Which other clinical sign might indicate malaria in a patient?

Splenomegaly, or an enlarged spleen, is a prominent clinical sign that may indicate malaria. In malaria, the lifecycle of the Plasmodium parasite leads to the destruction of red blood cells, resulting in anemia and the release of toxins, which can cause the spleen to become enlarged as it works to filter and remove infected cells from the bloodstream. The splenic response is a natural defense mechanism to the infection, and its enlargement can be a clear indicator of malaria, especially in endemic regions.

The other options, such as coughing, nausea, and diarrhea, can be associated with a range of different infections or illnesses and are not specific indicators of malaria. While a patient with malaria might experience these symptoms, they lack the direct connection to the disease process as seen with splenomegaly, making it a more definitive clinical sign for diagnosing malaria.