Pelvic inflammatory disease (PID) is caused by bacterial infections such as Chlamydia trachomatis and Neisseria gonorrhea that enter the reproductive tract. Symptoms include lower abdominal pain, fever, unusual discharge, painful intercourse and urination. Treatment involves antibiotics for both patients and partners to prevent further damage. Without treatment, PID can cause long-term complications like infertility, ectopic pregnancy, and chronic pain due to scar tissue and fallopian tube damage.