening, requiring tracheal dilation. Hospital serologies then resulted, showing ANA 1:320, p-ANCA 1:80, anti-MPO Ab 75 units and negative c-ANCA and anti-PR3 Ab. Renal biopsy showed no significant kidney involvement. Patient is well-maintained on methotrexate, prednisone, and multidisciplinary follow-up with decreasing antibody titers.
Discussion: This case highlights the diagnostic and phenotypic diversity of GPA, a rare vasculitis with an annual incidence of 0.5-20 cases per million and a prevalence of 20-160 cases per million [1]. GPA is typically associated with antineutrophil cytoplasmic antibodies (ANCA) targeting proteinase 3 (PR3), whereas vasculitides like microscopic polyangiitis are associated with ANCA positivity towards myeloperoxidase (MPO). However, 10% of GPA patients can be MPO-ANCA positive, associated with limited disease and higher prevalence of subglottic stenosis. While GPA affects the respiratory tract, subglottic stenosis occurs in just 10-20% of patients [2].This patient had an uncommon ANCA profile and subglottic stenosis. On methotrexate and steroids, he had symptom improvement and decreasing antibody titers, associated with lower mortality risk. This response contrasts with rising ANCA titers linked to higher relapse risk [3]. Initially concerning for croup or asthma exacerbation, his final diagnosis shows the need to include GPA in the differential for dyspneic patients with subglottic stenosis. Symptom resolution with medical and surgical management underscores the value of multidisciplinary intervention to prevent respiratory and organ compromise when GPA is suspected.
Conclusions: This case highlights the complexity of GPA and need to consider it in patients with refractory upper airway symptoms. Multidisciplinary evaluation and immunosuppressants can help decrease GPA-associated symptoms, organ dysfunction, and antibody titers.
.png)