The most common respiratory complaints prompting medical evaluation are shortness of breath and cough. Less frequent are hemoptysis and thoracic pain. As in any medical assessment, a detailed history and thorough physical examination are of paramount importance. Use of plain chest radiography for routine screening, once popular in the hope of uncovering silent disease amenable to therapy, is not routinely employed, as it has not been proven to decrease mortality or to be cost-effective. Chest radiography is now usually reserved for patients who have clinical manifestations of thoracic disease; serial chest radiographs often provide invaluable clues regarding the underlying problem. More sophisticated imaging techniques, including computed tomography (CT),1,2 along with tests of lung function, help complete the clinical picture.
Although seasoned clinicians may be adept at quickly spotting telltale diagnostic clues, a comprehensive medical history is central to patient evaluation. The history should include a detailed inventory of exposure to airborne substances that may result in lung injury. One of the most common offenders is cigarette smoke. An attempt should be made to quantify the exposure.
Often, the workplace is the site where toxic air is inhaled. An almost forgotten exposure to a toxic inhalant 20 years ago may explain certain types of pulmonary or pleural diseases. Symptoms that appear to improve during weekends or other periods away from work may be a clue to an occupational exposure that causes a respiratory ailment. A newly installed home humidifier or an air conditioning system that incorporates stagnant pools of water can point the way to resolving a mysterious illness. Brief residence in an area where either cryptococcosis (southwestern United States) or histoplasmosis (southern and midwestern United States) is endemic may help clarify the nature of an illness that mimics tuberculosis. A recent visit to a South or Central American country may bring into focus a more remote possibility (e.g., South American blastomycosis) (Fig. 27-1).
Exposure in an endemic area. A. Clear lung fields. B. South American blastomycosis. (Reproduced with permission from Dr. Nelson Porto.)
The history should include a thorough evaluation of prior and current medical problems. Rheumatologic disorders, such as systemic sclerosis (scleroderma), may be associated with interstitial lung disease, aspiration pneumonia due to esophageal involvement, or pulmonary vascular disease. Certain malignancies often metastasize to the lung (e.g., breast or colon carcinoma), or predispose to development of venous thromboembolism (e.g., pancreatic carcinoma). Infection with the human immunodeficiency virus (HIV) should not be overlooked, since pulmonary complications are often the initial presentation of acquired immunodeficiency syndrome (AIDS). Other causes of immunodeficiency, such as hematologic malignancy, or prior administration of chemotherapeutic agents, should heighten suspicion of infection as the cause of respiratory symptoms, as well as potential pulmonary drug toxicity.
Indeed, many pharmacologic agents, including ...