Joint Pain and Swelling

A painful joint does not identify one tissue or diagnosis. A sudden hot swollen joint needs urgent assessment, while persistent synovitis can require early rheumatology referral even when blood tests are normal.

Joint pain can come from several structures Arthralgia means pain felt in or around a joint. It does not prove that the joint itself is inflamed. Most freely moving limb joints are synovial joints. Their bone ends have articular cartilage and sit inside a capsule lined by synovium. The synovium produces synovial fluid, which supports low friction movement. Ligaments stabilise the joint, while nearby tendons, muscles and bursae support movement. Pain can arise from bone, synovium, capsule, ligaments or nearby structures. Pain can also be referred from another area, such as the hip or spine. Swelling does not always mean fluid inside the joint A joint effusion is excess fluid within a joint cavity. Synovitis is inflammation or thickening of the synovium and can contribute to an effusion. Haemarthrosis means bleeding into a joint. Injury, bleeding disorders or anticoagulant medicines can sometimes cause it. Bursitis causes swelling in a bursa, which is a small fluid filled sac near a joint. Tendon or soft tissue swelling can also resemble joint swelling. Clinicians first decide whether swelling is inside the joint or around it. This distinction provides a clue but does not establish the cause. The pattern is more informative than one symptom Monoarthritis means one joint is affected. Polyarthritis means several joints are affected. A sudden monoarthritis can occur with septic arthritis, gout, calcium pyrophosphate deposition, injury or haemarthrosis. These conditions can look very similar. Polyarthritis can occur with rheumatoid arthritis, psoriatic arthritis, viral illness and other inflammatory conditions. Infection and crystal disease can occasionally affect several joints. Symmetry, small joint involvement and morning stiffness provide useful clues. They do not confirm rheumatoid arthritis or exclude another diagnosis. A hot swollen joint needs urgent assessment Septic arthritis is an infection within a joint and requires treatment as soon as possible. It often develops quickly and commonly affects one joint. Fever or feeling unwell increases concern, but septic arthritis can occur without fever. Skin colour change can also be less visible on brown or black skin. Gout and calcium pyrophosphate deposition can also cause sudden severe inflammation. Their appearance cannot reliably exclude infection. Recent joint surgery, an artificial joint, immune suppression and rheumatoid arthritis increase septic arthritis risk. Infection can also follow injury or spread through the bloodstream. Contact NHS 111 or request an urgent GP appointment for sudden severe joint pain, swelling, heat or feeling hot, cold or shivery. Persistent synovitis needs timely assessment Persistent synovitis can cause swelling, warmth, stiffness and reduced function. Early morning stiffness lasting over thirty minutes can support an inflammatory pattern. The pattern is not specific because several inflammatory conditions can produce it. Osteoarthritis can also cause stiffness, swelling and episodic inflammation. NICE advises urgent rheumatology referral for suspected persistent synovitis when several joints or small hand or foot joints are affected. Referral should not wait for raised inflammatory markers, a positive rheumatoid factor or positive anti CCP antibodies. Normal results do not exclude rheumatoid arthritis. Skin psoriasis, nail changes or swollen fingers can support possible psoriatic arthritis. Recent infection, urinary symptoms, genital symptoms or eye inflammation can support reactive arthritis assessment. Osteoarthritis affects the whole joint Osteoarthritis is not simply cartilage wearing away until bones grind together. It can involve cartilage, bone, synovium, capsule, muscles and other joint tissues. Pain and physical function do not always match changes seen on an X ray. Some visible changes cause few symptoms, while significant pain can occur with limited imaging change. NICE supports a clinical diagnosis in adults aged forty five or over with typical activity related pain and no prolonged morning stiffness. Routine imaging is not needed when the pattern is typical. Imaging is considered when features are unusual or another diagnosis may be present. Examination separates several possibilities A clinician checks the exact location of swelling, warmth, colour change and tenderness. They compare both sides when that comparison is meaningful. They assess active movement, which the person performs, and passive movement, which the examiner produces gently. Painful restriction of both can support an intra articular problem. Greater restriction of active movement can occur with pain, weakness or a nearby tendon problem. These patterns are helpful but do not diagnose a mechanical block. The examination can include gait, muscle strength, skin, nails and nearby tendons or bursae. Pulses and sensation matter after injury or when circulation is questioned. Blood tests have important limits A full blood count and CRP can support assessment for infection or inflammation. Neither test identifies the cause or excludes septic arthritis alone. Rheumatoid factor and anti CCP antibodies can support rheumatoid arthritis assessment. Positive results are not diagnostic, and negative results do not exclude the condition. Serum urate measures urate in the blood. A high level supports gout assessment but does not prove that current joint pain is gout. Serum urate can fall during a gout flare. NICE advises repeating it after the flare when gout remains strongly suspected despite a lower result. Joint aspiration answers targeted questions Joint aspiration uses a needle to remove synovial fluid. The sample can be examined for cell patterns, crystals and microorganisms. Culture can identify some joint infections, while microscopy can identify urate or calcium pyrophosphate crystals. A negative early result does not always exclude infection. Finding crystals supports crystal arthritis but does not completely exclude septic arthritis. Clinicians interpret the fluid with what the person describes, the examination and blood results. When severe illness suggests infection, hospital treatment should not be delayed while every result is awaited. Antibiotics and joint drainage may both be required. Imaging is selected for a clinical question An X ray can assess fracture, alignment and selected structural changes. It may be normal early in infection or inflammatory arthritis. Ultrasound can detect an effusion, examine some nearby structures and guide aspiration. It cannot determine the cause of fluid by itself. MRI can assess deeper structures, bone and soft tissues when the clinical question requires it. No scan directly measures pain or excludes every joint disease. Treatment follows the cause Septic arthritis usually requires hospital antibiotics and drainage. Crystal arthritis, rheumatoid arthritis, osteoarthritis, injury and bursitis require different management. Steroid injection is not a routine response to an undiagnosed hot swollen joint. Infection must be considered before treatments that suppress inflammation. Osteoarthritis care can include tailored therapeutic exercise, information and weight management when appropriate. Early inflammatory arthritis may need disease modifying treatment from a specialist team. Do not start leftover antibiotics, change prescribed anticoagulants or inject a joint yourself. Medicine choices depend on the diagnosis and individual risks. When to get help Contact NHS 111 or request an urgent GP appointment for sudden severe joint pain, swelling, heat or skin colour change. Seek urgent help when you feel feverish or generally unwell. Seek urgent advice for new pain or swelling around an artificial joint or after recent joint surgery, injection or procedure. Go to A&E or call 999 after an injury if the joint looks deformed, you cannot bear weight, or numbness or tingling develops. Take a child to A&E or call 999 for sudden hip, knee or thigh pain. Do the same for inability to bear weight, fever or worsening illness. Contact NHS 111 or request urgent GP assessment for joint pain with a painful red eye, light sensitivity or blurred vision. Arrange a GP review for persistent swelling, morning stiffness over thirty minutes, recurring symptoms or joint pain affecting sleep and daily life. This lesson explains how clinicians assess joint pain and swelling. It cannot diagnose an individual joint problem or replace urgent medical care.

Joint pain, swelling and stiffness are patterns rather than diagnoses. Clinicians identify where the problem lies, assess urgency and use targeted tests without treating one finding as proof.