Gab Kovacs1 and Paula Briggs2
(1)
Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
(2)
Sexual and Reproductive Health, Southport and Ormskirk Hospital, Southport, UK
Definition
Incidence
Aetilogy and Pathogenesis
Clinical Assessment
History
Examination
Investigations
Treatment
Medical
Surgical
Complications
Prognosis
Definition
Fibroids are benign neoplastic lesions of the fibrous and muscle tissue of the uterus.
Incidence
They occur commonly, especially between 25 and 45 years of age. They are 2–3 times more common in Afro-caribean women.
Aetilogy and Pathogenesis
The cause of fibroids is unknown. The growth of fibroids depends on oestrogen, and they shrink after the menopause.
There is a familial tendency, but no specific genetic marker has been identified.
Fibroids are classified as subserous (on the peritoneal aspect of the uterus), intramural (within the wall of the uterus) and sub-mucous (distorting the uterine cavity), and pedunculated (Fig. 13.1).
Fig. 13.1
Uterine fibroids
Clinical Assessment
History
· Fibroids are often asymptomatic.
· Symptoms depend on the position and the size of the fibroid(s).
· Abnormal bleeding – HMB and IMB can occur.
· Pain
· Dysmenorrhoea – pain due to passing clots.
· Haemorrhage within the substance of the fibroid (red degeneration) can also cause pain (this is more common during pregnancy). Fibroids may cause pressure on pelvic nerves also causing pain, although this is uncommon.
· Pressure symptoms. Pressure on the bladder may cause frequency, urgency and occasionally urinary retention. Pressure on the bowel may result in constipation.
· Subfertility. Submucous fibroids may result in recurrent early pregnancy loss and/or subfertility.
Examination
On bimanual examination an enlarged uterus may be detected. There may be irregular enlargement if there are large fibroids.
Investigations
· Full blood count – Iron deficiency anaemia may result due to HMB.
· Ultrasound examination – Fibroids can be detected with U/S.
· CT or MRI scan. Fibroids can be accurately assessed using these imaging techniques, however they are not first line investigations.
· Hysteroscopy – This is most useful for submucous fibroids.
· Laparoscopy – this is good for assessing intramural and subserous fibroids.
Treatment
· Many fibroids are asymptomatic and do not require treatment. Treatment is indicated if the fibroids cause significant symptoms- abnormal bleeding, pressure symptoms or associated subfertility.
Medical
Hormonal
As fibroids are oestrogen dependent, reducing or inhibiting oestrogen will limit their growth. They are composed of muscle and fibrous tissue, but it is only the muscle, which is hormone sensitive. Consequently whilst hormones can shrink a fibroid, they cannot make it disappear. Once the hormonal treatment is ceased, the muscle tissue within the fibroid usually regrows.
· Combined Hormonal Contraception- Whilst not decreasing fibroid size, pills, patches and rings may improve HMB.
· Progestins- these work by counteracting the effect of oestrogen on the fibroids:
· Oral progestins – may decrease HMB, and result in some decrease in fibroid size.
· Depot progestins (SDI, depot injection)- may decrease fibroid size and improve HMB, but can be associated with unscheduled bleeding.
· Levonorgestrel intrauterine system (LNG-IUS)- unlikely to decrease fibroid size, but usually decreases HMB. Contraindicated if uterine cavity very large or irregular.
· GnRH agonists – these work by suppressing the release of FSH and consequent inhibition of follicular development, resulting in a hypo oestrogenic state. As fibroid growth depends on oestrogen stimulation of receptors, fibroids will shrink. Unfortunately this is only temporary, and the fibroids regrow once treatment is stopped.
· Ulipristal acetate (UPA). This is a progesterone receptor modulator administered orally in a dose of 5 mg daily for 3 months at time. Studies have shown a potential reduction in fibroid size of up to 50 %. Bleeding generally stops within 2 weeks of commencing treatment.
Other Medical
· NSAIDs and Tranexamic acid- no effect on fibroid size, but may improve HMB.
Surgical
Minor
Hysteroscopic resection (Transcervical Resection of Fibroids (TCRF)). This is only suitable for submucous fibroids less than 7–10 cm in diameter.
· Myomectomy. This can be performed either laparoscopically or by laparotomy. The laparoscopic approach is possible if there are only one or two fibroids, not exceeding 7 cm in diameter. Laparotomy is indicated if there are several or very large fibroids.
· Uterine artery embolisation (UAE). This technique is performed by interventional radiologists, using high definition x-ray, to deliver embolic particles (microspheres, gelatin foam or polyvinyl alcohol) via the uterine artery into the vessels supplying the fibroid. These particles then occlude the blood supply and the fibroid(s) undergo ischaemic necrosis.
· Myolysis – these methods are experimental. They use high frequency electric current or laser energy, directed by laparoscopic vision to destroy fibroid(s).
· MR Guided Focused Ultrasound Therapy (MrgFUS). This is another experimental technique which uses MRI and ultrasound to locate the fibroid. After measurement of the fibroid, the Ex-Ablate System®uses software to calculate the number and types of ultrasound generated energy pulses (sonications) to heat (up to 65–85 °C) and destroy it. MrgFUS can only be used if the ultrasound energy does not have to pass through bowel or bladder to access the fibroid.
Major
Hysterectomy. This is usually performed via laparotomy and totally and permanently removes the uterus and fibroids.
Complications
Fibroids may impair fertility or cause early pregnancy loss. Cervical fibroids may obstruct vaginal delivery. They may cause pressure symptoms- pain, frequency, urgency and constipation.
Sarcomatous change- this occurs very rarely (1/500). Whilst hard to diagnose clinically, rapid growth may be an indication.
Prognosis
Fibroids usually continue to grow during reproductive life, but shrink post menopausally. Management depends on symptoms, and treatment is only required if “the risk benefit equation” justifies it.