DON'T LOSE SIGHT OF GPA

ABSTRACT

CASE A 48-year-old female with no medical history presented with 2 days of decreased vision in the right eye. She reported painless blurry vision that progressed to near complete vision loss. The vision loss was accompanied by one month of progressively worsening cough, body aches, and subjective fevers. She denied smoking and reported no sick contacts. Physical exam was notable for submandibular lymphadenopathy, bilateral conjunctival injection, and grossly decreased vision of the right eye. She also endorsed decreased sensation in bilateral lower extremities distally. Her initial labs showed leukocytosis (13), thrombocytosis (754), and elevated inflammatory markers (ESR 105 and CPR 359). A chest CT showed bilateral upper lobe consolidations and scattered mass like opacities bilaterally. Ophthalmic exam of the right eye revealed multiple small retinal infarctions consistent with paracentral acute middle maculopathy. A CT head was negative and TTE showed no vegetation. Additional testing revealed negative TB, COVID, and normal complements. Initial ANCA testing was negative, however a repeat test was strongly positive for ANCA with PR3 significantly elevated to 428. She was diagnosed with granulomatosis with polyangiitis (GPA) vasculitis and treated with prednisone and started induction therapy of Rituximab. IMPACT/DISCUSSION: GPA is a small-medium vessel necrotizing vasculitis and the most common anti-neutrophil- cytoplasmic-antibody (ANCA) associated vasculitis. GPA classically involves the upper respiratory tract, lungs, and kidneys referenced by the ELK criteria (ENT, Lung, Kidney) commonly used for diagnosis. ENT findings are present in 70-100% of cases with the nasal cavity and paranasal sinuses most commonly involved. Roughly 50% have pulmonary involvement on presentation, as in this patient, while only 10-20% have initial renal involvement. A prodrome of systemic symptoms including body aches and fevers is often present. GPA is closely associated with c-ANCA, with autoantibodies to proteinase 3 (PR3) positive in over 80% of cases. This patient did have prodromal symptoms yet her primary presenting symptom of vision loss was atypical. Eye involvement is not part of the diagnostic triad yet it can occur in GPA. When it does present, it usually manifests as scleritis, conjunctivitis, or uveitis. Retinal infarctions, as seen in this patient, are uncommon and make this case an atypical presentation of GPA. Additionally, ANCA positivity is related to disease activity and a negative ANCA should not exclude GPA from a differential. Not all patients will be ANCA positive on initial presentation and 10% of patients with GPA will remain ANCA negative. CONCLUSION: Providers should consider atypical presentations of GPA in addition to the classic triad of ENT, Lungs, and Kidneys. Renal manifestations are often missing initially and involvement of other systems, such as ocular, can take place. With a positive c-ANCA and high clinical suspicion, treatment should not be delayed.