Answer is D (Renal vein thrombosis): Although presentation of patient is similar to that of hemolytic uremic syndrome the presence of marked enlargement of both kidneys takes the whole diagnosis in our of renal vein thrombosis. Note : Patient in question has marked enlargement of both kidneys which takes the whole diagnosis in our of renal vein thrombosis. Patients who have bilateral renal vein thrombosis may be difficult to distinguish from those with the hemolytic uraemic syndrome. - Both disorders may be preceded by gastroenteritis and in both children may present with dehydration, pallor and evidence of microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure. - The marked enlargement of kidneys of a child with renal vein thrombosis helps to distinguish the disorder. - Doppler flow study or angiography of IVC may be necessary to confirm the diagnosis.