DIFFERENTIAL DIAGNOSIS 



1395 



greater importance than in non-inoculated individuals. Harris's 

 atropine test may also at times help the diagnosis of enteric in 

 inoculated people, the test apparently not being affected by previous 

 vaccination. 



Differential Diagnosis. — The term ' enteric fever,' as already 

 stated, is used to cover three infections— typhoid fever, para- 

 typhoid fever A, and paratyphoid fever B, which clinically, at least 

 in the tropics, cannot be distinguished from one another, except by 

 bacteriological methods. Enteric fever imitates many diseases, and 

 many diseases resemble enteric fever, and this renders the differential 

 diagnosis complicated and difficult. Of the many fevers which may 

 possibly be mistaken for some usual or unusual attack of enteric 

 fever, we have chosen the following for differential diagnosis — viz., 

 malaria, the relapsing fevers, dengue, undulant fever, plague, yellow 

 fever, typhus, influenza, trichiniasis, acute miliary tuberculosis, 

 appendicitis, pneumonia, rat-bite disease, psittacosis, parenteric 

 fevers, ulcerative endocarditis, and pyaemia. 



Malaria. — Intermittent fevers are hardly likely to be confused 

 with enteric fever, but remittent fevers are liable to cause difficulty, 

 and may be recognized by the presence of the parasites in the peri- 

 pheral blood, by the presence of pigment in the leucocytes, by the 

 enlargement of the spleen, and the reaction to quinine. Moreover, 

 the attack of fever is usually sudden, the temperature quickly 

 rising to 105° F., while the pulse is, as a rule, not dicrotic, and if 

 the fever has lasted a few days, there is generally some sign of 

 anaemia. It must, however, be remembered that malaria is a not 

 infrequent complication of the first week of an attack of enteric 

 fever in the tropics, as malarial carriers are very apt to develop 

 this fever when commencing an attack of enteric fever. 



Relapsing Fevers. — In these fevers the onset is sudden, and char- 

 acterized by chills and severe pains in some region of the body, 

 while a careful examination of the blood in a first attack should 

 reveal the spirochaetes. 



Dengue. — Dengue begins suddenly with often severe pain in 

 some part of the body, and often congestion of the conjunctiva, 

 and perhaps a sensation of chilliness. It must not be forgotten 

 that typical cases of dengue fever sometimes develop enteric 

 fever. 



Undulant Fever. — This disease may very closely resemble enteric 

 fever, and during the first week can only be definitely recognized 

 in a locality in which both diseases occur by cultivation of the 

 specific germ from the blood, while later sweating and the undulating 

 type of fever, together with the articular symptoms, are charac- 

 teristic. 



Plague. — The ordinary severe type of plague may be recognized 

 by the sudden onset, the severity of the symptoms, the mental 

 dulness, and the full development of the typical symptoms and 

 bubo in a few hours. 



The milder forms of plague are more difficult to recognize, because 



