A 35-year-old Indian woman with SLE of 5 years' duration is evaluated for persistent joint pain and swelling. On examination, she has symmetrical polyarthritis affecting the hands, wrists, and knees. Which is the most common pattern of joint involvement in SLE?

## Most Common Joint Involvement Pattern in SLE **Key Point:** Non-erosive polyarthritis of the small joints (hands, wrists, and knees) is the most common articular manifestation of SLE, occurring in 60–90% of SLE patients at some point during their disease course. ### Characteristics of SLE Arthritis #### Non-Erosive Nature 1. **No radiographic bone erosions**: Unlike rheumatoid arthritis, SLE arthritis does not cause permanent joint damage or erosions on X-ray, even with chronic inflammation. 2. **Reversibility**: Joint symptoms and swelling typically resolve completely with treatment and do not lead to functional disability or joint deformity. 3. **Mechanism**: Immune complex deposition in synovial tissue causes inflammation, but the inflammatory process does not activate osteoclasts to the degree seen in RA. #### Distribution Pattern | Feature | SLE Arthritis | RA | Distinction | |---|---|---|---| | **Erosions** | Absent | Present | SLE is non-erosive | | **Sites** | Small joints (PIP, MCP, wrists, knees) | Small joints (PIP, MCP, wrists) | Both similar | | **Symmetry** | Symmetrical | Symmetrical | Both similar | | **Reversibility** | Yes, complete | No, permanent | Key difference | | **Deformity** | Jaccoud's arthropathy (rare) | Common | SLE deformity is rare | **High-Yield:** The distinction between SLE arthritis (non-erosive) and RA (erosive) is a classic NEET PG question. Remember: **SLE arthritis does NOT cause erosions**. ### Jaccoud's Arthropathy - **Definition**: Reversible joint deformity in SLE (and other connective tissue diseases) without erosions. - **Mechanism**: Ligamentous laxity and inflammation, not bone destruction. - **Frequency**: Occurs in ~5–10% of SLE patients with chronic arthritis. - **Reversibility**: Deformities can improve or resolve with disease control. ### Frequency of Articular Manifestations - **Polyarthritis** (most common): 60–90% of SLE patients - **Arthralgia without arthritis**: 40–50% - **Monoarticular or oligoarticular**: Rare (<10%) - **Erosive arthritis**: <5% (and when present, suggests overlap with RA or other conditions) **Clinical Pearl:** A patient with SLE presenting with erosive arthritis should raise suspicion for concurrent rheumatoid arthritis (overlap syndrome) or misdiagnosis; pure SLE arthritis is non-erosive. **Mnemonic:** **NERD** = **N**on-erosive, **E**arly reversible, **R**eversible, **D**istribution in small joints — features of SLE arthritis. [cite:Harrison 21e Ch 312]