CLINICAL MALARIA AND TREATMENT OF MULTIDRUG RESISTANCE FALCIPARUM IN THAILAND

Abstract

Clinical manifestations of malaria are nonspecific and range from asymptomatic to severe. The clinical presentations reflect complex interactions between the host, the environment, and the parasites. Signs and symptoms include fever, headache, muscle pain, abdominal pain, anorexia, nausea, vomiting, hepatosplenomegaly, jaundice and dark urine. In mild malaria, these signs and symptoms cannot differentiate malaria from common cold, influenza or other systemic diseases. Fever and malaise in malaria are believed to result from the release of endogenous cytokines [e. g. interleukin 1, 6 and 8 (IL-1, IL-6, IL-8) and tumor necrotic factor-α (TNF-α)] in response to parasite antigens. Other signs and symptoms of malaria are also associated with the rupture of parasitized red cells. In severe malaria, the clinical manifestations included cerebral malaria, pulmonary edema, renal failure, anaemia, and jaundice. Signs and symptoms of cerebral malaria are as follow alteration of consciousness, coma, dysconjugated eyeballs and convulsions. Among fatal cases, 80% died within the first 48 hrs of admission while the rest, death resulted from complications such as acute renal failure, pulmonary edema, bacterial infection, and lactic acidosis. 92% of the survivors had completed recovery. Treatment of multidrug resistant falciparum malaria in Thailand is complicated. New antimalarial drugs have been investigated at the Hospital for Tropical Diseases in the recent years. Artemisinine derivatives such as artesunate, artemether, arteether, dihydroartemisinin are also tested at the Bangkok Hospital for Tropical Diseases. Artesunate and artemether alone with a total dose of 600 to 750 mg produced cure rates of 80 to 95%. Artesunate suppositories have been proved successfully for the treatment of severe malaria. The artemisinin derivatives when used in combination with mefloquine cure rates improved to 95-100%. Dihydroartemisinin alone with a total dose of 480 mg given over 5 days gave a cure rate of 90%. At present, studies with the combination of artemisinin derivatives plus mefloquine in various doses and duration of treatment are being investigated. Until proven otherwise, the drug combinations are still recommended for all adult patients suffering from acute uncomplicated falciparum malaria contracted in multidrug resistant areas.In severe malaria, the choice of antimalarial chemotherapy depends on the clinical severity, the drug sensitivity of the parasites, and the availability and preparation of the drug. Quinine is widely available drug. Qinghaosu and its derivatives have been used successfully in treating both uncomplicated and severe falciparum malaria. Their effectiveness in eliminating the parasites have been extensively documented, however, the recrudescent rate is rather high (10-30%). In treating severe malaria, early diagnosis and early treatment are vital and the aim is to save patient's life. Prompt administration of an adequate and effective antimalarial drug is needed once the diagnosis is made. Other symptomatic and supportive treatment includes careful monitoring of fluid intake and urine output, frequent observations for complications with appropriate treatment and good nursing care.