Aetiology

As symptoms come and go in line with the menstrual cycle, it has long been thought that sex steroid hormonal changes were responsible for PMS. To fit with this theory, symptoms tend to be absent during non-ovulatory cycles, abolished by oophorectomy or treatment with ovulation inhibitors, and return with administration of exogenous hormones.^[2] However, the mechanism by which the changing hormone levels cause PMS symptoms is still elusive.

An alternative theory involves sex steroids and their effect on serotonin within the brain. Animal modelling has shown that serotonin may have a role modifying the effects of sex steroid-driven behaviour such as aggression and mood. In this theory, serotonin deficiency would create excessive swings in those behaviours. Also within this model, somatic symptoms such as breast tenderness and bloating represent a lack of willingness to tolerate these (normal) changes whilst being in a dysphoric state.

Epidemiology

Between 5-8% of women fulfil the criteria for a diagnosis of PMS.^[2] About 20% of these women seek medical help.^[3]

Risk factors

The following are known to increase the risk of PMS:^[3]

• PMS in the patient's mother.
• Smoking.
• Poor diet and lack of exercise.
• A lower level of academic achievement in the woman.

Presentation

Symptoms vary between cycles; they tend to worsen markedly about six days prior to menses and peak at two days beforehand. They improve a few days after starting the period. The main symptoms leading to a consultation are irritability and inability to cope with domestic or workplace demands.

• Physical symptoms usually lead to a consultation only when mastalgia, dysmenorrhoea or migraine have not responded to self-management.
• Difficult interpersonal relationships with a spouse or children may also precipitate a consultation. The risk of psychological illness appears to be higher amongst women who suffer menstrual problems.^[4]
• Psychosexual problems, loss of libido and dyspareunia may be reported but usually have to be specifically asked about.

There are no specific signs of the syndrome, so the problem is best delineated on the basis of a history and symptom diary kept over 2-3 months. There may be leg or breast oedema.

NB: the clinician should be careful not to accept without question parent-reported diagnosis of PMS in adolescent girls who may have more serious underlying psychological illness.^[5]

Differential diagnosis

This includes psychological conditions worsened by PMS. There is a need to consider depression, hyperthyroidism and hypomania.

The clinician should be careful to make a proper assessment before attributing symptoms to PMS, to avoid missing other causes of erratic or dysphoric behaviour.

Investigations

Ask the patient to keep a symptom diary over two complete cycles, to help with diagnosis. Later this will also help to assess effectiveness of any interventions.

• Check blood pressure and pulse rate.
• Consider breast and thyroid examination.
• Check that the patient's smear tests up-to-date.
• Consider pelvic examination, particularly if bloating is a major problem (this may be ascites due to alternative ovarian pathology), or other reason to suspect a physical cause of tummy swelling.

There are no useful tests to confirm the diagnosis. Consider other blood tests only if there is reason to suspect an alternative physical cause for symptoms.

Management

General measures

The most important part of the management is to reassure the patient that you understand her concerns and the disruption that symptoms are causing to her life. Quite often the friction caused by their irritability and volatility alienates the patients from usual sources of support at work and home. As PMS can be a long-term problem, there are lifestyle changes that may help the patient to cope with the symptoms. Reassure her that there are many ways to help and it is a matter of finding the best treatment strategy.

Mild symptoms may respond to lifestyle changes:^[3]

• Try regulating carbohydrate intake: complex carbohydrates every 2-3 hours and avoidance of excess sugar.
• Reducing saturated fats and caffeine: may improve mastalgia. Good diet may correct any subclinical nutrient deficiencies (eg magnesium and calcium) and improve symptoms.
• Reducing salt intake: may reduce fluid retention.
• Use of a firm, supportive bra - day and night.
• Support stockings: to help aching legs.
• Gentle exercise: is effective.

Try rescheduling more stressful tasks to the better half of the month. Get the patient to explain PMS to friends and family to improve support. Cognitive behavioural therapy may be useful in motivated patients. Relaxation exercises are helpful as are methods of coping with stress, such as assertiveness and time management training. Other remedies such as fennel tea and camomile tea may reduce breast tenderness. They act as a good substitute for tea and coffee, which may aggravate irritability further.

Pharmacological

Many treatments have been put forward but few have supportive evidence to justify their use. Treatment needs to be tailored to the severity of the PMS. Try simple analgesia, as required, for breast tenderness, headaches and period pains.

• Selective serotonin reuptake inhibitors (citalopram, fluoxetine, paroxetine) should be first-line for adult women with severe PMS. They have been shown to be effective in many trials,^[6] with 60-90% of women showing improvement with active treatment versus 30-40% for placebo treatments. They reduce both mood symptoms and somatic complaints and can be used in the community for women who predominantly have mood symptoms. This is an off-label use and the woman should be told this.
• Combined oral contraceptives are commonly thought to improve symptoms but there are few good trial data to support their use. Drospirenone plus 20 mg estradiol may help to treat premenstrual symptoms in women with PMS.^[7] It is a reasonable first-line option in women who also require contraception. Tricycling the pill has been shown to reduce frequency of symptoms.^[8]
• Oestrogen (at a high enough dose to inhibit ovulation) is one of the most effective treatments for PMS symptoms. It should be given as a transdermal patch or subcutaneous implant. 100, 150, or 200 micrograms may be necessary. If the woman has an intact uterus she will need to be given a progestogen to prevent endometrial hyperplasia. A progesterone-containing levonorgestrel-containing intrauterine system delivers this without causing symptoms to return.^[1]
• Alternatively, using gonadotrophin analogues with hormone replacement add-back therapy will also achieve ovulation inhibition whilst also providing uterine protection.

Surgery

There is no evidence supporting routine use of surgical treatments for PMS. Hysterectomy ± oophorectomy with oestrogen-only hormone replacement therapy (HRT) should be a last resort and the risk:benefit ratio should be carefully considered and documented. If a severe sufferer is sure that she does not want any more children, then it may be an option to consider.

Complications

In young women, consider birth control needs as well as premenstrual syndrome (PMS). Sometimes both can be met using the combined oral contraceptive pill (COCP).

PMS has been considered as a mitigating circumstance in some courts, for certain minor criminal offences such as shoplifting.

Prognosis

Most women can find effective solutions to their symptoms. A small number of women continue to be affected severely with worsening symptoms until the menopause.