Andrew P. Baranowski

EAU Guidelines on Chronic Pelvic Pain

CONTEXT These guidelines were prepared on behalf of the European Association of Urology (EAU) to help urologists assess the evidence-based management of chronic pelvic pain (CPP) and to incorporate the recommendations into their clinical practice. OBJECTIVE To revise guidelines for the diagnosis, therapy, and follow-up of CPP patients. EVIDENCE ACQUISITION Guidelines were compiled by a working group and based on a systematic review of current literature using the PubMed database, with important papers reviewed for the 2003 EAU guidelines as a background. A panel of experts weighted the references. EVIDENCE SYNTHESIS The full text of the guidelines is available through the EAU Central Office and the EAU Web site (www.uroweb.org). This article is a short version of the full guidelines text and summarises the main conclusions from the guidelines on the management of CPP. CONCLUSIONS A guidelines text is presented including chapters on chronic prostate pain and bladder pain syndromes, urethral pain, scrotal pain, pelvic pain in gynaecologic practice, neurogenic dysfunctions, the role of the pelvic floor and pudendal nerve, psychological factors, general treatment of CPP, nerve blocks, and neuromodulation. These guidelines have been drawn up to provide support in the management of the large and difficult group of patients suffering from CPP.

A trial of intravenous lidocaine on the pain and allodynia of postherpetic neuralgia

This study investigated the effect of intravenous lidocaine at two doses (1 mg/kg and 5 mg/kg over 2 hours) and an intravenous saline placebo on the pain and allodynia of postherpetic neuralgia (PHN). Twenty-four patients were studied using a randomized, double-blind, within-patient crossover design. Each patient received normal saline, lidocaine 0.5 mg/kg/h, and lidocaine 2.5 mg/kg/h for a 2-h period. The McGill Pain Questionnaire Short Form, visual analogue scores (VAS), and area of allodynia were measured at intervals during the infusions. Free plasma lidocaine levels were also measured. The results were statistically analyzed using Students t-test for paired data. The VAS for ongoing pain showed a significant reduction after all the infusions (P < 0.05). For dynamic pressure-provoked pain, the VAS was unaffected by placebo but showed a reduction at an equal level of significance with both lidocaine infusions (P < 0.05). The area of allodynia of PHN, as mapped by brush stroke, declined in association with intravenous lidocaine (0.5 mg/kg/h = P < 0.05; 2.5 mg/kg/h = P < 0.001). Placebo had no significant effect on the area of allodynia. These findings demonstrate a positive effect on pain and allodynia following a brief intravenous infusion of lidocaine. The higher dose infusion may produce plasma levels in the toxic range, with no significant clinical increase in response.

A novel treatment of postherpetic neuralgia using peppermint oil.

BackgroundPostherpetic neuralgia remains a difficult problem to treat. A number of therapies have been shown to be effective, but some patients have intractable pain. PatientThe case of a 76-year-old woman whose pain had been resistant to standard therapies is described. The pattern of quantitative sensory testing results for this patient led the authors to believe that she had an “irritable nociceptor” type of pathophysiology. InterventionThe patient was instructed to apply neat peppermint oil (containing 10% menthol) to her skin, resulting in an almost immediate improvement in her pain. This pain relief persisted for 4–6 hours after application of the oil. ResultsThe patient was successfully treated with topical peppermint oil. During 2 months of follow-up she has had only a minor side effect, with continuing analgesia. The authors believe this is the first evidence of peppermint oil (or menthol) having a strong analgesic effect on neuropathic pain. The possible mechanisms of action of peppermint oil are discussed.

A New Classification is Needed for Pelvic Pain Syndromes—Are Existing Terminologies of Spurious Diagnostic Authority Bad for Patients?

1. Lau WK, Blute ML, Weaver AL, Torres VE and Zincke H: Matched comparison of radical nephrectomy vs nephronsparing surgery in patients with unilateral renal cell carcinoma and a normal contralateral kidney. Mayo Clinic Proc 2000; 75: 1236. 2. McKiernan J, Simmons R, Katz J and Russo P: Natural history of chronic renal insufficiency after partial and radical nephrectomy. Urology 2002; 59: 816. 3. Miller DC, Hollingsworth JM, Hafez KS, Daignault S and Hollenbeck BK: Partial nephrectomy for small renal masses: an emerging quality of care concern? J Urol 2006; 175: 853. 4. Nuttall M, Cathcart P, van der Meulen J, Gillatt D, McIntosh G and Emberton M: A description of radical nephrectomy practice and outcomes in England: 1995-2002. BJU Int 2005; 96: 58. 5. Huang WC, Levey AS, Serio AM, Snyder M, Vickers A, Raj GV et al: Chronic kidney disease after nephrectomy in patients with renal cortical tumours: a retrospective cohort study. Lancet Oncol 2006; 7: 735. 6. Go AS, Chertow GM, Fan D, McCulloch CE and Hsu CY: Chronic kidney disease and the risks of death, cardiovascular events, and hospitalization. N Engl J Med 2004; 351: 1296.

Chronic pelvic pain

Chronic pelvic pain affects both men and women; there are probably common mechanisms that involve the central nervous system. In many cases, the symptoms may be localised to a single end organ. However, the involvement of the central nervous system may result in a complex regional pain syndrome affecting the whole pelvis and as a consequence, multiple-organ symptomatology. The initial trigger may be relatively benign but a predisposed individual may develop a range of significant sensory and efferent functional abnormalities. Stimuli not normally reaching threshold may be perceived and normal sensations may be magnified to become dysphoric or painful. Problems of emptying viscera and maintaining continence may occur. Significant musculoskeletal disability may arise as well as abnormalities of the autonomic nervous system. There is an association with systemic disorders. Also, psychological, behavioural, sexual and social problems arise. In the chronic pelvic pain syndromes, treatment of the end organ has a limited role, and multidisciplinary as well as interdisciplinary management is essential.

Differential effects of neuropathic analgesics on wind-up-like pain and somatosensory function in healthy volunteers.

Objectives: To investigate the effects of gabapentin, carbamazepine, and amitriptyline on temporal summation, simple nociceptive pain, and innocuous touch sensation in healthy volunteers. Methods: A placebo controlled four-way crossover double-blind randomized protocol was followed. Seventeen healthy subjects, male and female, aged 18 to 24, took part. Punctate pain, temporal summation pain to repeat punctate stimulation, and vibration detection threshold were assessed in triplicate. Study drugs were given as bedtime and early morning doses with assessments carried out midmorning. Results: Gabapentin and carbamazepine significantly reduced the intensity of temporal summation pain (P < 0.001 and P < 0.01 respectively), whereas amitriptyline significantly increased temporal summation pain (P < 0.001). None of the drugs affected pain produced by a single punctate stimulus (P > 0.05). Carbamazepine increased vibration detection thresholds (P < 0.05), but neither gabapentin nor amitriptyline had any detectable effect on vibration. Discussion: We have shown that gabapentin, carbamazepine, and amitriptyline, three pharmacologically different drugs, have distinct and quantifiable effects on somatosensory pathways in healthy volunteers. These findings provide a link between pharmacology of the study drugs and clinical effectiveness. The effects of gabapentin and carbamazepine on temporal summation pain show that these drugs can block centrally amplified wind-up pain in the absence of a neuropathic disorder.

Characterization of secondary hyperalgesia produced by topical capsaicin jelly—a new experimental tool for pain research

Peripheral administration of the nociceptive agent capsaicin is used as an experimental tool to study neurophysiological and pharmacological aspects of the generation and control of pain. When investigating secondary hyperalgesia phenomena, current topical and intradermal capsaicin delivery methods have two key limitations. Intradermal injection can evoke severe chemogenic pain and both delivery methods produce an unstable area of dynamic mechanical allodynia. We present validity studies of a new preparation for capsaicin delivery that overcomes these limitations. The novel capsaicin formulation consists of a water‐based semisolid jelly preparation containing 1% capsaicin which is applied topically under adhesive‐free occlusion to a small area of the skin. We demonstrate that in healthy human subjects this model evokes areas of flare, punctate hyperalgesia and mechanical allodynia which are equivalent to established models and that these areas are stable over time and reproducible on repeat experiments. The jelly formulation evokes only minimal chemogenic pain and, as the preparation remains in situ throughout the study providing constant capsaicin exposure, a stable area of dynamic mechanical allodynia is produced. These validation studies show that this novel capsaicin administration method is a practical, reliable and viable tool for investigating experimental secondary hyperalgesia.

Sensory threshold changes without initial pain or alterations in cutaneous blood flow, in the area of secondary hyperalgesia caused by topical application of capsaicin in humans

Changes in von Frey hair perception, pricking pain, and vibration thresholds were examined in six healthy human adults, in the zone of secondary hyperalgesia, 45 min following the topical application of capsaicin at concentrations of 0.05 and 0.1 mg/ml. In two of these subjects, cutaneous blood flow was monitored at 10-min intervals, before, during and after capsaicin application, using laser Doppler perfusion imaging. Thresholds for all three parameters were significantly reduced after capsaicin treatment, in a dose-dependent manner. However, there was no visible skin flare, and no change in cutaneous blood flow at these doses of capsaicin. The effects on von Frey perception threshold and vibration threshold have not been demonstrated previously, and may be indicative of central changes, initiated by afferent fibres (presumably C fibres) that are not vasoactive.

The twelfth rib syndrome

The twelfth rib syndrome appears to be a fairly common and underdiagnosed chronic pain syndrome. It is more common in women than men (3:1) and is usually described as a constant dull ache or sharp stabbing pain that may last from several hours to many weeks. Lateral flexion, rotation of the trunk, and rising from a sitting position classically aggravate the pain. Manipulation of the affected rib and its costal cartilage reproduces it exactly. The diagnosis of this syndrome is clinical, requires exclusion of specific etiologies, and should only be made when the patients symptoms can be exactly reproduced by manipulation of the affected rib. If symptomatology is complicated, it may be necessary to use an image intensifier for accurate location of the pain locus. Patients with this syndrome can be overinvestigated and have even undergone surgical procedures when this diagnosis has been overlooked. To describe the varied presentation of this syndrome, we describe the clinical manifestations in six patients.

Defining the Urological Chronic Pelvic Pain Syndromes

From an international symposium by the National Institutes of Health, June 16–17, 2008, the mechanisms around urogenital pain (UGP) are now much more clearly understood, with a move away from considering the ‘end-organ’ as being responsible towards a central neuroplasticity theory and as a consequence both a multidisciplinary and interdisciplinary approach to management.