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[Fr. peine, fr L. poena, a fine, a penalty, punishment]
As defined by the International Association for the Study of Pain, an unpleasant sensory and emotional experience arising from actual or potential tissue damage or described in terms of such damage. Pain includes the perception of an uncomfortable stimulus and the response to that perception. About half of those who seek medical help do so because their primary complaint is pain. Pain may arise in nearly any organ system and may have different characteristics in each system. Acute pain occurs with an injury or illness; is often accompanied by anxiety, diaphoresis, nausea, and changes in vital signs (such as tachycardia or hypertension); and ends after the stimulus is removed or the organ heals. Chronic or persistent pain lasts beyond the normal healing period. Musculoskeletal pain is often exacerbated by movement and may be accompanied by swollen joints or muscle spasm. Myofascial pain is marked by trigger-point tenderness. Visceral pain is often diffuse or vaguely localized, but pain from the lining of body cavities is often localized precisely, very intense, and sensitive to palpation or movement. Nerve pain usually stings or burns; it may be described as numbness, tingling, or shooting sensations. Colicky pain fluctuates in intensity from severe to mild and usually occurs in waves. Referred pain results when an injury or disease occurs in one body part but is felt in another.
Several factors influence the experience of pain, such as the nature of the injury or illness causing the symptom, the physical and emotional health of the patient, the acuity or chronicity of the symptom, the social milieu and/or cultural upbringing of the patient, neurochemistry, memory, and personality. SEE TABLE: Usual Adult Doses and Intervals of Drugs for Relief of Pain

Many clinicians use the mnemonic COLDER to aid the diagnosis of painful diseases. They will ask the patient to describe the Character, Onset, Location, and Duration of their painful symptoms, the features that Exacerbate or Relieve it. For example, the pain of pleurisy is typically sharp in character, acute in onset, located along the chest wall, and long-lasting; it is exacerbated by deep breathing or coughing and is relieved by analgesics or by holding still. By contrast, the pain of myocardial ischemia is usually dull or heavy, gradual in onset, located substernally, may be exacerbated by activity (but not by taking a breath or coughing), and relieved by nitroglycerin.

In 2000, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO, since 2007 called The Joint Commission,) issued standards of pain management , began surveying for compliance in 2001, and in 2004 added patient-safety goals; thus most U.S. health care facilities have devised policies and procedures that require pain-intensity rating as a routine part of care (the fifth vital sign). Pain intensity is usually assessed on a numerical scale, in which 0 = no pain, 1 to 3 = mild pain, 4 to 6 = moderate pain, and 7 to 10 = severe pain. However, obtaining a numerical rating of pain intensity is possible only if the patient can provide this report of the pain being experienced, which infants, children, the critically ill, and cognitively impaired usually are unable to do. The Wong-Baker FACES Pain Rating Scale, which uses visual representations of smiles or grimaces to depict the level of pain a patient feels, was developed for pediatric use and has been used successfully in other patient populations.

Health care professionals must be aware that pain in nonverbal patients can easily be overlooked; they must make a conscious effort to ensure that pain in these patients is assessed and treated. Observing subtle behaviors and being sensitive to contextual clues are two methods that health care professionals use to determine when nonverbal patients are in pain. When this judgment is made, a trial of pain-relieving medication may be used. The responses of the patient and any complications of treatment should be carefully observed and appropriate changes made in dosing or the type of analgesic drug as indicated.

Because pain is subjective, sympathy is an important part of relieving it. In addition to administering analgesics, health care professionals should use a wide range of techniques to help alleviate pain, including local application of cold and heat, tactile stimulation, relaxation techniques, diversion, and active listening.

Usual Adult Doses and Intervals of Drugs for Relief of Pain
Nonopioid Analgesics
Generic NameDose, mg*IntervalComments
Acetylsalicylic acid325-6504-24 hrEnteric-coated preparations available
Acetaminophen6504 hrAvoid in liver failure
Ibuprofen400-8004-8 hrAvailable without prescription
Indomethacin25-758 hrGastrointestinal and kidney side effects common
Naproxen250-50012 hrDelayed effects may be due to long half-life
Ketorolac15-60 IM4-6 hrSimilar to ibuprofen but more potent
Opioid Analgesics
Generic NameParenteral Dose (mg)PO Dose (mg)Comments
Codeine30-60 every 4 hr30-60 every 4 hrNausea common
Hydromorphone1-2 every 4 hr2-4 every 4 hrShorter acting than morphine sulfate
Levorphanol2 every 6-8 hr4 every 6 hrLonger acting than morphine sulfate; absorbed well PO
Methadone10-1006-24 hrDelayed sedation due to long half-life
Meperidine25-100300 every 4 hrPoorly absorbed PO; normeperidine is a toxic metabolite
Morphine10 every 4 hr60 every 4 hr
Morphine, sustained release30-9060-180 2 or 3 times daily
Oxycodone5-10 every 4-6 hrUsually available with acetaminophen or aspirin

Sites of Referred Pain
Organ of OriginLocation Felt
HeadExternal or middle ear
 Nose & sinuses
 Teeth, gums,
 Throat, tonsils
 Parotid gland, TMJ joint
 DiaphragmShoulder, upper abdomen
 HeartUpper chest, L shoulder, inside L arm, L jaw
 Stomach & spleenL upper abdomen
 DuodenumUpper abdomen, R shoulder
 Stomach & spleenL upper abdomen
 Stomach & spleenL upper abdomen
 Stomach & spleenL upper abdomen
 ColonLower abdomen
 AppendixPeriumbilical and R lower abdomen
 AppendixPeriumbilical and R lower abdomen

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