Acute respiratory distress syndrome
Clinically, ARDS is characterized by decreased compliance in the lungs ("stiff lungs"). On a microscopic level, it involves alveolar edema due to increased permeability from membrane destruction ("leaky capillaries") as well as neutrophil infiltration, which can lead to activation of a localized inflammatory response. Once the alveoli are damaged, they will start to collapse, leading to atelectasis derecruitment of the lung. Although mechanical ventilation is the mainstay of treatment, it can be challenging and must be done carefully and within specific parameters, as repetitive re-expansion and collapse of the alveoli can lead to mechanical injury known as atelectrauma and the elevated mean airway pressures or excess tidal volumes in the setting of decreased lung compliance result in alveolar barotrauma / volutrauma.
The Berlin Definition of ARDS was published in 2012, identifying specific criteria for diagnosis.
Related topics: respiratory distress syndrome in the newborn, respiratory failure
J80 – Acute respiratory distress syndrome
373895009 – Acute respiratory distress
- Pulmonary edema from heart failure – Can be diagnosed by left atrial hypertension and changes on an echocardiogram.
- Chronic interstitial lung disease – Usually will not be as acute in presentation, but will have a more gradual, indolent course and prior radiographic findings.
- Hypersensitivity pneumonitis – Will be in the clinical context of a recent inhalation; although not as severe, it can progress to ARDS.
- Diffuse alveolar hemorrhage – Bronchoscopy will show progressively more blood-tinged lavage samples.
- Acute interstitial pneumonia – Will resemble ARDS both radiographically and clinically, but without an obvious cause or stressor. Histopathology will show diffuse alveolar damage on lung biopsy. Some patients will benefit from steroids. This should be considered when ARDS does not improve despite aggressive treatment.