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Biomedical subjects

Michael I Bennett

Publications and source records attributed to Michael I Bennett.

7 recordsLinked to original sources
PubMed2006

Can pain can be more or less neuropathic? Comparison of symptom assessment tools with ratings of certainty by clinicians.

Chronic pain is generally regarded as being divided into two mutually exclusive pain mechanisms: nociceptive and neuropathic. Recently, this dichotomous approach has been questioned and a model of chronic pain being 'more or less neuropathic' has been suggested. To test whether such a spectrum exists, we examined responses by patients with chronic pain to validated neuropathic pain assessment tools and compared these with ratings of certainty about the neuropathic origin of pain by their specialist pain physicians. We examined 200 patients (100 each with nociceptive and neuropathic pain) and administered the self-complete Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS score) and the Neuropathic Pain Scale (NPS). Clinicians were asked to rate their certainty of the presence of neuropathic pain mechanisms on a 100 mm visual analogue scale (VAS) (0='not at all neuropathic in origin' to 100='completely neuropathic in origin'). The whole sample was divided into tertiles based on ascending ratings of diagnostic certainty by clinicians using the VAS and labelled 'unlikely', 'possible' and 'definite' neuropathic pain. There were significant differences in median S-LANSS and NPS composite scores between all tertile groups. There were also significant differences between many S-LANSS and NPS item scores between groups. We have shown that higher scores on both the S-LANSS and the NPS are indicative of greater clinician certainty of neuropathic pain mechanisms being present. These data support the theoretical construct that pain can be more or less neuropathic and that pain of predominantly neuropathic origin may be a useful clinical concept.

Chronic Disease↗
PubMed2006

The epidemiology of chronic pain of predominantly neuropathic origin. Results from a general population survey.

UNLABELLED: Progress in the understanding of chronic pain with neuropathic features has been hindered by a lack of epidemiologic research in the general population. The Leeds Assessment of Neuropathic Symptoms and Signs score (S-LANSS) was recently validated for use in postal surveys, making the identification of pain of predominantly neuropathic origin possible. Six family practices in 3 UK cities (Aberdeen, Leeds, and London) generated a total random sample of 6,000 adults. The mailed questionnaire included demographic items, chronic pain identification, and intensity questions, the S-LANSS, the Level of Expressed Needs questionnaire, and the Neuropathic Pain Scale. With a corrected response rate of 52%, the prevalence of any chronic pain was 48% and the prevalence of pain of predominantly neuropathic origin was 8%. Respondents with this chronic neuropathic pain were significantly more likely to be female, slightly older, no longer married, living in council rented accommodation, unable to work, have no educational qualifications, and be smokers than all other respondents. Multiple logistic regression modeling found that pain of predominantly neuropathic origin was independently associated with older age, gender, employment (being unable to work), and lower educational attainment. Respondents with this pain type also reported significantly greater pain intensity, higher scores on the NPS, higher levels of expressed need, and longer duration of pain. This is the first estimate of the prevalence and distribution of pain of predominantly neuropathic origin in the general population, using a previously validated and reliable data collection instrument. PERSPECTIVE: Chronic pain with neuropathic features appears to be more common in the general population than previously suggested. This type of pain is more severe than other chronic pain but distributed similarly throughout sociodemographic groups.

Adolescent↗
PubMed2005

The S-LANSS score for identifying pain of predominantly neuropathic origin: validation for use in clinical and postal research.

This article describes the development and validation of the S-LANSS score, a self-report version of the Leeds Assessment of Neuropathic Symptoms and Signs pain scale. The S-LANSS aims to identify pain of predominantly neuropathic origin, as distinct from nociceptive pain, without the need for clinical examination. Two hundred patients with chronic pain were asked to complete the S-LANSS unaided. A researcher then administered the S-LANSS scale and the Neuropathic Pain Scale (NPS) in interview format. An independent clinician determined the pain type (neuropathic versus nociceptive) and rated his or her certainty about diagnosis. The S-LANSS scale was also incorporated into a chronic pain questionnaire that was sent to 160 community patients and 150 newly referred patients waiting for pain clinic assessment. The S-LANSS scale correctly identified 75% of pain types when self-completed and 80% when used in interview format. Sensitivity for self-completed S-LANSS scores ranged from 74% to 78%, depending on the cutoff score. There were significant associations between NPS items and total score with S-LANSS score. In the postal survey, completed questionnaires were returned by 57% of patients (n = 174). Internal consistency and convergent validity of the survey S-LANSS scores were confirmed. The findings support the S-LANSS scale as a valid and reliable self-report instrument for identifying neuropathic pain and it is also acceptable for use in postal survey research. Establishing valid measures of symptoms and signs in neuropathic pain will allow standardized comparisons with other investigational measures. This might lead to new insights into the relationship between pathophysiologic mechanisms and clinical manifestations of pain.

Chronic Disease↗
PubMed2005

Vitamin C deficiency in cancer patients.

PURPOSE: To assess the prevalence of vitamin C deficiency within a group of hospice patients. To assess the relationship between plasma vitamin C, dietary intake and subsequent survival. METHODS: Patients with advanced cancer were recruited from a large hospice. Data were collected on demographic details, physical functioning and smoking history. An estimate was obtained of the number of weekly dietary portions consumed equivalent to 40 mg of vitamin C, the recommended daily intake. Plasma vitamin C was measured by a single blood sample. The study had local ethical approval. RESULTS: Fifty patients were recruited (mean age 65.2 years, 28 female). Plasma vitamin C deficiency was found in 15 (30%). Dietary intake of vitamin C was correlated to plasma vitamin C (r=0.518, P<0.0001). Low dietary intake, low albumin, high platelet count, high CRP level and shorter survival were all significantly associated with low plasma vitamin C concentrations (<11 micromol/L). There was no correlation between plasma vitamin C, smoking history or physical functioning. CONCLUSION: Vitamin C deficiency is common in patients with advanced cancer and the most important factors determining plasma levels are dietary intake and markers of the inflammatory response. Patients with low plasma concentrations of vitamin C have a shorter survival.

Acute Disease↗
PubMed2004

Gabapentin in the treatment of neuropathic pain.

This paper reviews the pharmacology and clinical effectiveness of gabapentin in the treatment of neuropathic pain. Gabapentin has antihyperalgesic and antiallodynic properties but does not have significant actions as an anti-nociceptive agent. Its mechanisms of action appear to be a complex synergy between increased GABA synthesis, non-NMDA receptor antagonism and binding to the alpha2delta subunit of voltage dependent calcium channels. The latter action inhibits the release of excitatory neurotransmitters. Clinically, several large randomized controlled trials have demonstrated its effectiveness in the treatment of a variety of neuropathic pain syndromes. Patients with neuropathic pain can expect a mean reduction in pain score of 2.05 points on an 11 point numerical rating scale compared with a reduction of 0.94 points if they had taken the placebo. Around 30% of patients can expect to achieve more than 50% pain relief and a similar number will also experience minor adverse events; the most common of which are somnolence and dizziness. In patients with neuropathic pain due to cancer, higher response rates might be observed with gabapentin when administered with opioids because of a synergistic interaction.

Acetates↗