Granulomatosis with polyangiitis or its mimic? A case report

Area of Science:

• Rheumatology
• Toxicology
• Pathology

Background:

• Granulomatosis with polyangiitis (GPA) and cocaine-induced midline destructive lesions (CIMDL) share overlapping clinical and histopathological features.
• Distinguishing between these conditions can be diagnostically challenging, particularly in cases involving upper airway manifestations.

Observation:

• A young woman initially diagnosed with GPA presented with upper and lower airway symptoms, constitutional signs, granulomas, and positive proteinase 3 (PR3)-ANCA.
• The diagnosis was complicated by hard palate perforation, positive urine toxicology for cocaine metabolite, and positive perinuclear ANCA, later identified as human neutrophil elastase (HNE)-ANCA.

Findings:

• The patient was ultimately diagnosed with a cocaine-induced GPA mimic, highlighting the coexistence of CIMDL and GPA-like features.
• This case underscores the importance of considering cocaine use in the differential diagnosis of ANCA-associated vasculitis affecting the airways.

Implications:

• Urine toxicology for cocaine and HNE-ANCA testing via ELISA are recommended for young patients presenting with GPA-like symptoms and limited airway disease.
• Cocaine abstinence is the primary therapeutic strategy for both CIMDL and cocaine-induced GPA mimic, emphasizing the role of substance abuse in autoimmune-like presentations.