Algorithm of Pain Research

As it does not understand and is unable to treat many forms of chronic pain, modern medicine very frequently appears impotent. The situation is complicated by the fact that the problem of pain has always been and remains the core of clinical thought for doctors in all branches of medicine. The «pain component» has an invisible presence in all stages of patient diagnosis and treatment, whether the discussion concerns disorders of the internal organs, circulatory system or peripheral nervous system. In essence, this is a multidisciplinary problem, which like no other includes practically all branches of modern fundamental medicine. Therefore, only a systematic approach to the analysis of pain, one that encompasses the key issues of this problem, can provide a sufficiently clear and comprehensive picture of not only the substance of the phenomenon in question, but also of the mechanisms involved in its appearance and abatement.

Despite the fact that the aforementioned thesis has been postulated in medical literature for sufficiently long time, there nevertheless has yet to occur a serious restructuring of the views of specialists concerning this clinical event. The classification we have developed may be of practical assistance in ascertaining the nature of a pain syndrome. It can realistically be regarded as a kind of diagnostic algorithm for clinical studies for the purpose of acquiring information of the highest significance for the determination of the essence of a pain syndrome. The classification is a vade mecum for the study of patients with chronic pain. It makes possible a diagnostic search independent of the nature, localization, and clinical manifestations of chronic pain. Indicators reflecting the mechanisms of the origination and development of chronic pain at the "tissue" and "neural" levels are of fundamental significance in the recognition of the nature of algesic phenomena.

The determination of the nature of pain is a quite complex intellectual process that consists of a number of sequential stages. In this responsible and at times difficult process, the physician must adhere to a definite sequence and a clear plan. The elucidation of the following factors is of fundamental significance in the diagnostic search.

Basis for Establishing the Nature of Pain Syndrome

Is the pain central or peripheral? There are no special diagnostic difficulties in establishing the character of the chronic pain in the majority of patients. A distinguishing feature of central pain is its stable association with a central pain dominant, as a result of which the peripheral factor partially or entirely loses its significance.

The form of chronic pain: which tissues and organs participate in its formation? The answer to this question is a fundamental one in establishing the nature of algesic phenomena, since it is the type of tissue involved in the morbid process that determines one or another trigger mechanism giving rise to pain at the periphery. Once the form of pain has been established, it becomes possible to correctly orient oneself in the selection of remedial measures that are capable of eliminating the source of painful irritation in peripheral tissues. The solution of the problem is complicated when pain arises from different tissues and organs at the same time. In such instances, unrecognized sources of painful irritation in the periphery make it impossible to entirely eliminate algesic phenomena at the focus of injury. Additional examination of the patient, as well as the physician's knowledge, experience, and intuition, are required in order to find correct answers to questions relating to the structure of the pain syndrome and the localization of the individual sources of pain in the peripheral tissues.

The type of chronic pain: what is its neurophysiological origin? After it has arisen in the peripheral tissues and organs, chronic pain acquires its definitive shaping in the segmental and suprasegmental structures of the nervous system. The determination of the division of the nervous system (somatic or vegetative) participating in the reception and processing of the sensory information arriving from the periphery is of practical significance. The type of pain sensitivity (somatic or vegetative) to be subjected to correction by the methods of reflex therapy for the purpose of eliminating disturbances in neural regulation at the focus of injury is established on the basis of the results of the sensory differentiation of painful sensations.

Determining the level of algesic dysfunction of the ganglia. The neuronal system of the ganglia is the first structure, before others, of the pain-conducting system that is engaged in the regulation of pain sensitivity of the peripheral tissues. The processes occurring in the ganglia, somatic or vegetative, are of key significance in the formation of chronic pain. Determining the level of dysfunction of the ganglia solves two problems: 1) it specifies the site of the pathologic determinant in the nervous system, and 2) identifies the interconnection between the ganglion involved in the morbid process and its metameric receptor field at the periphery, where the painful sensations are localized. These data are needed in pain treatment practice to ensure a goal-directed action on ganglia in order to normalize their functional state.

The origin of algesic pathology (that has resulted in chronic pain): primary or secondary? The answer to this question is found in the process of serious and thoughtful evaluation of patients. Most failures in pain-control therapy, the ill-advised prescription of various locally-acting procedures, and neglected possibilities of timely impact on the patient's body to enhance its state of health are associated in particular with the incorrect determination of the genesis of algesic pathology. It is very difficult to figure out the complex picture of clinical manifestations of an illness that has arisen on the basis of impairment of other organs and systems. This occurs especially frequently in the presence of physiological debilitation of regulatory factors, leading to blood, lymph, or tissue fluid biochemical indices exceeding homeostatic limits. Shifts in the internal milieu are associated in many instances with heightened elimination from, or on the other hand, retention by the body of metabolic products, hormones, mediators, or ions. A carefully taken history, involvement in the pathological process of the most varied organs and systems, and the failure of treatment measures facilitate suspicion of the secondary genesis of an illness.

The state of vegetative regulation: sympathotonia or parasympathotonia? This is an extremely important question, and its significance is sometimes underestimated. Not infrequently, despite a correct treatment plan, it is not possible, due to the presence of vegetative dystonia, to attain substantial improvement in patients' condition. This relates, first and foremost, to patients suffering from regulatory diseases. Pain-control therapy must be carried out in such patients only after the elimination of dysfunction of the vegetative nervous system and restoration of vegetative equilibrium.

It is difficult to overestimate the differentiation of the various forms and types of chronic pain (carried out in accordance with the principles of the Law of Tissue Specificity and Mutation of Mechanisms of Painful Phenomena) for the development of the principles of the individual approach to the rehabilitation of patients with chronic pain. Based on the foundation of the entire corpus of theoretical and practical knowledge, the contemporary model of chronic pain makes it possible to meaningfully (consciously) approach the elimination of algesic phenomena in the presence of the most diverse pathology of the body's organs and systems. The new knowledge is the "key" to the correct understanding and solution of the problems of pain applicably for all medical specialists.