Cohort Definition Name: “Antisynthetase syndrome”
Contributor name: Joel N. Swerdel
Contributor OrcId: 0000-0001-9491-2737
Logic Description: First occurrence of Antisynthetase syndrome.
Recommended study application: outcome, indication
Assertion statement: This cohort definition was executed on at least one real person-level observational health data source and resulted in a cohort with at least 1 person.
Submitted cohort definition:
antiSynSyn.txt (1.3 KB)
Target Clinical Description
Antisynthetase syndrome is a rare autoimmune disease characterized by the presence of specific autoantibodies known as antisynthetase antibodies. These antibodies target a group of enzymes called aminoacyl-tRNA synthetases, which are essential for protein synthesis within cells. Antisynthetase syndrome primarily affects the muscles and lungs but can also involve other organs such as the joints, skin, and kidneys. The exact cause of the condition is unknown, but it is believed to result from an abnormal immune response. Antisynthetase syndrome typically presents with a combination of myositis (inflammation of the muscles) and interstitial lung disease. It predominantly affects adults, with a higher incidence in women. Early recognition and treatment are important to manage symptoms and prevent long-term complications.
Presentation for Antisynthetase syndrome:
-
Muscle involvement: Muscle weakness, muscle pain, and fatigue, typically affecting the muscles around the shoulders, upper arms, neck, and thighs.
-
Interstitial lung disease: Shortness of breath, dry cough, and decreased exercise tolerance due to inflammation and scarring of lung tissue.
-
Raynaud’s phenomenon: Cold-induced color changes in the fingers or toes due to constriction of blood vessels.
-
Arthritis: Joint pain, swelling, and stiffness.
-
Skin manifestations: Gottron’s papules (red or violet patches over the knuckles), heliotrope rash (reddish-purple rash around the eyes), and mechanic’s hands (thickened, cracked skin on the palms and fingertips).
-
Fever and fatigue: General feelings of malaise and systemic symptoms.
-
Gastrointestinal involvement: Some individuals may experience dysphagia (difficulty swallowing) or other gastrointestinal symptoms.
Assessment for Antisynthetase syndrome:
-
Medical history and physical examination: Evaluation of symptoms, assessment of muscle strength and joint mobility, and identification of characteristic skin findings.
-
Blood tests: Detection of specific autoantibodies, such as anti-Jo-1 antibody, which is most commonly associated with antisynthetase syndrome. Other blood tests may include muscle enzyme levels (e.g., creatine kinase) and markers of inflammation (e.g., erythrocyte sedimentation rate, C-reactive protein).
-
Pulmonary function tests: Assess lung function and detect abnormalities suggestive of interstitial lung disease, such as decreased lung volumes and impaired gas exchange.
-
Imaging studies: Chest X-ray or high-resolution computed tomography (HRCT) to evaluate lung involvement and detect signs of interstitial lung disease.
-
Electromyography (EMG): Measures the electrical activity of muscles to assess muscle function and detect abnormalities.
-
Skin biopsy: In some cases, a biopsy of affected skin may be performed to confirm the presence of characteristic histopathological changes.
Differential diagnoses for Antisynthetase syndrome:
-
Idiopathic inflammatory myopathies: Conditions such as dermatomyositis, polymyositis, and inclusion body myositis, which can present with similar muscle and skin manifestations.
-
Other connective tissue diseases: Systemic lupus erythematosus, systemic sclerosis, and mixed connective tissue disease, which can have overlapping features with Antisynthetase syndrome.
-
Other causes of interstitial lung disease: Idiopathic pulmonary fibrosis, sarcoidosis, and occupational lung diseases.
Treatment plan for Antisynthetase syndrome:
-
Glucocorticoids: High-dose oral or intravenous corticosteroids, such as prednisone, are often used initially to control inflammation and manage symptoms.
-
Immunosuppressive medications: Additional immunosuppressive drugs like methotrexate, azathioprine, mycophenolate mofetil, or rituximab may be prescribed to reduce disease activity and maintain remission.
-
Pulmonary management: Treatment of interstitial lung disease may involve the use of immunosuppressive medications, oxygen therapy, pulmonary rehabilitation, and close monitoring of lung function.
-
Symptom-specific treatments: Medications for pain management, physical therapy to improve muscle strength and function, and interventions to address specific organ involvement as needed.
-
Multidisciplinary care: Collaborative care involving rheumatologists, pulmonologists, dermatologists, and other specialists to provide comprehensive management and address specific organ involvement.
Prognosis for Antisynthetase syndrome: The prognosis for individuals with Antisynthetase syndrome varies depending on the severity of organ involvement, response to treatment, and presence of complications. Early recognition and treatment can help control disease activity, minimize organ damage, and improve long-term outcomes. Some individuals may achieve remission or have mild disease with appropriate management, while others may experience persistent symptoms or complications. Lung involvement is a significant determinant of prognosis, and the development of severe interstitial lung disease can significantly impact survival and quality of life. Regular monitoring and follow-up with healthcare professionals are crucial to manage the condition effectively and optimize outcomes.