Pulmonary cavities: Their persistence and closure

• 1.

  Pulmonary cavities close primarily as a result of the inherent concentric retractility of the lung, the negative intrapleural pressure (chest wall pull) being eliminated by the occurrence of compensatory emphysema in the lung adjacent to the diseased area.

• 2.

  Lung abscess cavities close as a result of the above only in the presence of free drainage.

• 3.

  Lung abscesses and tuberculous cavities persist as a result of inefficient drainage; the former by the retention of sloughs and infected material, the latter by the trapping of air in the cavity resulting from a partial bronchostenosis chiefly operative during expiration.

• 4.

  The majority of tuberculous cavities are tension cavities from their inception and remain so until the later stage of the disease.

• 5.

  During the later stage of the disease tuberculous cavities persist because of the pull of the chest wall, for at this stage free bronchial drainage is usually present.

• 6.

  Bronchial occlusion is essential for inducing closure of tuberculous cavities.

• 7.

  All methods of treatment, excluding chemotherapy, from bed rest to thoracoplasty, are based on the same basic principles—viz., limitation of the inspiratory tug on and relaxation of the cavity and its draining bronchi with the ultimate production of an organic bronchostenosis.