The fallopian tubes extend from the uterus, one on each side, and both open near an ovary. During ovulation, the released egg (ovum) enters a fallopian tube and is swept along by tiny hairs towards the uterus.

Salpingitis is inflammation of the fallopian tubes. Almost all cases are caused by bacterial infection, including sexually transmitted diseases such as gonorrhoea and chlamydia. The inflammation prompts extra fluid secretion or even pus to collect inside the fallopian tube. Infection of one tube normally leads to infection of the other, since the bacteria migrates via the nearby lymph vessels.

Salpingitis is one of the most common causes of female infertility. Without prompt treatment, the infection may permanently damage the fallopian tube so that the eggs released each menstrual cycle can't meet up with sperm. Scarring and blockage of the fallopian tubes is the most frequent long-term complication of pelvic inflammatory disease (PID) and so this condition can sometimes be referred to as PID. However, the umbrella term of PID includes other infections of the female reproductive system, such as the uterus and ovaries.

In nine out of 10 cases of salpingitis, bacteria are the cause. Some of the most common bacteria responsible for salpingitis include:

• chlamydia
• gonococcus (which causes gonorrhoea)
• mycoplasma
• staphylococcus
• streptococcus.

The bacteria must gain access to the woman's reproductive system for infection to take place. The bacteria can be introduced in a number of ways, including:

• sexual intercourse
• insertion of an IUD (intra-uterine device)
• miscarriage
• abortion
• childbirth
• appendicitis.

Lifestyle factors that significantly increase a woman's risk of contracting salpingitis include:

• engaging in sexual intercourse without a condom
• prior infection with a sexually transmitted disease.

In milder cases, salpingitis may have no symptoms. This means the fallopian tubes may become damaged without the woman even realising she has an infection. The symptoms of salpingitis may include:

• abnormal vaginal discharge, such as unusual colour or smell
• spotting between periods
• dysmenorrhoea (painful periods)
• pain during ovulation
• uncomfortable or painful sexual intercourse
• fever
• abdominal pain on both sides
• lower back pain
• frequent urination
• nausea and vomiting
• the symptoms usually appear after the menstrual period.

Salpingitis is usually categorised as either acute or chronic. In acute salpingitis, the fallopian tubes become red and swollen, and secrete extra fluid so that the inner walls of the tubes often stick together. The tubes may also stick to nearby structures such as the intestines. Sometimes, a fallopian tube may fill and bloat with pus. In rare cases, the tube ruptures and causes a dangerous infection of the abdominal cavity (peritonitis). Chronic salpingitis usually follows an acute attack. The infection is milder, longer lasting and may not produce many noticeable symptoms.

Diagnosing salpingitis involves a number of tests, including:

• general examination - to check for localised tenderness and enlarged lymph glands
• pelvic examination - to check for tenderness and discharge
• blood tests - to check the white blood cell count and other factors that indicate infection
• mucus swab - a smear is taken to be cultured and examined in a laboratory so that the type of bacteria can be identified
• laparoscopy - in some cases, the fallopian tubes may need to be viewed by a slender instrument inserted through abdominal incisions.

Treatment depends on the severity of the condition, but may include:

• antibiotics - to kill the infection, which is successful in around 85 per cent of cases
• hospitalisation - including intravenous administration of antibiotics
• surgery - if the condition resists drug treatment.

Without treatment, salpingitis can cause a range of complications, including:

• Further infection - the infection may spread to nearby structures, such as the ovaries or uterus.
• Infection of sex partners - the woman's partner or partners may contract the bacteria and become infected too.
• Tubo-ovarian abscess - about 15 per cent of women with salpingitis develop an abscess, which requires hospitalisation.
• Ectopic pregnancy - a blocked fallopian tube prevents the fertilised egg from entering the uterus. The embryo then starts growing inside the confined space of the fallopian tube. The risk of ectopic pregnancy for a woman with prior salpingitis or other form of pelvic inflammatory disease (PID) is around one in 20.
• Infertility - the fallopian tube may become deformed or scarred to such an extent that the egg and sperm are unable to meet. After one bout of salpingitis or other PID, a woman's risk of infertility is about 15 per cent. This rises to 50 per cent after three bouts.