Radiologic and pathologic characteristics of mixed dust pneumoconiosis.

Modern radiologic technology has to led to increased diagnostic efficacy and accuracy in demonstrating pulmonary changes secondary to occupational dust exposure. This article presents three cases of typical and two cases of atypical silicosis with rounded atelectasis as seen in computed radiographic (CR), computed tomographic (CT), and scintigraphic images and autopsied lung specimens. Chest radiographs revealed both small rounded and small irregular opacities. Small irregular opacities on chest radiographs often proved to be reticular or honeycomb patterns on CT scans. Irregular opacities seen on CR and CT images represented interstitial fibrotic or mixed dust fibrotic changes associated with the accumulation of birefringent particles and emphysematous change, as noted at histologic analysis. CT scans and scintigrams were useful for visualizing parenchymal abnormalities, especially fibrotic change, emphysematous change, and pleural abnormalities.

Gastric-bypass-induced pneumothorax.

Substernal gastric bypass has been recently revived to palliate unresectable esophageal carcinoma. We report an unusual postoperative complication of gastric bypass: recurrent pneumothorax responding to nasogastric tube decompression of a distended thoracic stomach.

Pulmonary changes after exposure to vermiculite contaminated with fibrous tremolite.

Workers exposed to vermiculite contaminated with fibrous tremolite were surveyed for the presence of respiratory symptoms by questionnaire, and for pneumoconiosis by chest radiograph. Pulmonary function was measured by spirometry and single-breath carbon monoxide diffusing capacity ( DLCOsb ). Fiber exposure indexes, expressed as fiber/ml-yr, were derived for each worker from available industrial hygiene data and work histories. The estimated cumulative exposure for the work force ranged from 0.01 to 39 fiber/ml-yr. Discriminant analysis demonstrated significant correlates with shortness of breath and pleuritic chest pain to cumulative fiber exposure. The radiographic changes were limited to pleural changes and involved 4.4% of the population. Parametric and discriminant analysis demonstrated a significant correlation with radiographic changes and cumulative fiber exposure. There were no correlations between spirometry or DLCOsb and fiber exposure. Exposure to vermiculite contaminated with fibrous tremolite can cause pleural changes in occupationally exposed workers. This is supported by the previously identified 12 cases of benign pleural effusions in this working population and the association of pleural radiographic changes and pleuritic chest symptoms with cumulative fiber exposure. The lack of significant parenchymal radiographic, spirometric, and DLCOsb changes most likely reflects the low cumulative fiber exposure.

Metastatic pulmonary calcification in primary hyperparathyroidism.

Metastic pulmonary calcification (MPC) developed in a patient with primary hyperparathyroidism. Renal function was only minimally impaired (creatine clearance of 65 ml/min) the day prior to appearance of the lung infiltrate, but deteriorated (creatinine clearance of 14 ml/min) concomitantly with the appearance of MPC. Lung imaging with 99mTc bone-scanning agents helps differentiate MPC from other problems with similar clinical and roentgenographic findings, thus allowing prompt therapy.

The cervicothoracic continuum.

The anatomic communications between the neck and the mediastinum are described. Anatomic sections and drawing are used to demonstrate the normal compartments, their fascial envelopes, their contained structures, and their interrelationships. Selected cases are used to illustrate the spread of pathologic processes within the cervicothoracic region.