A Comprehensive Review of Sarcoidosis Diagnosis and Monitoring for the Pulmonologist

Abstract

Sarcoidosis is a systemic granulomatous disease with heterogenous clinical manifestations. Here we review the diagnosis of sarcoidosis and propose a clinically feasible diagnostic work-up and monitoring protocol. As sarcoidosis is a systemic disease, a multidisciplinary approach is recommended for best outcomes. However, since the lungs are frequently involved, the pulmonologist is often the referral physician for diagnosis and management. When sarcoidosis is suspected, diagnosis needs to be confirmed and organ involvement/impairment assessed. This process is also required to establish whether the patient is likely to benefit from treatment, as many cases of sarcoidosis are self-limited and remit spontaneously. Whether or not treatment is started, effective regular follow-up is necessary to monitor changes in the disease, including extension, progression, remissions, flare-ups, and complications.

Keywords: Biomarkers; Clinical evaluation; Diagnosis; Monitoring; Sarcoidosis.

Fig. 1

Suggested work-up in cases of suspected sarcoidosis. IGRA is usually preferred to check for latent tuberculosis, since sarcoidosis patients are often anergic to the intradermal Mantoux test ⁺Elevated serum renal and liver function tests may be common in sarcoidosis involvement even in the absence of other signs and/or symptoms. *25-Hydroxyvitamin D3, 1,25-hydroxyvitamin D3, and parathyroid hormone should be measured in patients with hypercalcaemia and/or hypercalciuria to assess the degree and the cause of calcium dysregulation; hypercalcaemia with low parathyroid hormone levels and normal or low 25-hydroxyvitamin D3 levels suggests sarcoidosis. **Autoantibodies are typically negative (seldom positive at low titers) in sarcoidosis, while lymphopenia may sometimes be observed. ⁺⁺There is often a polyclonal hypergammaglobulinaemia, but never a low blood level of gamma globulins DLco diffusing capacity of the lung for carbon monoxide, CT computed tomography, FBS fibrobronchoscopy, BAL bronchoalveolar lavage, ECG electrocardiogram, IGRA Interferon-γ release assay, HIV human immunodeficiency virus, ACE angiotensin-converting enzyme