Prevalence of HLA-B27 in patients with back pain attending a pain clinic.

101 patients presenting to a pain clinic with low back pain were tested for HLA-B27 status. Eight (7.9%) of the patients were positive for HLA-B27. This prevalence is similar to that recorded in the general population and suggests that few patients referred to our clinic with back pain have undiagnosed spondyloarthropathies.

The role of peripheral sudomotor blockade in the treatment of patients with sympathetically maintained pain.

The aim of the present study was to investigate the role of the peripheral cholinergic system in patients with sympathetically maintained pain (SMP). Thirty-three patients with SMP were given Bier's block with 0.6 mg of atropine in 10 ml of saline or 10 ml of saline in a randomised double-blind manner. Pain intensity, pain relief and mood were assessed before and after each block using the visual analogue scale (VAS). In addition pain intensity was assessed at the same time using a categorical scale (CS). There was at least 1 week between each injection, and during this week the patients reported their pain intensity daily, using the CS. Three patients failed to complete both wings of the study and thus the results of the remaining 30 patients were analysed using the Mann-Whitney U test and the Wilcoxon signed-rank test. No significant difference was found between atropine and saline on any parameter.

Cerebrospinal fluid kinetics of epidural clonidine in man.

Ten patients with deafferentation pain after spinal cord injury were given 150 micrograms clonidine epidurally. CSF and plasma samples were collected over the following 24 h, and drug concentrations were measured by radio-immunoassay. The results of only 6 patients are included in the pharmacokinetic analysis because the catheters were not in the epidural space in the remaining 4 patients. These analyses revealed a mean maximum CSF concentration of 228 ng/ml whereas the mean plasma concentration at all time points was less than 0.7 ng/ml. The elimination half-life of epidural clonidine was 66 +/- 2 min, while the absorption half-life was 31 +/- 7 min, Tmax was 60 +/- 7 min and Cmax was 228 +/- 56 ng/ml. The ratio of the area under the curve (AUC) for CSF and plasma was 52. One patient's catheter was intrathecal and 3 were not in the epidural space. The measured plasma concentrations were similar after all injections. As 4 of 6 patients with epidural catheters obtained pain relief and all 3 patients with spasms obtained relief from epidural clonidine, these data suggest that clonidine has a place in the treatment of patients with spinal cord injury.

Benzydamine cream for the treatment of post-herpetic neuralgia: minimum duration of treatment periods in a cross-over trial.

In a double-blind multiple-dose cross-over study benzydamine 3% cream was compared with placebo for the treatment of post-herpetic neuralgia. Pain relief, pain intensity, sleep, escape analgesic consumption and side effects were assessed by diary methods for the 2 week treatment periods, with 1 week run-in and 1 week wash-out. There were no significant differences between the 2 treatments. The implications of the results for other antiprostaglandin remedies recommended for treatment of post-herpetic neuralgia are discussed. An important observation with methodological significance for similar studies of chronic conditions was that short treatment periods may produce false positive results. Patients' expectations are high, and if the first study treatment is ineffective, initial significant benefit may be noted when crossing over to the next treatment; this may not last longer than 1 week. Cross-over studies in which neither treatment is effective may, therefore, produce erroneous results if treatment periods are shorter than 2 weeks.

Intravenous regional sympathetic blockade for pain relief in reflex sympathetic dystrophy: a systematic review and a randomized, double-blind crossover study.

The first aim was a systematic review of intravenous regional sympathetic blocks (IRSBs) in patients with reflex sympathetic dystrophy (RSD). Randomized controlled trials (RCTs) of IRSBs in patients with RSD were identified by MEDLINE search (1966 to May 1993) and by hand search of 30 journals (1950 to May 1993). Authors of eligible trials were asked for information on additional trials and for unpublished data. Seven RCTs of IRSBs in RSD were found. Four used guanethidine; none showed significant analgesic effect in IRSBs to relieve pain due to RSD. Two reports, one using ketanserin and one bretylium, with 17 patients in total, showed some advantage of IRSBs over control. RCT results were not combined because of the variety of different drugs and outcome measures and because of methodological deficiencies in most of the reports. The second aim was a randomized, double-blind, crossover study to assess the effectiveness of IRSBs with guanethidine. Patients fulfilling diagnostic criteria for RSD and who had reported pain relief after an open IRSB with guanethidine received IRSBs with guanethidine high dose, guanethidine low dose, and normal saline. Pain intensity and relief, adverse effects, mood, duration of analgesia, and global scores were recorded. Sixteen patients with diagnosis of RSD were recruited, but only nine entered the double-blind phase. The trial was stopped prematurely because of the severity of the adverse effects. No significant difference was found between guanethidine and placebo on any of the outcome measures.(ABSTRACT TRUNCATED AT 250 WORDS)

Unusual complications of the treatment of chronic spinal arachnoiditis.

The causes, diagnostic features, and therapy of chronic spinal arachnoiditis are reviewed. Two unexpected results from attempted epidural injections (one of lignocaine and clonidine, and one of lignocaine, clonidine, and morphine) in patients with this condition are described. The anatomical abnormalities of the epidural and subarachnoid spaces in such patients and the consequent unpredictable and potentially dangerous results that may follow drug injection into these spaces are discussed.

Reflectance pulse oximetry measurements from the retinal fundus.

Conventional transmission pulse oximetry is a noninvasive technique for the continuous monitoring of arterial oxygen saturation (SaO2) from peripheral vascular beds such as the finger tip or earlobe. In this paper we propose to exploit the unique transparency of the ocular media to make reflectance pulse oximetry measurements on the retinal fundus. This technique potentially offers significant advantages over conventional pulse oximetry, primarily the ability to monitor cerebral, as opposed to peripheral, oxygen saturation. We have developed an in vitro system to stimulate the retinal circulation and ocular optics. This system consists of a flexible cuvette located in a model eye and an extracorporeal blood circuit to stimulate arterial blood flow. The system was used to investigate the relationship between SaO2 and the R/IR ratio in reflectance pulse oximetry. To enable in vivo measurements to be made, we also modified a standard haptic contact lens to hold the pulse oximeter probe in front of the pupil. In a preliminary study, the lens was fitted to an awake volunteer and cardiac-synchronous signals were detected by the retinal pulse oximeter.

The pain clinic.

The pain clinic is any group of medical and/or health professionals who are treating pain symptomatically. These clinics may be "open", where any doctor may refer patients, or "closed", where only specialists may refer patients. The patients are referred because of intractable pain, defined as pain of at least one month's duration, which has not been relieved by conventional techniques. Collaboration between the various specialists involved with the patients and between the other specialist clinics is of paramount importance.

Autonomic variations after stellate ganglion block: are they evidence of an autonomic afference?

Sympathetic skin response and plethysomography were used to assess the sympatholytic effect of the stellate ganglion block with morphine and bupivacaine in patients affected by a sympathetic algodystrophy of the upper limb. Morphine did not show any analgesic or sympatholytic effect. The distribution of the sympatholytic effect and the clinical findings of pain relief without somatic sensory-motor impairments obtained with the local anaesthetic, support the presence of a blockade of the sympathetic efferent pathway as well as of an afferent contingent of fibres probably and mainly involved in sympathetic reflexes.

Association between paroxysmal trigeminal neuralgia and atypical facial pain.

Paroxysmal trigeminal neuralgia and atypical facial pain are both fairly common conditions that produce pain in the face of different character. Trigeminal neuralgia is sharp and shooting, brought on by facial movement, change of temperature and by touching the face at a specific point (the trigger point). Atypical facial pain is dull and unrelenting and its site is ill-defined. Trigeminal neuralgia is generally more common in older people, and affects women slightly more than men, and atypical facial pain generally affects younger people, with women predominating. The pains should never be confused. We have noticed that many patients with trigeminal neuralgia have additional symptoms of atypical facial pain and so we reviewed the records of the Pain Relief Unit retrospectively. Of the 83 patients identified with trigeminal neuralgia where records were adequate, 35 (42%) also had atypical facial pain. Five of these had developed it before the onset of trigeminal neuralgia and could be examples of pretrigeminal neuralgia. There were eight patients in the series with multiple sclerosis, of whom two also had atypical facial pain. There seemed to be no relationship between the development of atypical facial pain and the interventions used to treat trigeminal neuralgia. It is important that both conditions are identified and treated individually.

MRI and clinical study of an easy and safe technique of suprascapular nerve blockade.

Suprascapular nerve block is used with increasing frequency by anaesthetists and rheumatologists in the management of shoulder pain from a variety of disorders. In the classical technique, the needle is introduced into the supraspinous fossa perpendicular to the blade of the scapula and then is moved to enter the scapular notch, with the risk of pneumothorax or damage to the suprascapular nerve or vessels. However, it is not necessary to locate the scapular notch in order to perform this block. Introducing the needle parallel to the blade, i.e. away from the direction of the lung and the suprascapular nerve and vessels, and injecting the solution into the floor of the supraspinous fossa is an easy and safe technique. We report the results of a MRI and clinical study that confirm the efficacy of this approach.

Endometriosis and pelvic pain.

The majority of patients with pain associated with endometriosis will obtain benefit from the many and varied therapies available for the treatment of endometriosis. The minority who fail to obtain relief from the conventional therapies may obtain benefit from referral to a pain clinic.

Sick sinus syndrome manifest after spinal anaesthesia.

A case of sick sinus syndrome which presented as a cardiac arrest following spinal anaesthesia is reported. The diagnosis of sick sinus syndrome, the cardiovascular effects of spinal anaesthesia and the anaesthetic management of patients with the syndrome are discussed.

Intercostal neuralgia following stellate ganglion block. An infrequent complication.

The case is described of a 78-year-old female patient who experienced temporary but severe chest wall pain following stellate ganglion block. The possible mechanisms and treatment of this complication are discussed.

The minimum effective analgetic blood concentration of pethidine in patients with intractable pain.

1 Pethidine infusions were performed in 16 patients with intractable pain in order to define a minimum effective analgetic blood concentration (MEAC) range. 2 Pethidine blood concentrations at the return of pain following a period of analgesia were considered to provide a more useful estimation of the MEAC than that at the onset of analgesia. 3. The MEAC range found in 15 of the 16 patients was 0.10 mg/l to 0.82 mg/l (median 0.25 mg/l). The intravenous dose of pethidine used in this study did not provide analgesia in one patient. 4 If the MEAC was greater than 0.40 mg/l in any patient, then additional techniques were required to provide adequate long term analgesia, e.g. destructive neurolytic techniques or antidepressant therapy. 5 The pharmacokinetic properties of pethidine found in the majority of these patients were in the range considered to be normal. 6 The clinical pharmacokinetic properties of pethidine found in the majority of these patients were in the range considered to be normal. 6 The clinical pharmacokineticist has in important role to play in the investigation, diagnosis and treatment of patients with intractable pain by detecting those patients with atypical pharmacokinetic and/or pharmacodynamic characteristics towards analgesic drugs.

Anaesthesia and palliative care.

Palliative medicine provides end-of-life care to terminally ill patients with a focus on pain and symptom management, psychosocial and spiritual support and bereavement follow-up. This article reviews some of the more recent literature on the subject of palliative care focusing on educational barriers to quality palliative care, advances in quality assessment, and advances in pain and symptom management.

Regional anaesthesia for repeat Caesarean section in a patient with phantom limb pain.

The triggering of phantom limb pain by subarachnoid or epidural anaesthesia has been well described leading to the suggestion that neuraxial regional anaesthesia is relatively contraindicated in lower limb amputees. We report our experience of the provision of anaesthesia for repeat Caesarean section on two occasions in such a patient. Intrathecal fentanyl and morphine supplementation of bupivacaine successfully abolished peri-operative phantom limb pain, whereas epidural anaesthesia was associated with recurrence of phantom limb pain upon regression of the block.

Dose-response for analgesic effect of amitriptyline in chronic pain.

A randomised, double-blind, multiple dose, crossover study with three 3-week treatment periods was set up to compare the analgesic efficacy and adverse effects of amitriptyline in oral doses of 25, 50 or 75 mg. Patients used diaries to assess their pain, and clinic assessments were made at the end of each treatment period. It was found that in 29 patients with chronic (more than 2 months) pain, amitriptyline 75 mg provided significantly greater efficacy than amitriptyline 25 or 50 mg. There was no significant difference in mood scores between the different doses of amitriptyline, but sleep was judged significantly better with 75 mg compared with 25 mg. The incidence of adverse effects was significantly higher with the 75 mg dose, and the principal adverse effects were dry mouth and drowsiness. In the context of chronic pain, the analgesic effect of amitriptyline was shown to have a dose-response unrelated to mood elevation, but there was a dose-response for the incidence of adverse effects.