Differential Diagnosis for Wrist Pain with Low-Grade Fever
Septic arthritis is the most critical diagnosis to exclude immediately in any patient presenting with wrist pain and fever, as delayed treatment can lead to irreversible cartilage destruction within days. 1
Immediate Life-Threatening Considerations
- Septic arthritis of the wrist is the primary emergency diagnosis that must be ruled out first, as fever with joint pain is a red flag for infection 1
- Joint aspiration should be performed immediately without waiting for advanced imaging when infection is suspected 1
- Send aspirate for cell count, Gram stain, and aerobic/anaerobic cultures; add fungal cultures if immunocompromised 1
- Crystal analysis must be performed simultaneously, as gout and pseudogout can mimic infection and may coexist 1
Inflammatory Arthritis Differential
- Adult-onset Still's disease should be strongly considered when wrist arthritis presents with fever, typically accompanied by characteristic salmon-pink rash 2
- Rheumatoid arthritis characteristically targets the wrists with symmetric involvement and morning stiffness lasting >1 hour, though fever is not typical unless there is systemic disease activity 2
- Obtain ESR and CRP at baseline, as elevated acute phase reactants predict inflammatory arthritis 2
- RF and/or ACPA testing should be performed for RA evaluation, though negative tests do not exclude the diagnosis 2
Crystal Arthropathy
- Gout may present with fever and can superimpose on pre-existing osteoarthritis 2
- Joint aspiration with crystal analysis is essential to differentiate from infection 1
Infectious Considerations Beyond Septic Arthritis
- Soft tissue infection or abscess under any splint or immobilization device must be examined for, looking specifically for fluctuance suggesting abscess formation 1
- Ultrasound can identify fluid collections or abscesses and guide aspiration simultaneously 1
- Incision and drainage is necessary if abscess is present 1
Diagnostic Algorithm
Step 1: Immediate Assessment
- Examine for signs of infection: warmth, erythema, swelling, fluctuance 1
- Assess fever pattern and systemic symptoms (weight loss, malaise, rash) 2
- Determine if patient has been immobilized or splinted (infection risk) 1
Step 2: Urgent Laboratory and Aspiration
- Perform joint aspiration immediately if septic arthritis suspected—do not delay for imaging 1
- Obtain ESR, CRP, RF, ACPA 2
- Send aspirate for cell count, Gram stain, cultures (aerobic, anaerobic, fungal if indicated), and crystal analysis 1
Step 3: Initial Imaging
- Three-view wrist radiographs to exclude fractures and assess for erosions 2, 3
- Ultrasound can identify fluid collections and guide aspiration if needed 1
Step 4: Advanced Imaging (Only After Aspiration)
- MRI with IV contrast to stage infection extent or identify abscesses requiring drainage 1
- MRI can also quantify active synovitis and detect bone marrow edema (osteitis) if inflammatory arthritis is the diagnosis 2
Critical Clinical Pitfalls
- Never delay joint aspiration to obtain MRI when infection is suspected—this delays critical treatment and can lead to cartilage destruction within days 1
- Normal radiographs do not exclude significant pathology, particularly early inflammatory arthritis or infection 2
- Erosive hand osteoarthritis can mimic inflammatory arthritis with abrupt onset, marked pain, and mildly elevated CRP, but fever is not characteristic 2
- Haemochromatosis mainly targets MCPJs and wrists and should be considered in the appropriate clinical context 2
Pattern Recognition for Non-Infectious Causes
If infection is definitively excluded:
- Morning stiffness >30 minutes suggests inflammatory arthritis rather than mechanical causes 2
- Symmetric small joint involvement suggests RA 2
- Single ray involvement or DIPJ targeting suggests psoriatic arthritis 2
- Radial-sided pain suggests De Quervain's or scapholunate pathology 2
- Ulnar-sided pain suggests TFCC issues 2, 3