While the Italian designation of this type of fever as aestivo-autumnal has more general acceptance yet Koch’s term, tropical malaria, is eminently appropriate. The onset in malignant tertian is rather insidious so that the case may be suspected as one of typhoid fever. At the same time the first paroxysm is apt to show a tertian periodicity while subsequent ones, by only remitting, and not showing an intermission, give the temperature picture of a continued fever in which periodicity is not easily noted. At the same time a study of such a chart will probably show that the curve tends to approach normal every other day. The suggestion of periodicity is almost of as great value as the actual drop to normal in the intermission. The remittent or even continuous type of fever in malignant tertian tends to yield to an intermittent one after a week or more of such fever.
Very characteristic of malignant tertian paroxysms is that they set in with chilly sensations rather than a frank chill. It is for this reason that the so-called “dumb chill” is recognized as more serious than the frank unmistakable chill.
The main feature of malignant tertian paroxysms is the pronounced and prolonged hot stage, which frequently lasts from twenty to thirty-six hours and may run over into the rising temperature connected with the development of the succeeding generation of parasites.
The terms anticipation and postponement are frequently used to explain the drawn-out fever of this type of malaria.
There is great irregularity in time of development so that we get the impression of completed cycle before the accepted forty-eight hours as shown by a rising temperature within thirty-six hours—anticipation; or, instead of showing indications of a completion of cycle in forty-eight hours the fever still keeps up—retardation.
The descent of the fever curve is much more gradual than the rise at the onset of the paroxysm. The fine hair-like rings of the tropical parasite are the only schizont stages usually found in the peripheral blood. As the rings enlarge they fail to appear in the peripheral blood so that blood examination at such times will be negative. The finding of crescents is proof of a malignant tertian infection.
In view of the fact that one is likely to fail to find parasites just before or just after a paroxysm search should particularly be made for the pigment-carrying phagocyte—the melaniferous leucocyte.
In certain of the pernicious manifestations of malignant tertian, especially the hyperpyrexial type of cerebral malaria, the temperature may reach a very high degree, 107°F. to 110°F., and it is often mistaken for sun stroke by one not familiar with the fact that so-called sun stroke is often only this fatal form of malaria.
In algid pernicious malaria the axillary and, in particular, the rectal temperature remain elevated even with a subnormal surface temperature.