Musculoskeletal
Question 169 of 180
A 47 year old woman presents to the Emergency Department complaining of several months of fatigue and joint pains. She gives a three month history of general fatigue, morning stiffness, and bilateral hand, foot, and elbow stiffness that improves over the day. Her full blood count shows:
- Haemoglobin: 109 g/L
- White cell count: 11.3 x 109/L
- Platelets: 399 x 109/L
- MCV: 85 fl
Her main complaint is of pain to the metacarpophalangeal joints of both hands. What is the diagnosis?
Answer:
Suspect rheumatoid arthritis in anyone with persistent synovitis, where no other underlying cause is obvious (for example, psoriatic arthritis). RA typically causes symmetrical synovitis of the small joints of the hands and feet, although any synovial joint may be affected. Clinical features include:- Pain, swelling, heat and stiffness in affected joints
- Pain — usually this is worse at rest or during periods of inactivity.
- Swelling — around the joint (not bone swelling) giving a 'boggy' feel on palpation.
- Stiffness — early morning stiffness usually last over 1 hour (a history of prolonged morning stiffness is more helpful when forming a diagnosis than currently having morning stiffness for early RA).
- Rheumatoid nodules – hard, firm swellings over extensor surfaces
- Systemic features e.g. malaise, fever, sweats, weight loss, lymphadenopathy
- Extra-articular features
Rheumatoid Arthritis
Musculoskeletal
Last Updated: 12th February 2021
Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease, typically presenting as an inflammatory arthritis typically affecting the small joints of the hand and feet, and usually symmetrically, although any synovial joint may be involved. As RA progresses, any system of the body may be affected by the underlying inflammatory process, leading to an increased risk of premature death. RA onset can occur at any age, but it peaks between people aged 30–50 years. RA is 2–4 times more common in women than in men.
Complications
RA is associated with a number of complications and comorbidities.
- Complications of RA:
- Amyloidosis
- Anaemia
- Dry eye syndrome (keratoconjunctivitis sicca), peripheral ulcerative keratitis
- Felty's syndrome (enlarged spleen and low white blood cell count)
- Fatigue
- Increased mortality
- Interstitial lung disease, pleural effusion, fibrosing alveolitis
- Neuropathy
- Orthopaedic problems, for example:
- Carpal tunnel syndrome
- Increased joint replacement surgery
- Tendon rupture
- Cervical myelopathy
- Vasculitis, vasculitic ulcers, rheumatoid nodules
- Weight loss
- Comorbidities associated with RA:
- Cardiovascular disease (accelerated atherosclerosis is the leading cause of death in people with RA)
- Depression
- Lymphomas
- Serious infections
- Complications associated with drug treatment:
- Gastrointestinal problems — mainly due to the adverse effects of nonsteroidal anti-inflammatory drugs (NSAIDs)
- Infection — glucocorticoids and immunosuppressants increase the risk of infection
- Liver toxicity — methotrexate-related
- Malignancy — particularly TNF-alpha inhibitor-related (increased risk of skin cancer)
- Osteoporosis — low-dose glucocorticoid use in people with RA reduces bone mineral density and increases the risk of fractures. RA also increases the risk of osteoporosis in the absence of glucocorticoid use.
Clinical features
Suspect rheumatoid arthritis in anyone with persistent synovitis, where no other underlying cause is obvious (for example, psoriatic arthritis). RA typically causes symmetrical synovitis of the small joints of the hands and feet, although any synovial joint may be affected. Clinical features include:
- Pain, swelling, heat and stiffness in affected joints
- Pain — usually this is worse at rest or during periods of inactivity.
- Swelling — around the joint (not bone swelling) giving a 'boggy' feel on palpation.
- Stiffness — early morning stiffness usually last over 1 hour (a history of prolonged morning stiffness is more helpful when forming a diagnosis than currently having morning stiffness for early RA).
- Rheumatoid nodules – hard, firm swellings over extensor surfaces
- Systemic features e.g. malaise, fever, sweats, weight loss, lymphadenopathy
- Extra-articular features (see above)
Hand signs on examination
- Joint swelling, redness and heat – particularly MCPJs, PIPJs
- Subluxation and ulnar deviation at MCPJs
- Boutonniere’s deformity (PIPJ hyperflexion and DIPJ hyperextension)
- Swan-neck deformity (PIPJ hyperextension and DIPJ flexion)
- Z deformity of the thumb (IPJ hyperextension and MCPJ fixed flexion and subluxation)
- Bowstring sign (tendons appear prominent and stretched across a shrunken carpus)
- Inability to make a fist or flex fingers
- Positive metacarpophalangeal squeeze test - pain on squeezing the metacarpophalangeal or metatarsophalangeal joints together
Differential diagnosis
- Connective tissue disorders e.g. SLE
- Fibromyalgia
- Infectious arthritis (viral or bacterial)
- Osteoarthritis
- Polyarticular gout
- Polymyalgia rheumatica
- Psoriatic arthritis
- Reactive arthritis
- Sarcoidosis
- Septic arthritis
- Seronegative spondyloarthritis
Investigations
There is no specific diagnostic test for rheumatoid arthritis (RA), the diagnosis is clinical. Refer all people suspected of having RA for specialist assessment.
- Bloods
- FBC, CRP/ESR, U&Es, LFTs
- Rheumatoid factor
- This is present in 60–70% of people with RA.
- Anti-cyclic citrullinated peptide (anti-CCP) antibodies (if patient is negative for RF)
- These are found in about 80% of people with RA.
- X-ray
- Erosions
- Soft-tissue swelling
- Joint space narrowing
- Periarticular osteoporosis
- Joint deformity
Management
- Refer people with persistent synovitis with an unknown cause to a rheumatologist for an appointment (within 3 weeks of referral) for specialist assessment.
- Consider offering a nonsteroidal anti-inflammatory drug (NSAID) at the lowest effective dose for the shortest possible until a rheumatology appointment is available.
- Specialist treatment:
- A treat to target strategy is used — the aim is to achieve a target of remission or low disease activity if remission cannot be achieved.
- Conventional DMARD
- Specialists will usually offer a conventional disease modifying anti-rheumatic drug (cDMARD) as monotherapy, ideally within 3 months of the onset of symptoms — for example, oral methotrexate, leflunomide, or sulfasalazine. The dose is increased depending on tolerance until the treatment target is achieved.
- Short-term bridging treatment with glucocorticoids (oral, intramuscular or intra-articular) may be used when starting a new cDMARD to improve symptoms while waiting for the new DMARD to take effect (which can take 2–3 months).
- Additional cDMARDs may be offered in combination in a step-up strategy when the treatment target (remission or low disease activity) has not been achieved despite dose escalation.
- Once the treatment target has been achieved drug doses may be stepped down or stopped.
- Biological DMARD
- If the disease is severe and has not responded to intensive therapy with a combination of cDMARDs, biological DMARDs may be offered in combination with methotrexate, or alone (depending on the product licence) for people who cannot take methotrexate because it is contraindicated or because of intolerance.
- Glucocorticoids
- Glucocorticoids may be offered short-term treatment to manage flares in people with recent-onset or established disease to rapidly decrease inflammation.
- In people with established RA, glucocorticoids will only be continued long-term when the long-term complications of glucocorticoid therapy have been fully discussed, and all other treatment options (including biological and targeted synthetic DMARDs) have been offered.
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
