Causes The cause of appendicitis relates to blockage of the inside of the appendix, known as the lumen. The blockage leads to increased pressure, impaired blood flow, and inflammation. If the blockage is not treated, gangrene and rupture (breaking or tearing) of the appendix can result. Most commonly, feces blocks the inside of the appendix. Also, bacterial or viral infections in the digestive tract can lead to swelling of lymph nodes, which squeeze the appendix and cause obstruction. This swelling of lymph nodes is known as lymphoid hyperplasia. Traumatic injury to the abdomen may lead to appendicitis in a small number of people. Genetics may be a factor in others. For example, appendicitis that runs in families may result from a genetic variant that predisposes a person to obstruction of the appendiceal lumen. [Top] Symptoms Symptoms of appendicitis may include * pain in the abdomen, first around the belly button, then moving to the lower right area * loss of appetite * nausea * vomiting * constipation or diarrhea * inability to pass gas * low fever that begins after other symptoms * abdominal swelling Not everyone with appendicitis has all the symptoms. The pain intensifies and worsens when moving, taking deep breaths, coughing, or sneezing. The area becomes very tender. People may have a sensation called "downward urge," also known as "tenesmus," which is the feeling that a bowel movement will relieve their discomfort. Laxatives and pain medications should not be taken in this situation. Anyone with these symptoms needs to see a qualified physician immediately. People With Special Concerns Patients with special conditions may not have the set of symptoms above and may simply experience a general feeling of being unwell. Patients with these conditions include * people who use immunosuppressive therapy such as steroids * people who have received a transplanted organ * people infected with the HIV virus * peop