Musculoskeletal and Myofascial causes 

This is one of the mostly neglected causes of chronic pelvic pain in general practice and gynaecology clinics. Pain related to the anterior abdominal wall has been known since the third decade of the last century. The concept of trigger points became more important in recent years. Travell and Simons wrote an elaborate review in 1983. Trigger points are taught and tender muscle bands which are usually caused by local trauma, or persistent muscular spasm. This may result in increased metabolic activity, with release of certain metabolites that cause local fibrosis [Costello 1998], and shortening of the muscle with loss of function. Trigger points can be active causing continuous pain on movement, or inactive causing pain only on pressure. They may as well cause muscle twitching during needling or palpation. Sustained pressure on these points and massage can allow the muscle to stretch and regain its original length. Injection of the trigger points with local anaesthetics or phenol may lead to long lasting relief. In fact one study showed that local injection of 5% aqueous phenol resulted in complete or good pain relief in 56% of the patients for 3.5 years [Mehta and Ranger 1971]. All abdominal wall muscles can be involved especially the iliopsoas, rectus abdominus, external and internal obliques and pyramidalis

The same concepts are valid for the pelvic muscles which are important for the proper functioning and integrity of the pelvic viscera. Dysfunction or spasm of these muscles can lead to pelvic pain and other problems. The typical standing and sitting postures of these patients have been described before. Accordingly, a gynaecologist involved in the management of patients with chronic pelvic pain should have enough information to recognise these myofascial problems, and to refer patients as necessary to the corresponding specialist. Different body movements and posture can affect pain of musculoskeletal origin. It has also been described as variable affecting the patient differently at different times of the day, but does not wake the patient up at night.

Chronic levator ani syndrome is related to pelvic pain caused, or associated with overactive pelvic muscles and trigger points. An overactive pelvic muscle can cause continuous afferent impulses to the dorsal horn and higher centres leading to primary or secondary hyperalgesia respectively. This can be a protective mechanism following pelvic viscera or vulval inflammation or dysfunction. Treatment of such conditions may help with its management. Such spasm may lead to dyspareunia or pelvic pain which can be intensified by pressure on the affected muscle. Treatment plans are similar to those applied for anterior abdominal wall muscles, mainly inactivating the trigger points. Biofeedback by a trained physiotherapist is very useful to deal with this problem. One exercise to improve muscular function and coordination is to contract the pelvic muscles during expiration and relax them with inspiration. On the medical side, treatment with tricyclic antidepressants may have a good impact on nerve desensitisation. However, it usually takes long time to resolve as vulvodynia and the urethral syndrome may be involved. Occasionally, local anaesthetic injections of the pudendal nerve may be needed to give some relief. Such nerve block can be done where the nerve hooks around the ischeal spine.

Nerve inflammation and entrapment may follow trauma or previous surgery. This is especially so for the ilioinguinal and iliohypogastric nerves which are more vulnerable with lower abdominal incisions. In fact previous surgical procedures were considered as one of the commonest causes of abdominal wall pain [Stultz P, 1982]. The quality of pain can be variable, but as for any other neuropathic pain it is typically described as burning or shooting in nature. Such pain can be relieved by injection of local anaesthetics or phenol. Depending on the extent of nerve damage, partial loss of sensation [numbness] may be felt in the involved area.

Inguinal, femoral, spigelian, incisional and sciatic hernias are not commonly seen in the pelvic pain clinic. Nevertheless, all patients should be examined for such possibilities. A hernia can show as a swelling with a positive cough impulse, but occasionally it can be difficult to diagnose especially in obese patients. Accordingly, the absence of such a mass or impulse does not exclude the diagnosis. High frequency ultrasound scan examination of the anterior abdominal wall can show a fascial defect with the hernia sac protruding through. The exact appearance depends on the contents of the sac and the amount of air or fluid in case of bowel herniation. It may be useful to ask the patient to cough or strain during examination. This allows a better diagnosis of the enlarged hernial sac in doubtful cases. Such ultrasound examination should be performed in all patients with anterior abdominal wall mass or positive Carnett’s sign. The differential diagnosis of anterior abdominal masses should include desmoid tumours and endometriomas along pervious scars, lipomas, and spontaneous haematomas. Currently laparoscopic herniorrhaphy with mesh enforcement of the inguinal canal is becoming popular. This can reduce postoperative complications and allow early return to work when compared to the open technique. The recurrence rate is thought to be equal after laparoscopic and open repair. Furthermore, 30% of patients with a unilateral hernia may develop a hernia on the opposite side in the future.

Chronic coccygeal pain 

Patients suffering from chronic coccygeal pain usually have their symptoms accentuated when they sit on a firm or hard surface. The condition usually results from severe local trauma, or mild repetitive injuries to the coccyx. It is usually diagnosed by digital palpation of the coccyx during vaginal or rectal examinations. Usually the coccyx can be pushed backwards up to 30⁰, without any significant pain. However, with coccygeal injury or chronic coccygyeal pain, this will be intolerable and may cause severe pain.

Fibromyalgia 

Patients with fibromyalgia may present with chronic pelvic pain in the gynaecology clinic. They are prone to have other conditions including depression, irritable bowel syndrome, chronic fatigue syndrome and somatization [Lane et al, 1991]. Two conditions were set by the American College of Rheumatology before fibromyalgia could be diagnosed:

• Pain should be felt in all 4 quadrants of the body.
• More than 10 of the 18 possible sites should be tender during physical examination.