A medical resident is evaluating four adult patients admitted to the inpatient ward with overlapping signs of pulmonary dysfunction, renal impairment, and systemic illness. Match each patient's specific clinical and diagnostic presentation with the most accurate differential diagnosis.
- A 42-year-old woman with a history of adult-onset asthma presents with right-sided foot drop and asymmetric left hand numbness. Laboratory studies show a peripheral eosinophil count of 1,600/mm³ and elevated IgE. Electromyography confirms mononeuritis multiplex.Eosinophilic granulomatosis with polyangiitis
- A 55-year-old man presents with refractory sinusitis, a progressively collapsing nasal bridge, and new-onset hemoptysis. Urinalysis shows dysmorphic red blood cells and red blood cell casts. Biopsy of a pulmonary nodule reveals necrotizing granulomatous inflammation.Granulomatosis with polyangiitis
- A 60-year-old man presents with acute hemoptysis and rapidly progressive oliguric renal failure. He explicitly denies sinus pain, nasal discharge, or ear involvement. Lung biopsy reveals non-granulomatous necrotizing capillaritis.Microscopic polyangiitis
- A 28-year-old man with a 10-pack-year smoking history presents with sudden hemoptysis, severe dyspnea, and macroscopic hematuria. Chest radiograph demonstrates diffuse bilateral alveolar infiltrates. Renal biopsy demonstrates crescentic glomerulonephritis with smooth, linear IgG deposition along the basement membrane.Anti-glomerular basement membrane disease
Answer
The patients represent distinct manifestations of pulmonary-renal syndromes and small-vessel vasculitides: the asthmatic patient with eosinophilia has Eosinophilic granulomatosis with polyangiitis; the patient with upper airway necrosis and granulomas has Granulomatosis with polyangiitis; the patient lacking upper airway disease and granulomas has Microscopic polyangiitis; and the patient with linear IgG deposition has Anti-glomerular basement membrane disease.
Correctly formulating this differential diagnosis relies on recognizing key discriminators. Asthma and mononeuritis multiplex with eosinophilia point directly to Eosinophilic granulomatosis with polyangiitis. The presence of destructive upper airway disease and necrotizing granulomas defines Granulomatosis with polyangiitis. The absence of these features in a patient with a similar pulmonary-renal pattern suggests Microscopic polyangiitis. Finally, linear IgG immunofluorescence is the pathognomonic signature of Anti-glomerular basement membrane disease.
Step-by-Step Solution
Key Concept
Formulating a differential diagnosis for pulmonary-renal syndromes by integrating clinical phenotypes (asthma, upper airway disease) with distinct biopsy findings (granulomas, linear immunofluorescence).