Pain

Definition

• According to the International Association for the Study of Pain, pain is an unpleasant, subjective sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.

Pain Theories

Specific Theory

1. Proposes that body’s neurons & pathways for pain transmission are specific, similar to other senses like taste
2. Free nerve endings in the skin act as pain receptors, accept input & transmit impulses along highly specific nerve fibers
3. Does not account for differences in pain perception or psychologic variables among individuals.

Pattern Theory

1. Identifies 2 major types of pain fibers; rapidly & slowly conducting
2. Stimulation of these fibers forms a pattern; impulses ascend to the brain to be interpreted as painful
3. Does not account for differences in pain perception or psychologic variables among individuals.

Gate Control Theory

1. Pain impulses can be modulated by a transmission blocking action within the CNS.
2. Large-diameter cutaneous pain fibers can be stimulated (e.g. rubbing or scratching an area) and may inhibit smaller diameter fibers to prevent transmission of the impulse (“close the gate”).

Current Developments in Pain Theory

Indicate that pain mechanisms & responses are far more complex than believed to be in the past.

1. Pain may modulate at different points in the nervous system.
   • First-order neurons at the tissue level
   • Second-order neurons in the spinal cord that process nociceptor information
   • Third-order tracts & pathways in the spinal cord & brain that relay/process this information
2. The role of the pain experience in the development of new nociceptors and/or reducing the threshold of current nociceptor is also being investigate

Types of Pain

Acute Pain

1. Usually temporary, sudden in onset, localized, lasts for 6 months; results from tissue injury associated with trauma, surgery, or inflammation.

Types of Acute Pain

• Somatic: arises from nerve receptors in the skin or close to body’s surface; may be sharp & well-localized or dull & diffuse; often accompanied by nausea & vomiting
• Visceral: arises from body’s organs; dull & poorly localized because of minimal noriceptors; accompanied by nausea & vomiting, hypotension & restlessness
• Referred pain: pain that is perceived in an area distant from the site of stimuli (e.g. pain in a shoulder following abdominal laparoscopic procedure).

2. Acute pain initiates the “fight-or-flight” response of the Autonomic Nervous System and is characterized by the following symptoms:

• Tachycardia
• Rapid, shallow respirations
• Increased BP
• Sweating
• Pallor
• Dilated pupils
• Fear & Anxiety

Chronic Pain

1. Prolonged, lasting longer than 6 months, often not attributed to a definite cause, often unresponsive to medical treatment. Some people may go to a mild-drug dosage to help them with the pain and to give them a sense of relief.

Types of Chronic Pain

• Neuropathic: painful condition that results from damage to peripheral nerves caused by infection or disease; post-therapeutic neuralgia (shingles) is an example
• Phantom: pain syndrome that occurs following surgical or traumatic amputation of a limb.
  • The client is aware that the body part is missing
  • Pain may result of stimulation of severed nerves at the site of amputation
  • Sensation may be experienced as an itching, pressure, or as stabbing or burning in nature
  • It can be triggered by stressors (fatigue, illness, emotions, weather)
  • This experience is limited for most clients because the brain adapts to amputated limb; however, some clients experience abnormal sensation or pain over longer periods
  • This type of pain requires treatment just as any other type of pain does.
• Psychogenic: pain that is experienced in the absence of a diagnosed physiologic cause or event; the client’s emotional needs may prompt pain sensation.

2. Depression is a common associated symptom for the client experiencing chronic pain; feelings of despair & hopelessness along with fatigue are expected findings.

Pain Assessment

Tools/Instruments Used

1. A Verbal Report using an intensity scale is a fast, easy & reliable method allowing the client to state pain intensity & in turn, promotes consisted communication among the nurse, client & other healthcare professionals about the client’s pain status; the 2 most common scales used are “0 to 5” or “0 to 10”. With 0 specifying no pain & the highest number specifying the worst pain
2. A Visual Analog Scale is a horizontal pain-intensity scale with word modifiers at both ends of the scale, such as “no pain” at one end and “worst pain” at the other, clients are asked to point or mark along the line to convey the degree of pain being experienced
3. A Graphic Rating Scale is similar to the visual analog scale but adds a numerical scale with the word modifiers, usually the numbers “0 to 10” are added to the scale.
4. Faces Pain Scale children, clients who do not speak English & clients with communication impairments may have difficulty using a numerical pain intensity scale; the FACES pain scale may be used for children as young as 3 years old; this scale provides facial expressions (happy face reflects no pain, crying face represents worst pain)
5. Physiologic Indicators of Pain may be the only means a nurse can use to assess pain for a non-communicating client, facial & vocal expression may be the initial manifestations of pain; expressions may include rapid eye blinking, biting of the lip, moaning, crying, screaming, either closed or clenched eyes, or stiff unmoving body position

A B C D E method of pain assessment

1. This acronym was developed for cancer pain; however, it is very appropriate for clients with any type of pain, regardless of the underlying disease.
2. A = Ask about pain
3. B = Believe the client & family reports pain
4. C = Choose pain control options appropriate for the client
5. D = Deliver interventions in a timely, logical &coordinated fashion
6. E = Empower clients & families

P Q R S T assessment for pain reception

1. This method is especially helpful when approaching a new pain problem
2. P = What precipitated the pain?
3. Q = What are the quality & quantity of the pain?
4. R = What is the region of the pain?
5. S = What is the severity of the pain?
6. T = What is the timing of the pain?

Pain History

1. Location – when clients report “pain all over”, this generally refers to total pain or existential distress (unless there is an underlying physiologic reason for pain all over the body, such as myalgias); assess the client’s emotional state for depression, fear, anxiety or hopelessness.
2. Intensity – It is important to quantify pain using a standard pain intensity scale. When clients cannot conceptualize pain using a number, simple word categorizes can be useful (e.g. no pain, mild, moderate, severe).
3. Quality- Nociceptive pain are usually related to damage to bones, soft tissues, or internal organs; nociceptive pain includes somatic & visceral pains.
   • Somatic pain is aching, throbbing pain; example arthritis
   • Visceral pain is squeezing, cramping pain; example: pain associated with ulcerative colitis
4. Pattern – pain may be always present for a client; this is often termed baseline pain. Additional pain may occur intermittently that is of rapid onset & greater intensity than the baseline pain; known as breakthrough pain. People at end-of-life often have both types of pain. Cultural beliefs regarding the meaning of pain should be examined