A 46 year old female complains of chronic cough for the past 3 weeks. She was recently diagnosed with hypertension and placed on an angiotensin receptor blocker therapy (ARBs). Chest X-ray shows large nodular densities bilaterally. Bronchial biopsy showed granulomatous inflammation of the pulmonary artery. Lab investigations showed a positive cANCA with a serum creatinine of 3.6mg/dl. Urine analysis shows RBC casts and hematuria. The most likely cause for this presentation is

Answer: c) Granulomatosis with polyangitisGRANULOMATOSIS WITH POLYANGIITIS (WEGENER'S)More common in males; average age 40 yearsNecrotizing Granulomatous vasculitis characterized by triad ofNecrotizing granulomas of upper or lower respiratory tractNecrotizing or granulomatous vasculitis affecting small to medium-sized vessels, most prominent in the lungs and upper airwaysKidneys (focal necrotizing crescentic glomerulonephritis)Most common presentation - epistaxis, nasal crusting and sinusitisOther classic features: persistent pneumonitis with bilateral nodular and cavitary infiltrates, ulcerations of the nasopharynx and renal disease (proteinuria, hematuria, and red blood cell casts)Palpable purpura, digital gangrene, strawberry gums, subglottic stenosis, nasal septal perforationIncreased incidence of venous thrombotic eventsLab findingsHistology: Granulomas with geographic patterns of central necrosis and accompanying vasculitisIn contrast to other forms of glomerulonephritis, evidence of immune complex deposition is not found in the renal lesionPR3-ANCA positive in 90%Normocytic anemia, elevated ESR, leukocytosis, thrombocytosis Treatment of choice: cyclophosphamideChurg-Strauss - eosinophilic granulamatosis with polyangitis with a positive pANCA (in about 40% of the cases), cANCA is rarely positive.ACE inhibitors produce cough, but not ARBs.Microscopic polyangiitis - absence of nasopharyngeal involvement and granulomas of the lung.