Sarcoidosis: a review for the internist

The objective of the study was to estimate the prevalence and incidence of interstitial lung diseases (ILDs) in Seine-Saint-Denis, a multi-ethnic county of Greater Paris, France. Patients with ILDs were identified between January and December 2012 by using several sources; all potentially involved medical specialists from public and private hospitals, community-based pulmonologists and general practitioners, and the Social Security system. Diagnoses were validated centrally by an expert multidisciplinary discussion. 1170 ILD cases were reported (crude overall prevalence: 97.9/105 and incidence: 19.4/105/year). In the 848 reviewed cases, the most prevalent diagnoses were sarcoidosis (42.6%), connective tissue diseases associated ILDs (CTDs-ILDs) (16%), idiopathic pulmonary fibrosis (IPF) (11.6%), and occupational ILDs (5.0%), which corresponded to a crude prevalence of 30.2/105 for sarcoidosis, 12.1/105 for CTDs-ILDs and 8.2/105 for IPF. The prevalence of fibrotic idiopathic interstitial pneumonias, merging IPF, nonspecific interstitial pneumonia and cases registered with code J84.1 was 16.34/105. An adjusted multinomial model demonstrated an increased risk of sarcoidosis in North Africans and Afro-Caribbeans and of CTDs-ILDs in Afro-Caribbeans, compared to that in Europeans. This study, with a comprehensive recruitment and stringent diagnostic criteria, emphasises the importance of secondary ILDs, particularly CTDs-ILDs and the relatively low prevalence of IPF, and confirms that sarcoidosis is a rare disease in France.

Cardiac sarcoidosis (CS) causes substantial morbidity and sudden death. Early diagnosis and risk stratification are warranted. Ambulatory patients with sarcoidosis were interviewed to determine whether they experienced palpitations, syncope, or presyncope, and were evaluated with ECG, Holter monitoring, and echocardiography (transthoracic echocardiogram [TTE]). Those with symptoms or abnormal results were studied with cardiac MRI (CMRI) or positron emission tomography (PET) scanning. The diagnosis of CS was based on abnormalities detected by these imaging studies. Patients with CS were referred for risk stratification by electrophysiology study (EPS). Among the 62 patients evaluated, the prevalence of CS was 39%. Patients with CS had more cardiac symptoms than those without CS (46% vs 5%, respectively; p < 0.001), and were more likely to have abnormal Holter monitoring findings (50% vs 3%, respectively; p < 0.001) and TTE findings (25% vs 5%, respectively; p = 0.02). The degree of pulmonary impairment did not predict CS. Two of the 17 patients who underwent EPS had abnormal test findings and received implantable cardioverter-defibrillators. No patients died, had ventricular arrhythmias that triggered defibrillator therapy, or had heart failure develop during almost 2 years of follow-up. This diagnostic approach was more sensitive than the established criteria for identifying CS. CS is common among patients with sarcoidosis. A structured clinical assessment incorporating advanced cardiac imaging with PET scanning or CMRI is more sensitive than the established criteria for the identification of CS. Sarcoidal lesions seen on CMRI or PET scanning do not predict arrhythmias in ambulatory patients with preserved cardiac function, who appear to be at low risk for short-term mortality.

Sarcoidosis may consist of a number of distinct disease entities, one of which could be Löfgren's syndrome. Patients with Löfgren's syndrome have an acute onset of erythema nodosum (EN) and/or periarticular inflammation or arthritis of the ankles, with bilateral hilar lymphadenopathy (and in some cases parenchymal infiltrates) and usually fever. There is a known association between HLA-DRB1*03 and Löfgren's syndrome. To investigate whether human leukocyte antigen type influences clinical manifestations, including the disease course in Löfgren's syndrome. We clinically characterized and HLA-DRB1 typed 301 patients with Löfgren's syndrome. A total of 275 of the patients were followed for more than 2 years and classified as having a nonresolving or a resolving disease. Almost every DRB1*03-positive patient had a resolving disease within 2 years, and 49% of the DRB1*03-negative patients developed a nonresolving disease. Mucosal granulomas were identified significantly more often in DRB1*03-negative patients. Among DRB1*03-negative patients who were treated with oral steroids at disease onset, 80% developed a nonresolving disease. Patients with Löfgren's syndrome have a different disease course depending on whether they are DRB1*03 positive or not. This observation has clinical implications, and by comparing DRB1*03-positive and DRB1*03-negative patients with Löfgren's syndrome, we can search for additional markers of importance for developing a resolving or a nonresolving disease, respectively.