Symptoms of Joint Pain:

The dictum not everything that presents to the sports clinic is sports medicine should never be forgotten. In daily practise sports clinicians see many patients who have mechanical joint injuries; thus, it can be tempting to attribute a mechanical diagnosis to every patient who presents with a painful or swollen joint. It is, however, wise to maintain an index of suspicion for inflammatory joint disease masquerading as a mechanical condition. For example, a 3O-year-old runner may present with recurrent knee swelling but have no convincing history of injury. Swelling is very uncommon in patellofemoral pain and a meniscal injury is rare without trauma at that age. Thus, the athlete presents with a single swollen joint but no injury. The clinician should be alert to the possibility that this swollen knee may be caused by an inflammatory condition.

The diagnosing patients with the following four common presentations:

• The single swollen  joint
• Low back pain and stiffness
• Multiple joint symptoms
• Joint pain and pain all over

We also discuss when to use rheumatological investigations and how to interpret them.

The Patient with a Single Swollen Joint

In the athlete with a single swollen joint without a history of trauma, a possible inflammatory cause should be considered.  Summarizes the differential diagnosis of a single swollen joint.

Clinical perspective

The key to accurate diagnosis of a swollen joint is through taking a careful history and physical examination and having an appropriate index of suspicion. Inflammatory joint problems are characterized by pain, swelling, warmth, redness, night pain and prominent morning stiffness. In all athletes, and especially in children and adolescents, inflammatory, infective or neoplastic conditions should be considered in the light of these symptoms.

History

Many of the inflammatory diseases are associated with extra-articular features that may provide additional clues as to the diagnosis:

• Psoriatic arthritis may be associated with rash, nail dystrophy, tendon insertion pain (enthesopathy) or low back pain.
• A history of inflammatory bowel disease (ulcerative colitis, Crohn’s disease or celiac disease) suggests enteropathic arthritis. Urethral discharge or eye inflammation may suggest a reactive arthritis.
• Rheumatoid arthritis is characteristically a small joint (hands, wrists and feet), symmetrical polyarthritis but can present as a single swollen joint in 15% of cases.
• Hypothyroidism, hyperparathyroidism and hemochromatosis may be associated with calcium pyrophosphate dihydrate deposition in articular tissues that may manifest as an acute gout-like presentation (pseudo gout) or may have a sub acute or chronic course.
• Previous renal disease or diuretic use may give clues to diagnosing gout.
• Septic arthritis is uncommon in the normal joint but the possibility should be considered in  joints recently aspirated or in patients with arthritis, diabetes or impaired immune function.
• A family history of inflammatory arthritis is significant as first-degree relatives of patients with rheumatoid arthritis are four times more likely to develop the condition than the general population.

The Patient with Low Back Pain and Stiffness

A systematic illness is present in upto 10% of patients who present with low back pain. Because patients with low back pain gravitate to sports clinicians for management, it is important that clinicians have an index of suspicion for those patients with a non-mechanical cause for their low back pain.

Clinical Perspective

The differential diagnosis of low back pain is broad and is documented. This differential diagnosis includes inflammatory arthritis of the spine and sacroiliac joints, known as spondyloarthropathy. Spondyloarthropathy is a generic term applied to the clinical, radiological and immunological features shared by the following diseases:

• Ankylosing Spondylitis
• Reactive Arthritis following genitourinary or gut infection
• Psoriatic Arthritis
• Enteropathic Arthritis (Crohns disease, ulcerative colitis or celiac disease).

Although patients with these conditions have an increased likelihood of being positive for HLA B27, a negative result does not eliminate the diagnosis. Spondyloarthropathy has its greatest prevalence in young men and usually achieves near full disease expression by age 35 years; thus, patients commonly present to the sports clinician.

History

Patients with back pain due to spondyloarthropathy complain of pain that is worse at night, with prominent morning stiffness (of 2 hours or more), which is eased with gentle exercise and NSAIDs. This pain pattern is very different from the typical pain pattern of mechanical low back pain. Buttock or posterior thigh pain may be present, so this symptom does not distinguish the two types of back pain. When the patient describes morning back pain with prominent stiffness, the physician should ask whether there is a past history of psoriasis or nail dystrophy (psoriatic arthritis), inflammatory bowel disease (enteropathic arthritis), or recent genitourinary or gut infection (reactive arthritis). Spondyloarthropathy is characterized by inflammation of the entheses, commonly at the patellar tendon, Achilles tendon and the plantar fascia.

Peripheral joints may be involved with spondyloarthropathy, particularly an asymmetric, lower limb, large joint inflammation. The shoulder or hip is involved in 30% of patients with ankylosing  spondylitis. A history of extra-articular involvement such as anterior uveitis (iritis) and the rash of keratoderma blennorrhagica or circinate balanitis (reactive arthritis) may provide clues to the specific cause of back pain. It is important that the clinician actively seeks these associations as the athlete may not find them noteworthy to mention. There is often a strong family history of spondyloarthropathy ; for example, approximately 6% of siblings of patients with ankylosing spondylitis will develop the condition.

The Patient Presenting with Multiple Painful Joints

Occasionally patients may attend the sports medicine clinic with multiple joint pain (polyarthralgia) or multiple joint pain with synovitis (polyarthralgia). A systematic approach is vital to make an accurate diagnosis .Summarizes the differential diagnosis of the patient presenting with a polyarthritis.

History

The practitioner should begin by distinguishing polyarthritis with joint pain, stiffness and swelling from polyarthralgia alone. Joint inflammation is characterized by night pain, prominent morning stiffness (of at least 60 minutes but often for hours), swelling, warmth and loss of function. In many of these conditions the diagnosis is clinical. A key diagnostic feature is the onset and pattern of joint involvement.

Rheumatoid arthritis symmetrically affects the small joints of the hands, wrists and feet (PIP, MCP, MTP) and in the majority of patient’s onset occurs over weeks or months. Reactive arthritis (following genitourinary or gastrointestinal infection), on the other hand, is often more rapid in onset and has a propensity to asymmetric involvement of the large joints of the lower limb together with enthesitis (inflammation at the insertions of tendons, ligaments or capsules) or dactylitis (sausage digits) .The duration of symptoms should be recorded.

Parvovirus B19 polyarthritis frequently affects young women who care for small children (mothers or school teachers) who develop parvovirus B19 infection (fifth disease or slapped cheek syndrome). This condition may be indistinguishable from early rheumatoid arthritis. Symptoms and signs usually settle within six weeks, whereas rheumatoid arthritis often follows a chronic and progressive course. The presence or absence of extra-articular manifestations of rheumatological conditions may also aid accurate diagnosis. The pattern of joint involvement in polyarticular pseudogout or psoriatic arthritis often resembles rheumatoid arthritis but without nodulosis, vasculitis or other systemic features seen in rheumatoid arthritis.

The Patient with Joint Pain who ‘Hurts All Over’

A challenging presentation for any clinician is the evaluation of the athlete with widespread joint or muscle pain who hurts all over. These patients are often frequent attenders and it can be extremely rewarding to provide a diagnosis and the help they need. In many cases, patients with this presentation have little to find on clinical examination .The differential diagnosis of this presentations is broad and includes the conditions listed. Other possible diagnosis and directs the practitioner towards appropriate clinical evaluation.

Investigations must be directed towards a specific diagnosis but may include blood count, ESR, plasma immunoglobulin assay band electrophoresis, calcium, phosphate, thyroid function and creatine kinase tests.