A look at pain

Pain is a complex, subjective phenomenon that involves biological, psychological, cultural, and social factors. To put it succinctly, pain is whatever the patient says it is, and it occurs whenever she says it does. The only true authority on any given pain is the person experiencing it. Therefore, health care professionals must understand and rely on the patient’s description of her pain when developing a pain management plan. The Joint Commission requires that all patients be assessed for pain.




Each patient reacts to pain differently because pain thresholds and tolerances vary. Pain threshold is a physiologic attribute that denotes the smallest intensity of a painful stimulus required to perceive pain. Pain tolerance is a psychological attribute that describes the amount of stimulus (duration and intensity) that the patient can endure before stating that she’s in pain.

Theories about pain

Three theories attempt to explain the mechanisms of pain:

  • specificity
  • pattern
  • gate control

Let’s get specific

The specificity theory maintains that individual specialized peripheral nerve fibers are responsible for pain transmission. This biologically oriented theory doesn’t explain pain tolerance, nor does it allow for social, cultural, or empirical factors that influence pain.

Pain pattern

The pattern theory suggests that excessive stimulation of all nerve endings produces a unique pattern interpreted by the cerebral cortex as pain. Although this theory addresses the brain’s ability to determine the amount, intensity, and type of sensory input, it doesn’t address nonbiological influences on pain perception and transmission.

Opening the gate

The gate control theory asserts that some sort of gate mechanism in the spinal cord allows nerve fibers to receive pain sensations. (See Understanding the gate control theory.) This theory has encouraged a more holistic approach to pain management and research by taking into account the nonbiological components of pain. Pain management techniques, such as cutaneous stimulation, distraction, and acupuncture are, in part, based on this theory.

Categorizing pain by duration

There are two fundamental pain types that are classified according to their duration: acute and chronic.

Acute pain

Acute pain commonly accompanies tissue damage from injury or disease. It varies from mild to severe in intensity and typically lasts for a brief period (less than 6 months). Acute pain is considered a protective mechanism, alerting the individual to tissue damage or organ disease. A patient can get relief from acute pain, and the pain itself dissipates as the underlying disorder heals.

Relief and healing

Treatment goals for acute pain include relieving pain and healing the underlying injury or disease responsible for the pain. Palliative treatment may include surgery, drug therapy, application of heat or cold, or psychological and behavioral techniques to control pain.

Understanding the gate control theory



Chronic pain

The cause of chronic pain isn’t always clear. Chronic pain can stem from prolonged disease or dysfunction, as in cancer and arthritis, or it can be associated with a mental disorder such as post-traumatic stress syndrome. It can be intermittent, limited, or persistent and usually lasts 6 months or longer. Instead of stemming from an easily identifiable location, chronic pain is typically generalized. It’s also strongly influenced by the patient’s emotions and environment.

Not the pain next door

Patients with chronic pain often have difficulty describing what they’re feeling. Different patients also react to the pain in different ways. One may cry out or moan; another may simply withdraw. Changes in appetite and sleep may occur, and patients may become anxious or irritable, but vital signs frequently don’t change.

If you can’t beat it, work with it

With many patients unable to find complete relief, chronic pain can become a life-altering condition, making long-term pain management challenging. The main goal is to help patients participate as fully as possible in desired daily activities and to get adequate rest, which can improve emotional well-being. Treatments include the use of analgesic medications supplemented with such therapies as massage, heat or ice packs, exercise, meditation, and distraction.

Categorizing pain by physiologic source

Pain can be classified not just by its duration but also by its physiologic source.

Nociceptive pain

In nociceptive pain, injury or inflammation stimulates special injury-sensing receptors in the peripheral nervous system. The receptors then communicate this information to the brain, resulting in the sensation of pain. The two types of nociceptive pain are somatic pain, which comes from skin, musculoskeletal structures, or connective tissue, and visceral pain, which initiates in organs and the lining of body cavities.

Neuropathic pain

Damage to peripheral nerves or to the central nervous system can result in neuropathic pain. Patients describe this poorly localized type of pain as tingling, burning or fiery, or shooting. Types of neuropathic pain include phantom limb pain that occurs after a limb amputation as well as the peripheral extremity pain that diabetics often experience.


Assessing pain

The only way to get an accurate understanding of the patient’s pain is to ask him. Begin by asking the patient to describe his pain. Where does it hurt? What exactly does it feel like? When does it start, how long does it last, and how often does it recur? What provokes it? What makes it feel better? There are a variety of assessment tools that can help. Use one to obtain a more accurate and consistent description of pain intensity and relief — two important measurements. The key to effective pain management is an accurate baseline assessment and continual reassessment of the pain. (See Pain assessment tools.)

Pain assessment tools



Where does it hurt?

Find out how the patient responds to pain. Does his pain interfere with eating? Sleeping? Working? His sex life? His relationships? Ask the patient to point to the area where he feels pain, keeping in mind that:

  • localized pain is felt only at its origin
  • projected pain travels along the nerve pathways
  • radiated pain extends in several directions from the point of origin
  • referred pain occurs in places remote from the site of origin.

Nature’s source

Factors that influence the nature of a patient’s pain include duration, severity, and source. The source may be:

  • cutaneous, originating in the skin or subcutaneous tissue
  • deep somatic, which includes nerve, bone, muscle, and supporting tissue
  • visceral, which includes the body organs.
    Watch for physiologic responses to pain (nausea, vomiting, changes in vital signs) and behavioral responses to pain (facial expression, movement and positioning, what the patient says or doesn’t say). Also note psychological responses, such as anger, depression, and irritability.

All about attitude

Assess the patient’s attitude about pain. Ask him how he usually handles pain. Does he tell others when he hurts, or does he try to hide it? Does his family understand his pain and try to help him deal with it? Does he accept their help?