PCP presents as acute or subacute pneumonia that may initially be characterized by a vague sense of dyspnea alone but that subsequently manifests as fever and nonproductive cough with progressive shoness of breath ultimately resulting in respiratory failure and death. Although the initial chest radiograph may be normal when patients have mild symptoms, the classic radiographic appearance of PCP consists of diffuse bilateral interstitial infil-trates that are perihilar and symmetric yet anotherfinding that is not specific for PCP. The interstitial infiltrates can progress to alveolar filling Ref Harrison 19th edition 1358-1360