There are several possible causes for a 'swollen' fallopian tube (salpingitis) but the most common cause would be pelvic inflammatory disease. Pelvic inflammatory disease is a sexually transmitted infection that occurs when bacteria gain access through the cervix to the uterus and fallopian tubes, causes pain, fever
, and inflammation along with (often) vaginal discharge or pain with urination. Numerous bacteria are implicated in pelvic inflammatory disease, but two common players are chlamydia and gonorrhea. If your Ob GYN suspected pelvic inflammatory disease, then no doubt they performed some laboratory tests to confirm this and gave you some antibiotics to treat it.
Another possible cause of this finding would be endometriosis
, which occurs when cells from the lining of the uterus grow in places outside of the uterus, such as the fallopian tube. This can lead to pain and inflammation that especially fluctuates with the menstrual cycle. Your OB GYN may have given you anti-inflammatory medications or oral contraceptive pills if they suspected this diagnosis.
Regardless of the exact cause, it is important to follow up with your OB GYN doctor
and make sure that the inflammation is improving, because inflammation of the fallopian tubes that is long standing and untreated can lead to chronic pelvic pain and infertility.