Description
Asherman syndrome, also known as intrauterine adhesions (IUAs) or uterine synechiae, is a condition characterised by the formation of scar tissue within the uterine cavity. The adhesions may be thin or thick, spotty in location, or confluent, and may partially or completely occlude the uterine cavity. It can cause menstrual disturbances, infertility, and complications in pregnancy.
Pathogenesis
Asherman syndrome typically results from trauma to the basal layer of the endometrium, most commonly following intrauterine surgery such as dilation and curettage (D&C), particularly if performed shortly after childbirth or miscarriage. The damage to the endometrial lining can cause the uterine walls to adhere to each other, leading to the formation of intrauterine adhesions.
Grading
Asherman syndrome can be categorised by the extent of the adhesions:
- Mild: Adhesions involving less than one-third of the uterine cavity
- Moderate: Adhesions involving one-third to two-thirds of the uterine cavity
- Severe: Adhesions involving more than two-thirds of the uterine cavity
Epidemiology, Risk Factors & Associations
- The incidence of Asherman syndrome is difficult to ascertain, but it’s most commonly associated with intrauterine surgery, especially in the postpartum period or following a miscarriage.
- Other risk factors include infections of the endometrium (e.g., endometritis) and congenital malformations of the uterus.
Clinical Features
- Women with Asherman syndrome may present with amenorrhoea, hypomenorrhoea, infertility, or recurrent miscarriage.
- In severe cases, where the cervical ostia are occluded, women may present with cyclic pelvic pain due to haematometra.
Complications
- Infertility and recurrent miscarriage are the most common complications.
- Complications during pregnancy can include ectopic pregnancy, intrauterine growth restriction (IUGR), preterm birth, and placental disorders.
Pathological Features
Histopathology
- Macroscopic: On hysteroscopy, adhesions appear as bands of scar tissue within the uterine cavity.
- Microscopic: Adhesions are composed of fibrous tissue, often with minimal vascularisation.
Radiological Features
General Features
- Characteristically demonstrates intrauterine filling defects on hysterosalpingography (HSG) or hysterosonography.
Hysterosalpingography (HSG)
- HSG can show filling defects or irregularities in the uterine cavity, suggestive of intrauterine adhesions.
- In severe cases, the uterine cavity may not be visualised at all.
Ultrasound
- On ultrasound, a normal endometrial stripe may not be visualised. In severe cases, the uterine cavity may appear as a thin line or not be visualised at all.
MRI
- T1WI: The junctional zone might not be well visualised due to adhesions.
- T2WI: Hypointense bands within the hyperintense endometrium can be seen.
- T1 C+: The fibrous bands do not enhance post-contrast, in contrast to the surrounding endometrium which enhances post-contrast.
Diagnosis
The diagnosis of Asherman syndrome is typically suggested by history and clinical examination and confirmed by imaging studies such as hysterosalpingography or hysteroscopy.
Differential Diagnosis
- Endometrial polyps or submucosal fibroids: Can appear as filling defects on HSG, but are typically solitary and have a different clinical presentation.
- Congenital uterine anomalies: Can cause an abnormal appearance of the uterine cavity on imaging, but are usually diagnosed earlier in life and have a different clinical presentation.
Management
Treatment of Asherman syndrome typically involves hysteroscopic adhesiolysis, with the goal of restoring the normal uterine cavity. Postoperative management may involve hormonal therapy to promote endometrial regrowth and prevent reformation of adhesions, as well as the use of intrauterine devices or barriers. A fertility specialist should be involved in the care of these patients due to the associated risk of infertility and recurrent pregnancy loss.