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Biomedical subjects

David Bowsher

Publications and source records attributed to David Bowsher.

13 recordsLinked to original sources
PubMed2003

Factors influencing the features of postherpetic neuralgia and outcome when treated with tricyclics.

This paper retrospectively reviews features of postherpetic neuralgia (PHN) in up to 279 personal patients in relation to treatment outcome when treated with tricyclic antidepressants (TCAs). Factors affecting characteristics of PHN: (i) Patients with allodynia (89%) and/or burning pain (56%) have a much higher visual analogue pain intensity score than those without; (ii) Acyclovir (ACV) given for acute shingles (HZ) does not reduce the incidence of subsequent PHN, but reduces the pain intensity in PHN patients with allodynia; (iii) ACV given for acute HZ reduces the incidence of burning pain in subsequent PHN, but not of allodynia; (iv) ACV given for acute HZ reduces the incidence of clinically detectable sensory deficit in subsequent PHN. Factors affecting outcome of TCA-treated PHN: (i) The point in time at which TCA treatment is commenced is by far the most critical factor: started between 3 and 12 months after acute HZ onset, more than two-thirds obtain pain relief (NNT=1.8); between 13 and 24 months, two-fifths (41%) (NNT=3.6); and more than two years, one-third (NNT=8.3). Background and paroxysmal pain disappear earlier and are more susceptible of relief than allodynia. (ii) Twice as many (86%) of PHN patients without allodynia obtain pain relief with TCA treatment than those with (42%); (iii) the use of ACV for acute HZ more than halves the time-to-relief of PHN patients by TCAs; (iv) PHN patients with burning pain are significantly less likely to obtain pain relief with TCAs than those without (p<0.0001).

Acyclovir↗
PubMed2002

Human "autotomy".

We describe two cases of self-injurious behaviour. One was a man with central post-stroke pain with maximal pain in the tip of the nose, who excavated his ala nasae--in which he subsequently continued to experience phantom pain. The second case a man who, following ophthalmic herpes zoster and possibly mild postherpetic neuralgia. He subsequently scratched his anaesthetic forehead down to the bone, while denying he experienced any pain. We would describe the first case as one of true autotomy; but the second as destruction of an anaesthetic part of the body. The implications for human and animal physiopathology are discussed.

Aged↗
PubMed2002

Poststroke shoulder pain: a prospective study of the association and risk factors in 152 patients from a consecutive cohort of 205 patients presenting with stroke.

BACKGROUND AND PURPOSE: Shoulder pain is known to retard rehabilitation after stroke. Its causes and prognosis are uncertain. This study describes the incidence of poststroke shoulder pain prospectively, in an unselected stroke population in the first 6 months after stroke and identifies risk factors for developing pain. METHODS: 297 patients with possible stroke were screened and stroke diagnosed in 205 cases. The 152 patients entered the study of which 123 patients were assessed up to 6 months. This cohort, with a mean age of 70.6 years, was examined at 2 weeks, 2, 4, and 6 months. A history of shoulder pain, Barthel score, anxiety and depression score were recorded. Full neurological and rheumatological examination was undertaken, using the contralateral side as a control. Pain outcome and stroke outcome was recorded at subsequent visits. RESULTS: 52 (40%) patients developed shoulder pain on the same side of their stroke. There was a strong association between pain and abnormal shoulder joint examination, ipsilateral sensory abnormalities and arm weakness. Shoulder pain had resolved or improved at 6 months in 41 (80%) of the patients with standard current treatment. CONCLUSIONS: Shoulder pain after stroke occurred in 40% of 123 patients surviving, consenting and not too unwell to participate. This included 52 patients of an original cohort of 205 patients presenting with stroke. Eighty percent of patients made a good recovery with standard treatment Patients with sensory and or motor deficits represent at risk sub-groups.

Adult↗
PubMed1992

A double-blind trial of naloxone in central post-stroke pain.

Intravenous naloxone has been claimed to produce pain relief in opioid-resistant central post-stroke pain (CPSP, 'thalamic syndrome'). In a double-blind trial, carried out in 20 patients with established CPSP, naloxone (up to 8 mg in 20 ml vehicle) was tested against normal saline; each patient was randomly given naloxone or saline and the other substance 2 or 3 weeks later. VAS and verbal pain scores were obtained immediately before and after naloxone or saline injection, and subjective ratings followed for 2 weeks. Three patients obtained transient pain relief with naloxone, 4 with saline, and another 4 with both. Statistical tests failed to show any influence of giving naloxone first or second. In all cases except one, pain relief had disappeared by the evening of the day on which the test was performed; one case, following naloxone, continued to experience pain relief until the following morning. We therefore conclude that intravenous naloxone is of no value in alleviating the pain of CPSP.

Adult↗
PubMed1991

Comparative effectiveness of different stimulation modes in relieving pain. Part I. A pilot study.

In this pilot study, to assess the optimal stimulation parameters, 3 different forms of transcutaneous electrical nerve stimulation were performed in 27 patients. Conventional continuous stimulation with a constant frequency of 70 Hz, burst stimulation (90 msec trains of pulses with an internal frequency of 100 Hz repeated at 2 Hz, each train consisting of 10 pulses), and frequency-modulated stimulation (continuous pulses changed from 90 Hz to 55 Hz over 90 msec) were randomly delivered to the patients for half an hour in 3 separate sessions. The patients were blind to the modes of stimulation. This pilot study demonstrated that patients preferred modulated stimulation modes such as frequency modulation and burst rather than conventional constant mode.

Adult↗
PubMed1991

Comparative effectiveness of different stimulation modes in relieving pain. Part II. A double-blind controlled long-term clinical trial.

Part I of our earlier pilot study demonstrated that patients preferred modulated stimulation forms - frequency modulation and burst - rather than conventional continuous mode. To assess whether long-term therapeutic effects validate the immediate test results, this trial was performed in 14 patients with 21 pain conditions. Considering the results of the pilot study, the test stimulator was modified and 4 different forms of transcutaneous electrical nerve stimulation were randomly delivered to each patient who was blind to the modes of stimulation for 20 min. A second observer assessed the pain scores using visual analogue scales. The stimulation modes employed were: (1) conventional continuous stimulation (continuous pulses with a constant frequency of 70 Hz), (2) burst stimulation (80 msec long trains of pulses, each train consisting of 8 pulses, with an internal frequency of 90 Hz repeated 1.3 times a second), (3) high-rate frequency modulation, HRFM (continuous pulses changed from 90 Hz to 55 Hz over 90 msec, 1.3 times a second), (4) low-rate frequency modulation, LRFM (continuous pulses changed from 60 Hz to 20 Hz over 90 msec, 1.3 times a second). After the test treatment of 4 sessions in the clinic, depending on the pain scores and duration of pain relief recorded, the most effective stimulation mode was determined for each patient and a portable stimulator preset appropriately for that mode was given to be used at home, under our supervision, for 3 months. Fourteen pain conditions out of 21 (66%) responded well to the therapy; the majority preferred was the HRFM and burst-type stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Clinical and instrumental evaluation of sensory function before and after percutaneous anterolateral cordotomy at cervical level in man.

Sensory perception thresholds were assessed by clinical testing and by quantitative instrumental testing before and after operation in 16 subjects for whom unilateral percutaneous cervical cordotomy was performed for the relief of pain due to malignant disease, and compared with clinical assessments of sensory function. We were able to confirm the association between deficit in pin-prick sensation and pain relief in the majority of instances, though the completeness or otherwise of pain relief does not correspond to absence of pin-prick sensation. There is no objective interference with low threshold mechanical sensation as measured instrumentally, although cordotomised subjects do not experience startle, tickle, or cutaneous erotic sensation when subjected to appropriate low intensity tactile sensation. Quantitative instrumental testing shows that the greatest deficits produced by cordotomy are in the sensations of skinfold pinch (? = tissue-damage pain) and skin cooling. The latter is transduced in the periphery by A delta fibres; sensations of warmth and hot pain, transduced by primary afferent C fibres, are much less significantly affected. Our findings thus fail to resolve the question as to whether chronic clinical pain is mainly an A delta- or a C fibre-mediated phenomenon.

Adult↗
PubMed1990

Sensory and autonomic measurements in idiopathic trigeminal neuralgia before and after radiofrequency thermocoagulation: differentiation from some other causes of facial pain.

(1) Quantitative measurements of somatosensory thresholds and skin temperature were made before (24 cases), 3-5 days after (12 cases), and 6 months after (11 cases) successful radiofrequency thermocoagulation of the proximal root and gasserian ganglion in 24 cases of idiopathic trigeminal neuralgia (TGN), 18 of whom had not previously undergone any interventional procedure; and in 3 cases of compressive non-TGN neural and 4 of non-neural facial pain at presentation. (2) There were no differences in somatosensory thresholds between the skin innervated by the affected divisions and the unaffected mirror-image areas in previously unoperated cases of TGN and non-neural facial pain ('atypical facial pain') prior to operative intervention; but there were significant differences in tactile (von Frey) thresholds in the cases of non-TGN facial pain of neural origin. (3) In TGN immediately after operation, thresholds for all modalities except cold sensation were significantly raised. Six months later, tactile and tragus pinch pain thresholds had returned to normal; but thresholds for warmth, hot pain, and pinprick remained elevated. However, in cases who had had previous procedures for TGN between 9 months and 5 years earlier, all thresholds except pinprick and possibly hot pain had returned to normal. (4) Prior to operation for TGN, the skin temperature in the affected division was significantly lower than that in the contralateral unaffected division, presumably due to vasoconstriction. In previously operated cases in whom TGN had re-appeared, cutaneous vasoconstriction was also demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Contralateral mirror-image pain following anterolateral cordotomy.

A hypothesis is put forward to explain the occurrence of mirror-image pain following pain relief by anterolateral cordotomy. This depends upon the fact that some nociceptive neurones in the deep spinal grey matter have bilaterally symmetrical receptive fields, one-half of which is normally subject to tonic descending inhibitory control. It is suggested that some cordotomy lesions may damage this descending inhibitory pathway. Experience following naloxone injection in our own cases further suggests that this inhibitory mechanism may normally involve enkephalinergic interneurones.

Aged↗