Possible prognostic significance of a brief rise in parasitaemia following quinine treatment of severe Plasmodium falciparum malaria.

An increase in parasitaemia is not uncommon after initiation of treatment for Plasmodium falciparum malaria, but its exact significance is unknown. The time-course of parasitaemia was assessed retrospectively in 33 patients with severe imported malaria. In 19 patients (group 1) mean parasitaemia (+/- SEM) fell promptly after starting quinine treatment, from 24.9 +/- 4.1% on day 0 to 9.7 +/- 2.3% on day 1 and 1.8 +/- 0.7% on day 2. In 14 other patients (group 2), parasitaemia did not change significantly or increased, with mean parasitaemia (+/- SEM) of 9.5 +/- 2.1% on day 0, 17.2 +/- 2.6% on day 1, and 3.7 +/- 1.8% on day 2. Simplified acute physiology scores on admission (mean +/- SEM) were 17.4 +/- 1.4 in group 1 and 11.7 +/- 1.0 in group 2 (P = 0.006). The mean number of complications of malaria per patient (+/- SEM) was 2.9 +/- 0.5 in group 1 and 1.6 +/- 0.3 in group 2 (P = 0.046). Two group 1 patients died. Initially, more than 95% of peripheral blood parasites were tiny and small rings in both groups, and this distribution was unchanged on day 1, suggesting that the parasitaemia increase in group 2 was not due to release of sequestered mature parasites. In severe falciparum malaria, a rise in parasitaemia after treatment initiation may be of favourable prognostic significance and should not lead to aggressive therapeutic approaches such as exchange transfusion.