Sarcoidosis Diagnosis and Management

Clinical Presentation

The American Thoracic Society recommends identifying highly probable clinical features, including Löfgren's syndrome, characteristic skin lesions, ocular manifestations, erythema nodosum, and seventh cranial nerve paralysis, to aid in the diagnosis of sarcoidosis 1
Pulmonary symptoms, such as persistent dry cough, dyspnea, and chest pain, are present in approximately 90% of cases 1
Regular follow-up is recommended for patients with Löfgren's syndrome, which often has a favorable prognosis with spontaneous resolution within 2 years in most cases, as suggested by the American Thoracic Society 1

Chest radiography is the initial test of choice, looking for bilateral hilar adenopathy, upper lobe or diffuse infiltrates, and peribronchial thickening 1
Chest CT is useful for detecting perilymphatic nodules, perilobular and fissural distribution with upper and posterior predominance 1
Cardiac MRI is the preferred test for suspected cardiac involvement, while PET scan is used for suspected extrapulmonary involvement 1
Laboratory tests, including serum calcium and vitamin D levels, liver function tests, renal function tests, complete blood count, and angiotensin-converting enzyme (ACE) level, are recommended to support the diagnosis of sarcoidosis, according to the American Thoracic Society 1
Biopsy of the most accessible involved organ, showing non-caseating granulomas, and bronchoalveolar lavage (BAL) showing lymphocytosis or elevated CD4:CD8 ratio, are diagnostic tests used to confirm sarcoidosis, as suggested by the American Thoracic Society 1

The American College of Chest Physicians recommends that the diagnosis of sarcoidosis requires three essential criteria:

Criteria	Description
Clinical presentation	Compatible symptoms and signs
Histopathologic evidence	Non-caseating granulomas in at least one organ
Exclusion of alternative causes	Rule out other granulomatous diseases

Elevated serum ACE (>50% of upper limit of normal) is considered a supportive finding, and ACE level is a "probable" supportive test for sarcoidosis diagnosis, according to the American Thoracic Society 1

It is essential to rule out other granulomatous diseases, including infections, malignancy, berylliosis, vasculitides, IgG4-related disease, and common variable immunodeficiency 1
Medication-induced granulomatous reactions, such as those caused by immune checkpoint inhibitors or anti-TNF-α agents, should also be considered 1
The diagnosis should exclude other granulomatous diseases such as tuberculosis, fungal infections, lymphoma, berylliosis, IgG4-related disease, vasculitides, and common variable immunodeficiency, as noted by the American Thoracic Society 1

Baseline ECG is recommended for all patients with extracardiac sarcoidosis, and for suspected cardiac involvement, cardiac MRI is preferred, and if MRI is unavailable, dedicated PET is recommended over echocardiography, as suggested by the American Thoracic Society 1
For suspected pulmonary hypertension, initial testing with transthoracic echocardiography is recommended, and if echocardiogram suggests PH, right heart catheterization is recommended, according to the American Thoracic Society 1
For neurological involvement, MRI with gadolinium enhancement is highly specific, and for osseous involvement, X-ray, CT, or MRI can show osteolysis, cysts, or trabecular pattern, as recommended by the American Thoracic Society 1

Systemic corticosteroids are the mainstay of treatment for symptomatic cases of sarcoidosis, with immunosuppressive drugs potentially required for refractory cases, as suggested by the European Respiratory Society 1
Common pitfalls in diagnosis and management include misdiagnosis due to failure to exclude other granulomatous diseases, incomplete evaluation, and over-reliance on ACE levels, as reported by the American College of Chest Physicians 1