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Biomedical subjects

Michael J Cousins

Publications and source records attributed to Michael J Cousins.

At least 19 recordsLinked to original sources
PubMed2006

Complex regional pain syndrome in children and adolescents.

Complex regional pain syndrome (CRPS) is a disorder characterised by pain, sensory and motor disturbances and represents a significant medical entity. This report discusses two cases of CRPS in children and adolescents, highlighting several critical issues for clinicians in the diagnosis and management of CRPS in these populations. Early diagnosis, referral and appropriate intervention are essential in decreasing pain, suffering and resorting function for children and adolescents with CRPS.

Adolescent↗
PubMed2006

Chronic pain and reduced work effectiveness: the hidden cost to Australian employers.

Cost estimates of the impact of chronic pain on work have largely focussed on absenteeism, excluding the hidden contribution of reduced work effectiveness to lost productivity. This paper aims to estimate the cost of lost productivity due to chronic pain in Australia, not only in terms of absenteeism but also reduced work effectiveness. Data on chronic pain in Australia and its impact on work were obtained from the 1997 New South Wales Health Survey (n=17,543) and the Northern Sydney Area Pain Study (n=2,092), both of which were population-based and used random-digit dialing sampling methods. This was combined with relevant Australian population and labour force data obtained from the Australian Bureau of Statistics. From this we estimated annual lost productivity costs arising from both chronic pain-related days absent and 'reduced-effectiveness workdays'. There were estimated to be 9.9 million workdays absent due to chronic pain annually in Australia, equating to a cost of AUD 1.4 billion per annum. Under the assumption that reduced-effectiveness workdays affect productivity costs in the same way as lost work days, the total number of lost workday equivalents was 36.5 million, with the total annual cost of lost productivity due to chronic pain estimated as AUD 5.1 billion per annum. In conclusion, while the impact of reduced work effectiveness on days worked with pain on productivity is uncertain, it has the potential to account for the majority of lost productivity costs associated with chronic pain. Interventions which target working despite pain have the potential to significantly reduce lost productivity costs due to chronic pain.

Absenteeism↗
PubMed2006

Intrathecal catheter granuloma associated with isolated baclofen infusion.

Intrathecal (IT) baclofen is an effective management strategy for controlling spasticity in patients unresponsive to maximal oral therapy. We present the case of a 57-yr-old woman who was rendered quadriplegic after a complete spinal cord transection at the C6 level. Her course was complicated by severe spasms, which were uncontrolled despite titrating orally administered baclofen to 80 mg/d. IT baclofen testing was performed with good response, and administration was commenced via an implanted intrathecal pump 6 mo after the injury at an initial dose of 200 microg/d. Catheter revision was required 2 wk later as a result of catheter displacement. The initial IT baclofen dose was gradually increased to achieve good control at a level of 400 microg/d. After a period of stability lasting 38 mo, her lower limb spasms dramatically increased in severity and remained poorly controlled despite repeated dose increases. Contrast pumpogram and computed tomography myelogram were performed to exclude a mechanical cause for this apparent increase in baclofen requirement. These investigations revealed neither catheter displacement nor fracture as suspected but, rather, displayed the presence of a catheter tip-associated mass. Catheter tip granuloma has not previously been described in a patient receiving IT baclofen alone. This suggests that although uncommon, the possibility of catheter-associated granuloma must be considered in all patients receiving IT baclofen presenting with altered neurological function or significant increase in drug requirement.

Baclofen↗
PubMed2006

Magnetic resonance spectroscopy detects biochemical changes in the brain associated with chronic low back pain: a preliminary report.

Magnetic resonance (MR) spectroscopy is a noninvasive technique that can be used to detect and measure the concentration of metabolites and neurotransmitters in the brain and other organs. We used in vivo (1)H MR spectroscopy in subjects with low back pain compared with control subjects to detect alterations in biochemistry in three brain regions associated with pain processing. A pattern recognition approach was used to determine whether it was possible to discriminate accurately subjects with low back pain from control subjects based on MR spectroscopy. MR spectra were obtained from the prefrontal cortex, anterior cingulate cortex, and thalamus of 32 subjects with low back pain and 33 control subjects without pain. Spectra were analyzed and compared between groups using a pattern recognition method (Statistical Classification Strategy). Using this approach, it was possible to discriminate between subjects with low back pain and control subjects with accuracies of 100%, 99%, and 97% using spectra obtained from the anterior cingulate cortex, thalamus, and prefrontal cortex, respectively. These results demonstrate that MR spectroscopy, in combination with an appropriate pattern recognition approach, is able to detect brain biochemical changes associated with chronic pain with a high degree of accuracy.

Brain↗
PubMed2005

Self-management of chronic pain: a population-based study.

While effective self-management of chronic pain is important, clinic-based studies exclude the more typical pattern of self-management that occurs in the community, often without reference to health professionals. We examined specific hypotheses about the use of self-management strategies in a population-based study of chronic pain subjects. Data came from an Australian population-based random digit dialling computer-assisted telephone survey and included 474 adults aged 18 or over with chronic pain (response rate 73.4%). Passive strategies were more often reported than active ones: passive strategies such as taking medication (47%), resting (31.5%), and using hot/cold packs (23.4%) were most commonly reported, while the most commonly reported active strategy was exercising (25.8%). Only 33.5% of those who used active behavioural and/or cognitive strategies used them exclusively, while 67.7% of those who used passive behavioural and/or conventional medical strategies did so exclusively. Self-management strategies were associated with both pain-related disability and use of health services in multiple logistic regression models. Using passive strategies increased the likelihood of having high levels of pain-related disability (adjusted OR 2.59) and more pain-related health care visits (adjusted OR 2.9); using active strategies substantially reduced the likelihood of having high levels of pain-related disability (adjusted OR 0.2). In conclusion, we have shown in a population-based study that clinical findings regarding self-management strategies apply to the broader population and advocate that more attention be given to community-based strategies for improving awareness and uptake of active self-management strategies for chronic pain.

Activities of Daily Living↗
PubMed2004

Chronic pain and frequent use of health care.

Little is known about the relationship between chronic pain status and overall use of healthcare. We examined whether disabling chronic pain was associated with more frequent use of healthcare in three settings: primary care, emergency departments, and hospital admissions. We used data from Computer-Assisted Telephone Interviews (CATI) of 17,543 residents in New South Wales, Australia aged 16 and over who were randomly sampled using a population-based two-stage stratified sample and random digit dialing methods. The overall response rate was 70.8%. Compared to chronic pain respondents with no or limited pain-related disability, those with most pain-related disability reported more: primary care visits in the last 2 weeks and last 12 months (adjusted mean number of visits 0.59 vs 0.40 and 10.72 vs 4.81, both P < 0.005); hospital admissions (0.46 vs 0.18, P < 0.005); and emergency department visits (0.85 vs 0.17, P > 0.005). In modelling, having chronic pain per se, or having chronic pain with any level of activity interference predicted health care use after adjusting for age, gender, self-rated health, psychological distress, comorbidity and access to care. Higher levels of pain-related disability predicted health care use more than other pain status variables. There was a strong association between pain-related disability and greater use of services. Further work is needed to understand the nature of this association. Given the fluctuating course of chronic pain over time, there is a significant segment of the population that may be at risk of developing higher levels of disability associated with increased use of services.

Adolescent↗
PubMed2004

Intracranial hypotension caused by cervical cerebrospinal fluid leak: treatment with epidural blood patch.

UNLABELLED: This report describes treatment with cervical epidural blood patch of low cerebrospinal fluid (CSF) pressure headache resulting from spontaneous CSF leak via a tear in a cervical dural cuff. The leak was diagnosed by a dynamic computed tomography (CT)-myelography study followed by gadolinium enhanced magnetic resonance imaging(MRI)-scan. The epidural needle was inserted with the aid of image intensifier and CT-scan to guide the needle to the precise site of the CSF leak. Blood mixed with gadolinium was injected, and subsequent MRI scanning provided the first description of spread of blood after cervical epidural blood patch. IMPLICATIONS: Low cerebrospinal fluid (CSF) pressure may cause severe posturally-related headache. In the patient, a vertebral disc protrusion in the neck seems to have contributed to a CSF leak. An injection of blood into the epidural space at the precise site of the CSF leak was followed by complete and lasting resolution of the headache.

Blood Patch, Epidural↗
PubMed2004

Persistent pain as a disease entity: implications for clinical management.

Pain has often been regarded merely as a symptom that serves as a passive warning signal of an underlying disease process. Using this model, the goal of treatment has been to identify and address the pathology causing pain in the expectation that this would lead to its resolution. However, there is accumulating evidence to indicate that persistent pain cannot be regarded as a passive symptom. Continuing nociceptive inputs result in a multitude of consequences that impact on the individual, ranging from changes in receptor function to mood dysfunction, inappropriate cognitions, and social disruption. These changes that occur as a consequence of continuing nociceptive inputs argue for the consideration of persistent pain as a disease entity in its own right. As with any disease, the extent of these changes is largely determined by the internal and external environments in which they occur. Thus genetic, psychological and social factors may all contribute to the perception and expression of persistent pain. Optimal outcomes in the management of persistent pain may be achieved not simply by attempting to remove the cause of the pain, but by addressing both the consequences and contributors that together comprise the disease of persistent pain.

Chronic Disease↗
PubMed2003

Chronic pain-related disability and use of analgesia and health services in a Sydney community.

OBJECTIVES: To describe the clinical features, antecedents and impact of chronic pain. DESIGN: Telephone survey of randomly selected household respondents. SETTING: Northern Sydney Health Area, metropolitan Sydney, July to September 1998. PARTICIPANTS: 2092 English-speaking residents aged 18 years or over. MAIN OUTCOME MEASURES: Age- and sex-adjusted prevalence of chronic pain (pain experienced every day for 3 months in the previous 6 months), pain-related disability, and use of health services and analgesic medications. RESULTS: Chronic pain affected 474/2092 respondents (22.1%; 95% CI, 20.2%-24.0%), with high levels of pain-related disability in 129/439 (27%). Nominated causes of chronic pain were injury in 173 (38%), most commonly sports injury (54; 13%), and a health problem in 132 (29%). Pain was work-related in 62 (14%). A musculoskeletal condition was the leading diagnosis (127; 26%). Of the 474 with chronic pain, 374 (78%) had consulted at least one health practitioner for pain in the previous 6 months, comprising medical practitioners (consulted by 292 [60%] and including general practitioners [55%]), allied health professionals (245; 50%), and alternative practitioners (99; 21%). Current or recent use of oral analgesic medications (often over-the-counter preparations) was common (339; 70%). Higher levels of pain-related disability were associated with greater use of medications and health services. CONCLUSIONS: Our study shows that chronic pain is common and often results from injury. It highlights the importance of timely interventions to prevent progression from acute to chronic pain and the need for a coordinated approach to managing pain-related disability.

Adolescent↗
PubMed2003

Chronic pain, work performance and litigation.

The overall population impact of chronic pain on work performance has been underestimated as it has often been described in terms of work-related absence, excluding more subtle effects that chronic pain may have on the ability to work effectively. Additionally, most studies have focussed on occupational and/or patient cohorts and treatment seeking, rather than sampling from the general population. We undertook a population-based random digit dialling computer-assisted telephone survey with participants randomly selected within households in order to measure the impact of chronic pain on work performance. In addition, we measured the association between pain-related disability and litigation. The study took place in Northern Sydney Health Area, a geographically defined urban area of New South Wales, Australia, and included 484 adults aged 18 or over with chronic pain. The response rate was 73.4%. Working with pain was more common (on an average 83.8 days in 6 months) than lost work days due to pain (4.5 days) among chronic pain participants in full-time or part-time employment. When both lost work days and reduced-effectiveness work days were summed, an average of 16.4 lost work day equivalents occurred in a 6-month period, approximately three times the average number of lost work days. In multiple logistic regression modelling with pain-related disability as the dependent variable, past or present pain-related litigation had the strongest association (odds ratio (OR)=3.59, P=0.001). In conclusion, chronic pain had a larger impact on work performance than has previously been recognised, related to reduced performance while working with pain. A significant proportion were able to work effectively with pain, suggesting that complete relief of pain may not be an essential therapeutic target. Litigation (principally work-related) for chronic pain was strongly associated with higher levels of pain-related disability, even after taking into account other factors associated with poor functional outcomes.

Age Distribution↗
PubMed2003

A longitudinal study of the prevalence and characteristics of pain in the first 5 years following spinal cord injury.

A longitudinal cohort study of 100 people with traumatic spinal cord injury (SCI) was performed to determine the prevalence and severity of different types of pain (musculoskeletal, visceral, neuropathic at-level, neuropathic below-level) at 5 years following SCI. Prospective data on the characteristics of pain up to 6 months following injury had been collected previously and allowed comparisons between the presence of pain at different time points. In addition, we sought to determine the relationship between the presence of pain and physical factors related to the injury such as level of lesion, completeness and clinical SCI syndrome. We also obtained information regarding mood, global self-rated health and the impact of pain on function. Of the 100 subjects in the original cohort, 73 were available for follow up. When all types of pain were included, 59 of the 73 subjects (81%) reported the presence of pain. Musculoskeletal pain was the most common type of pain experienced and was present in 43 subjects (59%), at-level neuropathic pain was present in 30 subjects (41%), below-level neuropathic pain was present in 25 subjects (34%) and visceral pain was present in four subjects (5%). Overall, 58% reported their pain as severe or excruciating and those with visceral pain were most likely to rate their pain in these categories. There was no relationship between the presence of pain overall and level or completeness of lesion, or type of injury. However, tetraplegics were more likely to report below-level neuropathic pain. This study prospectively demonstrates the differing time courses of different types of pain over the first 5 years following SCI. There was a strong correlation between the presence of both types of neuropathic pain at 5 years and earlier time points but both visceral pain and musculoskeletal pain demonstrated a poor correlation between time points. Chronic visceral pain occurs in a small percentage of patients and does not correlate with the presence of visceral pain early following injury. Those with neuropathic pain early following their injury are likely to continue to experience ongoing pain and the pain is likely to be severe. In contrast, chronic musculoskeletal pain is more common but less likely to be severe and cannot be predicted by the presence of pain in the first 6 months following injury.

Adult↗
PubMed2003

Conversion disorder after implant of a spinal cord stimulator in a patient with a complex regional pain syndrome.

IMPLICATIONS: This case history describes the treatment of a patient suffering with persistent pain. He was treated surgically with implantation of a spinal cord stimulator. After surgery, a partial paralysis that could not be explained medically and that was probably related to emotional factors occurred, and cognitive behavioral treatment was begun. This paper discusses the importance of considering social and psychological factors when medical treatment options are considered.

Adult↗
PubMed2003

Intrathecal administration of morphine, but not small dose, induced spastic paraparesis after a noninjurious interval of aortic occlusion in rats.

UNLABELLED: We sought to investigate the dose-response relationship for the effect of intrathecal morphine on the transient spastic paraparesis after short-lasting spinal ischemia in rats. Spinal ischemia was induced by aortic occlusion for 6 min with a balloon catheter in rats previously implanted with an intrathecal catheter for drug delivery. After ischemia, the animals were allowed to recover, and 3, 10, or 30 microg of morphine or saline was injected intrathecally at 30 min after reperfusion. In a separate group, the quantal bioassay for the effect of intrathecal morphine on neurological function after ischemia was performed to calculate 50% effective dose values for inducing paraparesis at 2 h of reperfusion. Subsequently, histopathology of the spinal cord was assessed at 48 h of reperfusion. Intrathecal injection of 30 or 10 micro g of morphine, but 3 micro g of neither morphine nor saline, caused a progressive development of hindlimb spasticity. The 50% effective dose values for inducing paraparesis were 16.1 +/- 1.5 microg in assessing behavioral analysis at 2 h after intrathecal morphine. Histopathological analysis of spinal cords in the 30- microg group revealed the presence of dark-staining alpha-motoneurons in lumbosacral segments. We conclude that spinal administration of a large dose of morphine after transient aortic occlusion may be associated with a potential risk of paraparesis and the corresponding development of neurological dysfunction. Careful attention should be paid when intrathecal morphine is used for pain control after thoracoabdominal aortic aneurysm repair. IMPLICATIONS: Spinal administration of large-dose morphine after transient aortic occlusion may be associated with a potential risk of irreversible spinal neuronal degeneration and the corresponding development of neurological dysfunction.

Analgesics, Opioid↗
PubMed2003

Ketamine in chronic pain management: an evidence-based review.

Ketamine has diverse effects that may be of relevance to chronic pain including: N-methyl-D-aspartic acid, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, kainate, gamma-aminobutyric acid(A) receptors; inhibition of voltage gated Na(+) and K(+) channels and serotonin, dopamine re-uptake. Ketamine has been in clinical practice for over 30 yr; however, there has been little formal research on the effectiveness of ketamine for chronic pain management. In this review we evaluate the available clinical data as a basis for defining the potential use of ketamine for chronic pain. Literature referenced in this review was obtained from a computer search of EMBASE and MEDLINE from 1966 through August, 2002. Search terms included ketamine, ketalar, pain, painful, analgesic, and analgesia. Abstracts were screened for relevance and publications relating to chronic pain use were obtained. Levels of evidence were stratified according to accepted guidelines (level I-IV). For central pain, there is level II and level IV evidence of efficacy for parenteral and oral ketamine. For complex regional pain syndromes, there is only level IV evidence of efficacy of epidural ketamine. For fibromyalgia, there is level II evidence of pain relief, reduced tenderness at trigger points, and increased endurance. For ischemic pain, a level II study reported a potent dose-dependent analgesic effect, but with a narrow therapeutic window. For nonspecific neuropathic pain, level II and level IV studies reported divergent results with questionable long-term effects on pain. For phantom limb pain and postherpetic neuralgia, level II and level II studies provided objective evidence of reduced hyperpathia and pain relief was usually substantial either after parenteral or oral ketamine. Acute on chronic episodes of severe neuropathic pain represented the most frequent use of ketamine as a "third line analgesic," often by IV or subcutaneous infusion (level IV). In conclusion, the evidence for efficacy of ketamine for treatment of chronic pain is moderate to weak. However, in situations where standard analgesic options have failed ketamine is a reasonable "third line" option. Further controlled studies are needed.

Chronic Disease↗