BY ALFRED L. LOOMIS, M.D.
SYNONYMS.—English and American: Acute sthenic exudative pneumonia; Primary lobar pneumonia; Vera peripneumonia; and Pneumonitis. Fr. Fluxion du poitine and Fièvre pneumonique; Ger. Pneumonia lobaris and Lobäre Lungenentzündung.
DEFINITION.—Croupous pneumonia is an acute general disease with a characteristic local pulmonary lesion. Anatomically considered, it is an acute inflammation of the vesicular structure of the lungs, resulting in infiltration of the alveoli, with inflammatory products, which renders them impervious to air. This condition is known as hepatization.
HISTORY.—Until the time of Laennec, pneumonia and pleurisy were described as one disease. Hippocrates said that pleurisy was "a disease quickly fatal, and characterized by sputa of various colors." Although these two diseases were undifferentiated, accurate descriptions of the lesions and objective signs of pneumonia have come to us from the earliest medical writers.1
1 Thucydides, The Plague at Athens, B.C. 430.
Much of the early history of this disease is interwoven with the detailed accounts of a great variety of pulmonary symptoms which occurred in the epidemics and plagues which prevailed in Eastern Europe in the centuries just preceding the Christian era, and in Western and Southern Europe during the sixteenth and seventeenth centuries. The black death has been regarded by some as an epidemic of pneumonia. While it is probable that in most of these epidemics the lung was early involved, and that its implication hastened death, yet no proof exists to sustain the belief that they were other than epidemics of typhus fever, dysentery, and those (as yet unknown) fevers which collectively were named plagues. That many of these plagues were complicated by pneumonia there is scarcely room for doubt.
French investigators were the first to separate the pneumonic process from all other morbid processes which occur in the thoracic organs. Valsalva, Morgagni, and Boerhaave gave accurate descriptions of pneumonia, but they did not sharply distinguish it from pleurisy. Bichat and Pinel separated collapse of the lung attending pleuritic effusion from inflammation of the lung-substance.2 Laennec was the first to draw the line sharply between pneumonia and pleurisy, and to him, more than to any other observer, is due the credit of describing pneumonia as a distinct disease. With his labors begins a new era in the history of pulmonary inflammations.
2 Nos. phil., ii., Pinel.
Grisolle's work3 is especially valuable in statistics relating to the climatic element in the development of pneumonia and its comparative frequency among different races. The elaborate treatise on the geographical distribution of pneumonia by Ziemssen has furnished data for a more accurate knowledge of its geographical boundaries. Following in the footsteps of Laennec, Chomel, Stokes, Addison, and many laborers of our own day have furnished the material from which the clinical and pathological history of pneumonia is now being constructed.