My cousin had this from an STD she got from her cheating husband. She also had an ectopic pregnancy and had to have the tube removed. That's when the doctor found the infection.
She had suspected he was messing around, and she knew she hadn't been, and the tests confirmed the inflammation was from an STD, not some other kind of infection. Needless to say, she divorced him.
Because he cheated on her with some skank, she didn't know to get tested, and it nearly took her life. She also wasn’t able to get pregnant again. All because of a cheating husband.