A 45-year-old man presents to his physician with hematuria. Renal biopsy demonstrates a focal necrotizing glomerulitis with crescent formation. The patient has a history of intermittent hemoptysis and intermittent chest pain of moderate intensity. A previous chest x-ray had demonstrated multiple opacities, some of which were cavitated. The patient also has chronic cold-like nasal symptoms. Which of the following is the most likely diagnosis?

**Core Concept**
The patient's presentation of hematuria, focal necrotizing glomerulitis with crescent formation, and chronic symptoms such as intermittent hemoptysis, chest pain, and cold-like nasal symptoms suggests a systemic vasculitic process. The renal biopsy findings are indicative of a rapidly progressive glomerulonephritis (RPGN), which is often seen in ANCA-associated vasculitis.

**Why the Correct Answer is Right**
The patient's symptoms and biopsy findings are consistent with Granulomatosis with Polyangiitis (GPA), formerly known as Wegener's granulomatosis. GPA is a form of ANCA-associated vasculitis characterized by the presence of anti-neutrophil cytoplasmic antibodies (ANCA) and the presence of granulomatous inflammation in the respiratory tract. The disease often presents with symptoms such as hemoptysis, chest pain, and nasal symptoms due to the involvement of the lungs and upper respiratory tract. The renal involvement, as seen in this patient, is a common complication of GPA, leading to RPGN and crescentic glomerulonephritis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Churg-Strauss syndrome is another form of ANCA-associated vasculitis, but it typically presents with asthma, eosinophilia, and a different set of symptoms not seen in this patient.
**Option B:** This option is incorrect because Goodpasture's disease is a rare autoimmune disease that causes RPGN and pulmonary hemorrhage, but it is not associated with the systemic symptoms and granulomatous inflammation seen in GPA.
**Option C:** This option is incorrect because IgA nephropathy is a common cause of hematuria, but it is not associated with the systemic symptoms and crescentic glomerulonephritis seen in GPA.
**Option D:** This option is incorrect because Lupus nephritis is a common cause of RPGN, but it is not associated with the specific combination of symptoms and biopsy findings seen in GPA.

**Clinical Pearl / High-Yield Fact**
GPA is a classic example of a systemic vasculitic process that requires a high index of suspicion for diagnosis. The presence of ANCA, granulomatous inflammation, and specific symptoms such as hemoptysis and nasal symptoms should prompt consideration of GPA in patients with RPGN and systemic symptoms.

**Correct Answer:** B.

✓ Correct Answer: D. Wegener's granulomatosis