01OverviewDefinition, clinical context and the essential points that orientate the chapter.
The referral decision is driven by objective inflammation and phenotype, not diagnostic certainty. Confirm synovitis through soft joint-line swelling, warmth, effusion or painful restriction. Map every joint and examine tendons, entheses, digits, skin, nails and eyes. Record duration and function. Early disease may be intermittent, asymmetric or seronegative; photographs and review during a flare can support an evolving pattern without justifying unsafe delay when swelling is present.
Refer every adult with suspected persistent synovitis of undetermined cause for specialist opinion. Mark the referral urgent, even with normal inflammatory markers or negative serology, when small hand or foot joints are involved, more than one joint is affected, or at least three months elapsed before medical advice was sought. Offer RF when examination confirms synovitis and, if RF is negative, consider anti-CCP; run testing in parallel and never wait for results before referring. Use HLA-B27 only within a compatible spondyloarthritis assessment.
Referral quality affects triage. Include onset, joints swollen, stiffness, extra-articular features, infection and drug history, function, examination, blood results, imaging and treatments already given. Highlight pregnancy, immunosuppression, work impact and rapid progression. A generic 'joint pains, rule out RA' referral without objective findings may delay the correct clinic or obscure an emergency.
While awaiting review, use safe analgesia, maintain activity within tolerance and address smoking and vaccination when appropriate. If a short glucocorticoid intervention is necessary, document the indication, infection assessment, dose, duration and response. Confirm receipt of the referral and provide a route back when symptoms progress; the administrative handoff is part of clinical safety.
Key points
- Refer suspected persistent synovitis affecting more than 1 joint or the small joints of the hands or feet to rheumatology within 3 working days of primary-care presentation; refer every persistent synovitis of uncertain cause without waiting for normal inflammatory markers, negative serology or normal early radiographs.
- Refer rheumatoid-pattern synovitis even when CRP, ESR, RF and anti-CCP are normal and early radiographs show no erosion.
- For suspected axial or peripheral spondyloarthritis, use age at onset, inflammatory back pain, enthesitis, dactylitis, psoriasis, uveitis, bowel disease and family history rather than HLA-B27 alone.
- Examine and document objective swelling; 'joint pain' without anatomy does not allow safe triage.
- Before routine referral, identify a septic-joint phenotype and arrange aspiration, cultures and acute orthopaedic or medical assessment.
- Do not use empirical long courses of oral corticosteroid as a substitute for referral because they mask infection, change the baseline and create cumulative harm.
- Baseline FBC, renal and liver tests, CRP or ESR and targeted serology help later treatment but must run in parallel with the referral.
- Give the patient a clear explanation, expected timeframe and return instructions for fever, one rapidly hotter joint, eye pain, breathlessness, weakness or reduced urine output.
02AetiologyUnderlying causes, associations and risk factors, with why each one matters.
Early autoimmune synovitis
Rheumatoid, psoriatic and undifferentiated inflammatory arthritis often begins before antibodies, radiographic change or the complete disease pattern becomes visible.
Spondyloarthritis spectrum
Inflammation may centre on entheses, whole digits, sacroiliac joints or asymmetric lower-limb joints and associate with psoriasis, uveitis or bowel disease.
Infectious and crystal mimics
Septic, viral, reactive and crystal arthritis can resemble early immune disease and need exposure history, aspiration and targeted testing.
03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.
- 1Synovial, entheseal or infectious inflammation
Objective swelling may arise from autoimmune synovitis, enthesis-centred spondyloarthritis, crystal-triggered innate inflammation or joint infection; distribution, tempo and associated features determine the pathway.
- 2Time-dependent tissue injury
Persistent inflammatory synovium, enthesitis or infection can damage cartilage, bone, tendon and function, so appropriate referral or acute treatment should not await a fully evolved label.
- 3Phenotype evolution
Undifferentiated arthritis can resolve, persist or acquire defining rheumatoid, psoriatic or systemic features, making longitudinal review part of diagnosis.
04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.
Soft swelling of MCP, PIP, wrist or MTP joints lasting weeks with prolonged morning stiffness warrants urgent specialist assessment despite normal screening tests.
Dactylitis, enthesitis, asymmetric lower-limb arthritis, psoriasis, nail disease, uveitis or inflammatory bowel disease should be made explicit in the referral.
Back pain beginning before age forty-five, night waking, buttock pain and improvement with movement supports axial assessment even when radiographs are normal.
Acute severe monoarthritis with fever, immunosuppression, skin infection or a prosthesis requires urgent acute-team sampling and specialty management instead of routine referral.
Proteinuria, haematuria, hypoxia, neuropathy, visual symptoms, cytopenia or myocarditis redirects toward urgent systemic-rheumatic and organ-specialty review.
05InvestigationsWhat to request, why it matters and how to interpret it.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Documented swollen-joint examinationFirst step - Why
- Provide the core evidence for inflammatory-arthritis triage and a baseline for specialist review.
- Interpretation and limitations
- State exact joints and whether swelling is synovial, effusive, bony or oedematous; tenderness without swelling is not interchangeable.
- 02
FBC, renal, liver, CRP and ESR - Why
- Identify inflammation, organ disease and baseline abnormalities relevant to differential diagnosis and future DMARD safety.
- Interpretation and limitations
- Normal results do not cancel referral. Cytopenia, renal or liver change may increase urgency or suggest systemic disease, infection or malignancy.
- 03
RF, followed by anti-CCP when indicated - Why
- Support rheumatoid diagnosis and prognosis when objective synovitis has a compatible phenotype.
- Interpretation and limitations
- Offer RF after examination confirms synovitis and consider anti-CCP if RF is negative. Send tests alongside referral; neither negative serology nor a pending result should delay it.
- 04
Targeted spondyloarthritis testing and imaging - Why
- Support axial or peripheral assessment when specific clinical features are present.
- Interpretation and limitations
- HLA-B27 negativity and normal CRP do not exclude disease; use NICE radiography and MRI sequence for persistent axial suspicion.
- 05
Synovial fluid when infection or crystals are possible - Why
- Prevent routine referral from missing a time-critical septic or crystal joint.
- Interpretation and limitations
- Send culture and crystals together. Identified crystals do not exclude infection, especially with systemic illness or immunosuppression.
06Differential diagnosisRealistic alternatives and the features that help distinguish them.
Rheumatoid arthritis
Persistent symmetrical small-joint swelling and prolonged stiffness supports rheumatoid arthritis even with normal markers and negative antibodies.
Peripheral spondyloarthritis
Dactylitis, enthesitis, psoriasis, nail change, uveitis, bowel disease or asymmetric lower-limb arthritis indicates a spondyloarthritis referral pathway.
Crystal or septic arthritis
Abrupt monoarthritis, marked warmth, fever, immunosuppression or a prosthesis requires synovial culture and crystal analysis before routine referral assumptions.
Non-inflammatory musculoskeletal pain
Bony enlargement, load-related symptoms and absence of objective swelling support osteoarthritis or periarticular disease, with review if the pattern changes.
07ManagementImmediate care, first-line treatment, alternatives and escalation.
01Specialist referralRefer while tests runFirst stepPersistent synovitis exists without current sepsis or organ-threatening features.+
- 1Map swollen joints, function and extra-articular findings; offer RF and, after a negative result, consider anti-CCP for a rheumatoid phenotype while obtaining baseline bloods.
- 2Send the referral without awaiting tests. For suspected persistent synovitis affecting more than 1 joint or the small joints of the hands or feet, refer within 3 working days of primary-care presentation; also mark it urgent under NG100 when symptoms began at least 3 months before medical advice was sought.
- 3Confirm receipt, manage symptoms with a reviewed plan and arrange reassessment if the appointment is delayed or disease progresses.
02Possible spondyloarthritisName the associated featuresEnthesitis, dactylitis, inflammatory axial pain or asymmetric arthritis occurs with psoriasis, uveitis, bowel disease or family history.+
- 1Examine skin, scalp, nails, entheses, digits, spine and peripheral joints and record previous extra-articular episodes and family disease.
- 2Refer through the axial or peripheral spondyloarthritis pathway and request imaging or HLA-B27 only according to the NICE sequence and local service.
- 3Do not dismiss the referral because radiography, HLA-B27 or inflammatory markers are negative when the clinical pattern remains compelling.
03Acute infection concernUse the hot-joint pathway insteadOne joint is abruptly hot, severely restricted or associated with sepsis, bacteraemia risk or a prosthesis.+
- 1Perform urgent systemic assessment and blood cultures, and involve the responsible acute orthopaedic team to arrange joint or deep-tissue sampling; do not perform an unplanned first-contact aspiration of a prosthetic joint.
- 2If septic or unstable, begin resuscitation and parenteral antibiotics after blood cultures without delaying treatment. If stable, obtain appropriate deep samples before antibiotics and follow the acute surgical plan.
- 3Arrange drainage and final culture review, then refer residual or recurrent inflammatory disease after infection has been addressed.
08ComplicationsImportant consequences, why they occur and why they matter clinically.
Diagnostic and treatment delay
Waiting for serology or erosions can postpone disease-modifying treatment while active synovitis causes preventable structural damage and functional loss.
Missed urgent infection
Routing an acutely infected joint to routine rheumatology can allow rapid cartilage destruction, bacteraemia, sepsis and prosthetic failure.
Missed systemic or extra-articular disease
Failure to identify uveitis, psoriasis, inflammatory bowel disease or pulmonary–renal and neurological features can delay organ-specific treatment and misroute urgent care.
09Monitoring and follow-upTreatment response, safety checks and longer-term review.
- Track referral receipt, appointment date and any triage request for additional information.
- Repeat swollen-joint, function and systemic review if symptoms evolve while the patient waits.
- Review NSAID and glucocorticoid exposure for renal, gastrointestinal, cardiovascular, metabolic and infection harms.
- Act on late blood, imaging or synovial-culture results rather than assuming the specialist service will see them.
- Document explicit return instructions and a named route for one hot joint, fever, eye symptoms, breathlessness, weakness or renal change.
10Special situationsVariants, exceptions and circumstances that change the usual approach.
Referral precedes certainty
Early-arthritis services exist to resolve uncertain inflammatory phenotypes before damage, not only to accept already proven rheumatoid arthritis.
Negative tests are not vetoes
Normal markers, antibodies and radiographs have incomplete sensitivity and must not override persistent objective synovitis.
Good referrals contain anatomy
Exact swollen joints, entheses and associated features allow safer triage than a long symptom list without examination.
A hot joint changes destination
Septic arthritis requires immediate sampling and source control; a routine inflammatory clinic cannot safely absorb that delay.
Handover needs confirmation
Submitting a referral without confirming receipt or providing a deterioration route leaves a preventable gap in care.
11Common pitfallsFrequent interpretation and management errors.
- 01
Waiting for a positive RF, anti-CCP or HLA-B27 before referral.
- 02
Failing to state which joints are objectively swollen.
- 03
Sending a septic-joint presentation to a routine clinic.
- 04
Using repeated corticosteroid courses to bridge an administrative delay without review.
- 05
Assuming a normal radiograph excludes early inflammatory disease.