There are three joint pain calls you might receive whilst you're on call or on the wards. We have split them into three articles (with links below) allowing us to expand appropriately for each section.
Assessment
For those with multiple joint or chronic pain which has flared, the most important distinction is between inflammatory or mechanical pain. History & distribution can assist with this.
  • Site of pain and stiffness
  • Distribution and timing of symptoms. How is the patient affected? Ensure you ask how pain limits function – can screen for this by asking about mobility including stairs, personal care such as feeding, washing and dressing, shopping and cooking.
  • Is there any morning stiffness? If so how long does this typically last
  • Any systemic features? Fatigue, fever, rashes, weight loss
  • Preceding symptoms and events – reactive arthritis occurs approx. 2 weeks after a URTI, diarrhoeal or GU infection.
  • Any relevant PMH including psoriasis, IBD or recent STI, anterior uveitis.
  • Consider medication history – Arthralgia is a known side effect of ACEi, PPI, quinolones, gonadorelin analogues and tibolones.
  • Family history of inflammatory joint disease or psoriasis.
  • Any red flags: Pain at rest or at night, pain that wakes them from sleep, recent foreign travel
Inflammatory vs Mechanical joint pain
Inflammatory pain (RA, infected joint, seronegative spondyloarthropathy, gout)
  • Worse pain in the morning which improves on use (worst at rest) with morning stiffness for more than 60 minutes. There may be general fatigue as disorders are systemic. 
  • It responds well to NSAIDs
  • Often there is joint swelling with overlying skin erythema & warm to touch
  • Typically it is more symmetrical affecting the smaller joints
    • Symmetrical in rheumatology means it affects the same group of joints bilaterally, it doesn't mean identical joints
  • Seronegative spondyloarthropathies tend to be more axial with enthesitis or large joint in a more asymmetric pattern
Mechanical (osteoarthritis)
  • Pain increases on use so gets worse throughout the day with morning stiffness lasting less than 30 minutes
  • It responds less well to NSAIDs
  • There is less inflammation and more bony swelling in weight-bearing joints or those that are frequently used e.g. carpometacarpal and base of the thumb
  • No systemic involvement (no extra-articular manifestations and less general fatigue)
Osteoarthritis
Wear and tear, thought to be due to more cartilage being worn away than is replaced. It is caused by a combination of genetic factors, stress on the joint due to weight or repetitive use, sedentary lifestyle and sometimes previous trauma to the joint.

Look for:
  • Mechanical sounding pain in the hip, knee, DIP or CMC joints
  • Bony swelling at the DIP joints are common (Heberden's nodes) as is squaring of the thumb base
    • Bouchard's nodes at the PIP joint may also occur
  • Crepitus may be audible or palpable on joint movement
  • There may also be weakened grip or reduced range of movement
Investigations
  • A suggestive history is sufficient for diagnosis in those over 45
  • X rays features can be remembered with the mnemonic "LOSS"
    • Loss of joint space
    • Osteophytes
    • Subarticular sclerosis (increased density of the bone along the joint line)
    • Subchondral cysts (fluid filled holes in the bone)
Management
  • Pain is likely to be lifelong therefore management strategies need to be cautious & careful
  • Non-pharmacological – weight loss, regular exercise to strengthen muscles around joints improve stability and function
  • Follow the principles outlined in "Prescribing Analgesia"
    • Paracetamol or topical NSAIDs is safer
    • Topical capsaicin (chilli pepper extract) can be effective but expensive
    • Avoid long term opiates or NSAIDs
    • Consider PPI cover if NSAIDs are used
  • Intra-articular steroid injections can work but can't be used too frequently (a few times each year depending on the joint)
  • Joint replacement is used in uncontrolled pain and severe impairment of function despite above – commonly in the knee, hip, shoulder and elbow
Rheumatoid Arthritis
From medical school you will know this is an autoimmune condition with increased frequency in women, smokers & younger onset is a poor prognostic factor (classically presents in 40s). There is chronic inflammation of the synovial lining, tendon sheaths & bursa.

Look for:
  • Inflammatory sounding pain classically in a symmetrical distribution over the PIP & MCP joints with systemic symptoms
  • MCPJs & PIPJs may have deformity (see below) and/or boggy swelling due to synovitis. 
    • MCP swelling may result in loss of the groove between the knuckles in a formed fist
    • DIP joints are almost NEVER affected. Consider osteoarthritis, overlap or psoriatic arthritis
  • Other involvement includes: Forefoot (MTP erosion) "walking on marbles", Wrist, ankle & cervical spine. Knee, hip & shoulders are less frequently affected
    • Cervical spine may lead to a restriction in flexion. Patient is at risk of atlantoaxial subluxation which could cause spinal cord compression (higher risk if patient is being intubated) 
  • Rheumatoid nodules occurring in up to 20% (commonly at the elbow) suggest seropositive disease (i.e. antibody positive)
  • Extra-articular manifestations: anaemia, pleural effusion, pneumonitis, pericarditis
Investigations
Diagnostic criteria is based on the American College of Rheumatology. Things to consider include:
  • Raised ESR/CRP
  • Small joint involvement
  • RhF & anti-CCP positive
  • More than 6 weeks of symptoms
  • X-ray findings of soft tissue swelling, periarticular osteopaenia, juxta-articular erosions & joint space narrowing
  • US findings of synovitis
Management
  • Quitting smoking & improving cardiovascular risk factors
  • Early treatment with an MDT approach. If having a flare discuss these with the rheumatology team including the specialist nurses for consideration of prednisolone
  • Disease Modifying Anti-Rheumatic Drugs (DMARDs) and/or biologics are often used
Seronegative Spondyloarthropathies
  • Rarer collection of disorders which include: ankylosing spondylitis, psoriatic arthritis & reactive arthritis
  • Classically have inflammatory sounding axial large joint involvement with enthesitis (achilles tendonitis, plantar fasciitis). 
  • Ankylosing spondylitis tends to have sacroiliitis for which MRI can be very sensitive. Extra-articular manifestations include anterior uveitis, apical fibrosis & aortic regurgitation. 
  • Psoriatic arthritis can occur with or without the rash. It is more common in those with nail changes. Dactylitis can be quite prominent. 
  • If suspected, often the pain responds well to NSAIDs but involve your rheumatology team & the MDT (particularly physiotherapy)
  • Enteropathic arthritis tends to affect 10-20% of those with inflammatory bowel disease which looks similar & treating the underlying IBD will help
References & Further Reading
Written by Dr Emma Monteith FY1
Edits by Dr Akash Doshi CT2