###Human: What is the cause for having blood in stool with stomach pain? ###Assistant: Hi. Mesenteric lymph node enlargement can be seen in children without a cause, and it is called as primary mesenteric lymphadenitis. In secondary causes, infections like tuberculosis or enteric fever or viral fever can also cause it. Blood in the stool can also occur due to infectious colitis or ileitis or intussusception. Do stool examination, endoscopy, montaux test, and chest X-ray. Consult a pediatrician soon after doing these tests. The doctor will examine the condition and will treat it accordingly.