Why has this man with immunosuppression got shortness of breath and a cough?
Although there is no focus of airspace opacification, there is hazy ground glass attenuation change involving both lungs and a reticular pattern of opacification. The lungs are of normal volume, there is no collapse and no pleural effusion. Further features in the history were gradual weight loss. A whole body CT was performed to look for sources of infection and lymphadenopathy. This is a selected axial slice on lung windows.
A mid and lower zone diffuse ground glass pattern was seen, with admixed areas of interlobular septal thickening, giving a "crazy paving" pattern. Some small cystic spaces were observed too. No nodules, nodes or pleural effusions were seen. The heart was not enlarged.
A diagnosis of pneumocystic pneumonia (PCP) was made, the causative organism of which is pneumocystic jirovecii. This is seen almost exclusively in immunocompromised patients, particularly those with AIDS.