How does silica exposure affect arthrosis and what are the management options?

Silica Exposure and Arthrosis: Effects and Management Options

Occupational exposure to silica is associated with an increased risk of developing osteoarthritis (OA), particularly in individuals with high exposure levels (>0.048 mg/m³), requiring comprehensive management strategies including workplace modifications, physical therapy, and appropriate pharmacological interventions.

Relationship Between Silica Exposure and Arthrosis

Silica exposure has been linked to several musculoskeletal conditions, including osteoarthritis. The evidence suggests:

• Strong evidence exists that occupational activities involving exposure to silica can increase the risk of developing osteoarthritis in men and women 1
• High silica exposure (>0.048 mg/m³) is associated with significantly higher incidence rates of seropositive rheumatoid arthritis (2.59; 95% CI 1.24 to 4.76) compared to non-exposed or less-exposed groups 2
• Occupational activities involving lifting, cumulative physical loads, full-body vibration, and kneeling/squatting/bending increase the risks of developing OA 1

Risk Assessment and Diagnosis

When evaluating a patient with suspected silica-related arthrosis:

• Assess occupational history focusing on industries with high silica exposure:

  • Construction industry
  • Mining operations
  • Cement industry
  • Brick manufacturing
  • Pottery and ceramic work
  • Foundry work 3, 4

• Clinical examination remains the method of choice for detecting arthritis 1

• In doubtful cases, ultrasound, power Doppler, and MRI may help detect synovitis 1

• Laboratory tests should include complete blood cell count, urinary analysis, transaminases, and antinuclear antibodies to exclude other diseases 1

• Monitor for factors predicting persistent and erosive disease:

  • Number of swollen and tender joints
  • ESR or CRP levels
  • Rheumatoid factor and anti-CCP antibodies
  • Radiographic erosions 1

Management Strategies

Non-Pharmacological Interventions

1. Primary Prevention:

   • Minimize silica dust concentrations in the workplace
   • Implement ventilation and dust extraction systems
   • Use personal protective equipment (PPE)
   • Conduct regular medical surveillance of exposed workers 3

2. Physical Therapy:

   • Dynamic exercises and physical activity are strongly recommended for all patients with hand, hip, and knee OA 1
   • Occupational therapy is beneficial as an adjunct to pharmaceutical interventions 1
   • Hydrotherapy can be applied as an adjunct treatment 1

3. Orthoses/Assistive Devices:

   • Orthoses should be considered for symptom relief in patients with hand OA 1
   • Assistive devices can help maintain work ability 1

Pharmacological Management

1. First-line Treatments:

   • Topical NSAIDs are strongly recommended for hand OA 1
   • Oral NSAIDs should be considered after evaluation of gastrointestinal, renal, and cardiovascular status 1
   • Acetaminophen/paracetamol can be used for symptom relief 1

2. Second-line Treatments:

   • Systemic glucocorticoids may reduce pain and swelling and should be considered as adjunctive treatment (mainly temporary) 1
   • Intra-articular glucocorticoid injections should not generally be used in patients with hand OA but may be considered in patients with painful interphalangeal joints 1
   • Methotrexate is considered the anchor drug for patients at risk of developing persistent disease 1

3. Treatments Not Recommended:

   • Nutraceuticals (glucosamine, chondroitin) are not recommended for hand OA 1
   • No evidence supports the use of disease-modifying drugs in OA 1

Surgical Options

• Surgery should be considered for patients with structural abnormalities when other treatment modalities have failed 1
• For thumb base OA, trapeziectomy is the recommended surgical approach 1
• For proximal interphalangeal joints, arthroplasty (typically silicone implants) is preferred 1
• For distal interphalangeal joints, arthrodesis is recommended 1
• Rehabilitation is important post-operatively 1

Monitoring and Follow-up

• Disease activity should be assessed at 1-3 month intervals until remission is achieved 1
• Structural damage should be assessed by radiographs of hands and feet every 6-12 months during the first few years 1
• Functional assessment (e.g., HAQ) can complement disease activity and structural damage monitoring 1
• Long-term follow-up should be adapted to the patient's individual needs, considering:
  • Severity of symptoms
  • Presence of erosive disease
  • Use of pharmacological therapy that needs re-evaluation 1

Special Considerations

• Silica exposure may cause multiple diseases including silicosis and silica-associated tuberculosis 5
• The risk of silica-related conditions is exacerbated by HIV in low-income countries 5
• Patients with silica exposure should be monitored for both respiratory and musculoskeletal complications 3, 4
• Immunomodulation and oxidative stress have been observed in silica-exposed workers, which may contribute to disease pathogenesis 6

By implementing these comprehensive management strategies, healthcare providers can effectively address both the occupational exposure to silica and the resulting arthrosis, improving patient outcomes and quality of life.