Although chronic pain affects around 20% of adults in Europe and the USA, there is substantial evidence that it is inadequately treated. In June 2009, an international group of pain specialists met in Brussels to identify the reasons for this and to achieve consensus on strategies for improving pain management.

Chronic pain is currently under-diagnosed and under-treated, partly because doctors’ training in pain management is often inadequate. This situation looks certain to become worse with the rapidly increasing elderly population unless there is a wider adoption of best pain management practice. This paper reviews current knowledge of the development of chronic pain and the multidisciplinary team approach to pain therapy. The individual topics covered include nociceptive and neuropathic pain, peripheral sensitization, central sensitization, the definition and diagnosis of chronic pain, the biopsychosocial model of pain and the multidisciplinary approach to pain management. This last section includes an example of the implementation of a multidisciplinary approach in Belgium and describes the various benefits it offers; for example, the early multidimensional diagnosis of chronic pain and rapid initiation of evidence-based therapy based on an individual treatment plan. The patient also receives continuity of care, while pain relief is accompanied by improvements in physical functioning, quality of life and emotional stress. Other benefits include decreases in catastrophizing, self-reported patient disability, and depression. Improved training in pain management is clearly needed, starting with the undergraduate medical curriculum, and this review is intended to encourage further study by those who manage patients with chronic pain.

The basic mechanisms underlying acquired generalized muscle weakness and paralysis in critically ill patients remain poorly understood and may be related to prolonged mechanical ventilation/immobilization (MV) or to other triggering factors such as sepsis, systemic corticosteroid (CS) treatment and administration of neuromuscular blocking agents (NMBA). The present study aims at exploring the relative importance of these factors by using a unique porcine model. Piglets were all exposed to MV together with different combinations of endotoxin-induced sepsis, CS and NMBA for five days. Peroneal motor nerve conduction velocity and amplitude of the compound muscle action potential (CMAP) as well as biceps femoris muscle biopsy specimens were obtained immediately after anesthesia on the first day and at the end of the 5-day experimental period. Results showed that peroneal nerve motor conduction velocity is unaffected whereas the size of the CMAP decreases independently of the type of intervention, in all groups after 5 days. Otherwise, despite a preserved size, muscle fibre specific force (maximum force normalized to cross-sectional area) decreased dramatically for animals exposed to MV in combination with CS or/and sepsis. These results suggest that the rapid declines in CMAP amplitude and in force generation capacity are triggered by independent mechanisms with significant clinical and therapeutic implications.

In critically ill patients, mechanisms underlying diaphragm muscle remodeling and resultant dysfunction contributing to weaning failure remain unclear. Ventilator-induced modifications as well as sepsis and administration of pharmacological agents such as corticosteroids and neuromuscular blocking agents may be involved. Thus, the objective of the present study was to examine how sepsis, systemic corticosteroid treatment (CS) and neuromuscular blocking agent administration (NMBA) aggravate ventilator-related diaphragm cell and molecular dysfunction in the intensive care unit. Piglets were exposed to different combinations of mechanical ventilation and sedation, endotoxin-induced sepsis, CS and NMBA for five days and compared with sham-operated control animals. On day 5, diaphragm muscle fibre structure (myosin heavy chain isoform proportion, cross-sectional area and contractile protein content) did not differ from controls in any of the mechanically ventilated animals. However, a decrease in single fibre maximal force normalized to cross-sectional area (specific force) was observed in all experimental piglets. Therefore, exposure to mechanical ventilation and sedation for five days has a key negative impact on diaphragm contractile function despite a preservation of muscle structure. Post-translational modifications of contractile proteins are forwarded as one probable underlying mechanism. Unexpectedly, sepsis, CS or NMBA have no significant additive effects, suggesting that mechanical ventilation and sedation are the triggering factors leading to diaphragm weakness in the intensive care unit.

Background: Long-term pain is a debilitating condition that is costly to treat and has a significant impact on patient quality of life. Classical opioids have been used for the treatment of pain for centuries and are one of the most effective drug classes available for acute severe pain and long-term pain. However, concerns regarding adverse effects, tolerance to analgesic effects and the potential for addiction have resulted in a reluctance to prescribe and use opioids for the management of long-term non-cancer pain. Adverse events, including gastrointestinal side effects such as constipation, nausea and vomiting, and central nervous system side effects such as sedation are responsible for as many as one in five patients discontinuing opioid treatment, often leading to inadequate pain relief and poor patient quality of life. Therefore, new analgesic therapies are needed that are associated with fewer adverse effects, whilst providing sustainable pain relief for patients with long-term pain.

In many countries, the number of elderly people has increased rapidly in recent years and this is expected to continue; it has been predicted that almost a quarter of the population in the European Union will be over 65 years of age in 2035. Many elderly people suffer from chronic pain but it is regularly under-treated, partly because managing these patients is often complex. This paper outlines the extent of untreated pain in this population and the consequent reduction in quality of life, before articulating the reasons why it is poorly or inaccurately diagnosed. These include the patient's unwillingness to complain, atypical pain presentations, multiple morbidities and cognitive decline. Successful pain management depends upon accurate diagnosis, which is based upon a complete history and thorough physical examination, as well as an assessment of psychosocial functioning. Poor physician/patient communication can be improved by using standardized instruments to establish individual treatment targets and measure progress towards them. User-friendly observational instruments may be valuable for patients with dementia. In line with the widely accepted biopsychosocial model of pain, a multidisciplinary approach to pain management is recommended, with pharmacotherapy, psychological support, physical rehabilitation and interventional procedures available if required. Declining organ function and other physiological changes require lower initial doses of analgesics and less frequent dosing intervals, and the physician must be aware of all medications that the patient is taking, in order to avoid drug/drug interactions. Non-adherence to treatment is common, and various strategies can be employed to improve it; involving the elderly patient's caregivers and family, using medication systems such as pill-boxes, or even sending text messages. In the long term, the teaching of pain medicine needs to be improved -particularly in the use of opioids -both at undergraduate level and after qualification.

Early intervention plays an important role in preventing pain chronification and, as key influencers in the management of patients with acute pain, it is critical that primary care physicians are equipped with the necessary awareness, education and skills to manage pain patients appropriately.

With comprehensive examination over time, signs of CIPNM can be seen early in ICU course, and appear more likely to occur in patients with sepsis and corticosteroid treatment.