Question

The most likely diagnosis in a patient with multiple pulmonary cavities, haematuria, and red cell casts is

• A. Anti-GBM disease
• B. Churg-Strauss allergic granulomatosis
• C. Systemic lupus erythematosus
• D. Wegener's granulomatosis

Hint:

Focus on which vasculitis specifically causes cavitating lung nodules, not just diffuse lung bleeding.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The patient has two things happening together: multiple cavitating lesions in the lungs, and a urine picture of haematuria with red cell casts, which points to active glomerulonephritis rather than a simple bleed from the kidney or bladder. This combination of lung and kidney disease is a classic pulmonary-renal syndrome, and the pattern of the lung lesions is the key clue to the diagnosis.

Step 2: Key Concept or Approach:
The way to separate the pulmonary-renal syndromes is to ask whether the lung disease is diffuse alveolar haemorrhage or discrete necrotising, cavitating nodules, and whether the associated vasculitis is ANCA-driven, anti-GBM antibody driven, or immune-complex driven. Multiple cavitating pulmonary nodules together with a pauci-immune, ANCA-associated glomerulonephritis (red cell casts, little immune deposit on biopsy) is the signature combination of a specific necrotising granulomatous vasculitis.

Step 3: Working Through the Options:
Wegener's granulomatosis (now called granulomatosis with polyangiitis) is a necrotising granulomatous vasculitis of the upper and lower respiratory tract that classically produces multiple cavitating lung nodules along with a pauci-immune crescentic glomerulonephritis, giving haematuria with red cell casts; it is strongly associated with c-ANCA directed against proteinase-3, which is exactly the picture described. Anti-GBM disease (Goodpasture syndrome) also combines lung and kidney disease, but the lung injury there is diffuse alveolar haemorrhage from anti-basement-membrane antibodies attacking the alveolar capillaries, giving diffuse infiltrates rather than discrete cavitating nodules, so it does not fit. Churg-Strauss allergic granulomatosis (eosinophilic granulomatosis with polyangiitis) is built around a history of asthma and marked peripheral eosinophilia, with pulmonary infiltrates that are typically transient and non-cavitating, and severe renal disease is comparatively uncommon, none of which matches this stem. Systemic lupus erythematosus can cause an immune-complex glomerulonephritis with red cell casts, but its pulmonary involvement is usually pleuritis, interstitial disease, or pleural effusion, not cavitating nodules, so it does not explain the lung findings.

Step 4: Conclusion:
The correct option is Wegener's granulomatosis, the classic cause of cavitating pulmonary nodules with haematuria and red cell casts.