Atypical Pneumonia of Unknown Etiology

A Clinical, Roentgenological, and Pathological Correlation

¹ Station Hospital, Fort Custer, Michigan
² General Hospital 297, Fort Custer, Michigan

In a study of some five hundred patients representing a cross section of an epidemic of acute respiratory tract infection numbering some six thousand cases, twenty-five per cent were found to have atypical pneumonia.

Atypical pneumonia should not be considered a disease entity but part of a syndrome in which the pulmonary lesions are but one manifestation of a generalized infection. So considered it might well be a physiological accident and not a pneumonia in the accepted sense of the term.

The pathology is described, evidence being advanced that it is an interstitial pneumonitis and that the pathology is similar to that found in other virus infections of the pulmonary tract.

The process is divided into four phases, namely, the bronchitic, the peribronchitic, the alveolar, and broncho-alveolar. A description of the physical and x-ray findings peculiar to each phase is given. Explanation for these findings is attempted by correlating them with the pathology.