Systemic Lupus Erythematosus

Introduction

• Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease associated with antinuclear antibody (ANA) production
• Clinical manifestations of SLE can involve nearly every organ system, including the skin, heart, lungs, kidneys, nervous system, blood and musculoskeletal system
• Patients with SLE may initially present to the orthopaedist, because joint pain is one of the earliest and most common symptoms of SLE, occurring in 50-95% of patients

Natural History

• Incidence 4.6/100,000 
• More common in women than in men (9:1 ratio)
• Usually diagnosed between ages 15-35

Clinical Presentation

Musculoskeletal Findings

• Arthritis
  • Symmetric
  • Migratory
  • Preferentially affects small joints of hands, wrist, and knees
  • There may also be soft tissue swelling and/or subcutaneous nodules
• Muscles
  • Myalgia : generalized muscle ache occurs in 40-80% of patients
  • Myositis : 5-11% of patients
• Bone (side effects of chronic steroid therapy)
  • Avascular necrosis
  • Osteoporosis
  • Stress fractures
• Cartilage : Pain in costo-chondral junctions
• Tendons : Degenerative rupture associated with longstanding disease and chronic steroid use

Differential Diagnosis

Lupus arthritis must be differentiated from rheumatoid arthritis. Features that suggest lupus arthritis rather than rheumatoid arthritis are the following:

• Migratory arthritis disappearing from a joint in a matter of days
• Morning stiffness lasting only minutes (RA lasts hours)
• Pain out of proportion to physical exam
• Involvement of PIP>MCP>wrist>knee joints (RA: MCP>wrist>knee) 

Diagnostic Criteria

Criteria defined by the American Rheumatologic Association.  Any 4/11 must be present (serially or simultaneously) for the diagnosis

1. Malar butterfly rash
   • Malar eminences
   • Spares nasolabial folds
2. Discoid rash
   • Raised erythematous patches
   • Keratotic scaling
3. Photosensitivity
4. Oral ulcers (painless)
5. Arthritis
   • Non-erosive arthritis
   • Involves 2 or more peripheral joints
   • Manifests as tenderness, swelling and effusion
6. Serositis
   • Pleuritis
   • Pericarditis
7. Renal dysfunction
   • Proteinuria
   • RBC casts
8. Neurologic dysfunction
   • Seizure
   • Psychosis
9. Hematologic dysfunction
   • Hemolytic anemia
   • Leukopenia
   • Thrombocytopenia
   • Lymphopenia
10. Immunologic evidence
    • LE cell
    • Anti-DNA antibody
    • Anti-SM antibody
    • False positive test for syphilis
11. Positive ANA

Treatment

Arthritis

• NSAIDs
  • Predominantly for inflammation
  • Consider adding PPI, if history of peptic ulcers or GI bleeding
  • Lupus nephritis is a relative contraindication for NSAIDs and selective COX-2 inhibitors
• Acetaminophen: for pain with little inflammation
• Antimalarials (hydroxycholoquine): add to NSAIDs in non-responders
• Methotrexate or leflunomide: for resistant inflammatory arthritis
• Tricyclic antidepressants (amitriptyline): for pain refractory to the above treatments

Avascular Necrosis

• Best treatment is prevention
• Avoid chronic high-dose corticosteroids

Osteoporosis Prevention

• Indicated for all SLE patients
• Lifestyle factors
  • Stop smoking
  • Limit alcohol
  • Exercise
• Calcium and vitamin D supplements
• Limit dose and duration of steroids
• Bisphosphonate: indicated for patients with
  • Osteoporosis
  • Osteopenic fractures
  • Bone loss >5% per year 

References

• Cuccurullo, S (ed).  Physical Medicine and Rehabilitation Board Review. Demos Medical Publishing, 2004
• Egol, KA et al. Orthopaedic Manifestations of Systemic Lupus Erythematosus.  Bull Hosp Jt Dis.  60(1):29-3, 2001
• Schur, PH and Wallace, DJ.  Musculoskeletal manifestations of systemic lupus erythematosus.  In: Up To Date, Basow, DS (Ed), Up To Date, Waltham, MA, 2008
• Zoma, A.  Musculoskeletal involvement in systemic lupus erythematosus.  Lupus.  13(11):851-3, 2004