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Hypostatic pneumonia usually results from the collection of fluid in the dorsal region of the lungs and occurs especially in those (as the bedridden or elderly) confined to a supine position for extended periods.
- Pneumonia resulting from infection developing in the dependent portions of the
lungs due to decreased ventilation of those areas, with resulting failure to drain
bronchial secretions occur primarily in old people or those debilitated by who remain recumbent in the same position for long periods.
Cause
- Hypostatic pneumonia is caused by passive or dependent congestion of the lungs. Blood is unable to pass readily through the vasculature of the lung, which can lead to a shift in fluid from the circulatory to the pulmonary spaces. It often occurs secondary to some other disease process causing chest pain (e.g., congestive heart failure). Shallow respiration can lead to improper ventilation of the dependent lung, loss of surfactant activity, and accumulation of respiratory secretions and inflammatory exudate in lower airways. Compression of the abdominal contents in recumbent patients restricts the downward movement of the diaphragm, reducing tidal volume and ventilation of alveoli.
Signs
- Coughing is not always a prominent clinical sign, but as the condition progresses, dyspnea and cyanosis become apparent. Secondary bacterial infection is common.
Diagnosis
- Radiographs reveal increased pulmonary density and the mediastinal space may show atelectasis.