Thoracic mass lesions in immuno-incompetent patients

Cavitary pulmonary infarct in immunocompromised hosts

Pulmonary disease in immunocompromised patients is common, but cavitary lung disease is less common and is usually associated with a fungal or mycobacterial infection. Pulmonary embolism is a noninfectious cause of a cavitary pulmonary process. Pulmonary embolism causes infarction in fewer than 15% of cases, and only about 5% of infarctions cavitate. Herein we describe two cases of cavitary infarcts in immunocompromised patients and review the clinical aspects of pulmonary infarcts and cavitation. Cavitary pulmonary infarction has been reported only rarely in immunocompromised patients. It is a dangerous but treatable pulmonary disease that must be considered in the differential diagnosis of immuno-compromised patients with lung disease.

Lung abscess: a changing pattern of the disease

Alcoholic stupor with aspiration has been the most commonly recognized cause of lung abscess. Eighty-nine patients treated for lung abscess in a large community hospital from 1968 through 1982 have been described. Forty-six percent of these patients were 60 to 80 years of age. The most common predisposing factors included pneumonia, immunosuppression steroid therapy, carcinoma at a distant site, alcoholism, and lung cancer. Surgical therapy was employed in 23 patients when there was suspicion of cancer and failure to improve with medical management. Fifty-seven percent of patients were either cured or improved at the time of discharge. Twenty-nine percent died from other causes during hospitalization, and 9 percent died as a direct result of the abscess. Thus, the patients encountered in the community hospital setting tended to be older and had a wide variety of illnesses that precipitated the development of lung abscesses.

Pulmonary disease in the immunocompromised host. 1

With few exceptions, pulmonary complications in the immunocompromised host will proceed to death unless the clinician intercedes. The differential diagnosis of diffuse pulmonary disease in this setting includes (1) infection, most commonly from opportunistic organisms; (2) recurrence or extension of the basic underlying disease process to involve the lungs; (3) adverse pulmonary reaction to drugs; (4) a new, unrelated disease process such as cardiac pulmonary edema or pulmonary emboli; and (5) any combination of these categories. Up to a third of these patients have two or more complications, such as pneumonitis from two different opportunistic organisms or an opportunistic infection and a drug-induced pulmonary complication. An understanding of the host defense that is compromised enables the clinician to narrow the differential diagnosis. The most common types of impairment of defense mechanisms are reductions in the number of granulocytes, B-lymphocytes, or T-lymphocytes, and not uncommonly, two or all three of these types of cells are involved. Impairment of each of these cell types is associated with an increased frequency of infection by a particular group of organisms. Consequently, the clinician can be somewhat selective if empiric therapy is being considered. In the immunocompromised patient, most pulmonary complications, including drug-induced pulmonary disease and pulmonary emboli, are associated with fever that mimics an infection. Up to 25% of the pulmonary complications in these patients are noninfectious.