What is meant by afternoon tidal fever?

Afternoon tidal fever refers to a periodic feverish phenomenon occurring during the afternoon (especially after noon). This type of fever usually follows a fixed pattern, appearing at approximately the same time each day, similar to the rising and falling of tides. The main characteristic of afternoon tidal fever is generalized body heat, often accompanied by a sensation of heat radiating outward from deep within the bones, also known as "bone-steaming tidal fever." Traditional Chinese Medicine (TCM) holds that afternoon tidal fever is primarily caused by internal heat due to yin deficiency. Afternoon is the time when the Yangming meridian's qi is predominant; excessive yang qi combines with insufficient yin, leading to hyperactivity of yang qi in the body and thus fever. Additionally, afternoon tidal fever may be accompanied by symptoms such as dry mouth and throat, dizziness, irritability, and insomnia. It is important to note that afternoon tidal fever is not unique to any specific disease and may also be related to other factors such as excessive heat in the gastrointestinal tract or stagnant heat.