Heat effusion

Also fever. Abnormal bodily heat that can be detected by palpation or that is experienced subjectively; fever. Heat effusion occurring with aversion to cold or aversion to wind at the onset of illness indicates external evils invading the fleshy exterior. If the aversion to cold is more pronounced than the heat effusion, the pattern is one of wind-cold. Pronounced heat effusion with only aversion to wind suggests wind-heat. Heat effusion without aversion to cold occurs in various patterns. Distinction is made between vigorous heat [effusion], tidal heat, vexing heat in the five hearts, steaming bone tidal heat, baking heat [effusion], and generalized heat failing to surface.

Types

Vigorous heat [effusion] (壮热 zhuàng rè), a persistent high fever without aversion to cold, occurs as external evil passes from the exterior into the interior of the body.

Tidal heat (潮热 cháo rè), heat effusion that recurs at regular intervals, usually every afternoon, is in most cases due to internal heat from yīn vacuity. Because the heat effusion feels as though it is radiating out from the innermost part of the body, it is also called steaming bone tidal heat. See also postmeridian tidal heat and late afternoon tidal heat.

Baking heat effusion (烘热 hōng rè) is the steady heat effusion that is associated with damage to yīn, and attended by heart vexation, insomnia, and oppressive feverishness.

Vexing heat in the five hearts (五心烦热 wǔ xīn fán rè) refers to heat in the center of the soles and palms, and the center of the chest. It is usually a sign of yīn or blood vacuity but may also occur when evils are deep-lying in the yīn aspect or when fire becomes depressed.

Generalized heat failing to surface (身热不外扬 shēn rè bù wài yáng) is caused by dampness trapping hidden heat so that the heat can only be felt after longer palpation.

High fever (高热 gāo rè), heat effusion as shown by a high reading on the thermometer, is a modern medical term now often used in Chinese medical literature. See also gān heat effusion; qì vacuity heat effusion; hot back; hot head.

Etymology

Chin 发 fā, emit, put forth, effuse; 热 rè, heat. Chinese has no unique term for the notion of a hot state of the body that corresponds to the English fever (from the Latin febris, related to fovere, to warm or keep warm), it expresses the idea as giving off heat. In describing different types of fever (see examples above), 发 is often dropped. As a result, the notion of fever is poorly distinguished in the terminology from heat as a cause of disease or a morbid state. Although there is a conceptual distinction between fever and heat, as seen the observation that mild fever may be occur in wind-cold patterns, the borderline between the two in other contexts is not always clear. Consequently, 身热不外扬 shēn rè bù wài yáng, for example, could be rendered as fever or generalized heat failing to surface. Furthermore, the concept of（发）热is wider than that of fever in that it denotes palpable body heat or heat sensations (as in yīn vacuity) that are not normally described in English as fever either in the colloquial or in the modern medical sense of the word. At the risk of obscuring a familiar concept with an unfamiliar expression, the term heat effusion is here introduced. The word effusion is enclosed in brackets where it does not appear, yet is implicit in the Chinese. The word fever is retained in terms of biomedical origin, e.g., high fever.