Rheumatoid arthritis is a debilitating condition that can cause long term disability. Early diagnosis is essential for prompt treatment to help prevent joint erosion
Andrew Finney, PGCHE, BSc, DipN, RN, is clinical skills lecturer, School of Nursing and Midwifery, Keele University; Cath Thwaites, PGCHE, MSc, DipN, ONC, RGN, is lecturer/practitioner in rheumatology nursing, School of Nursing and Midwifery, Keele University and Staffordshire Rheumatology Centre.
Finney A, Thwaites C (2010) Rheumatoid arthritis 1: background, symptoms and ensuring prompt diagnosis and treatment. Nursing Times; 106: 9, early online publication.
The first in this two-part unit on rheumatoid arthritis examines background on the condition, incidence and key signs and symptoms. It also discusses diagnostic criteria and investigations.
Keywords Rheumatoid arthritis, Long term conditions, Musculoskeletal
This article has been double-blind peer reviewed
1. Know the signs of inflammation.
2. Understand and be able to recognise the symptoms of rheumatoid arthritis.
Rheumatoid arthritis (RA) is an autoimmune condition characterised by joint inflammation, causing pain and stiffness. The last decade has seen a dramatic change in early diagnosis, treatment and management of this long term condition, meaning a brighter outlook for those living with it. This two-part unit examines the diagnosis, treatment and management of RA.
The Department of Health (2007) defined long term conditions as those that cannot, at present, be cured but can be controlled by medication and other therapies. Musculoskeletal disorders account for a high proportion of long term conditions. Many are managed within the specialism of rheumatology, an area of medicine which has been conducting research into treatment and management.
The term “rheumatic diseases” accounts for over 200 conditions that affect the joints, bones, muscles and soft tissue of the musculoskeletal system (Hill and Ryan, 2000). Arthritis is a commonly accepted yet non-specific term in which 200 variations have been characterised. Musculoskeletal conditions constitute the largest single cause of disability in the developed world (Hill, 2006).
Perhaps the most common form of inflammatory arthritis is rheumatoid arthritis (RA). It affects an estimated 580,000 people in England, with 26,000 new cases diagnosed each year (National Audit Office, 2009).
This autoimmune condition is characterised by joint inflammation, causing pain, swelling, heat and stiffness. It is a systemic disease that also causes fatigue, weight loss, flu-like symptoms and anaemia. The condition is also unpredictable in nature, fluctuating with alternating periods of high disease activity and remission. RA can initially present in a similar way to other conditions such as polymyalgia rheumatica (PMR), other inflammatory joint diseases and even malignancy. Symptoms may come and go, and consequently a definitive diagnosis may take months to be confirmed.
RA is a symmetrical inflammatory arthritis that primarily affects the synovial joints such as hands and feet, shoulders, wrists, knees and ankles (Arthritis Research Campaign, 2002). Its cause is unknown, although it is established that the immune system is triggered and becomes overactive, producing antibodies which work against the body (auto antibodies). At this point the body no longer recognises its own synovium, which lines tendons and synovial joints, and this therefore becomes a target for inflammation (synovitis). Persistent synovitis can lead to joint damage and ultimately deformity and disability.
The progression of RA and its inflammatory process can affect all systems of the body. For this reason it is associated with complications and comorbidities such as cardiovascular disease, anaemia, osteoporosis and depression.
The likelihood of developing RA increases with age; peak onset is thought to be in the 40s and 50s. RA is two to four times more common in women than men and causes approximately one third of people to stop work within two years of onset (NICE, 2009).
Who is affected?
RA does not distinguish between age, race or social class, and contrary to popular opinion it is found in all climates. Inflammatory arthritis also affects children, with one in 10,000 diagnosed with juvenile idiopathic arthritis every year (ARC, 2003).
Although RA affects women more than men, in very older people it is more common in men than women (Hill and Ryan, 2000). Siblings of people with RA have an increased risk of developing it themselves, yet it is not considered a hereditary disease. Fewer than 100 new cases of inflammatory joint disease are diagnosed in the UK per 100,000 each year, and 24 of these are RA (Luqmani et al, 2006).
Lifestyle factors are not a direct cause but are sometimes associated with the condition. There is evidence to suggest a link between RA and smoking (Mattey et al, 2002), while moderate alcohol consumption and high intake of vitamin C are thought to reduce the risk of developing the condition (ARC, 2002).
Detecting signs and symptoms
Progression of RA is usually slow; rapid onset is thought to occur only in around 20% of cases. Inflammation, tenderness and mild stiffness – usually with symmetrical distribution - can be early symptoms, as can fatigue and weight loss. Some people delay reporting symptoms to their GP until they have become severe; for this reason, patients will often report irritability, anxiety and depression due to increasing pain and the limiting of mobility and daily activities.
Inflammation of the synovial membrane surrounding the joint capsules and tendon sheaths is called synovitis. The synovial membrane is the inner membrane of tissue that lines a joint and secretes synovial fluid with the main function of lubricating the joint. Fig 1 shows a healthy joint and one that has been affected by arthritis.
It has been suggested that pathological changes caused by synovitis occur in three stages (Hill and Ryan, 2000):
- Cellular stage: joints become warm, swollen and tender, causing stiffness and restricted movement;
- Inflammatory stage: granulocytes accumulate in the synovial fluid before their destruction during the inflammatory process causes the release of lysosomal enzyme (Hill and Ryan, 2000);
- Destructive stage: primarily affects the hyaline cartilage as vascular granulation tissue or “pannus” starts to erode the outer cartilage around the joint. It is typical for synovitis to initially affect the small joints of the hands and feet although any synovial joint can be affected.
Diagnosis can be difficult in some people, as RA can present in several ways and in the same way as other conditions. It is diagnosed by clinical history, physical examination and investigations such as blood tests and X-rays and/or ultrasound. In an attempt to classify the condition and provide consistency in diagnosis, the American Rheumatism Association reached consensus on diagnostic criteria (Arnett et al, 1988). It identified seven key diagnostic criteria and agreed that four of the seven should be present to reach a diagnosis of RA (Box 1).
Box 1. Seven diagnostic criteria for RA
- Morning stiffness - around the joints with no normal movement for one hour;
- Arthritis in three or more joints - this must be present for at least six weeks;
- Arthritis of hand joints - including wrists and finger joints for at least six weeks;
- Symmetrical arthritis - bilateral involvement in two joints;
- Rheumatoid nodules - subcutaneous nodules over and around bony prominences;
- Rheumatoid factor - a blood test that is positive in less than 5% of normal controls;
- Radiographic changes - evidence of erosions and decalcification in joints involved.
Source: Arnett et al (1988)
Diagnosis in practice
While the seven diagnostic criteria have been useful in providing strict inclusion criteria for clinical trials, they have proved less helpful as a tool for diagnosis in clinical practice, due to their rigid constraints. Many people diagnosed with RA do not present in such a typical way but clinicians’ experience and knowledge enables a diagnosis to be made. Luqmani et al (2006) suggested that the validity of guidelines for RA can be tested by using a composite index of disease assessments, disease activity score (a 28 joint count, testing for tenderness and swelling), drug toxicity, disability and joint damage. NICE (2009) recommended that people with suspected persistent synovitis should be referred for specialist opinion and diagnosis should be based on clinical findings. NICE (2009) recommended urgent referral for patients with any of the following:
- The small joints of the hands or feet are affected;
- More than one joint is affected;
- A delay of three months or longer between onset of symptoms and seeking medical advice.
Since no single blood test can provide a diagnosis of RA, a range of tests are taken to provide an overview of patients’ health and wellbeing. However, recognised patterns in blood results indicate an acute inflammatory response. Key blood tests help to identify the presence of inflammation and assist in diagnosis, along with clinical examination and patient history.
A number of key blood tests are used to aid diagnosis of RA and monitor blood levels for disease activity while patients are being actively treated with drug therapy. These are:
Full blood count to ascertain haemoglobin, platelet and white blood cell levels: many people with persistent inflammation develop anaemia. This is often referred to as anaemia of chronic disease or normochromic, normocytic anaemia;
Liver function and biochemistry tests: these are performed as a baseline to ascertain whether the major organs are able to metabolise and excrete drugs effectively. Certain liver enzymes are temporarily elevated in the presence of inflammation (predominantly alkaline phosphatase and gamma glutamyl transferase and others with drug toxicity (alanine transaminase and aspartate transaminase). However, abnormally elevated liver enzymes may be indicative of other conditions or due to medication and this should be considered when assessing patients;
Levels of inflammation may be assessed by one of several blood tests:the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) or plasma viscosity (PV):
- ESR indicates the presence of inflammation but is not specific to RA. The result may be raised in many other conditions or illnesses including anaemia, malignancy and infection. Age and gender can also influence the result. A normal range is 0-25mm/hr. In active RA an ESR of >100 mm/hr is not uncommon;
- CRP is also a non-specific marker of inflammation. It is a good indicator of the acute inflammatory phase as it reacts much faster than an ESR. A normal CRP ranges from 0-8mg/L. A CRP result of up to 100mg/L may suggest active RA, whereas a CRP of >200 indicates infection is present;
- Plasma viscosity is another measure of inflammation - a normal range is 1.50-1.72cP.
The ranges given for the three tests above are known standard ranges in rheumatology, although they may vary slightly between hospitals.
Immunological tests include the rheumatoid factor (RF), anti nuclear antibody (ANA) and anti-cyclic citrullinated peptide (anti-CCP). These are measurements of auto antibodies, which are groups of immune proteins produced by the immune system that mistakenly target and damage specific tissues and organs. These tests assist in the diagnosis or exclusion of specific rheumatological conditions:
- RF is an important immunological investigation as it determines whether RA is sero-positive or sero-negative. The significance of this is that sero-positive RA may progress to a more aggressive form of the condition. Approximately 80% of people with RA are RF positive. However, a positive RF alone does not mean a diagnosis of RA, as it is thought that up to 5% of the population are RF positive without having RA. Positive RF also occurs in other conditions such as leprosy, tuberculosis and systemic lupus erythematosus;
- ANA helps in excluding other inflammatory joint conditions such as SLE, primary Sjögren’s syndrome and dermatomyositis. ANAs are antibodies that are able to bind to certain structures within cell nuclei; they indicate the presence of autoimmunity and therefore provide an indication of autoimmune illness;
- Anti-CCP helps in determining the prognosis of RA and is predictive of joint damage. It is a relatively new test and therefore not performed as a standard investigation in all centres. A negative result does not exclude the condition. Anti-CCP antibodies have not been found at a significant frequency in other diseases to date, and are more specific than RF for detecting RA.
Other diagnostic tests
Although new drug therapy in RA aims to prevent joint damage, erosions may still be detected on diagnosis. In the past X-rays have been useful measures for monitoring joint deterioration where bony erosions clearly appear like punctured holes.
The use of ultrasound scanning is becoming standard practice in assessing and measuring the degree of synovitis in joints and soft tissues. It can also ascertain early erosions and tendon rupture (Kane et al, 2004).
GPs and community nurses are becoming more experienced in recognising early symptoms of RA. Ideally, prompt referral to a rheumatologist normally takes place within three months of symptoms being reported, enabling early diagnosis and initiation of treatment. Escalation and monitoring of appropriate medication is paramount to patient safety, while aiming to prevent complications. Over the last decade, advances in pharmacological treatments have been shown to slow down joint destruction and ultimately disability, such as disease-modifying and biological drugs. This provides a more optimistic outlook for people with RA.
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Part 2 of this unit, to be published in next week’s issue, examines the impact of RA and treatment options
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Arthritis Research Campaign (2003) When Your Child Has Arthritis. An Information Booklet. Chesterfield: ARC.
Arthritis Research Campaign (2002) Arthritis: The Big Picture. Chesterfield: ARC.
Department of Health (2007) Background. London: DH.
Hill J(2006) Rheumatology Nursing: A Creative Approach. Chichester: Wiley.
Hill J, Ryan S (2000) Rheumatology: A Handbook for Community Nurses. London: Whurr Publishers.
Kane D et al (2004) Musculoskeletal ultrasound - a state of the art review in rheumatology. Clinical indications for musculoskeletal ultrasound in rheumatology. Rheumatology; 43: 829-38.
Luqmani R et al (2006) British Society for Rheumatology and British Health Professionals in Rheumatology guideline for the management of rheumatoid arthritis (the first two years). Rheumatology; 10.1093/rheumatology/kel215a.
Mattey DL et al (2002) Relationship among the HLA-DRB1 shared epitope, smoking and rheumatoid factor production in rheumatoid arthritis. Arthritis and Rheumatism; 47: 4, 403-7.
National Audit Office (2009) Services for People with Rheumatoid Arthritis. London: NAO.