DIAGNOSTIC APPLICATIONS OF THE BLOOD-COUNT 227 



German Measles is not accompanied by leucocytosis. 



Hooping-cough. — There is a high grade of leucocytosis (20,000 

 to 60,000), due mainly to an increase of lymphocytes. This is said 

 to occur before the hooping occurs and to be of diagnostic value, 

 but leucocytosis with lymphocytosis is so common in children 

 that little value should be attached to it unless really high figures 

 are found. 



Influenza. — Here the blood-count may be of value, since, in 

 contradistinction to the majority of acute febrile diseases, there 

 is no leucocytosis if complications are absent. In other febrile 

 diseases of rapid onset — pneumonia, tonsillitis, rheumatic fever, 

 septic affections, plague, etc. — leucocytosis is almost constant. 



Rheumatism. — Except in the very mildest cases there is leuco- 

 cytosis, and, according to Turk, Ewing, and others, when there 

 are more than 20,000 there is almost certainly some complication, 

 such as endocarditis, pericarditis, pneumonia, or hyperpyrexia. I 

 believe this may be taken as a safe general rule, though excep- 

 tions do occur. 



Turk believes that a clue to prognosis may be got from the 

 percentages of eosinophiles present ; with a proportion above the 

 normal the case is likely to be a mild one. 



Tuberculosis. — There is usually marked anaemia of the 

 secondary type, but in cases with sweating and diarrhoea this 

 may be masked by the concentration of the blood ; an apparent 

 improvement in this respect may in reality be a bad sign. The 

 leucocytes are usually normal, though the lymphocytes may be 

 rather high. 



Where secondary septic infection takes place — e.g., in a vomica 

 — the blood is that of sepsis ; there is a variable leucocytosis, 

 excess of polynuclears, and advancing anaemia. 



The blood-count is not of much value in the diagnosis of 

 tubercle ; it is of some value in prognosis. Increase in the poly- 

 nuclears and in the grade of anaemia are bad signs in phthisis. 



There are one or two precautions to be noted in special cases. 

 In tuberculous empyema there is fyequently a secondary infection, 

 and the presence of a leucocytosis does not show that the disease 

 is not tuberculous ; the same thing applies to tuberculous abscesses 

 in other parts, including the joints. 



Tuberculous meningitis appears to offer the most marked 

 exception to the rule, that uncomplicated tubercle does not cause 

 leucocytosis. Here there is often moderate leucocytosis, and 



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