High prevalence of confirmed, but also of potential and believed, neuropathic pain in pain clinics.

BACKGROUND AND AIMS: Epidemiological data about neuropathic pain are still scarce. A national survey, based on neurologic clinical diagnosis, was performed to determine its prevalence among patients attending pain clinics. METHODS: An epidemiological cross-sectional study involving pain clinics across all regions in Spain was carried out. Pain specialists evaluated the medical files and the clinical condition of patients attending their practices systematically during 1 day. They used the revised definition and grading system proposed in 2008 to decide whether a given patient had definite (i.e., confirmed), probable (potential) or possible (believed) neuropathic pain. Also, they provided a diagnostic label for neuropathic pain conditions and appraised treatment adequacy. RESULTS: In a single day, 178 pain specialists provided data from 2173 patients. Definite, probable and possible neuropathic pain was cited in 639 (29.4%), 304 (14.0%) and 97 (4.5%) patients, respectively. Almost two-thirds of these were women. A diagnostic label of primary pure central and/or peripheral neuropathic pain was cited in 344 (15.8%) patients. The most common diagnostic label (568 patients) was low back pain or sciatica causing mixed neuropathic pain. Definite neuropathic pain diagnosis was less likely in patients with mixed pain conditions and in women derived from primary care. Co-morbid depressive or anxiety symptoms were usual. CONCLUSIONS: Definite (confirmed) neuropathic pain alone was as prevalent as neuropathic pain ascertained with screening questionnaires in prior recent European studies. The clinical relevance of the surplus of patients with potential and believed neuropathic pain ascertained by clinicians is uncertain.

Effect of a simple dose-escalation schedule on tramadol tolerability : assessment in the clinical setting.

OBJECTIVE: To assess the effect of a very simple dose-escalation schedule on tramadol tolerability in clinical practice. This schedule consists of starting treatment with sustained-release tramadol 50mg twice daily, and escalating the dose around 7 days later to 100mg twice daily. METHODS: Data from 1925 outpatients with non-malignant chronic pain were collected in this multicentre, prospective, comparative, non-randomised, open, observational study. RESULTS: A total of 1071 patients (55.6%) were included in the dose-escalation group (50mg group) and 854 patients (44.4%) in the control group (sustained-release tramadol 100mg twice daily; 100mg group). The proportion of patients who interrupted tramadol treatment due to the occurrence of adverse reactions was significantly lower in the 50mg group (5.6%) than in the 100mg group (12.6%) [p = 0.001]. In line with this, the proportion of patients who experienced at least one adverse reaction was significantly lower in the 50mg group (18.4%) than in the 100mg group (30.4%) [p = 0.001] and, interestingly, the two most frequently reported adverse reactions, nausea and dizziness, were found with a significantly lower frequency in the 50mg group (p < 0.001). Multivariate analysis showed that the risk of safety-related treatment cessations was 2.3 times higher in the 100mg group than in the 50mg group, and 2.2 times higher in females than in males. The two treatments were equally effective in reducing pain intensity (p = 0.121), measured as a reduction in pain score obtained by means of a visual analogue scale. CONCLUSION: The instauration of tramadol treatment, starting with sustained-release 50mg capsules twice daily and escalating the dose some days later to 100mg twice daily, was shown to be an effective and easy way to improve tramadol tolerability in clinical practice, whilst maintaining its analgesic efficacy.

Efficacy and tolerance of oral dipyrone versus oral morphine for cancer pain.

In a double-blind, randomised and parallel clinical trial, two oral doses of dipyrone (1 and 2 g) administered every 8 h were compared with 10 mg of oral morphine given every 4 h for the relief of chronic cancer pain. A total of 121 patients with cancer pain without gastric involvement participated in a 7-day treatment course and were allocated to receive either dipyrone 1 g (n = 41), dipyrone 2 g (n = 38) or morphine (n = 42). Drug efficacy was analysed according to the degree of pain relief using a 100-mm visual analogue scale, and the number of patients who decided to increase the dose of the analgesic drug on day 4. The analgesic effect of dipyrone, 2 g every 8 h, was similar to that of morphine. The efficacy of both schedules was significantly greater than that of dipyrone, 1 g every 8 h. Dipyrone at either 1 or 2 g doses tended to be better tolerated than morphine, although the differences were not statistically significant.

Electrophysiologic effects of unilateral right and left stellate ganglion block on the human heart.

To determine the electrophysiologic effects of stellate ganglion (SG) block on the human heart, the two SGs were anesthetized separately, with a 24-hour interval between the two procedures, in 13 patients with episodes of supraventricular tachycardia (six had Kent bundles). Left SG block caused: (1) a lengthening of the AH interval, measured at fixed atrial rates of 10 +/- 12 msec (p less than 0.01); (2) a marked depression of the VA conduction in six of the seven patients with measurable VA interval (in two patients it produced complete VA block); (3) a slowing of 20 to 40 msec of the cycle of an electrically induced reciprocating tachycardia; and (4) failure to modify the QT interval duration. In contrast, right SG block produced asymmetric or opposite changes and prolonged the QT interval (7.6 +/- 8.8 msec, p less than 0.05). Atrial and ventricular refractoriness was not significantly altered by SG block. Retrograde effective refractory period of the Kent bundle changed 20 to 60 msec after unilateral SG blockade. Thus, this study suggests that the human conduction system and the Kent bundles receive an appreciable sympathetic influence from the SG. Like experimental studies, we also found an asymmetric response to unilateral SG block and a dominance, in most of our patients, of the left SG. The influence on myocardial refractoriness was less apparent.

A neurological complication following interscalene brachial plexus block.

A case is reported of the unfortunate development of permanent neurological damage to the motor outflow of at least two of C7, C8 and T1 motor nerve roots, following an attempted block of the brachial plexus using the interscalene approach.