In the course of the past two years I have encountered several cases of acute pulmonary disease supervening in apparently healthy persons, which have been admitted to the hospital with the diagnosis of acute lobar pneumonia, but in which the subsequent course of the disease has made it evident that the true condition was that of pulmonary embolism and infarction, resulting from a venous thrombosis which, at the time of the onset of the illness, was latent. These cases would almost certainly have passed for instances of atypical pneumonia with a complicating venous thrombosis, had it not been for the fact that at this time I was interested in observing the clinical manifestations of thrombophlebitis as it occurs in the course of typhoid fever, and had been much impressed by the frequency with which pulmonary embolism occurred before any local signs of thrombosis could be detected.
CONNER LA. PULMONARY ATTACK SIMULATING PRIMARY LOBAR PNEUMONIA, CAUSED BY PULMONARY EMBOLISM AND INFARCTION FROM A LATENT VENOUS THROMBOSIS. Arch Intern Med (Chic). 1914;XIII(3):349-360. doi:10.1001/archinte.1914.00070090002001