What is Pain ?
PAIN is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.
Pain is that hurt
“Global Day Against Pain” on October 11th 2004″
Is normally associated with trauma, surgery, some medical conditions, cancers and certain physiological events. Trauma is usually due to injuring oneself in road vehicle accidents, falls, factory accidents, natural catastrophes, war injuries, burns, radiation & chemical injuries. The pain may arise from skin, subcutaneous tissues, muscles, bones or injuries to internal organs. This kind of pain is due to sensitization of the fine nerve endings in the affected tissues, leading to release of chemical mediators and finally electrical transmission along the nerve roots and spinal cord to the brain. With the recovery and healing of the affected tissue/organ, the pain lessens and finally disappears, unless some permanent damage to the nerve structures occurs. After surgery, similar changes leading to a painful condition ensue, though here the trauma is much more controlled and the recovery is faster. With the healing of the scar, the pain reduces. Some medical conditions are extremely painful and have the potential to proceed on to become chronic pain states. Acute peritonitis, pancreatitis, appendicitis, cholangitis, pneumonitis (pneumonia), herpes zoster, arthritis, collagen vascular diseases, raised intracranial pressure, angina, and myocardial infarction etc. When treated properly and adequately, most of these conditions resolve and the associated pain is abolished as well. Cancers, the most feared conditions are associated with severe acute as well as chronic pains. There are variable reasons for pain in cancer patients which can be of both nociceptive and neuropathic in nature. The pains can be due to the disease itself, pressure on some structure or metastases. Certain physiological states are also associated with pain, e.g. menstruation, pregnancy and childbirth, dental eruptions etc. Age related bone loss, i.e. osteoporosis, when severe, can also lead to pains.
There are many reasons for chronic pains. Though there are no fixed time frames by which the pain may be labeled acute or chronic, but as a generalization any pain continuing longer than 3 months is labeled as chronic. Some pains may be labeled chronic from an earlier time also. Chronicity may be due to the ongoing disease process or may represent plasticity in the nervous system. Plasticity of the nervous system represents alteration in the behavior of the conducting neurons which start sending false alarms to the higher centres. This process may be labeled as deafferentation process also. Sympathetic nervous system activity may be linked to certain categories of pains in some patients where sympathetic efferents and primary afferent in the spinal cord may be held responsible. Blocking or altering the sympathetic supply has been seen to be helpful in such situations and is an established procedure in these pain conditions. In many situations, the disease or illness that initiated the pain has long subsided or cured but the pain remains. For this reason, pain has been appreciated as not just a symptom of other diseases but a disease in itself, which has been duly recognized by WHO also, e.g. post herpetic neuralgia, neuralgias, neuropathies, chronic pancreatitis etc. Diseases like fibromyalgia and chronic fatigue syndromes are examples of generalized bodyaches. These conditions could be related to certain metabolic disorders like diabetes, hypothyroidism, alcoholism etc , but in majority of patients are without any underlying pathology or cause.