What finding in a pleural effusion would suggest tuberculosis?

• A. Low protein concentration
• B. High glucose levels
• C. High pleural lymphocytes
• D. Low lymphocyte count

Answer: (C)

A finding of high pleural lymphocytes in the context of a pleural effusion is suggestive of tuberculosis. Tuberculous pleural effusions are typically characterized by an exudative process, meaning that the effusion contains proteins, cells, and other substances due to an inflammatory response. In these cases, lymphocytes, particularly T-lymphocytes, predominate in the pleural fluid due to the immune response mounted against the Mycobacterium tuberculosis infection.

When evaluating pleural effusions, the profile of the cells present can provide important clues about the underlying cause. In the case of tuberculosis, the presence of a high lymphocyte count reflects the body's response to this chronic infection. Other indicators such as a high protein concentration and low glucose levels can also be present in tuberculous effusions, but it is the lymphocyte predominance that is particularly distinctive.

In contrast, low protein concentration and high glucose levels are more typical of transudative effusions, which are caused by conditions like congestive heart failure or cirrhosis. A low lymphocyte count would not be characteristic of tuberculosis, as it indicates a different underlying pathology where a less robust immune response is mounted. Thus, the high pleural lymphocytes serve