Monitoring

Monitoring for complications (idiopathic inflammatory myopathy [IIM]-disease activity and extramuscular manifestations)

  • Creatine kinase (if raised at initial presentations) should be monitored regularly as a biomarker for disease activity.

  • Monitoring of extramuscular manifestations disease activities should be individualized according to IIM-subtype and clinical manifestations. These include:

    • Lung function tests and HRCT

    • Echocardiogram

    • Cancer screening

All IIM-subtypes except for antisynthetase syndrome and inclusion body myositis have a twofold to sevenfold increased risk of malignancy compared with the general population. The risk for malignancy is highest within 3 years before and up to 3 years after myositis diagnosis, but remains elevated for an extended time period, up until 10 years in some subtypes.[140][141][142][143]​​[144]​​

The International Guideline for Idiopathic Inflammatory Myopathy Associated Cancer Screening proposes that the risk of cancer differs according to IIM-subtype, type of MSA/MAA present, and clinical features.[74]

  • High-risk factors include: dermatomyositis, anti-TIF1gamma, Anti-NXP2, Age >40 years at IIM onset, persistent high disease activity despite therapy, dysphagia (moderate to severe), and cutaneous necrosis.

  • Intermediate-risk factors include: clinically amyopathic dermatomyositis, polymyositis, immune-mediated necrotizing myopathy, Anti-SAE1, Anti-HMGCR, Anti-Mi2, Anti-MDA5, and male gender.

  • Low-risk factors include: antisynthetase syndrome, overlap myositis, Anti-SRP, Anti-Jo1, Non-Jo1, antisynthetase antibodies, MAA, Raynaud’s phenomenon, inflammatory arthropathy, and interstitial lung disease.

All patients with IIM should receive a basic cancer screening panel at the time of IIM diagnosis. These are:[74]

  • Comprehensive history

  • Comprehensive physical exam

  • Complete blood count (CBC)

  • Serum liver function test

  • Serum erythrocyte sedimentation rate and/or plasma viscosity

  • Serum c-reactive protein

  • Serum protein electrophoresis

  • Urinanalysis

  • Plain chest x-ray radiograph

For IIM patients with at least two high-risk or two intermediate-risk factors, an enhanced screening panel is recommended. This includes comprises:[74]

  • CT scan of neck, thorax, abdomen and pelvis

  • Cervical screening

  • Mammography

  • Prostate-specific antigen

  • CA-125

  • Pelvic or transvaginal ultrasonography for ovarian cancer

  • Fecal occult blood

  • Nasoendoscopy for adult-onset IIM in geographic regions where the risk of nasopharyngeal carcinoma is increased

Additional screening to be considered may include 18F-FDG PET-CT, and upper and lower gastrointestinal endoscopy.

The International Myositis Assessment and Clinical Studies Group recommends that the basic cancer screening panel be repeated annually for 3 years following IIM diagnosis in patients with two or more high-risk factors.[74]

Monitoring for corticosteroid treatment adverse effects

  • Bone density is measured at baseline and every 18-24 months during corticosteroid treatment. Calcium and vitamin D supplementation is recommended. Bisphosphonate is used for osteoporosis prophylaxis.

  • Initial fasting blood glucose and regular blood glucose levels are recommended in chronic corticosteroid treatment, to detect corticosteroid-induced diabetes.

  • Chest x-ray is performed before starting corticosteroids, to detect pulmonary infections such as tuberculosis.

  • Proton pump inhibitors may be prescribed if the patient develops gastrointestinal discomfort or has a history of peptic ulcer disease.

  • Blood pressure (BP) is measured on each visit, as accelerated hypertension and renal failure could occur particularly in patients with scleroderma or overlap myositis.[108][145]

  • Eye exams are performed periodically to check for cataracts and glaucoma.

Monitoring for immunosuppressant treatment adverse effects

  • Methotrexate: CBC, renal function, liver function tests (LFTs), chronic hepatitis B and C infection status, and chest x-ray are checked as per local guidelines. Measurement of baseline and periodic PFTs with diffusion can be considered.

  • Azathioprine: CBC and liver function tests are checked as per local guidelines.

  • Mycophenolate: CBC, renal function, liver function tests, chronic hepatitis B and C infection status, and chest x-ray should be checked before commencement as per local guidelines. CBC, renal function, and liver function tests should be monitored regularly.

  • Intravenous immune globulin (IVIG): measurement of baseline renal function is recommended because of risk of IVIG-induced renal failure.[108]​ Patients should also be assessed for presence of chronic hepatitis B and/or C viral infections prior to commencement of IVIG treatment as postinfusion infections have been reported.

  • Tacrolimus: CBC, renal function, liver function tests, chronic hepatitis B and C infection status, and chest x-ray should be checked before commencement as per local guidelines. Monitoring BP and checking electrolytes and renal function are recommended. Serum trough tacrolimus levels should also be monitored periodically.

  • Cyclosporine: CBC, renal function, liver function tests, chronic hepatitis B and C infection status, and chest x-ray should be checked before commencement as per local guidelines. Monitoring BP and checking electrolytes and renal function are recommended. Serum trough cyclosporine levels should also be monitored periodically.

  • Rituximab: CBC, renal function, chronic hepatitis B and C viral infections status, and serum immunoglobulin G/A/M should be checked at baseline. CBC should also be monitored 2-4 weeks after treatment with rituximab to assess for neutropenia. Serum immunoglobulin G/A/M should be measured at least 6 months after rituximab treatment and before rituximab treatment is repeated.

Use of this content is subject to our disclaimer