Pattern Differentiation-Treatment and Disease Differentiation-Treatment
The idea of pattern differentiation and treatment was first contributed by Zhang Zhongjing, so calling him the Medical Sage is no exaggeration; TCM doctors through the dynasties are all his spiritual descendants. It is commonplace that pattern differentiation and treatment began with Zhang Zhongjing; in fact, disease differentiation and treatment also began with him.
We know that the Shanghan Lun and the Jingui Yaolue (Essentials from the Golden Cabinet) are Zhang Zhongjing's two outstanding medical works. The Shanghan Lun is characterized by "different treatments for the same disease"—the same "disease" receives different regimens. The Jingui Yaolue treats "same treatment for different diseases"—different "diseases" receive the same regimen. In fact, combining the two gives us pattern differentiation-treatment and disease differentiation-treatment.
The core of both lies in differentiation (bian), which means to identify, that is, to recognize and distinguish. The ancients said a doctor faces two difficulties: the first is not knowing the disease, the second is not knowing the drugs. Not knowing the disease means inadequate recognition of the illness; not knowing the drugs means inadequate recognition of their uses. If a doctor does not clearly understand diseases and the uses of drugs, the clinic becomes harmful.
The character zheng (pattern) has been interpreted differently by medical experts across the dynasties. Some today equate it with zheng (symptom); I personally think that understanding is wrong. This zheng is the zheng of "evidence," not a phonetic loan character. The ancients chose words with great care; the character for symptom plainly existed, yet they set it aside and used zheng instead—not without reason. In so serious a work as a medical text, and given Zhang Zhongjing's rigorous attitude, it is unlikely he would use a loan character at such a crucial point.
Putting it all together, pattern differentiation-treatment means identifying the disease through a series of pieces of evidence and then treating the patient on that basis. When a patient comes seeking help, how should the doctor prescribe, and on what grounds? This requires differentiating the pattern and the disease—clearly identifying what state the patient is in and which drugs are suitable—which means gathering all the patient's indications for medication.
A good many of our Chinese TCM scholars love the profound and mysterious; some directly call Chinese medicine the "Way." If you ask them to explain further what this Way is, they cannot themselves say clearly. Then they parrot Laozi's "the Way that can be spoken is not the constant Way" to fob you off, striking an ineffable pose when in truth they themselves do not understand. This is called making others enlightened while oneself in the dark. Muddled oneself, they hope through their words to make others clear—it cannot be done.
Chinese medicine traveled to Japan and was warmly received there. Japanese physicians are especially particular about zheng in applying TCM: there is abdominal zheng, pulse zheng, and drug zheng. To judge a disease and use a drug, there must always be articulable evidence; without it they do not rashly talk or prescribe. This research method has its shortcomings, but it fits the clinical spirit. A clinician who values theory over objective reality is somewhat playing with human life.
In sum, pattern differentiation-treatment is identifying evidence in order to judge and treat; disease differentiation-treatment is identifying the disease in order to treat. Pattern differentiation-treatment does not necessarily equal disease differentiation-treatment. Under pattern differentiation, several diseases may be regarded as one pattern: a patient may have pleurisy and costal pleurisy, yet in TCM pattern differentiation they may all be grouped as a shaoyang pattern and ruled by the Bupleurum (Chaihu Tang) series of formulas. Pattern differentiation and disease differentiation should not be isolated. Sometimes disease differentiation gives poor results, and sometimes pure pattern differentiation cannot cure at all.
An old TCM doctor named Zhang Haifeng once mentioned that in the past, when treating nephritis and similar diseases, TCM could not root it out; when it recurred, doctors blamed the patient for eating salt, sometimes ordering salt abstinence for months on end—how could anyone bear that? In fact such patients did not relapse because of salt; under pattern differentiation the root had not been eradicated. Zhang said that at first he too believed recurrence was due to salt. But now diagnostic instruments are advanced; when he checked later, he found the root cause was still present and the relevant markers remained high.
This is the weakness of pattern differentiation: if you merely relieve the patient's symptoms without addressing the root, the illness will not go away; given the chance it recurs. This is very evident in treating cancer and similar diseases. A TCM formula may make the patient feel vigorous and even gain weight, but the cancer cells remain and the disease can recur at any time. We should recognize this shortcoming. When you mention the shortcomings of pattern differentiation to some die-hard TCM fans, they flare up as if you stepped on their tail. Many in the TCM world are hidebound to a fatal degree, which is why reform is so difficult; it is lamentable.
The evidence for pattern differentiation is multifaceted: pulse signs, symptoms, abdominal signs, and external manifestations observed from the patient's complexion and habits. Inspection, auscultation-olfaction, inquiry, and palpation—these gather clinical evidence through the doctor's observation of the patient's appearance and movements, listening to the patient, professional questioning and recording, and palpation of the pulse, chest, and abdomen. On this evidence the doctor decides what treatment the patient should receive.
Medicine has developed to today, and most of what doctors can do amounts to no more than this. If there is any improvement, it is that science has advanced and instruments are sophisticated enough to make up for the diagnostic means of old. But for the great majority of minor complaints these instruments are not used; in hospitals, whether TCM or Western, most of the time doctors still rely on that original set of inspection, auscultation, inquiry, and palpation.
Among these clinical clues, some are felt by the patient himself—we may call them symptoms. Some are not felt by the patient and cannot be called symptoms; they can only be observed by the doctor. TCM is a discipline that "observes the exterior to know the interior"; how detailed the doctor's identification is plays a key role in outcome. The more carefully one identifies, the more accurate the judgment, the more precise the measures, and the better the result.
Gathering this clinical evidence requires a patient process. Many doctors are perfunctory in clinic, seeing patients very hurriedly, and so their conclusions are inadequate. This phenomenon is strikingly similar across the dynasties; today when we go to a hospital we are often dismissed in a minute or two. Zhang Zhongjing's era was no better, which is why in his preface to the Shanghan Lun he criticized many doctors for treating carelessly and gathering clinical evidence inadequately.
Good doctors and good detectives have much in common: both need meticulous analytical ability and must value objective evidence. Bad doctors and bad detectives are alike too—bad doctors see patients in great haste. Some doctors may form a prejudice about the disease at first glance, and then the evidence-gathering becomes something like torture: they question selectively according to their prejudice, and if what the patient says happens to match the disease they suspect, they conclude at once.
Actually that is wrong. Does expression between people truly convey reliable information? Anyone who has studied hermeneutics knows that language does not always transmit the truth; it has a funnel effect, filtering out much that is important. Not to mention that once a doctor forms a prejudice, a single leaf blinds the eye: they see selectively and lose comprehensiveness.
When I first began taking histories I did not recognize this and asked carelessly. Now I get to the bottom of things. For example, asking whether the patient is usually thirsty: some say yes, they feel thirsty. Then some doctors write in the case record "patient thirsty," which may not be right. Some thirst is not pathological; the patient is not professional and so answers offhand. Who does not feel thirsty? Everyone does; ask them that and of course they say yes. You must go on: how much water do you drink a day? Do you prefer hot or cold drinks? Is the thirst accompanied by agitation? The patient may tell you he does not like drinking water and does not feel agitated even when thirsty. How can a doctor carelessly write "thirsty" in the record? If one of your key criteria is itself wrong, pattern differentiation will of course go awry.
When pattern differentiation is wrong, the drugs are bound to fail; when it is right, they are very effective. TCM does not necessarily cure disease in one dose, but when the formula matches the pattern it can at least "remove the pattern with the medicine." Many diseases cannot be cured—cancer, AIDS, hepatitis B, and such stubborn illnesses. Neither Chinese nor Western medicine can yet claim to cure them; cures are isolated cases. For these, simply clearing the patient's pattern is good enough. Once the pattern is gone, the patient at least lives with quality and may live longer. That is about all medicine can do for diseases humanity has not yet conquered.
When I began studying medicine I was bent on curing every patient—a wish only a god could fulfill; a doctor cannot. If a doctor brags that his cure rate for terminal disease is high, you need not even check: he is a fraud. My mother suffered for years from stroke sequelae and cancer; I exhausted my mind seeking treatment and met countless charlatans who claimed to cure such diseases. I am a fairly rigorous person and investigated them one by one; the result showed that the probability of lying was one hundred percent.
But this does not mean TCM itself is a fraud. Is Chinese medicine effective? I would say it is very effective. We often say that when the formula matches the pattern, one bowl of decoction does the job; Chinese herbs truly have this effect. The key is whether the doctor has truly differentiated accurately.
I used to lack confidence in my own skill and did not dare treat myself when ill. Once I had severe diarrhea; Western medicine and antibiotics and every gastroenteritis drug were tried and would not stop it. Then I judged for myself that this called for Huanglian Jiedu Tang (Coptis Detoxification Decoction). The prescription was simple: Huangqin (Scutellaria) 6 g, Huangbai (Phellodendron) 6 g, Huanglian (Coptis) 9 g, Zhizi (Gardenia) 9 g. One package boiled to a bowl; I drank half a bowl and it stopped. I did not drink the other half. That was how fast it worked.
My nephew once caught a cold; my father, caring for him back home, took him to the hospital for injections. For more than ten days it would not improve, and his white blood cell count was very low. The doctor prescribed a white-cell-raising drug and said that if the count was still low at a checkup half a month later, leukemia must be ruled out. My mother had just died of cancer, so my father was greatly alarmed. When I got home I used Chinese medicine to induce sweating; once he sweated he was fine, and the white count normalized.
Of course this does not mean TCM is superior to Western medicine; one or two diseases prove nothing. Nor does it mean I am especially skilled—anyone who has studied medicine has occasional moments of such miraculous effect, but not every time.
Whether TCM or Western medicine, the key to treating disease lies in clearly identifying the disease and the indications for medication.
There was a Japanese physician named Yoshimasu Todo (Yoshimasu Tōdō), much respected in Japanese TCM circles. He wrote a book named Yao Zheng (Drug Indications), specifically on the indications of various drugs. It is very popular; many Japanese TCM doctors take it as a clinical canon. He especially emphasized that using a drug must rest on very reliable indications.
Why do I repeatedly mention Japanese TCM? Because in reality I see that many TCM doctors in China have gone off track, and TCM has gone off track in the common Chinese understanding.
Now some patients come right up and ask: am I kidney-deficient? On TV and in print media the same talk is everywhere. Kidney deficiency, spleen deficiency, lung deficiency—many patients pigeonhole themselves into these and then ask whether they should take such-and-such a drug.
Just yesterday a patient asked me whether taking Dihuang Wan would be good for her. I asked her what symptoms she had; not a single one corresponded to the indications of Dihuang Wan, yet she was bent on tonifying the kidney. Because many patients hear that cancer patients are often kidney-deficient and that tonifying the kidney helps, she thought she would give herself a tonic.
Can medicine taken like this work? Chinese herbs are not prescribed this way; a TCM doctor must have indications. Liuwei Dihuang Wan requires the indications for Liuwei Dihuang Wan; Guipi Wan requires the indications for Guipi Wan. If you go around declaring which organ is deficient in the patient without regard to physical signs and then proceed to tonify that organ, you are talking nonsense. That is the idealist route. I often stress to people that TCM is not idealistic; it highly values evidence.
This evidence-respecting spirit begins with the Shanghan Lun: Guizhi Tang has strict indications, Mahuang Tang has strict indications, Gegen Tang has strict indications. What the pulse must be, which symptoms must be present for which prescription, and which drugs must be added to which formula for which symptoms—all are perfectly clear. If a cold patient is already pouring with sweat and you then use the strong sudorific Mahuang Tang, you are sending the patient to the gate of hell. Conversely, if all the indications for Mahuang Tang are present and you hesitate and dare not use it, you miss the best chance.
Pattern differentiation-treatment is very close to evidence-based medicine: when the indications for medication are unclear, the doctor should rather prescribe nothing than guess wildly and prescribe at random. Many of today's TCM "masters" discourse glibly on theory yet achieve little clinically; that is why.
In the past, when a patient's symptoms did not match any formula I knew, I would guess and prescribe according to basic TCM theory. The resulting formulas would not kill the patient, but as for efficacy—there was none. Now, if I myself cannot clearly differentiate the patient's condition, I do not prescribe; I flip through TCM books and Western books until I am certain what the condition is, and only then write the prescription.
The Shanghan Lun is a clinical work; the whole book has no wasted words and no subjective mystery. Zhang Zhongjing was an honest man: for some diseases he knew the symptoms but could not treat them, so he merely recorded the condition without a prescription. For some difficult-to-treat diseases he plainly stated "difficult to treat." For diseases he could treat, if he prescribed he always explained clearly what course the patient could expect.
Can the Shanghan Lun then be the clinical canon for all diseases? Many TCM doctors, out of love for Zhang Zhongjing, push him to extremes and magnify the book's power without limit; that too is wrong. I think if Zhang Zhongjing returned to life he would not wish to see this. Many formulas in the Shanghan Lun do indeed treat many diseases beyond narrow cold damage; that is not strange—it is normal for one drug to treat several diseases, and Western drugs do this too. It is also not strange that many different diseases present similarly and can be cured the same way.
In broad direction, the Shanghan Lun still focuses on treating narrow cold damage. But the pattern-differentiation spirit it pioneered far transcends the treatment of narrow cold damage. I believe that in studying the Shanghan Lun, what one should most learn is Zhang Zhongjing's rigorous clinical attitude, his seek-truth-from-fact style, and his meticulous care—these are the basic qualities a clinician should possess.