A non-surgical condition which resembles appendicitis is called mesenteric adenitis. The mesentery is a lining covering the intestines. It contains blood vessels and lymph glands.
When acute infection exists, such as in cases of tonsillitis, bronchitis, pneumonias, etc., these abdominal glands may become swollen, tender, and painful, causing nausea. vomiting and abdominal pain. It resembles acute appendicitis.