From the Guidelines
The workup for sarcoidosis should begin with a thorough history and physical examination, focusing on multi-system symptoms, and initial testing should include chest X-ray, pulmonary function tests, complete blood count, comprehensive metabolic panel, calcium levels, and angiotensin-converting enzyme (ACE) levels, as recommended by the American Thoracic Society clinical practice guideline 1. The diagnosis and detection of sarcoidosis require a comprehensive approach, including clinical, radiological, and histological evidence of non-caseating granulomas.
- Initial testing should include:
- Chest X-ray
- Pulmonary function tests
- Complete blood count
- Comprehensive metabolic panel
- Calcium levels
- Angiotensin-converting enzyme (ACE) levels
- High-resolution CT scan of the chest is essential to evaluate lung involvement.
- Definitive diagnosis requires histopathological confirmation through biopsy of affected tissues, typically transbronchial lung biopsy or mediastinal lymph node sampling, as stated in the european position paper on rhinosinusitis and nasal polyps 2020 1. Additional specialized testing may include:
- Bronchoalveolar lavage
- Electrocardiogram
- Echocardiogram
- Ophthalmologic examination
- 24-hour urine calcium For extrapulmonary involvement, targeted imaging such as cardiac MRI, brain MRI, or PET scan may be necessary. Tuberculosis should be excluded with tuberculin skin test or interferon-gamma release assay. The workup aims to confirm the diagnosis through demonstration of non-caseating granulomas, assess disease extent and severity, rule out alternative diagnoses, and determine if treatment is necessary. This comprehensive approach is important because sarcoidosis is a multisystem granulomatous disease that can affect virtually any organ, with the lungs and lymphatic system most commonly involved. Serum soluble interleukin-2 (sIL-2R), angiotensin converting enzyme (ACE) and lysozyme levels have become useful tools in the diagnosis of sarcoidosis and for evaluating disease activity, in addition to fluorodeoxyglucose-positron emission tomography (FDG-PET) 1.
From the Research
Sarcoidosis Workup
The workup for sarcoidosis involves a comprehensive assessment of organ involvement and exclusion of other diseases with similar findings. 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, 3.
Organ Assessment
Screening for pulmonary, cardiac, ocular, neurologic, and renal involvement, as well as hypercalcemia, is recommended in the workup for sarcoidosis 4. This includes:
- Pulmonary imaging and pulmonary function tests to assess pulmonary involvement
- A clear history, including palpitations and collapse, and a baseline electrocardiogram or 24-h Holter monitoring to assess cardiac involvement
- Ophthalmological assessment at diagnosis
- Serum calcium level and serum creatinine level to assess renal involvement
- Screening for hypercalciuria at the time of diagnosis may be beneficial 4.
Clinical Presentation
Sarcoidosis can present with a range of symptoms, including:
- Unexplained cough, shortness of breath, or constitutional symptoms 2
- Skin lesions, uveitis, liver or splenic involvement, peripheral and abdominal lymphadenopathy, and peripheral arthritis 3
- Cardiac and neurological manifestations, which can be the initial manifestation of sarcoidosis 3
- Hypercalcemia and renal dysfunction 3.
Diagnostic Challenges
The diagnosis of sarcoidosis can be challenging due to its nonspecific symptoms and the lack of a single reliable diagnostic test 2, 5. However, the use of advanced technologies, such as endobronchial ultrasound-guided biopsy, high-resolution computed tomography, magnetic resonance imaging, and 18F-fluorodeoxyglucose positron emission tomography, has improved the ability to reliably diagnose this condition and accurately forecast its prognosis 5.