Definition of Pain
In dictionaries, pain (ICD-9: 780.96) is defined as a sensation of hurting or of strong discomfort in some part of the body, caused by an injury, a disease, or a functional disorder and transmitted through the nervous system. A nurse, Margo McCaffery, who worked for years with clients in pain and conducted extensive research in the field of pain, defines pain as whatever the experiencing person says it is, existing when he or she says it does. This definition is perhaps the most useful because it acknowledges the client’s complaint, recognizes the subjective nature of pain, and implicitly suggests that diverse measures may be undertaken to relieve pain.
The IASP and the American Pain Society (APS) define pain as an unpleasant sensory and emotional experience arising from actual or potential tissue damage or described in terms of such damage. Again, this definition further confirms the multiple components of pain in a person’s psychological and physiological existence. Pain is the most common complaint of persons seeking medical attention.
Acute pain (ICD-9: 338.1x) is a warning that something is wrong in normal body functioning. It warns of inflammation, tissue damage, infection, injury, trauma, or surgery somewhere in the body. Acute pain is often accompanied by anxiety. It comes on suddenly and can last for hours or days, perhaps even months. Such pain may be manifested as an increase in heart rate, blood pressure, and muscle tension and a decrease in salivary flow and gut motility. The primary goal of treatment is to diagnose the source of pain and remove it. Acute pain disappears once the underlying cause of the pain is treated.
Chronic pain (ICD-9: 338.2x) most often starts as an acute pain but continues beyond the normal expected time for resolution. It may also be described as a pain that recurs. Chronic pain is no longer useful or beneficial. It is frequently debilitating, exhausting an individual’s physical and emotional resources. It is often difficult to manage. Complete relief of chronic pain does not always occur. The treatment goal of chronic pain is to minimize the pain and maximize a person’s functioning. The intent is to decrease the level of pain so that everyday activities can be performed. Because of this goal, a multidisciplinary approach to treatment is often necessary. This approach blends physical, emotional, intellectual, and social skills.
Chronic pain can further be described as
- Nociceptive pain
- Neuropathic pain
Nociceptive pain is sometimes called tissue pain. It is derived from damage to tissues rather than nerves. The nerve cells (called nociceptors) carry the pain sensation to the spinal cord where it is then relayed to the brain. This pain is well localized, often has an aching or throbbing quality, and is constant. The pain is called somatic if it is the result of damage or injury to muscles, tendons, and ligaments. Somatic pain may be further classified as cutaneous if the pain comes from the skin or deep if the pain comes from deeper musculoskeletal tissues.
Neuropathic pain comes from a nervous system lesion. It may be further identified as neural pain if the lesion is in the brain or spinal cord. It is referred to as peripheral neuropathic pain if the lesion is along the cranial or spinal nerves. Neuropathic pain is often described as severe, sharp, stabbing, burning, cold, numbness, tingling, or weakness. Some individuals feel the pain move along the nerve path from the spine to the extremities. Neuropathic pain does not usually respond to routine analgesics.
It is quite possible for individuals to experience nociceptive and neuropathic pain at the same time in certain conditions. Specialists in pain management define additional types of pain. The most common are listed here:
- Angina pain (ICD-9: 786.51) occurs when the blood supply to the heart muscle is disrupted. It is often described as crushing or tightness and burning pain in the chest.
- Breakthrough pain (ICD-9: 338.x) results from the reoccurrence of chronic pain that earlier responded to pain management.
- Malignant (cancer) pain (ICD-9: 338.3) comes from the disease of cancer (tumor, abnormal growth) or the treatment for the cancer (surgery, radiation, chemotherapy).
- Phantom limb pain (ICD-9: 729.2) is the pain felt from an amputated body part. Military personnel who suffered the loss of a limb often describe this pain as squeezing or burning. The brain mistakenly interprets the nerve signals as coming from the missing limb.
- Psychogenic pain (ICD-9: 307.80) is often experienced by individuals with psychological disorders. They have very real pain but without a physical cause.
The Experience of Pain
How pain is experienced is based, in part, on several variables:
- Early experiences of pain. Did management of pain in the past have a positive or negative impact? Generally, a person’s fear of pain increases with each pain experience.
- Cultural backgrounds. Research shows that culture generally does not influence how a person perceives pain but does influence how a person responds to pain. Early in life, children learn from those around them. For example, children may learn that a sports injury does not hurt as much as trauma from an automobile accident. Further, they learn what behaviors are acceptable or unacceptable. These behaviors vary among cultures. Rarely are these expectations changed; in fact, these perceptions are believed to be normal and acceptable.
- Anxiety and depression. Does anxiety increase or decrease pain? Is depression the cause or result of pain? Some believe there is a relationship between anxiety and depression and pain. The longer the duration of pain, the greater is the occurrence of depression. It is important to address anxiety and depression when treating individuals in pain.
- Age. Pain perception does not change significantly with age, yet the way an elderly person responds to pain treatment may differ from that of a younger person. For example, as a person ages, a slower metabolism and greater ratio of body fat to muscle mass dictates that a smaller dosage of analgesics may be required.
- Sex. Recent research suggests that females and males experience pain differently. In fact, females demonstrate a greater frequency of pain-related symptoms in more bodily areas than do males. In addition, when pain-free individuals were exposed to a variety of painful stimulus, females exhibited greater sensitivity to the experimentally induced pain than did males. It also was evident that women attach an emotional aspect to the pain they experience, while men concentrate only on the physical sensations they experience. This sensory focus for men allowed them to endure more pain and suffer less than the women.