ARDS in Patients Without Risk Factors

In 8–9% of diagnosticated acute respiratory distress syndromes (ARDS) the etiology of respiratory failure remains unknown. Once common causes of ARDS have been ruled out (i.e., negative microbiological tests), high-resolution CT-scan (HRCT), bronchoalveolar lavage and eventually open lung biopsy (OLB) are often required for diagnosis, if achieved. Although a wide range of clinical entities might be eventually found, therapeutic management mainly consists of corticosteroids and immunosuppression, except for malignant lesions. Outcomes, especially when reversible features are detected, seem comparable to ARDS due to common causes.