Disorders of Menstruation

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Contents

Introduction

Disorders of menstruation account for many of the symptoms that fall within the remit of gynaecology. Other symptoms that can bring a patient to the attention of a gynaecologist include a vaginal discharge, lower abdominal pain, pelvic pain and dyspareunia (pain on intercourse).


Menorrhagia

Menorrhagia is excessive menstrual blood loss. Defining what constitutes an abnormal degree of blood loss can be difficult because the passage of menstrual blood per vaginam is a normal physiological event, unlike any other form of blood loss, such as haemoptysis, haematemesis or malaena (which are abnormal no matter their degree). Thus, establishing when menstrual blood loss becomes menorrhagia can be problematic.

A value of 80ml of blood per menstrual period is cited as the upper limit of normal but measuring the volume of menstrual blood is not practicable under most circumstances. Instead, the patient is used as her own reference point and the evaluation of menorrhagia includes establishing changes in the patient's pattern of menstrual bleeding.

In essence the prudent approach is to assume that if the patient says that her periods have become heavier, they have.

There are various causes of menorrhagia.

Dysfunctional uterine bleeding (DUB) is the commonest cause of menorrhagia. In 90% of cases the patient has an menstrual cycle in which ovulation does not occur. This means that the corpus luteum does not form and no rise in progesterone levels occurs during what should be the secretory phase of the cycle. Instead, the action of oestrogen on the endometrium is largely unopposed and the endometrium becomes excessively thick before menstruation finally develops. Endometrial curettings may give an indication of the problem, provided that the date of the patient's last period is supplied to the pathologist: if curettings taken at day 18 still show proliferative phase endometrium this implies an anovulatory cycle.

In the remaining 10% of cases of DUB the patient is ovulating. However, there are alterations in progesterone secretion and this can cause irregular loss of the endometrium, resulting in a prolonged duration of menstrual bleeding.


Metrorrhagia

Metrorrhagia is irregular bleeding from the uterus. If the bleeding is also heavy the term menometrorrhagia is employed. Sometimes the pattern of metrorrhagia may be that of intermenstrual bleeding: bleeding that occurs between the full menstrual period. Many of the causes are the same as those of menorrhagia.


Postmenopausal Bleeding

Postmenopausal bleeding is the passage of blood from the vagina once the menopause has been completed. It is a symptom that needs to be taken particularly seriously, although it is not always due to a sinister cause. The possible aetiologies include the following.

The presence of endometrial cancer in this list is the reason why the symptom warrants prompt and thorough investigation.


Dysmenorrhoea

Dysmenorrhoea is an abnormal degree of pain associated with menstruation. It suffers from the same problems of definition as menorrhagia in that a degree of pain during menstruation is a common aspect of the physiology of menstruation. In general, dysmenorrhoea is considered to be pain that requires treatment to relieve it or limits activities.

Dysmenorrhoea has various causes.

Endometriosis finally makes its appearance in this list. Although it often features in other versions of the lists given above, the nature of endometriosis means that it is distant from the uterine cavity and therefore cannot readily cause bleeding via the vagina (with the exception of vaginal endometriosis which is actually unusual). If endometriosis is included in these lists it may be prudent to add a qualification to it should the examiner be inflexible.


Primary Amenorrhoea

Primary amenorrhoea is the failure to begin menstruation by the age of sixteen years; an alternative definition is a failure to begin menstruation within two years of the development of other secondary sexual characteristics. It is rare and may be a manifestation of a condition that has already been diagnosed. The offending entities include the following.

An imperforate hymen causes cryptomenorrhoea: menstruation occurs but no vaginal bleeding can happen because the blood cannot leave the uterus and instead accumulates in the uterus and later the fallopian tubes. The disease will present with worsening pelvic pain.


Secondary Amenorrhoea

Secondary amenorrhoea is the absence of menstruation for at least six months in a woman who has previously menstruated. The most common cause is pregnancy. Lactation also induces amenorrhoea, although as it follows pregnancy it is sustaining amenorrhoea rather than causing it from scratch.

Other than pregnancy (and lactation) there are abnormal causes of secondary amenorrhoea.

Asherman's syndrome is a rare condition in which the walls of the endometrial cavity have become adherent and endometrium damaged.


Dyspareunia

Dyspareunia is pain that is experienced during sexual intercourse. Although not a menstrual disorder it is included here as a symptom of gynaecological disorders. It can be divided into superficial and deep types. Superficial dyspareunia is experienced in the vulva and may reflect vulva disease. It may also be a consequence of inadequate arousal and lubrication prior to penetration, or be due to spasm of the superficial muscles (vaginismus) which makes penetration painful.

Deep dyspareunia is experienced on deeper penetration and can be caused by pelvic disease. It has been suggested that the ovaries are as sensitive to the pain as the testes but are not normally vulnerable to being subjected to painful stimuli. However, if the ovaries adopt an abnormal position close to the vaginal fornices (as may occur if they are tethered by endometriosis, or are enlarged by a neoplasm) then they can be impacted by penetration.


Investigations

There are an array of investigations that can be used to pursue gynaecological disorders.

Pelvic ultrasound is useful for evaluating the ovaries and uterus. The ultrasound can be performed by the transvaginal method if necessary.

The pipelle biopsy is a technique for sampling the endometrium in outpatients. The samples can be of debatable quality in some instances but in others it may avoid a more complicated procedure.

Dilatation and curettage (D+C) is an investigation that is performed under general anaesthetic. The cervix is dilated and the endometrium is curetted. This provides a larger sample than a pipelle biopsy.

Hysteroscopy is a form of endoscopy in which the endometrial cavity is visualised. Targetted biopsy can be performed.

Laparoscopy and dye insufflation is concerned primarily with establishing the patency of the fallopain tubes. Dye is introduced to the uterine cavity under pressure and laparoscopic visualation determines if the dye emerges from the fimbrial end of the fallopian tubes. The laparoscopy itself is useful for a general look around.