What is Salpingitis Isthmica Nodosa?
Salpingitis isthmica nodosa (SIN), sometimes also called a “diverticulosis of the fallopian tube,” occurs in between 0.6% to 11% of healthy women who can bear children. This condition is often linked to issues with fertility and pregnancies that develop outside the uterus, also known as ectopic pregnancies. Doctors and researchers aren’t entirely sure about the cause of SIN, but many believe it likely develops due to certain acquired conditions. Medical efforts to manage SIN mainly focus on restoring and preserving a woman’s ability to conceive and maintain a healthy pregnancy.
Moving on to the layout of the female reproductive system: A fallopian tube’s typical dimensions range from 10 to 14 cm in length, with an external diameter of about 1 cm. These tubes connect the ovaries (where eggs are produced) to the uterus (or womb), and consist of four distinct sections: The fimbriae, infundibulum, ampulla, and the isthmus, which attaches the fallopian tubes to the uterus. The isthmus has a relatively small central cavity or lumen (1-2mm) enclosed by a three-layered muscular wall. This wall structure has a middle circular layer, surrounded by an inner and an outer longitudinal layer.
SIN brings about lumpy swellings, that can be up to a few centimeters big; predominantly in the isthmus part of the fallopian tube. Nevertheless, this condition can affect all other sections of the tube as well. The outer covering or “serosa” of these swellings shows a smooth yellow, grey, or brown color.
What Causes Salpingitis Isthmica Nodosa?
Salpingitis isthmica nodosa (SIN) is a condition that was initially mentioned in 1887 by Chiari, but its cause remains a mystery. Currently, three main theories suggest infection, cellular invasion, and birth defects might be behind the occurrence of SIN.
One of the most accepted of these theories says an infection may occur during a woman’s child-bearing years, leading to a long-lasting inflammation in the fallopian tube. Studies have shown women with past inflammation (salpingitis) frequently have evidence of a certain bacterium, C. trachomatis, in the affected fallopian tube, implying a connection between a previous infection with this bacterium and SIN. Some research revealed that almost 90% of women with SIN had signs of inflammation in the affected tube, concluding that SIN might happen due to infection during reproductive years or because early infection boosts the odds of future infections, leading to SIN.
The second theory that does not involve inflammation suggests an overgrowth of the inner layer of the fallopian tube might cause SIN. This expansion ultimately breaks into the tube wall, resulting in cyst formation, stiffening of tissues (fibrosis), and thickening of the muscular wall. It is suggested that the disease might act like adenomyosis, a condition that involves unusual outgrowth of the inner lining of the uterus (endometrium) into the muscular parts of the uterus.
The final theory, hypothesized by von Recklinghausen in 1896, involves the possibility of a birth defect being a cause. It suggests that the tube-like glands might actually be remnants of the Wolffian ducts, one of two pairs of ducts in a fetus that develops into reproductive or urinary parts, which is suggested by their location on the isthmus where the Wolffian and Mullerian ducts intersect during development. Other previously proposed causes include prolonged spasms in the fallopian tube and abnormal tissue growth (neoplasia). Despite these multiple theories, most evidence points toward an environmental, not inherited, cause.
Risk Factors and Frequency for Salpingitis Isthmica Nodosa
Salpingitis isthmica nodosa is a condition that occurs in 0.6 to 11% of healthy, fertile women. However, this condition is more prevalent in women dealing with infertility or ectopic pregnancies, where its occurrence ranges from 2.8% to 57%. It is also found to be nine times more common in women of Jamaican origin as compared to those of White race. The right fallopian tube tends to be affected twice as often than the left one. Still, in only 4% of cases, it is found in both tubes.
- Salpingitis isthmica nodosa happens in 0.6 to 11% of healthy, fertile women.
- This condition is more common in cases of infertility or ectopic pregnancies, with a prevalence of 2.8% to 57%.
- It’s nine times more likely to occur in women of Jamaican origin than those of White race.
- The condition is almost twice as likely to affect the right fallopian tube than the left one.
- Only in 4% of cases does it affect both fallopian tubes.
Signs and Symptoms of Salpingitis Isthmica Nodosa
Sinus node disease, also known as SIN, can be tricky to diagnose because it does not always produce noticeable symptoms. Often, people aren’t aware they have it until they are investigated for other conditions such as infertility or pelvic pain. It’s most frequently detected in individuals who have previously experienced an ectopic pregnancy or struggle with fertility. However, having SIN doesn’t necessarily mean you will have fewer children than those who don’t have the condition. Most people find out they have SIN between the ages of 30 and 35.
Testing for Salpingitis Isthmica Nodosa
Hysterosalpingography (HSG) is a medical imaging procedure that helps your doctor inspect your uterus and fallopian tubes, and it’s nowadays one of the main ways doctors check for infertility or the presence of a condition called salpingitis isthmica nodosa, or SIN. SIN is a disorder that affects the fallopian tubes and may cause infertility. If you haven’t had an HSG in the last year, it may still be possible that you have this disorder.
In an HSG, the doctor will inject a dye into your uterus and fallopian tubes. The dye helps your fallopian tubes show up very clearly on X-ray images. If you have SIN, you will typically see small bunches of contrast dye (resembling tiny pouches or diverticula) in the narrowest part of the fallopian tubes. These dye collections will cluster over a small section (1 to 2 cm) of the tube, usually no deeper than 2mm. Occasionally, these little pouches may make a continuous line with the main tube channel, and small flecks of dye can be seen above and below the main tube. Complications of SIN can indeed lead to a fluid-filled fallopian tube (hydrosalpinx), tube blockage, or even spread into the area where the fallopian tube meets the uterus.
Alternatively, doctors can use a diagnostic tool called a laparoscopy to identify SIN. In this procedure, surgeons use a thin, lighted tube with a camera to look directly inside your abdomen and visually examine your fallopian tubes. In cases of SIN, a patient’s fallopian tubes show nodular swelling and thickness in the narrow part. But keep in mind that the detection of these bumps alone isn’t enough for a concrete diagnosis of SIN; they must be further investigated via a microscopic examination of the tissue. During laparoscopy, a special dye can be used to spot the individual small pouches along the tube. In severe SIN cases, the architecture of the fallopian tubes may look obviously abnormal. But in less severe cases, the surgeon can use diluted blue dye to reveal small repetitive indentations along the fallopian tube.
Treatment Options for Salpingitis Isthmica Nodosa
Assistive reproductive technology, mainly in the form of in vitro fertilization (IVF), is a commonly used method for helping individuals with fertility issues. IVF involves fertilizing an egg outside the body in a laboratory and then implanting it into the womb. Thanks to advancements in this technology, its success rates have greatly improved. For instance, with up to five cycles of IVF, the chance of having a live birth increases to 80.1%.
For many years, reconstructive surgery involving the proximal part of the fallopian tubes was the standard treatment for certain fertility issues. This procedure has been shown to yield pregnancy rates of 34%. However, with the introduction of more advanced microsurgical procedures, which carry fewer risks and complications, this has changed. Microsurgical procedures have led to pregnancy rates as high as 68% within the first two years following the surgery. These procedures tend to yield the best outcomes in women under 37 who undergo surgery on both tubes.
In some cases, less invasive procedure such as transcervical catheterization, which restores patency to the fallopian tubes, can be used. While this particular procedure is associated with lower pregnancy rates, it is sometimes preferred due to its less invasive nature, lower cost, and the fact that it maintains the length of the tubes. Further, if fertility is not an issue and the patient has symptoms, surgical removal of the fallopian tubes, or a salpingectomy, may be recommended.
Medication treatment for fertility issues can also involve the use of gonadotrophin-releasing hormone analogs (GnRH-a). GnRH-a works by creating an environment in the fallopian tubes that allows them to become unblocked. This treatment approach is similar to how adenomyosis is managed. This type of medication is suggested as a non-surgical treatment option for females dealing with obstructive fertility issues caused by conditions like endometriosis.
What else can Salpingitis Isthmica Nodosa be?
Carcinoma, a type of cancer, may look similar to SIN (Squamous Intraepithelial Neoplasia), a precancerous condition, because they often show similar placement of the glands. However, SIN typically doesn’t show a strong reaction in the surrounding tissue (stromal response) and doesn’t exhibit abnormal cell changes (atypia).
Differentiating between tubular endometriosis, a condition where tissue similar to the lining of the uterus grows in other places, and SIN can be a challenge when using a type of X-ray procedure called hysterosalpingography. Nonetheless, a closer examination under the microscope (histological analysis) can confirm the presence of tissue lining (tubal epithelium lining) the glands in SIN, which can help distinguish it from tubular endometriosis.
What to expect with Salpingitis Isthmica Nodosa
Although SIN (Salpingitis Isthmica Nodosa), a condition that involves inflammation and nodular formation in the fallopian tubes, does not directly lead to death, it can significantly increase a person’s risk of having an ectopic pregnancy (a pregnancy where the fetus grows outside the womb). Ectopic pregnancies have a mortality rate of 2% in the developing world and 0.2% in developed countries.
The treatment for SIN is aimed at restoring and maintaining fertility. Various medical interventions, including In-Vitro Fertilization (IVF – a complex series of procedures used to treat fertility or genetic problems and assist with the conception of a child), GnRH-a’s (Gonadotropin-Releasing Hormone Agonists – drugs used in fertility treatments), TCA (Transcervical resection of Adenomyosis – a procedure to remove adenomyosis, a condition where the inner lining of the uterus breaks through the muscle wall of the uterus), and IR interventions (Interventional Radiology – a subspecialty of radiology which utilizes minimally-invasive image-guided procedures to diagnose and treat diseases) have all been used successfully in recent years.
Possible Complications When Diagnosed with Salpingitis Isthmica Nodosa
Ectopic Pregnancies
Ectopic pregnancies, where the embryo attaches outside the uterus, can have a connection to Salpingitis isthmica nodosa, a unique form of tube scarring. In general, about 10% of females with ectopic pregnancies in the tube also have this condition. In cases where the ectopic pregnancy is specifically in the isthmus of the fallopian tube, the incidence of Salpingitis isthmica nodosa increases to 45.9%.
Infertility
Studies have shown that Salpingitis isthmica nodosa could be a potential factor in female infertility. In one study by Karasick and colleagues, 8.7% of females undergoing testing for infertility were diagnosed with this condition. Another research by Saracoglu and team found that it was present in 7.4% of infertile women with tube blockages.
Hydrosalpinx
Hydrosalpinx is a condition where the fallopian tube is filled with fluid due to a blockage at the far end of the tube. This is known to be a possible complication of Salpingitis isthmica nodosa.
Medical Issues Related to Salpingitis isthmica nodosa:
- Ectopic pregnancies in the fallopian tube (10%)
- Isthmic ectopic pregnancies (45.9%)
- Infertility (8.7% – Karasick’s study)
- Infertility due to fallopian tube obstruction (7.4% – Saracoglu’s study)
- Hydrosalpinx (known potential complication)
Preventing Salpingitis Isthmica Nodosa
Salpingitis isthmica nodosa, often referred to as SIN, is often caused by inflammation or an infection. Because of this, one of the best ways to lower the risk of developing SIN and its complications is by quickly identifying and treating it, or even better, preventing it. This is primarily achieved through thorough education about sexually transmitted diseases (STDs).
Many believe that Chlamydia, a common STD, might be the leading cause of SIN. Consequently, regular testing for this disease is highly recommended, especially for those who are at a higher risk of contracting it. This screening can conveniently be done during a pap smear, which is a routine test that checks for cervical cancer.
