Understanding New and Severe Abdominal Pain

When diarrhea is not a prominent symptom, fever and pain in the lower abdomen can be signs of a serious infection. You should have your symptoms evaluated by a doctor right away.

You are younger than 50, but if you are approaching this age (particularly if you have a history of constipation) you may have the infection, "diverticulitis." Many adults form "diverticuli" as they age, which are hollow tubular bulges that branch from the colon lining like small pockets. These pockets can accumulate bacteria and can cause symptoms much like appendicitis, but on the left side. Between episodes of infection, diverticuli can be asymptomatic, or they may cause pain or brisk bleeding.

It is also possible for a pocket of infection (abscess) to form near to the rectum if bacteria contaminate the surrounding tissue. This can cause pain in the left lower abdomen and fever. This diagnosis is called a "perirectal abscess" or "perianal abscess."