Musculoskeletal conditions

Chapter 8


Musculoskeletal conditions




Background


The musculoskeletal system comprises of hard (bone and cartilage) and soft (muscles, tendons, ligaments) tissues. It is responsible for mobility and provides protection to vital structures. Most musculoskeletal problems occur as a result of injury or organic illness. The majority of patients presenting to a community pharmacist will have an acute and self-limiting problem, which will resolve spontaneously. Chronic conditions such as osteoarthritis will be encountered routinely when issuing prescriptions to patients.


The key role of the pharmacist when dealing with patients with a musculoskeletal problem is to establish the cause, its severity and whether it can be self-managed appropriately or requires further investigation.



General overview of musculoskeletal anatomy


The skeletal system of the human body is composed of 206 bones. At the point of contact between two or more bones an articulation (joint) is formed. This system of bones and joints maximises movement whilst maintaining stability. There are two basic types of joints:



Bones and joints cannot move by themselves. The integrity of the musculoskeletal system depends on the interaction between skeletal muscle and bones, and co-ordinated movement is only possible because of the way muscle is attached to bone. Tendons attach the end of the muscle to the bone or another structure upon which the muscle acts. To perform such a function tendons are composed of very dense fibrous tissue.


Joints require additional stability and support. Strong bands of fibrous tissue known as ligaments bind together bones entering a joint to provide this additional support and stability. It is often the integrity of the connecting structures that are damaged in a musculoskeletal injury. The simplified diagram of the medial aspect of the knee joint in Fig. 8.1 illustrates the relationship of the connective structures to the skeleton and musculature.



The knee joint is an example of a synovial joint. The femur, tibia and fibula do not touch each other because they are covered with articular cartilage and separated by the synovial cavity. The knee joint also contains bursae – small fluid sacs – that provide protection at points in the joint where friction or pressure is great. These can become inflamed, leading to bursitis.



History taking


Gaining an accurate history from the patient should provide enough information to determine if their injury is within the scope of a community pharmacist. By the very nature of musculoskeletal injuries, if someone manages to come into the pharmacy then the injury is unlikely to be serious. Information gathering should concentrate on when the injury occurred, what precipitated the injury, the level of discomfort, any restriction in range of motion and whether the injury appears to be worsening, and finding out what expectations the patient has.


In general, any patient who presents with an injury that is causing extreme discomfort or the pain is worsening, adversely affects mobility and has been present for more than a week would probably be better managed by a GP or physiotherapist/sports therapist and referral should be made.



Acute low back pain




Prevalence and epidemiology


Back pain is most common between the ages of 30 and 55 years with prevalence rates similar for men and women, although 50 to 90% of pregnant women develop low back pain. Studies and statistical data have shown that in developed countries 60 to 90% of adults will experience an episode of low back pain at some point in their adult lives. Back pain is most common in those with skilled manual, partly skilled and unskilled jobs. Occupational risk factors in developing back pain include those who perform heavy manual labour, frequent bending, twisting and lifting and people who remain in static positions for long periods of time such as truck and car drivers who drive long distances each year. Sports, which involve excessive twisting, such as, golf and gymnastics can also lead to back pain.



Aetiology


In the majority of cases an exact cause cannot be determined for the patient’s symptoms and is often referred to as simple, non-specific or uncomplicated low back pain. Pain originates from the lumbosacral region and is often mechanical in origin (Fig. 8.2) and includes problems caused by muscles, tendons, ligaments and discs. Contributory factors in the cause of low back pain are a general lack of fitness, occupational (as above) and psychosocial, for example anxiety and depression. Serious underlying pathology is very rare with infection and malignancy accounting for less than 1% of cases.




Arriving at a differential diagnosis


The vast majority of patients (95%) who present in the pharmacy will have simple back pain that will, in time, resolve with conservative treatment. The remaining cases will have back pain with associated nerve root compression. It is extremely unlikely that a pharmacist will encounter a patient with serious spinal pathology, such as infection or malignancy. However, pharmacists should be mindful that age can affect the diagnosis. Table 8.1 highlights those conditions that can be encountered by community pharmacists and their relative incidence.



Taking a thorough history is of key importance when evaluating a patient with low back pain. Begin questioning the patient with traditional questions regarding the pain: location, radiation, evidence of trauma, the effect pain has on mobility and factors which aggravate or relieve the pain. Asking a number of symptom-specific questions will aid differential diagnosis (Table 8.2).





Conditions to eliminate



Likely causes



Sciatica: Sciatica typically occurs in the healthy middle-aged adult. Pain is acute in onset and radiates to the leg. Pain starts in the lower back and as it intensifies radiates into the lower extremity. Disc herniation usually involves those between L4 and L5 and L5–S1 vertebrae (Fig. 8.2), although most occur between L5 and S1. If disc herniation is minimal pain is characterised by being dull, deep and aching. It is usually felt in the upper part rather than the lower part of the leg and spreads from the lumbar spine. If the disc ruptures or herniates under strain then the pain is usually lancinating in quality, shooting down the leg like an electric shock. Valsalva movements, for example coughing, sneezing or straining at stool, often aggravate pain. Referral is needed for confirmation of the diagnosis. GPs can perform a straight-leg raising test whereby the pain of sciatica can be induced by elevating the leg of the patient when lying down. Prognosis is good, although improvement and recovery is often slower than in low back pain alone.



Osteoarthritis: Patients in whom pain lasts longer than 12 weeks are said to suffer from chronic back pain. In the context of low back pain pharmacists should only manage acute problems; however patients will present with chronic symptoms and seek advice, especially on drug management. Degenerative joint disease is the most common cause of chronic low back pain in people older than fifty. It is associated with advancing age, and affects up to one-third of people aged over 65 and is twice as common in women. It can be localised to a single joint or involve multiple joints and most commonly affects the hands, knees, hips, neck, and low back. It is thought that an imbalance of synthesis and degradation of cartilage is responsible for the disease, which affects the whole joint. It is characterised by pain of insidious onset that progressively increases over months or years and is exacerbated by exertion and relieved by rest. Stiffness in the affected joint occurs typically in the morning and after prolonged rest but usually only lasts for 15 to 30 minutes.



Unlikely causes






Causes of low back pain not related to back pathophysiology


It must be remembered that acute illness, for example colds and influenza, can give rise to generalised aching or pain. Likewise, pre-rash pain associated with shingles and referred pain from abdominal organs (e.g. pyelonephritis) can present as low back pain. A careful history of the presenting symptoms should enable exclusion of such conditions.



image Trigger points indicative of referral

























Symptoms/signs Possible danger/reason for referral
Fever Infection
Pain that radiates away from lower back area Sciatica
Young or older people (<20, and >55 years old)
Numbness
Persistent and progressively worsening pain
Weight loss
Feeling unwell		 Possible sinister spinal pathology
Bowel or bladder incontinence Cauda equina syndrome (rare and very unlikely to be seen by a pharmacist)
Back pain from structures above the lumbar region Outside scope of community pharmacist
Failure of symptoms to improve after 4 weeks Requires further investigation as pain becoming subacute (approx. 6 weeks duration) and requires medical intervention



Evidence base for over-the-counter medication


Pharmacists can appropriately treat patients with uncomplicated acute low back pain. The goal of treatment is to provide relief of symptoms and a return to normal mobility.




Analgesics (paracetamol, aspirin, NSAIDs, e.g. ibuprofen, diclofenac)


All systemic analgesics when prescribed as monotherapy have proven efficacy in pain relief at standard doses. However, the use of non-steroidal anti-inflammatory drugs (NSAIDs) for 7 to 10 days is widely advocated. A systematic review of NSAIDs in acute or chronic low back pain found treatment with an NSAID produced significant short-term improvement compared with placebo (Roelofs et al 2008). The review identified 65 trials, 28 of which were rated as ‘high quality’. The study failed to find any difference among the various NSAIDs. It also found that NSAIDs were no better than paracetamol for LBP. The authors did note that paracetamol had fewer side effects. Based on this observation, paracetamol may be the best first-line choice for most people. Patients must be advised to see their GP if symptoms fail to improve after 7 days.



Compound analgesics (paracetamol/codeine, aspirin/codeine or paracetamol/dihydrocodeine)


It is recognised that combination analgesics with high doses of opioids are effective in acute and chronic pain. However, in the UK, codeine and dihydrocodeine can only be prescribed OTC provided their respective maximum strengths do not exceed 1.5% and the maximum dose does not exceed 20 or 10 mg, respectively. In practice, this equates to commercially available products with a maximum dose of 12.8 mg of codeine and 7.46 mg of dihydrocodeine. At these doses their painkilling effect has been called into question and a number of papers have concluded that OTC doses are too low to produce statistically significant reductions in pain compared to single agents. However, the opioid dose might be sufficient to cause side effects such as constipation. Elderly patients are particularly susceptible to opioid side effects and might, in rare circumstances, experience drowsiness even at OTC doses.




Caffeine


It has long been claimed that caffeine enhances analgesic efficacy and a number of proprietary products contain caffeine in doses ranging from 15 to 110 mg. A Cochrane review (Derry et al 2012) identified 19 studies (n = 7238), which involved mainly paracetamol or ibuprofen, with 100 to 130mg caffeine. Findings showed that there was a small but statistically significant benefit with caffeine used at doses of 100 mg or more, which was not dependent on the pain condition or type of analgesic. The authors concluded that the addition of caffeine (100 mg) to a standard dose of commonly used analgesics provides a small but important increase in the proportion of participants who experience a good level of pain relief. In light of this new data, if recommending caffeine-containing products, only those with 100 mg or more of caffeine should be given.



Topical NSAIDs


Topical NSAIDs have been available OTC in the UK since ibuprofen was deregulated in 1988. Since then, a number of other NSAIDs have been deregulated from prescription only control. For NSAIDs to work they must penetrate the skin, be absorbed into tissues and be in sufficiently high concentration to inhibit COX enzymes. Experimental results suggest that NSAIDs do penetrate the skin but peak plasma concentrations are greatly lower than oral NSAIDs (approximately 5% of oral plasma levels). A recent systematic-review identified 47 studies comparing topical NSAIDs to placebo (Massey et al 2010). The review found topical NSAIDs to be significantly better than placebo, with achieving 50% pain relief with topical NSAIDs compared to 43% for placebo. The authors stated that there was insufficient data to reliably compare topical NSAIDs to each other, or to oral NSAIDs, but concluded that NSAIDs can provide good pain relief in acute musculoskeletal conditions, without the adverse events seen with oral NSAIDs.



Rubefacients


Rubefacients (also known as counter irritants) have been incorporated in topical formulations for decades. They cause vasodilation, producing a sensation of warmth that distracts the patient from experiencing pain. It has also been hypothesised that increased blood flow might help disperse chemical mediators of pain, although this in unsubstantiated. Numerous chemicals are listed as being rubefacients. Bandolier (http://www.medicine.ox.ac.uk/bandolier/) have produced a detailed summary of topical analgesics, and within this document usefully reviewed what constituted a rubefacient. Their effect in controlling acute and chronic pain was reviewed by Matthews et al (2009). Seven studies (n = 697) for acute pain involved use of salicylates. Data showed there was no difference between topical salicylates and a topical placebo.





Complementary therapies


Back pain accounts for more visits to a complementary practitioner than any other pain condition. In one study, 10% of people complaining of back pain had visited a complementary practitioner (osteopath, chiropractor, acupuncturist).


A limited, but growing body of clinical evidence exists to assess whether complementary therapies are effective. In light of the growing public interest and the expanding volume of literature, four Cochrane reviews have been conducted on heat and cold therapy (French et al 2006), herbal remedies (Gagnier et al 2006), acupuncture (Furlan et al 2005) and massage (Furlan et al 2008) respectively.



Herbal remedies: Several herbal medicines are promoted as treatments for various types of pain, some of which have been tested for the relief of symptoms of low back pain. A Cochrane review (Gagnier et al, 2006) reviewed three active constituents; Harpagophytum procumbens (Devil’s Claw), Salix alba (white willow bark), and Capsicum frutescens (cayenne). Devil’s Claw (standardised daily dose of 50 mg or 100 mg harpagoside) reduced pain more than placebo and a standardised daily dose of 60 mg was equally effective as 12.5 mg of rofecoxib (Vioxx, now withdrawn from the market). Similarly, Willow Bark (standardised daily dose of 120 mg and 240 mg of salicin) was also more effective than placebo and 240 mg of salicin was as effective as 12.5 mg of Vioxx. Cayenne (as a plaster) reduced pain more than placebo. It therefore appears that these products can be used as viable alternatives to conventional medicine.


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Feb 16, 2017 | Posted by in PHARMACY | Comments Off on Musculoskeletal conditions

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