Dysmenorrhoea (period pain; menstrual cramps)

• What is dysmenorrhoea?
• Statistics on dysmenorrhoea
• Risk factors for dysmenorrhoea
• Progression of dysmenorrhoea
• Symptoms of dysmenorrhoea
• Clinical examination of dysmenorrhoea
• How is dysmenorrhoea diagnosed?
• Prognosis of dysmenorrhoea 
• How is dysmenorrhoea treated?
• References

What is dysmenorrhoea (period pain; menstrual cramps)?

Dys – painful; meno – month; rrhea – flow.
Dysmenorrhoea refers to pain occurring before or during menstruation or both. It is also commonly referred to as period pain or menstrual cramps. It is classified into primary and secondary.
Primary dysmenorrhoea occurs when pelvic anatomy and ovarian function are normal and no organic cause can be found for pain.
Secondary dysmenorrhoea describes pain due to pelvic pathology. It can occur at any age but most commonly observed in women 20-45 years of age.

Statistics on dysmenorrhoea

It is one of the most common gynaecologic complaints in young women, affecting approximately 40-70% of women of reproductive age, with 10% of women describing severe symptoms. The true incidence is however difficult to establish due to inconsistent definition.

Risk factors for dysmenorrhoea

The exact mechanisms of primary dysmenorrhoea are unclear, but pain has been associated with high levels of prostaglandin in the uterus. This high prostaglandin levels increases uterine muscle contraction, leading to reduction in blood flow to uterine muscles (a sort of uterine angina).
The response to prostaglandin inhibitors in patients is a confirmation of this hypothesis. Other factors that may be involved include vasopressin, leukotrienes and prostanglandin E.

Symptoms of dysmenorrhoea

Primary dysmenorrhoea usually coincides with the start of menstruation. The initial onset is usually shortly after first menses.
Secondary dysmenorrhoea is associated with a later age of onset, after years of pain free menses and the patient is usually over 30 years of age. The pain begins as a dull pelvic ache 3 – 4 days before the menses and becomes more severe during menstruation. Other symptoms that may be associated with it include: pain during sex, irregular cycles, heavy bleeding, bleeding in between cycles or after sex. It should be noted that all these symptoms can also be caused by other gynaecological conditions.
Symptoms experienced may vary in different individuals and these include:

• Low midline abdominal or pelvic pain;
• Pain may radiate to back or thighs;
• Varies from a dull dragging to a severe cramping pain;
• Maximum pain at beginning of the period;
• May commence up to 12 hours before the menses appear;
• Usually lasts 24 hours but may persist for 2 – 3 days;
• May be associated with nausea and vomiting, headache, syncope or flushing;
• No abnormal findings on examination;
• Pain also associated with psychological distress – anxiety, depression or both.

Clinical examination of dysmenorrhoea

Physical examination will include a pelvic examination (an abdominal and internal examination) in order to determine the underlying cause. This will allow differentiation between primary dysmenorrhoea and other causes of pain associated with a medical condition.
It may not entirely differentiate primary from secondary dysmenorrhoea.

How is dysmenorrhoea diagnosed?

There are no specific tests to diagnose primary dysmenorrhoea. Specific investigations are ordered based on history, examination findings and severity of pain or other associated symptoms.
Investigations are only important if a secondary cause is suspected or in refractory cases of primary dysmenorrhoea. For patients with secondary, investigations should be directed to the most likely cause.
Common causes of secondary dysmennorrhoea include endometriosis, uterine fibroids, pelvic adhesions, pelvic inflammatory disease, ovarian cysts, gastrointestinal disturbances and very rare causes such as malignant tumors of the uterus, ovary, bowel or bladder. Investigations should be directed to the most likely after history and examination.
Specific investigations that may be recommended include:

• Trans-vagina pelvic ultrasound – detect ovarian cysts, uterine fibroids.
• Endo-cervical swabs (similar to a PAP smear test) to exclude sexually transmitted infections.
• Blood tests looking for markers of infection and to check haemoglobin levels to exclude anaemia which may be associated with heavy bleeding.
• Other investigations such as laparoscopy and assessment of the uterine cavity by dilation and curettage under anaesthesia in theatre. These may be necessary to determine underlying pathology if severe symptoms, but they are rarely done.
• In the absence of any pathological findings following these special investigations, referral to urological, gastroenterological or surgical specialists is indicated.

Prognosis of dysmenorrhoea

Successful treatment with NSAIDs is reported in 60-100% of cases.

How is dysmenorrhoea treated?

Non-medical therapies that have been recommended to relieve pain include:

• Regular exercise;
• Avoid smoking and excessive alcohol;
• Recommend relaxation techniques such as yoga;
• Avoid exposure to extreme cold;
• Place a hot water bottle over the painful area and curl the knees onto the chest.

The management with medical and surgical interventions depends on the severity of pain and impact on daily activities.

Medical

Pharmacotherapy is still the most reliable and effective treatment for relieving symptoms.
Medical options include:

• Simple analgesics (e.g. aspirin or paracetamol);
• Prostaglandin inhibitors (e.g. mefic) or anti-inflammatory drugs(e.g. celebrex, brufen, ) at first suggestion of pain (if simple analgesics ineffective);
• Combined oral contraceptive pills (COCP);
• Vitamin B1 (thiamine) 100 mg daily.

Anti-inflammatory drugs and COCP are the most commonly used therapeutic modalities for the management of primary dysmenorrhoea. These agents have different mechanisms of action and can be used adjunctively in refractory cases.
Anti-inflammatory drugs produce varying degree of symptomatic relief and successful treatment has been reported in 60-100% of cases. They should be started as soon as menstruation begins or just before if patient can predict onset. The newer class of anti-inflammatory drugs such as celebrex which target specific receptors have lesser side-effects but efficacy is still the same. Common side effects with anti-inflammatory drugs include: gastro-intestinal upset, dizziness and headaches.
Combined oral contraceptives are useful for pain and for the added advantage of contraception. They work by suppressing the proliferation of the endometrium and indirectly diminish prostaglandin synthesis.
Other proposed therapies include: progestogens, spasmolytics, TENS, acupuncture, transdermal nitroglycerin, minerals and vitamin supplements, herbal remedies. These therapies have not been well studied.
A Cochrane Review found that the most beneficial medication was the NSAIDS, and also vitamin B1 and magnesium proved effective. There was no evidence so far that the vitamin B6, vitamin E or herbal remedies were effective. Spinal manipulation was unlikely to be beneficial.
The lack of response to NSAIDs and COCP (or the combination) may suggest the likelihood of a secondary cause for dysmenorrhea which may require further investigation.

Surgical treatment

The role of surgical treatment in managing dysmenorrhoea is limited due to the associated complications and the recurrence of symptoms. This may be indicated in severe secondary dysmenorrhoea or primary dysmenorrhoea which is refractory to medical treatment.

References

1. Impey L. Obstetrics and Gynecology. 2nd ed. USA: Blackwell; 2006.
2. Murtagh, John General practice online [electronic resource]: Lower abdominal and pelvic pain in women. 4th ed. N.S.W: McGraw Hill, 2007.
3. Twigg J. Dysmenorrhoea. Current Obstetrics & Gynaecology; 2002 (12): 341-5 Elsevier Science Ltd Available from: http://www.sciencedirect.com/science/journal/09575847
4. Talley NJ, O’Connor S. Clinical Examination: A systematic guide to physical diagnosis. 5th ed. Australia: Elseiver; 2006.
5. MIMS Australia: Non-steroidal anti-inflammatory agents. MIMS, 2006 (4): 147-157