complications involving the spleen have been reported with infarction , abscess , subcapsular hematoma , rupture , and hyper - reactive malarial splenomegaly ( hms ) or tropical splenomegaly syndrome .
the latter is commonly understood as an immunological reaction from the infected host and may be confused with lymphoproliferative syndromes .
hms is usually described in tropical residents as a result of chronic malarial infection , and is mostly recognized in young and middle - aged adults .
a unique case of hms complicated by splenic infarct affecting a caucasian child is reported .
a 4-year 11-month - old boy from the united states was staying with his family in a tribal region in indonesia in the preceding five months .
he had recurrent febrile illnesses during this period and had been given chloroquine intermittently as prophylaxis , but his general health started to deteriorate about a month before admission .
he was first admitted to a local hospital and was diagnosed to have plasmodium vivax infection .
he was treated with chloroquine ( the exact treatment could not be verified ) but the condition did not improve .
he was also found to have increasing splenomegaly and severe anemia ( lowest hemoglobin recorded , 3.6 g / dl ) .
red cell transfusion was carried out twice before he was evacuated to singapore for further management .
the liver and spleen were grossly enlarged at 6 cm and 8 cm below the costal margins , respectively .
the first full blood counts showed hemoglobin 9.8 g / dl , white cells 5.48  10/l , platelet 123  10/l .
immature trophozoites and gametocytes characteristic of plasmodium falciparum were also seen ( figure 1 ) , with a parasite load of 0.1% .
treatment with atovaquone 500 mg - proguanil 200 mg for three days was commenced . 

figure 1photomicrograph of the peripheral blood film with giemsa stain ( 100 ) showing an immature trophozoite ( t ) and a gametocyte ( g ) characteristic of plasmodium falciparum infection . 
 
photomicrograph of the peripheral blood film with giemsa stain ( 100 ) showing an immature trophozoite ( t ) and a gametocyte ( g ) characteristic of plasmodium falciparum infection .
computed tomography revealed enlarged liver and spleen with no signs of thrombosis in the portal venous system .
an area of infarction was found in the anterior aspect of the lower pole of the spleen ( figure 2 ) . 

figure 2axial and coronal contrast - enhanced computed tomography showing an infarct in the anterior aspect of the lower pole in the enlarged spleen . 
 
axial and coronal contrast - enhanced computed tomography showing an infarct in the anterior aspect of the lower pole in the enlarged spleen .
two days later , his hemoglobin dropped to 8.3 g / dl and another red cell transfusion was given .
tests for glucose-6-phosphate dehydrogenase deficiency , direct coombs test , and occult blood in stool were negative .
serum ferritin ( 664 mg / ml ) , bilirubin ( 15 mol / l ) , aspartate transferase ( 37 u / l ) , and alanine transferase ( 14 u / l ) were normal .
serologic tests for hepatitis b , hepatitis c , human immunodeficiency virus , and parvovirus b19 were negative .
lymphocyte subsets showed a mild increase in b cells ( 663/l , normal 65620 ) only . a week after completion of the anti - malarial treatment ,
the liver was no longer palpable and the spleen was 4 cm below the costal margin .
repeat hemoglobin was 11.7 g / dl , identical to the post - transfusion measurement .
parasite load was less than 0.01% , and no more parasites were seen on the blood film a week later .
hyper - reactive malarial splenomegaly is believed to be an immunological complication of malarial infection .
defective function of suppressive t cells leads to dysregulation of b cells and over - production of igm .
the deposition of immune complexes in the reticuloendothelial system results in the enlargement of the liver and spleen even in the absence of significant parasitemia as illustrated in this case .
differentiation from chronic lymphoproliferative disorders is important in the adult patient , but this is usually not an issue in childhood , though the condition has rarely been reported in pediatric ages .
however , diagnostic confusion may happen as hms may be mistaken as other febrile illnesses in the young child , or when the child presents late after returning from an endemic area .
splenic infarct is an unusual complication from malarial infection , but it is often innocuous and no treatment is required .
splenic infarct has to be distinguished from abscess which has also been noted after malarial infection .
spontaneous rupture is a recognized risk in patients with grossly enlarged spleens with an estimated risk of 2% in those affected by malaria .
clinicians evaluating patients returning from the tropics should be aware that diagnostic and therapeutic details from remote healthcare facilities may be difficult to verify .
failure to eradicate the parasite may be encountered because of inaccurate parasite identification , re - infection , inadequate drug dosing , drug resistance , or omission of the treatment for the hepatic stage of infection .
it is not clear if the malaria parasite had been misidentified or a co - infection with two malarial species had not been found at the initial stage in the reported case .
nevertheless , severe splenic complications following malaria should be looked out for in any child returning from the tropics , and they should be followed up for radical cure .
 a 4-year - old boy from the united states had been staying in indonesia for five months when he presented with fever , severe lethargy , progressive weight loss , and abdominal distension . 
 he was first diagnosed with plasmodium vivax infection in indonesia and received treatment with chloroquine . however , his condition continued to deteriorate and he required erythrocyte transfusion for severe anemia . 
 three weeks into his illness , he was found to have low parasitemia with plasmodium falciparum with massive hepatosplenomegaly in singapore . 
 a splenic infarct was also documented on computed tomography . 
 treatment with atovaquone - proguanil resulted in stabilization of the hemoglobin level and rapid reduction in splenic size , with clearance of malarial parasites from the bloodstream . 
 although reported typically in adult tropical residents , hyper - reactive malarial splenomegaly may occasionally be found in the pediatric traveler . 
 clinicians receiving children returning from the tropical regions should be aware of this potentially life - threatening complication of partially treated malaria . 
Introduction
Case Report
Discussion