Biomedical subjects

Flemming Winther Bach

Publications and source records attributed to Flemming Winther Bach.

6 recordsLinked to original sources

PubMed2006

[Pain and depression].

Pain and depression are often associated. The frequency of pain complaints in depressed patients is 13-100%. In general, depressed patients have a higher pain threshold than do controls, but lower and unchanged thresholds have also been observed. The frequency of depression in chronic pain patients is 1.5-100%. Pain etiology, short education, marital status, gender, psychiatric family history and unemployment are risk factors for depression. Possible mechanisms underlying the pathophysiology of depression and pain could be involvement of the monoamines (5-HT and NA) and the HPA axis.

Central Nervous System↗

PubMed2005

Sensory function and quality of life in patients with multiple sclerosis and pain.

Central neuropathic pain is well known in multiple sclerosis (MS), but the underlying mechanisms are unclear. In the present study we studied sensory function in MS patients with pain, MS patients without pain and healthy subjects in order to clarify the role of sensory abnormalities in pain. Fifty MS patients with pain were randomly recruited from a previous epidemiological MS study in Aarhus County, Denmark. Age and gender stratified MS patients without pain (N=50) and healthy subjects (N=50) served as controls. Patients with pain underwent a structured pain interview. Sensory function was examined by bedside and quantitative sensory testing. Quality of life was assessed using the health-related quality of life questionnaire, SF-36. Patients with pain had lower pressure pain threshold than pain-free patients (260 kPa vs. 322 (median), P=0.02) otherwise quantitative sensory testing was similar. Pain patients more frequently had cold allodynia (9/50 vs. 0/50, P=0.003) and abnormal temporal summation (10/48 vs. 3/49, P=0.03). Fifty-eight percent had central pain. Central pain patients did not differ from musculoskeletal pain patients in quantitative sensory testing, but allodynia was more common in MS patients with central pain. Pain patients scored lower in all dimensions of SF-36 compared with pain-free patients and healthy subjects. The results suggest that pain in MS is central in more than half of the patients and is associated with mechanical or thermal hyperalgesia.

Adult↗

PubMed2004

Reduced cold pressor pain tolerance in non-recovered whiplash patients: a 1-year prospective study.

UNLABELLED: Whiplash injury and chronic whiplash syndrome represent major health problems in certain western communities, pain being the main symptom. Sensitization of the nociceptive system may play a role for non-recovery after whiplash injury. AIMS: This study examined if tolerance to endure pain stimuli may predict outcome in whiplash injury. In a prospective fashion, 141 acute whiplash patients exposed to rear-end car collision (WAD grade 1-3) and 40 ankle-injured controls were followed and exposed to a cold pressor test, respectively, 1 week, 1, 3, 6 and 12 months after the injury. VAS score of pain and discomfort was obtained before, during and after immersion of the dominant hand into cold water for 2 min. The McGill Pain Questionnaire showed that ankle-injured controls had higher initial pain scores than the corresponding whiplash group, while whiplash-injured subjects had higher scores at 6 months; pain scores being similar at other time points. No difference was found in cold pressor pain between recovered whiplash patients and ankle-injured subjects. Non-recovery was only encountered in whiplash injury. Eleven non-recovered whiplash patients (defined as: handicap after 1 year) showed reduced time to peak pain from 1 week to 3 months (P<0.001), 6 months (P<0.01), but not 12 months after the injury. A larger pain area was seen in non-recovered vs. recovered whiplash-injured subjects during the entire observation period (P<0.001). Non-recovery after whiplash was associated with initially reduced cold pressor pain endurance and increased peak pain, suggesting that dysfunction of central pain modulating control systems plays a role in chronic pain after acute whiplash injury.

Accidents, Traffic↗

PubMed2004

Symptoms and signs in patients with suspected neuropathic pain.

The study sought to determine if symptoms and signs cluster differentially in groups of patients with increasing evidence of neuropathic pain (NP). We prospectively looked at symptoms and signs in 214 patients with suspected chronic NP of moderate to severe intensity. According to a set of clinical criteria the patients were a priori classified as having the so-called 'Definite NP' (n = 91), 'Possible NP' (n = 71), or 'Unlikely NP' (n = 52). A recording of symptoms including pain descriptors, intensity of five categories of pain, Short Form McGill Pain Questionnaire, and Major Depression Inventory were done. Sensory tests including repetitive pinprick stimulation, examination for cold-evoked pain by an acetone drop and brush-evoked pain were carried out in the maximal pain area and in a control area. High intensity of superficial ongoing pain, and touch or cold provoked pain was associated with chronic pain classified as definite or possible neuropathic. Intensity of deep ongoing pain, and 'paroxysms' was similar in the three groups. Brush-evoked pain was more frequent in definite NP. The McGill Pain Questionnaire and the used pain descriptors could not distinguish between the three clinical categories. Although certain symptoms (touch or cold provoked pain) and signs (brush-evoked allodynia) are more prominent in patients with definite or possible NP, we found considerable overlap with the clinical presentation of patients with unlikely NP.

Adult↗

PubMed2004

Differential effects of peripheral ketamine and lidocaine on skin flux and hyperalgesia induced by intradermal capsaicin in humans.

The capsaicin-induced flux in the primary and secondary hyperalgesic area after pretreating the capsaicin injection site with local ketamine, lidocaine or saline 10 min prior to injection was examined in this study. Twelve healthy volunteers participated in two randomized, double-blinded, placebo-controlled, cross-over experiments. In the first experiment, the skin on the volar forearm was pretreated with s.c. ketamine or saline, 10 min prior to capsaicin injection. Flux was recorded before and continuously after the injection of capsaicin in the primary and secondary hyperalgesic area. Spontaneous pain, evoked pain and areas of hyperalgesia were measured. In the second experiment, a similar capsaicin test was carried out 10 min after pretreating the skin with s.c. lidocaine or saline. Ketamine reduced flux significantly both in the primary and secondary hyperalgesic area. Lidocaine reduced flux significantly in the primary hyperalgesic area. No effect was observed on flux in the secondary hyperalgesic area. Only lidocaine reduced spontaneous pain, evoked pain and areas of hyperalgesia, whereas ketamine had no effect. Our results suggest that there is no simple and close relation between vascular and sensory reactions to pharmacological manipulation following intradermal capsaicin injection. We propose distinct mechanisms for local lidocaine and ketamine based on the differential effects of local lidocaine and ketamine on flux and pain.

Administration, Cutaneous↗

PubMed2003

Aftersensations in experimental and clinical hypersensitivity.

This study examined aftersensations after repetitive pinprick stimulation in nerve injury patients with allodynia and in capsaicin sensitized skin in control subjects. Forty-one patients and 12 male control subjects were stimulated repetitively with a computer-driven von Frey hair in sensitized skin and in contralateral normal skin at 0.2 and 2.0Hz. Pain during and after stimulation was scored on an electronic visual analogue scale and sampled on a computer. Maximum evoked pain, time to pain onset, duration of pain and duration of aftersensations were calculated from stored data. Aftersensations were significantly more frequent in sensitized skin than in contralateral normal skin in both control subjects and patients. Pain was evoked more frequently and maximum evoked pain score was significantly higher in sensitized skin compared to contralateral normal skin in both groups. Furthermore, evoked pain score was frequency dependent with a significantly higher pain score at 2.0 than at 0.2Hz. There was a significant positive correlation between maximum evoked pain scores and duration of aftersensations both in patients and control subjects. No difference was observed in maximum pain score, time to pain onset and duration of aftersensations between the groups. Findings suggest that aftersensations and evoked pain are mediated by a common mechanism, which most likely is central. The clinical manifestation of aftersensations can be mimicked in an experimental pain model so aftersensations may be another useful parameter in assessment of central sensitization.

Adult↗