Advances in imaging of cardiopulmonary involvement in sarcoidosis:

Why do people die from pulmonary sarcoidosis?

PURPOSE OF REVIEW

In sarcoidosis, the design and validation of an appropriate risk stratification strategy is hampered by the considerable variability in initial presentation, disease evolution, and outcome. Although spontaneous resolution of the disease is described in a large proportion of patients, approximately 20-30% would present with chronic or progressive lung disease that has been associated with morbidity and mortality. Higher morbidity and mortality can be related to both the disease severity and extent as well as its treatments. We review the utility of integration of clinical, pathological, and radiological features of pulmonary sarcoidosis to detect pulmonary sarcoidosis patient at risk of developing severe, fibrotic lung disease.

RECENT FINDINGS

Recently published studies suggested a mortality rate of 11-14 per 1000 person-years. Demographic characteristics such as age, sex, and race may play a role but conflicting evidence are reported depending on the origin of the population. To date, there are no tools that can reliably predict the exact group of pulmonary sarcoidosis patients to progress to fibrosis. Imaging contributes significantly to the diagnosis and management of patients with sarcoidosis as it can provide useful information regarding the discrimination between reversible and irreversible disease, the extent of the parenchymal damage and the presence of possible complications. Symptoms and lung function tests are the rest of the key determinants and their change over time should be considered.

SUMMARY

This review concentrates on the definition of advanced pulmonary sarcoidosis and determinants of mortality in the pulmonary sarcoidosis group of patients.

Pulmonary sarcoidosis: an update

Sarcoidosis is a multisystem disease characterized by the presence of noncaseating granulomas, the exact etiology of which is yet to be determined. Pulmonary involvement occurs in the majority of patients and its severity ranges from asymptomatic involvement of mediastinal lymph nodes to progressive pulmonary fibrosis and chronic respiratory failure that is insensitive to treatment. Diagnosis of pulmonary sarcoidosis requires a compatible clinical picture supported by radiologic and pathologic data. A recent development in establishing the diagnosis of pulmonary sarcoidosis is endobronchial ultrasound that increases the yield of transbronchial needle aspiration of hilar and/or mediastinal lymph nodes. Fluorodeoxyglucose positron emission tomography (FDG-PET) is highly sensitive in detecting occult sites of disease and is of value in guiding biopsies of these sites. A combined imaging modality using both FDG-PET and CT scan is more sensitive than PET alone and is now the standard of care in patients requiring biopsies of active lesions. Biologic agents like anti-tumor necrosis factor antibodies are being used as second line treatment in those patients dependent on steroids or in cases of refractory sarcoidosis. Lung transplantation is the final option in suitable patients with end-stage pulmonary sarcoidosis.