Tropical splenomegaly syndrome in New Guinea I. Natural history

Abstract
The course of the tropical splenomegaly syndrome has been observed for periods of up to years in 75 adults living in the Upper Watut Valley of New Guinea. During this time there were 27 deaths, 2 from septicaemia and another 8 from similar fulminating febrile illnesses. The mortality rate in those with Grade V splenomegaly was 57%, almost 3 times that of the remainder. Serial hospital assessment of 26 subjects demonstrated progression of the disease, characterized by further enlargement of the spleen and a fall in haemoglobin concentration in 9; increases in splenic red cell pool, in plasma volume and in serum IgM concentration were sometimes, but not invariably, associated. In none of the total group of 75 subjects was a decrease in spleen size observed. Thus the natural history of the tropical splenomegaly syndrome is that of a progressive disease with a high mortality in the fully developed case. Periodic fluctuations in the clinical severity of the disorder are frequently seen and are largely related to the occurrence of episodes of acute haemolysis; however, spontaneous remission has not been observed.