Neuropathic States

Chronic pelvic pain may have a strong neuropathic element, as mentioned before in this manuscript. Pain outflow from different pelvic viscera and somatic areas converge into the dorsal horn, spinal cord and brain centres. Prolonged stimulation of pain receptors in these organs can lead to peripheral nerve sensitisation and upregulation of dorsal horn receptors, resulting in primary and secondary hyperalgesia respectively. Accordingly, efferent nerve impulses from the central nervous system can cause pain in different organs, not affected by the initial injury or disease. Such phenomenon can also follow actual nerve injury, inflammation, ischaemia or dysfunction resulting in wrong messages being sent to higher pain centres. The end result will be a lower pain threshold and pain out of proportion to nociceptive and non-nociceptive stimuli. Practical examples of visceral hyperalgesia include irritable bowel syndrome and interstitial cystitis. The presence of both problems in the same individual may represent viscero-visceral conversion. As well, viscerosomatic hyperalgesia may occur in cases of interstitial cystitis or dysmenorrhoea leading to pelvic muscles trigger points and levator ani syndrome.

Management of chronic pelvic pain will not be successful without proper attention to neuropathic pain. It can be the most important factor causing treatment failure, despite proper surgical interventions to deal with the primary pathology.

Management of neuropathic pain

Both medical and surgical means are used to deal with neuropathic pain but psychological support is equally important to improve the chances of success.

Medical methods

Neuropathic pain is usually not responsive to standard or over the counter simple analgesics. Certain drugs are now available for that purpose, but may not be equally effective in different cases. Furthermore, they may need several weeks before having a real impact on the patient’s symptoms. This information should be conveyed to all patients with this type of pain to help them readjust their expectations to this fact, and not to get disheartened in few days because of ‘failure of medication’.

Tricyclic antidepressants (amitriptyline) in small incremental doses [10 - 30 mg] every night are known to reduce the intensity of neuropathic pain. However, there is usual resentment by some patients to take antidepressants as it carries certain stigma, in their views. Gentle persuasion and explanation goes a long way in convincing the majority of patients.

Gapapentin [neurotin] which is GABA analogue, and other anti convulsant drugs can be useful especially for patients with burning pain sensation. It is usually used as part of a polypharmacy including NSAID and amitriptyline. Accordingly, a smaller starting dose [100 mg] should be used before being increased slowly depending on the patients’ response. The dose can be reduced down to the lowest possible, once pain has been controlled. Patients should be monitored for side effects as it can cause dizziness, ataxia, confusion and vertigo.

Serotonin and norepinephrine reuptake inhibitors have also proved useful in the treatment of neuropathic pain, but are not first line management drugs.

Repeated weekly injections of trigger points with local anaesthetics to desensitise the nerve receptors are useful for anterior abdominal wall and pelvic muscles tender points. This can lead to initial worsening of the pain before significant improvement is felt. Targeting the pudendal nerve near the ischeal spine has been mentioned before for the management of the levator ani syndrome.

Biofeedback to reduce muscles spasm and tenderness and to reduce nerve outflow should be done under the supervision of a trained physiotherapist.

Surgical methods

Surgical nerve ablation has been used for a long time in the treatment of chronic pain in general. The three techniques used in the management of chronic pelvic pain are laparoscopic uterosacral nerve ablation [LUNA] and excision [LUNE], and laparoscopic presacral neurectomy [LPSN]. All these techniques have been described in detail before in this chapter.

Caution

Despite all the good intentions and great efforts made by the medical profession, many patients still suffer from chronic pelvic pain without having the chance to get specialists care. Furthermore, many conditions are regularly missed in busy gynaecology, urology and gastroenterology clinics, because of the nature of the problem itself. Chronic pelvic pain is a disease and not a symptom. Many causes may be involved in the same patient to different degrees. Furthermore, gynaecological problems may cause urological or intestinal symptoms, and with the later two may cause muscular pelvic pain through viscerosomatic conversion. Examples of the commonly under diagnosed problems are:

• Interstitial cystitis
• Levator ani syndrome
• Vulvodynia and vestibulitis
• Pelvic congestion syndrome
• Myofascial anterior abdominal wall problems

This can only emphasise the need for a dedicated management team with structured proactive protocols and follow up procedures with regular auditing of management outcome. Hopefully, with better resources and understanding, such teams will be the norm rather than an exception in most hospitals with full communication with primary care providers.