The colonic component of the splenic flexure occurs lateral to the mesenteric confluence. Hemorrhage secondary to splenic and hepatic tumors can also cause ventricular arrythmias. Primary diseases of the spleen are splenic torsion and splenic tumors. Despite the destruction of platelets by splenic macrophages, the spleen is normally not enlarged. May result from diaphragmatic or peridiaphragmatic lesions, renal calculi, splenic injury or ruptured ectopic pregnancy. Signs of splenomegaly may include a palpable left upper quadrant abdominal mass or splenic rub. Splenectomy can cure the variceal bleeding due to splenic vein thrombosis. Symptoms of splenic torsion include lethargy, abdominal distension and pale mucous membranes. Abdominal pain remains the leading chief complaint in patients diagnosed with a splenic infarct. Usually this involves leaving parts of splenic parenchyma in pouches of omentum. Furthermore there is a deficiency of other splenic cells e.g. splenic macrophages. Any factor that directly compromises the splenic artery can cause infarction. Severe side effects include splenic rupture and allergic reactions. Both the short gastric arteries and the splenic artery supply it with blood. In less than one percent of cases of infectious mononucleosis splenic rupture may occur.