It is not strictly speaking a disease, but it may cause unpleasant symptoms in certain individuals. It is mostly found in women aged 30 to 50 and the cause is unknown. Some surgical procedures are associated with a break in the barrier between the endometrium and the muscle layer and may lead to adenomyosis.
These procedures include Caesarean sections, curettage of the uterus and termination of pregnancy. Adenomyosis is not associated with the development of cancer.
How does adenomyosis cause symptoms?
The ectopic (in the wrong place) glands in the muscle will react to hormonal changes during the menstrual cycle exactly in the same way as normal endometrial glands.
In the first half of the cycle, which starts after menstruation, the developing egg cell in the ovary will stimulate the production a hormone called oestrogen. This hormone is designed to thicken the normal endometrium in order to prepare for a possible pregnancy.
The same ‘thickening’ or growth also happens in the adenomyosis deposits.
After ovulation the hormone progesterone is secreted by the ovary and this will cause further changes in the endometrial glands. When a pregnancy does not occur, the hormone levels will start to decrease before the next menstruation.
During menstruation the endometrial glands become very thin and some of the tissue is shed, which is seen as menstrual blood. The same process will occur in the glands of adenomyosis and over months the repeated shedding of tissue may lead to the development of a small cyst (bubble) of blood deep in the muscle of the uterus.
These cysts are called adenomyomas. Adenomyosis may cause enlargement of the uterus and may cause pain and heavy menstruation. The pain is often cyclical and is worse around the time of menstruation. This is referred to as dysmenorrhoea in medical terms.
After the menopause the level of oestrogen declines significantly. The symptoms associated with adenomyosis may clear completely or reduce in intensity. Some women may experience a significant improvement after pregnancy.
How is it diagnosed?
It may be very difficult to diagnose adenomyosis with certainty. A good history combined with an internal pelvic examination is possibly the best way to diagnose the condition. The doctor will find an enlarged uterus with tenderness.
If the condition is severe, adenomyomas may be seen on ultrasound examination but usually the uterus only appears uniformly enlarged. Other special forms of imaging such as Magnetic Resonance Imaging (MRI) may be more accurate, but is rarely used due to the cost. In many cases the diagnosis is only confirmed when the uterus is examined by a pathologist after a hysterectomy.
Mild symptoms are usually well controlled by means of medical management. Simple painkillers from the non-steroidal anti-inflammatory class (NSAIDs) are very effective. Hormonal treatment, to reduce the effects of oestrogen, is also widely used. The combined oral contraceptive or the two/three month contraceptive injections will reduce pain and bleeding problems. A medicated intra-uterine contraception device that releases a progesterone-like hormone may also improve symptoms.
In a small number of situations an operation may be done to remove adenomyomas without removing the rest of the uterus. This is only done if there are significant symptoms and there is a wish for future fertility.
If the symptoms do not settle on medical treatment a hysterectomy may be indicated. This is only an option if the family is complete. A hysterectomy will offer complete and permanent relief if the symptoms were indeed caused by adenomyosis. Removal of the endometrium by a procedure called an endometrial resection is not a good option, because the symptoms may persist and a hysterectomy might eventually become necessary.