Clinical characteristics and disposition kinetics of the hepatomegaly associated with acute, uncomplicated, Plasmodium falciparum malaria in children

The clinical characteristics and the kinetics of the disposition of the hep atomegaly associated with acute, uncomplicated Plasmodium falciparum malari a were investigated in 162 children in an endemic area of Nigeria. Hepatome galy was significantly more common in the younger than in the older childre n. Complete resolution occurred in 48%, following antimalarial chemotherapy . In the children in whom hepatomegaly did not resolve, a reduction in live r size of < 17% by the time parasitaemia was cleared (usually on day 3) was associated with non-resolution of hepatomegaly by days 7 or 14 of follow-u p. An increase in liver size to at least 125% of the baseline value by day 4 or 5 was associated with a lack of therapeutic response, providing the ch ild involved was aged < 5 years. In the children who had complete clearance of parasitaemia and resolution of hepatomegaly, there was no significant r elationship between the parasitaemia-derived conventional indices of therap eutic response [i.e. time to clearance of 50% (PC50) or 90% (PC90) of the p arasitaemia, and the parasite-clearance time (PCT)] and the corresponding p arameters derived from measurement of liver size [i.e. time for resolution of 50% (HR50) or 90%, (HR90) of the hepatomegaly and the hepatomegaly-resol ution time (HRT)I in the same patients. However, as the HR50:PC50, HR90:PC9 0 and HRT:PCT ratios were similar (range = 1.6-2.1), the liver parameters m ay have therapeutic application. In the children with drug-sensitive P. falciparum infections and in whom he patomegaly completely resolved, the area produced by plotting liver size ag ainst time (i.e. the area under the curve of hepatomegaly v. time, or AUC(h p)) increased in proportion to the liver size below the costal margin (P = 0.02, from analysis of variance), but there was no significant difference i n the half-li,es of hepatomegaly (t1/2(hp)) or in the ratios of liver size to AUC(hp), indicating that the kinetics of the resolution of hepatomegaly were linear in the range examined. Comparison of the kinetic indices of hep atomegaly and parasitaemia showed that, although the half-lives of parasita emia and hepatomegaly and the corresponding clearance values were similar, there was no correlation beta-een these parameters among those in whom hepa tomegaly completely resolved and parasitaemia completely cleared. These res ults indicate that routine clinical measurement of the liver size in childr en with hepatomegaly during acute, uncomplicated, P. falciparum malaria may have some use in evaluating and monitoring the therapeutic responses of in fections. The resolution of hepatomegaly, a reflection of pathological chan ges, lags behind clearance of parasitaemia in children with P. falciparum m alaria, and supports the use of the liver 'rate' as a malariometric index f or assessing the intensity of transmission in endemic areas.