Few current topics generate as much interest and enthusiasm as does pain. Because this ubiquitous symptom has remained so long a mystery, any discovery or theory concerning its mechanism and alleviation is even more intriguing.
We know pain exists, but we may be unable to find its cause. If we do find the cause, there may be no correlation between the extent of disease and the degree of patient suffering. A condition that causes excruciating pain in one person may be completely tolerable to another. Even if the cause is removed, suffering may continue.
Pain is entirely subjective, but we know it exists when we see the distressed patient. We cannot see the pain, but we recognize its presence in facial expression, verbal description, body language, and objective clinical signs (eg, pallor, rapid pulse, sweating, and others). The patient may feel that he must convince us of its reality, but
Goodman CE. Pathophysiology of Pain. Arch Intern Med. 1983;143(3):527-530. doi:10.1001/archinte.1983.00350030141023