ARDS in Catastrophic Antiphospholipid Syndrome
Abstract & Commentary
By David J. Pierson, MD, Editor, Professor, Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, is Editor for Critical Care Alert.
Synopsis: In this study of a registry of patients with catastrophic antiphospholipid antibody syndrome, 21% developed ARDS. Patients with ARDS did not differ otherwise from the other patients in the registry, and the mortality was the same.
Source: Bucciarelli S, et al. The acute respiratory distress syndrome in catastrophic antiphospholipid syndrome: analysis of a series of 47 patients. Ann Rheum Dis. 2006;65:81-86.
Using a website-based international registry of patients with catastrophic antiphospholipid syndrome (CAPS), Bucciarelli et al sought to determine how often ARDS occurred as a complication. There were 220 patients with CAPS in the registry, reported by physicians in 20 different countries. Patients had a mean age of 38 years, and 70% were female. Of the 220 patients, 48% had primary antiphospholipid syndrome, 40% had systemic lupus erythematosus, and the remainder had a variety of other primary diseases. ARDS was diagnosed by the patients’ managing physicians, using a definition of bilateral infiltrates on chest radiograph, PaO2/FIO2 < 200 mm Hg, and the absence of clinical evidence of cardiogenic pulmonary edema.
Some pulmonary involvement was present in 68% (150/220) of the CAPS patients in the registry. Forty-seven patients (21%) were diagnosed as having ARDS, of whom 19 (40%) died. There were no differences in age, sex, precipitating factors, clinical manifestations, or mortality among patients with CAPS and ARDS as compared with patients with CAPS who did not develop ARDS.
Catastrophic antiphospholipid syndrome is characterized by multiple vascular occlusive events, usually affecting small vessels, occurring over a short period of time in the presence of antiphospholipid antibodies. Many patients who develop the syndrome have lupus, although it occurs in other diseases and also as an apparently isolated phenomenon. Specific diagnostic criteria for CAPS, also called Asherson’s syndrome, are evidence of involvement of 3 or more organs, systems, or tissues; development of these manifestations simultaneously or within a one-week period; biopsy confirmation of small-vessel occlusion from at least one site; and laboratory confirmation of antiphospholipid antibodies.
Because the diagnosis of ARDS in this study was assigned by each patient’s managing physician, and because the website from which the data for this study were taken is no longer available at the URL provided in the article, the validity of the incidence figures cited by Bucciarelli et al is uncertain. Although the number of ARDS cases reported was relatively small, there did not appear to be any differences among CAPS patients who did and did not develop the syndrome. It is noteworthy that mortality was not increased among patients who developed ARDS. However, it seems clear that the development of ARDS is a frequent and serious phenomenon among patients with CAPS.