Pain is an unpleasant sensation caused because of actual or possible injury to the body. According to the International Association for the Study of Pain, pain can be defined as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage."
What causes pain?
Pain can be caused due to several causes such as injury, infection, cancer or simple headache. It may occur after an injury (a fall, a broken bone), in illness (flu, toothache, headache, ear pain) or in serious disease (such as appendicitis, cancer). The nerve cells at the site of the damage, infection or injury sense pain and send a signal to the brain, which perceives it and elicits a response.
Perception and transmission of pain in the body involves the nerves and the brain.
Transmission of the pain message from the nerve endings to the brain is controlled by certain chemical messengers (known as mediators and hormones). These chemical sensitise the receptors to pain and then trigger or increase the painful sensation. If the pain is severe, they may cause inflammation and fever as well.
Classification of pain
There are many ways to classify pain such as temporal (time or duration), by etiology or physiological, but a common way to classify pain is based on time or duration of pain;
Treatment of pain
Treatment of pain includes both medications and non-drug approaches. Medications commonly used for pain relief include opioid analgesics and non-opioid analgesics. Most people with acute pain get relief from pain with the use of simple pain relievers such as acetaminophen and ibuprofen. If you have chronic pain, your doctor may prescribe adjuvant analgesics (such as amitriptyline, desipramine, fluoxetine, gabapentin and pregabalin) and non-drug pain treatments in addition to pain relieving medications. Non-drug pain treatments include applying cold or warm compresses, ultrasonography that provides deep heat (diathermy), transcutaneous electrical nerve stimulation (TENS) and acupuncture.