Idiopathic chronic eosinophilic pneumonia, characterized by aggregates of lymphocytes and eosinophils within the septal walls and the alveolar spaces, typically in the periphery of the lung fields, and accompanied by high fever, night sweats, and dyspnea. This is a disease of exclusion, once other causes of pulmonary eosinophilia have been ruled out.
In addition to obstructive lung disease (COPD), smoking is also is associated with restrictive or interstitial lung diseases. Desquamative interstitial pneumonia (DIP) and respiratory bronchiolitis are two related examples of smoking-associated interstitial lung disease. The most striking histologic feature of DIP is the accumulation of large numbers of macrophages containing dusty-brown pigment (smoker’s macrophages) in the air spaces (
Fig.
13.23 ). The alveolar septa are thickened by a sparse inflammatory infiltrate (usually lymphocytes); interstitial fibrosis, when present, is mild. Pulmonary function tests usually show a mild restrictive abnormality. Overall, patients with DIP have a good prognosis and an excellent response to steroids and smoking cessation; however, some patients progress despite therapy. Respiratory bronchiolitis is a common lesion found in smokers that is characterized by the presence of pigmented intraluminal macrophages akin to those in DIP, but in a “bronchiolocentric” distribution (first-and second-order respiratory bronchioles). Mild peribronchiolar fibrosis also is seen. As with DIP, affected patients present with gradual onset of dyspnea and dry cough, and the symptoms recede with smoking cessation.
Fig. 13.23 Desquamativeinterstitialpneumonia.Thereisaccumulationoflargenumbersofmacrophageswithinthealveolarspaceswithonlyslightfibrousthickeningofthealveolarwalls.
PulmonaryEmbolism,Hemorrhage,andInfarction
Thromboembolism causes approximately 50,000 deaths per year in the United States and even when not directly fatal often complicates the course of other diseases. The true incidence of nonfatal pulmonary embolism is not known. Some cases undoubtedly occur outside the hospital in ambulatory patients, in whom the emboli are small and clinically silent. Even among hospitalized patients, no more than one-third are diagnosed before death. Autopsy data on the incidence of pulmonary embolism vary widely, ranging from 1% in the general hospitalized population, to 30% in individuals dying after severe burns, trauma, or fractures.
Blood clots that occlude the large pulmonary arteries are almost always embolic in origin. More than 95% of all pulmonary emboli arise from thrombi within the large deep veins of the legs, most often those that have propagated to involve the popliteal vein and larger veins above it. The influences that predispose to venous thrombosis in the legs are discussed in Chapter 4, but the following risk factors are paramount: (1) prolonged bed rest (particularly with immobilization of the legs); (2) surgery, especially orthopedic surgery on the knee or hip; (3) severe trauma (including burns or multiple fractures); (4) congestive heart failure; (5) in women, the period around parturition or the use of oral contraception pills with high estrogen content; http://ebooksmedicine.net (6) disseminated cancer; and (7) primary disorders of hypercoagulability (e.g., factor V Leiden) (Chapter 4).