What is dilation of the fallopian tubes?

Dilation of the Fallopian Tubes (Hydrosalpinx)

Dilation of the fallopian tubes, medically known as hydrosalpinx, is a condition where the fallopian tube becomes blocked and filled with fluid, resulting in a distended, fluid-filled tubular structure. This condition most commonly occurs as a result of pelvic inflammatory disease (PID), but can also develop from other causes of tubal obstruction 1.

Pathophysiology and Causes

Hydrosalpinx develops when the distal (farthest) end of the fallopian tube becomes occluded, leading to:

• Accumulation of fluid within the tube
• Gradual distension and dilation of the tubal structure
• Formation of a characteristic C- or S-shaped tubular structure 2

Common causes include:

• Pelvic inflammatory disease (most common cause) 1
• Previous pelvic or abdominal surgery
• Endometriosis
• Tubal pregnancy complications
• Fallopian tube tumors
• Incomplete salpingectomy (surgical removal of fallopian tubes) 3

Diagnostic Imaging

Hydrosalpinx can be identified through various imaging modalities:

1. Transvaginal Ultrasound (first-line imaging):

   • Appears as an anechoic (fluid-filled), tubular structure
   • Characteristic features include well-defined echogenic wall, folded configuration, and linear echoes protruding into the tube lumen
   • Lacks peristaltic activity (distinguishing it from bowel) 4
   • 86% sensitive in detecting hydrosalpinx 5

2. MRI:

   • Shows fluid-filled C- or S-shaped tubular structure arising from upper lateral margin of uterus
   • Can characterize the nature of fluid contents (important for differential diagnosis)
   • Fluid with high signal intensity on T1-weighted images may suggest hematosalpinx (blood-filled tube)
   • 95% sensitive and 89% specific for evaluation of hydrosalpinx 5, 2

3. Hysterosalpingography (HSG):

   • Traditional gold standard for evaluating tubal patency
   • Shows filling defect or complete blockage of the fallopian tube 5

Clinical Significance

Hydrosalpinx has significant implications for:

1. Fertility:

   • Associated with lower implantation and pregnancy rates in assisted reproductive technology (ART)
   • Disrupts the endometrial environment through mechanical and chemical factors 1
   • May require treatment before fertility procedures

2. Pain and Symptoms:

   • Can cause chronic or acute pelvic pain
   • May present as part of postmenopausal subacute or chronic pelvic pain 5
   • Sometimes discovered incidentally during imaging for other conditions

Management Options

Treatment depends on fertility desires and symptom severity:

1. For women pursuing IVF/fertility treatment:

   • Salpingectomy (surgical removal of the affected tube) is the preferred approach before IVF 1
   • Performed laparoscopically when possible

2. For women desiring natural conception:

   • Salpingostomy (surgical creation of a new opening in the tube) may be considered
   • Caution: associated with ectopic pregnancy rates up to 10% 1

3. For proximal tubal occlusion:

   • Fallopian tube recanalization - a minimally invasive procedure performed on an outpatient basis
   • Should be considered as first-line therapy for proximal occlusion 6

4. For symptomatic hydrosalpinx without fertility concerns:

   • Salpingectomy to relieve symptoms and prevent complications
   • Complete removal of fallopian tubes is strongly recommended during hysterectomy to prevent later hydrosalpinx formation 3

Complications and Considerations

• Hydrosalpinx may be associated with other pelvic pathology requiring evaluation
• Antibiotic prophylaxis may be considered during procedures if there is a history of PID or if hydrosalpinx is noted 5
• Complete removal of fallopian tubes during hysterectomy is recommended to prevent subsequent hydrosalpinx formation 3

When hydrosalpinx is identified, thorough evaluation is essential to determine the underlying cause and appropriate management strategy, particularly for women with fertility concerns or experiencing pain.