Which diagnosis is suggested by basilar infiltrates with a meniscus?

The presence of basilar infiltrates with a meniscus suggests a diagnosis of pleural effusion. A meniscus indicates fluid level, which is characteristic of an accumulation of fluid in the pleural space. In imaging studies like a chest X-ray, a pleural effusion often presents as a concave upper border (meniscus) at the costophrenic angles, particularly when it is significant.

In contrast, pneumonia generally presents with opacities or consolidation on imaging rather than a meniscus, as it is due to an inflammatory process in the lung parenchyma itself. ARDS (Acute Respiratory Distress Syndrome) and IRDS (Infant Respiratory Distress Syndrome) would also show diffuse infiltrates but not as a fluid level indicative of pleural effusion. Tuberculosis can present with various radiographic findings, typically appearing as nodules or cavitary lesions rather than the characteristic meniscus seen in cases of significant pleural effusion.

Thus, the specific presentation of basilar infiltrates with a meniscus points towards the diagnosis of pleural effusion.