Etiology of pelvic inflammatory disease
The primary cause is always a bacterial infection. While the normal flora of the vagina consists of mainly bacteria and some fungi, a couple of centimeters away, the healthy inner genitals are usually sterile. The thick cervical mucus has antibacterial activity under physiological circumstances that prevent bacteria from penetrating into the sterile uterine cavity. Only the pathogens of certain sexually transmitted diseases, mainly gonorrhoea and Chlamydiabacteria may penetrate through the cervix and cause an ascending infection.
The bacterial members of the normal vaginal flora can reach the pelvic organs with the instruments used for abortion, curettage, by the insertion or removal of an intrauterine device, or during miscarriage and delivery, or incidentally through the thread of an intrauterine device.
While in case of sexually transmitted diseases the canalicular spread is typical, the infections caused by delivery and instruments or in certain cases those occurring near the intrauterine devices spread typically by lymphogenous and canalicular route.
Course of the disease
Based on the course of the disease the classic pelvic inflammatory disease can be differentiated: there is an acute inflammation accompanied by severe lower abdominal pain, excessive vaginal discharge, feeling of fullness or bloating, bladder spasm during urination, or in some cases accompanied by pain radiating to the limbs and waist and high fever. This acute infection develops as a superinfection of a previously damaged Fallopian tubes; it is always a polymicrobial disease i.e. the infection is caused by different bacteria. The treatment consists of a high-dose combination of antibiotics applied for a prolonged time (at least for 14 days). Hospitalization and intravenous antibiotics may be required for the treatment of severe cases or in less severe cases wher the patient is nulliparous.
When the inflammation is caused by a sexually transmitted Chlamydia trachomatis bacterium, the symptoms are much less severe and the patient has no fever. The lack of symptoms is the consequence of Chlamydia bacteria multiplying in columnar epithelial cells and their life cycle is longer than average bacteria’s. Therefore the infection spreads slowly along the epithelial layer ascending through the epithelial layer of the cervix, the uterus, and then the Fallopian tube. In case of an extendedChlamydia infection the inflammation and as a consequence, scarring may spread in the whole abdominal cavity, including the surface of the liver. Since Chlamydia bacterium infects only the columnar cells and the transitional cells of the urethra, the first station of the infection is not the vagina, since it is covered with non-keratinized stratified squamous epithelium, but the canal of the cervix. First localized inflammation develops, followed by an excessive, purulent cervical-os discharge that is usually accompanied by a vaginal infection called bacterial vaginosis with bad-smelling, watery vaginal discharge. If the infection is diagnosed in time, Chlamydia infection can be cured with appropriate antibiotic treatment without severe residual symptoms. In case of a prolonged or repeated inflammation the cervical epithelium is thickened and its discharge production is increased. This discharge appears as complaints of viscid vaginal discharge. If the infection is not diagnosed in time it starts to ascend slowly towards the Fallopian tubes. When the infection reaches the uterine cavity or the developed infection spreads to the connective tissues and ligaments around the uterus cervical motion tenderness develops. Lower abdominal pain occurs during sexual intercourse or gynaecological exam. The infection often takes a latent form; the greatest danger is that it can go unnoticed and severely damage the Fallopian tubes; its late complications may be infertility, ectopic pregnancy, or chronic pelvic pain, or during a gynecology intervention it may furnish a perfect basis for acute pelvic inflammatory disease, or abscess formation in severe cases. Its typical example is when Fallopian tube permeability is checked during an infertility test. A contrast dye is injected through the cervix and the uterine cavity into the Fallopian tubes in this case. When the Fallopian tubes are permeable, the contrast dye gets into the abdominal cavity that can be observed easily on an X-ray. Should bacteria be driftet from the vagina or the inflamed cervix with the injected solution during the intervention, they may infect the previously damaged Fallopian tube that can even lead to a severe inflammation.
Late complications of pelvic inflammatory disease
A very nasty characteristic of pelvic inflammatory diseases is that they don’t disappear without traces. The changes, that later cause the complications usually develop during several previous (even asymptomatic) inflammations. The wall of the Fallopian tube is thickened; the movement of the Fallopian tube that is similar to the bowel peristaltic movement is weakened or stopped, the tiny cilia of the ciliated columnar epithelium lining the canal of the Fallopian tube are damaged, therefore the stream induced by their wavelike movement towards the uterine cavity is stopped. Should the wall of the Fallopian tube be severely scarred or the adhesions formed around the Fallopian tubes strike the Fallopian tube- the canal gets blocked. The blocked Fallopian tube leads to infertility. If only the function of the Fallopian tube is damaged or the canal is not blocked totally it may lead to ectopic pregnancy. The thickened mucous membranes due to the repeated inflammation produce an excessive amount of discharge that may cause chronic discharge. Its interesting form is when discharge cumulates in the dilated Fallopian tube that is blocked towards the abdominal cavity, then from time-to-time it is emptied causing a sudden, excessive mucous vaginal discharge.
The scarring around the Fallopian tubes or along the ligaments of the uterus may be the source of a chronic pelvic pain. It blocks the function of the surrounding organs – the bowel peristaltic movement, the release of mature eggs in the ovarium –, as well as the uterus and its adnexa loose their mobility, and become fixed as a consequence of scarring.
Abscess
In most of the cases abscess develops as a superinfection of the previously damaged Fallopian tube. Abscess is a collection of pus demarked from its environment by a wall. Should the abscess contain the Fallopian tube only, we speak about pyosalpinx (purulent salpingitis), should the process affect the whole wall of the Fallopian tube and should it spread to the surrounding organs, therefore to the ovarium and the bowels, a tubo-ovarian abscess is developing. The combination of antibiotic treatment and surgery gives a chance for recovery in case an abscess is formed. The affected fallopian tube and even the ovarium (in case of a tubo-ovarian abscess) should be removed during surgery! Important! Should the inflammation affect the uterus, like in case of an inflammation near a carelessly used intrauterine device, or after delivery, a febrile miscarriage, the removal of the uterus may be required!
According to these it is clearly understandable that pelvic inflammatory disease can be cured effectively, without any residual symptoms in its early stage only. Should the disease progress, the treatment requires a strict and prolonged medication with the combination –in many cases- of surgery and the risk of late complications and the incidental loss of certain organs is significantly increased at the same time. Infections may be prevented more easily than diagnosed and cured!
The most important risk factor in the development of pelvic inflammatory diseases is the number of sexual partners during the life, the gynecological surgeries (abortion) or the improper use of intrauterine devices. So the prevention of unintended pregnancies and therefore abortions is highly recommendable, for instance by contraceptive pills, and so the prevention of sexually transmitted diseases, simply by the use of condoms. During the use of intrauterine devices it is very important to maintain the normal vaginal flora, to treat vaginal infections in time and the change of the intrauterine devices in time according to the instructions./strong
