Extreme Leukocytoses in Pertussis

The marked leukocytosis occurring in pertussis is generally recognized and frequently used in the diagnosis of mild and obscure cases of the disease. Frohlich, 1 in 1897, was probably the first to draw attention to its occurrence. 2 He reports a constant high leukocyte count in about eighty cases studied during an epidemic of pertussis in Breslau. Frohlich's observation was shortly afterward confirmed in the classical investigation of Meunier. 3 The latter made repeated blood counts on 104 cases. The average of his maximum counts was 27,800 per cubic millimeter, and he obtained 23,700 as the general average at the height of the disease. Several leukocyte counts exceeded 40,000 and the highest noted was one of 51,150. The reports of counts of 80,000 and more in this disease are relatively few in the literature, and but eight were found which surpassed 100,000. This paper was undertaken to emphasize these extraordinarily