DAH is associated with many different conditions. Many, like Wegener's granulomatosis (WG), have a capillaritis. WG, however, shows no electron dense deposits or immunofluorescent staining.
Two other types of lesions are shown below.
Alveolar Hemorrhage
Diffuse alveolar hemorrhage (DAH)
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DAH is associated with many different conditions. Many, like Wegener's granulomatosis (WG), have a capillaritis. WG, however, shows no electron dense deposits or immunofluorescent staining. Two other types of lesions are shown below. | ||||||
This photo shows RBCs (red) and proteinaceous exudate (pink) in alveolar spaces. The alveolar walls have increased numbers of inflammatory cells including PMNs (capillaritis). An iron stain will show hemosiderin-filled macrophages about 2 days after the bleed.
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In systemic lupus erythematosus, DAH is associated with focal, electron dense deposits in the alveolar-capillary basement membrane (arrow). A type I cell lies to the right of the tip of the arrow and the endothelial cell lies to the left. The asterisk marks the capillary lumen. | ||||||
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At higher magnification, the electron dense deposit shows a layered, "fingerprint" pattern (best seen at the arrow). These deposits account for a "lumpy-bumpy," discontinuous pattern seen by immunofluorescence. | ||||||
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DAH in Goodpasture's syndrome is accompanied by a linear immunofluorescence seen at the arrow. Ultrastructurally, deposits are absent. | ||||||
