A Brief Discussion on the Clinical Approach to Damp-Warm Epidemic
1. Pathogenesis
When the epidemic evil first arises, it enters by mouth and nose, moves through the throat and lung, and lodges in the middle, blocking the connection between surface and interior. With the interior qi stagnant, there is chest oppression; with the surface qi stagnant, there is bodily heaviness and pain. When it invades the lung collaterals, there is dry cough with hemoptysis. Warm and turbid evils steam and ferment; the lung loses its function of clear descent; clear qi cannot move; thus breath becomes rapid with phlegm production, the diaphragm is blocked and counterflow rises, leading to oppressive obstruction of the lung qi and shortness of breath, worsened on exertion. When the evil lodges in the middle burner, putrefying heat steams and ferments — the function of upbearing, downbearing, transport, and transformation is disordered; the middle burner is thrown into chaos. Turbid qi rising counterflow yields vomiting; descending yields diarrhea — heat-laden discharge the color of rotten sauce, lotus-paste, or medicinal water.
2. Treatment Principle
The Wenbing Tiaobian, article 43, on damp-warm: "Headache with aversion to cold, body heavy and painful, tongue white and not thirsty, pulse wiry-thin and soggy, complexion pale-yellow, chest oppressed and no hunger, body heat in the afternoon — looking like yin-deficiency, the illness hard to resolve quickly. This is called damp-warm. To sweat brings clouding of spirit and deafness, at worst the eyes shut and the patient cannot speak; to purge brings violent diarrhea; to moisten deepens the disease and does not resolve. In late summer, deep autumn, and winter the method is the same. Sanren Tang governs." This points out that damp-warm epidemic is not to be treated as cold-damage; one must not rashly sweat or purge.
So too Lin Zhihan in Wenyi Cuiyan, citing Yu Jiayan: "The evil of warm epidemic moves straight along the central road, spreads through the three burners. The upper burner is clear-yang, so clear evil enters from above; the lower burner is turbid-yin, so turbid evil enters from below; the middle burner is the meeting of yin and yang — both clear and turbid evils must here divide. At extremity, the three burners are intermixed: what rises to the limit descends, what descends to the limit rises. The cold-damage evil strikes the outer mantle, so it scatters with one surface-release; the epidemic evil moves on the central road, so surface-release does not scatter it (the heat falls and rises again). Cold-damage entering the stomach yard brings fullness and hard stool — hence purgation may be used; the epidemic evil spread in the middle burner is diffuse and not gathered."
He also says: "Many in the world speak of cold epidemic. Looking at its presentation — fierce chills and strong fever, headache, vexing pain in bones and joints, fever though not greatly thirsty, prevalent within the lanes and households, all sufferers alike, as if of epidemic cause — it is not like damp-disease without much headache or bone-pain but with great thirst. So it is called 'cold epidemic'. ... Before it transforms to heat and there is aversion to cold, use pungent-warm to release the muscle layer; once transformed to heat, like wind-warm pattern, use pungent-cool to clear heat. The principle is one." This again says that damp-warm epidemic is not treated as cold-damage epidemic. At the onset of cold epidemic, with aversion to cold, pungent-warm muscle-releasing may be used; once heat-transformed, pungent-cool clears heat. But damp-warm epidemic is not to be over-sweated, still less treated with pungent-warm dry-heat, lest heat be aided and fluids damaged.
3. Method of Treatment
When the epidemic first arises and chills predominate, this is usually war-sweating — right qi and evil qi contending. Generally one waits quietly for chills to cease and turn to fever, because chills are short and the fever that follows is long. The patient should drink rice-broth to support sweating. If giving medicine, do not over-sweat, and certainly do not use pungent-warm dry-heat. Choose huoxiang, xiangru, zisu, fabanxia, fermented soybeans — pungent-scattering, evil-lifting herbs.
When there is mild aversion to cold and high fever, Haoqin Qingdan Tang combined with Baihu Tang, modified, may be used. The epidemic evil transmits and transforms quickly; draining heat is the first task. But in chills, one must not over-block with cold, since cold may bring reversal cold-counterflow. When sweat does not come during chills, reversal-counterflow is also likely; if it does not turn, the case is dire. In treatment, grasp the cardinal symptoms, seek the inner pattern, observe the contention of evil and right and the key turning of the disease's course. The four-fold differentiation-method below may guide diagnosis and treatment.
(1) Differentiating damp-warm-heat mutual transformation. In the course of disease there may be damp predominating over heat, heat over damp, or damp and heat equally heavy. Treat by following whichever predominates. Early: damp evil may slightly predominate. Mid-course: damp and heat both heavy. Late: heat may predominate over damp; even when damp-heat has not retreated, yin fluids show damage. This is the harder stage — clear and transform damp-heat while protecting qi and yin. On the basis of aromatic damp-resolution and evil-removal, add a little fluid-engendering: huafen (trichosanthes root), shihu, shashen, and the like.
(2) Differentiating war-sweating. The epidemic evil first reaches the surface, then the interior. Suddenly war-sweating comes — channel qi outflows — the pulse should at once become quiet, the body cool, vexation and thirst cease. If recurrent: the interior evil has not yet gone, the epidemic evil transmits at both surface and interior, interior qi is blocked. War-shaking without sweat is dangerous, for the middle qi is weak — it can only sink, not rise and issue. The next day at the same hour, war comes again; if cold-counterflow returns and sweat issues, the patient lives. While war-shaking is at its height, yin and yang contend, right and evil grapple — wait quietly. Wenyi Cuiyan: "After sweating, drink much rice-broth to nourish the stomach qi."
After heavy sweating, with rapid breath and bodily heat, use Renshen Baihu Tang with cangzhu. If stools are loose, use raw yiyi in place of polished rice. If fluids are damaged, Zhuye Shigao Tang will do — add aromatic damp-resolvers (huoxiang, peilan, liuyi san) and heat-clearing toxin-resolvers (jinyinhua, lianqiao) as needed. When fever lowers, cough often appears with increased phlegm. This is a sign that lung qi has been opened, heat has retreated, fluids returned.
(3) Differentiating dyspnea. Pant-like but not true pant, rapid breath with chest oppression and nasal flaring — replete pattern; short breath insufficient for respiration, low faint speech — deficient pattern. When warm epidemic spreads in the upper burner and scorches the lung, the order of clear-descent is not carried out. Method: clear-descend and resolve toxin together. Use Maxing Shigan Tang, reducing gancao and adding changpu, yujin, sangbai, suzi, tinglizi, peilan, zhizi, etc. With qi exhaustion and fluid damage, fortify qi and yin — use Shashen Maidong Tang with additions. With insufficiency of heart-qi, Shengmai San or yangshen (American ginseng) decoction; also yangshen decoction taken with lingyang (antelope-horn) powder.
(4) Differentiating tongue body and coating. Tongue body pale-white and somewhat enlarged, coating thin-white: at onset this tongue is mostly damp-turbid stagnation, yang qi blocked, the epidemic-pestilent evil quickly damaging the true original qi (with lowered immune function). Accompanying signs: high fever heavier in the afternoon, slight aversion to cold with bodily pain, head distended and unclear, dry cough, chest oppression and bound breath, sticky sweat, body weary and weak, walking unsteady, bitter mouth, no appetite for food and drink, loose brown stool 3–4 times daily, scant urine, large slow pulse. Three-burner clearing and aromatic transformation may be used — qinghao, xingren, huangqin, raw yiyi, liuyi san, zhimu, shigao, and the like.
Tongue tip red, coating white-thick and slimy: damp-turbid blocking the membrane source, chest and abdomen oppressed and distended, fever with aversion to cold, drowsy and stuporous, sweat not abating fever. To the above method add houpo, binglang.
Tongue red, coating yellow-thick-slimy-dry, persistent high fever heavier at midnight, sweat profuse or pouring, no appetite, scant urine, stools alternating dry and loose: damp-turbid stagnating in the three burners, the clear orifices clouded; qi and ying both blazing. Combine the above method with Qingying Tang or Baihu Tang. If damp-heat or jaundice, Ganlu Xiaodu Dan.
4. Conclusion
In short: the epidemic evil transmits quickly, the pattern advances quickly, the right qi is easily exhausted. One must grasp the pathogenesis: support the right and drive out the evil, drive out the evil and restore the right. Every second counts; the epidemic evil should always be moved and freed.
Generally the early stage is easy to treat; the late stage with great damage to qi and yin is harder. When cough comes with blood, evil scorches the lung collaterals, breath is rapid and nostrils flare, sweat is profuse and the pulse large-scattered without force — these are signs the lung's capacity to engender and transform is nearing exhaustion, with turbid phlegm blocking. If the patient can still take medicine, Houzao San and Shedan Chenpi powder can dispel phlegm. Even baifan (alum) powder 1 g can resolve phlegm — but not for long, as it tends to cause diarrhea.
For diarrhea, Zhoushi Huishengdan. For lowering fever, Jufang Zhibao Dan. To the decoction (mahuang, xingren, shigao, suzi, tinglizi, changpu, yujin) one may add lingyang powder taken separately.
By past experience, the Three Treasures — Angong Niuhuang, Zhibao, Zixue — and lingyang powder protect the right and reduce fever with clear effect. Differentiation: phlegm-heat with spirit-reversal — Angong Niuhuang; damp evil stagnating, clouded spirit with desire to sleep — Zhibao; constipation with persistent high fever — Zixue. The Three Treasures and lingyang may be used as needed in any stage.