From the Guidelines
The initial workup for sarcoidosis should include a comprehensive clinical evaluation, chest X-ray, pulmonary function tests, laboratory studies, and often a biopsy to confirm the diagnosis. Begin with a thorough history and physical examination, focusing on multi-system symptoms like fatigue, cough, shortness of breath, skin lesions, joint pain, and eye symptoms. Laboratory tests should include complete blood count, comprehensive metabolic panel, serum calcium, 25-hydroxyvitamin D, angiotensin-converting enzyme (ACE) levels, and inflammatory markers like erythrocyte sedimentation rate and C-reactive protein. Pulmonary function tests typically show restrictive patterns with decreased diffusion capacity. High-resolution chest CT is more sensitive than X-ray and can reveal characteristic findings like hilar lymphadenopathy and pulmonary nodules. Tissue biopsy showing non-caseating granulomas is the gold standard for diagnosis, commonly obtained from accessible sites like lymph nodes, skin lesions, or lung tissue via bronchoscopy with transbronchial biopsy. Additional specialized testing may include electrocardiogram, ophthalmologic examination, and tuberculin skin test to exclude tuberculosis. This comprehensive approach is necessary because sarcoidosis is a multisystem granulomatous disease with variable presentation, and diagnosis requires exclusion of other granulomatous conditions.
Some key points to consider in the initial workup include:
- A thorough clinical evaluation to identify multi-system symptoms and determine the extent of disease involvement
- Laboratory tests to assess for inflammatory markers, serum calcium, and ACE levels
- Pulmonary function tests to evaluate for restrictive patterns and decreased diffusion capacity
- Imaging studies, such as chest X-ray and high-resolution chest CT, to identify characteristic findings like hilar lymphadenopathy and pulmonary nodules
- Tissue biopsy to confirm the diagnosis and exclude other granulomatous conditions
According to the European Respiratory Journal study 1, the management of sarcoidosis can be challenging, and a comprehensive approach is necessary to diagnose and treat the disease. The study also highlights the importance of considering the patient's quality of life and risk of death or permanent disability when making treatment decisions. Another study published in the European Respiratory Review 1 provides Delphi consensus recommendations for a treatment algorithm in pulmonary sarcoidosis, which includes glucocorticoids as initial therapy for most patients, with non-biologics and biologic therapies considered in severe or extrapulmonary disease.
Overall, the initial workup for sarcoidosis should be comprehensive and tailored to the individual patient's needs, with a focus on confirming the diagnosis, assessing the extent of disease involvement, and identifying the most effective treatment approach.
From the Research
Initial Workup for Sarcoidosis
The initial workup for sarcoidosis involves a combination of clinical, radiologic, and pathologic evaluations. The diagnosis relies on three criteria:
- A compatible clinical and radiologic presentation
- Pathologic evidence of noncaseating granulomas
- Exclusion of other diseases with similar findings, such as infections or malignancy 2
Diagnostic Tests
Several diagnostic tests can be used to support the diagnosis of sarcoidosis, including:
- Chest X-ray or high-resolution computed tomography (HRCT) scans to assess lung involvement and detect granulomas
- Serum angiotensin-converting enzyme (ACE) levels, which can be elevated in patients with sarcoidosis, especially those with active disease 3, 4
- Gallium scans, which can help localize areas of disease involvement and assess disease activity 3, 4
- Pulmonary function tests (PFTs) to evaluate lung function
- Tissue biopsy, such as transbronchial or ultrasound-guided biopsy of mediastinal lymph nodes, to confirm the presence of noncaseating granulomas 5
Clinical Evaluation
A careful history and physical examination are essential to identify "footprints" of sarcoidosis or features suggesting alternative diagnoses. Some presentations may be classic and do not require tissue confirmation, but a tissue biopsy should be performed if doubt exists 5. The clinical evaluation should also consider epidemiologic factors, such as age, ethnicity, and geographic location, as well as the mode of onset and initial clinical course 2.
Imaging Studies
HRCT scans can distinguish between active inflammatory changes and irreversible fibrosis, and can be useful in assessing disease severity and monitoring response to treatment 6. HRCT scans can also help identify atypical sarcoidosis patterns, which may be associated with chronic disease and lower ACE levels 6.
Laboratory Tests
Serum ACE levels can be used to monitor disease activity and response to treatment, but should be interpreted in conjunction with other diagnostic tests and clinical evaluations 3, 4. A negative ACE level, combined with a normal gallium scan, can have a high predictive value for excluding active sarcoidosis 4.