Hypersensitivity pneumonitis and mesangiopathic glomerulonephritis: an unusual pulmonary-renal syndrome

A broad range of disorders can manifest themselves as pulmonary-renal syndromes; the etiology and pathophysiology of most of these remain unknown. Although the occurrence of classic hypersensitivity pneumonitis with glomerulonephritis is rare, there is the possibility of at least some commonality of pathologic mechanisms. We present a case of mesangiopathic glomerulonephritis with renal failure complicated by a hypersensitivity-type pneumonitis, both of which were responsive to corticosteroids. The differential diagnostic considerations and alternate explanations for this syndrome are presented, as is the possibility that the renal and pulmonary abnormalities in this case represent a single disorder.