I. Clinical Problems of Diffuse Pulmonary Fibrosis

The problem about which I propose to speak is that which confronts the physician faced with a patient in whom diffuse reticular or nodular opacities have been found in the chest radiograph. I discussed this problem in 1952 at a meeting of the British Tuberculosis Association, and then listed 76 possible causes of such shadows (Scadding, 1952). My colleague Dr. Blair has added two more to the list since then (Blair, 1954). I propose to omit from my discussion today those conditions which present only with acute symptoms. This eliminates some, and leaves 48 possible causes of such shadows in patients who present with chronic symptoms or without symptoms. The clinician's first problem in such cases is that of diagnosis; and indeed in many cases it is his only problem. In many instances the diagnostic problem may be solved for all practical purposes by very simple means. The occupational history may be sufficient to provide a diagnosis beyond reasonable doubt. It is important in taking the history that all occupations which the patient has ever followed should be elicited, since the exposure giving rise to the shadows present may have occurred many years ago. Similarly a history of residence in certain parts of the world may give the clue to certain diagnoses which otherwise would be unlikely: e.g. histoplasmosis, of which the residue in the form of scattered calcified nodules may be seen in persons who have lived at any time in an endemic area.