Rocky Mountain Spotted Fever
Infection with rickettsial organisms such as Rickettsia rickettsii produce a hemorrhagic rash and hemorrhages in many internal organs including the lung (left photo). The changes are secondary to vasculitis (center photo). The endothelial cells are swollen and there is a mononuclear perivascular innflammation. Mononuclear interstitial pneumonia is seen in the photo on the right.
From the slide collection of the late Dr. Charles Kuhn
1 minute clinical correlation