160 PATHOLOGY OF TYPHUS IN MAN 



The only disease of which we know that gives a histological 

 picture in the skin similar to typhus is Rocky Mountain 

 spotted fever. The differences between the two are quantita- 

 tive rather than qualitative. In Rocky Mountain spotted 

 fever the destruction of the blood vessel walls is more exten- 

 sive and the perivascular accumulations are less pronounced 

 and do not form discrete tubercle-like nodules as in typhus. 

 The vessel lesions, with the "nodules" described by Fraenkel 

 and others, constitute the type picture in skin of typhus. 

 (Plate XI, fig. 34 and Plate XIV, fig. 39.) 



The diagnosis of typhus by microscopic examination of 

 skin sections may be made, in our opinion, without finding 

 the " nodules " of Fraenkel. The finding of lesions of the intima 

 with thromboses in blood vessels in a disease with an acute 

 exanthem other than Rocky Mountain spotted fever is suffi- 

 cient. In very early cases and very late cases the blood vessel 

 lesions may be overlooked; but we believe their presence to 

 be constant. The "nodules," as Fahr (1915), Fraenkel, and 

 Jaffe have insisted, cannot be found in every section. Serial 

 sections are required. Of the twenty-eight skin excisions we 

 failed to find characteristic perivascular "nodules" in four; 

 and in these four cases only a few slides were made from the 

 specimen. With the thirty-six autopsies from which skin was 

 studied, the serial section method was not used, but many 

 blocks of skin were taken from all parts of the body, arm, 

 shoulder, chest, abdomen, thigh, and ankle. Definite cir- 

 cumscribed infiltrations of the "nodule" type were found 

 only in thirteen cases, but in most of the remaining cases the 

 diagnosis of typhus could be made by one familiar with the 

 histology of the disease. 



The earliest reaction we have found (in skin excised the 

 first day of the rash) consists of swelling of the endothelium 

 of capillaries and small arteries and veins. The capillaries 

 about coil glands and of the papillae are most extensively 

 affected; but the vessels of the sub-papillary plexus also show 

 reaction at this early stage. The swollen cells occlude capil- 

 laries completely and mitotic figures of endothelial cells 



