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Pain is multidimensional; more than one test or measure may be needed in the examination.
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Pain may be the cause or the result of other musculoskeletal impairments, so both examination and plan of care should address these relationships.
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Identifying the primary source of pain mediation will assist the therapists with developing an appropriate plan of care.
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Despite insufficient evidence for the use of specific therapy interventions for pain modulation, patients will seek treatment for their pain.
Pain is defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage. It is the primary reason that patients seek medical attention. As described in Chapter 113 , pain mechanisms are complex and multidimensional. The pain experience is unique to each individual patient, thus making the assessment and management of pain challenging to therapists and surgeons.
The Joint Commission on Accreditation of Healthcare Organizations (JCAHO) requires assessment and appropriate management of pain within accredited facilities. Pain is considered the “fifth vital sign” and should be measured regularly along with the other vital signs: blood pressure, heart rate, respiratory rate, and temperature. Although not all clinicians treating hand and upper extremity patients work in a JCAHO-accredited institution or clinic, pain assessment is essential in hand rehabilitation. Our initial assessment of pain allows us to select the appropriate intervention and to determine whether a particular intervention has been effective in alleviating pain. Also, if the nature of the pain is not straightforward, clinicians need to determine the extent and location of the pain as a way to determine the underlying cause of the patient’s pain or source of pain mediation.
Pain is usually a symptom associated with musculoskeletal conditions commonly seen in hand rehabilitation, including multiple trauma. It may also be associated with pathology of the cardiovascular, pulmonary, integumentary, neuromuscular, metabolic, and endocrine systems. Pain may occur secondary to impairments in circulation, ventilation, joint integrity, muscle performance, and posture. The presence of pain may result in the loss of motion, decreased muscle performance, decreased sensory discrimination, and edema. Secondary to these impairments, functional limitations are likely to be reported with activities of daily living, work duties, and sports and leisure activities. Therefore, the assessment of pain is almost always inclusive of a comprehensive regional examination with medical screening. Furthermore, the management of pain will include strategies to relieve pain as well as interventions to address the impairments that caused the pain or resulted from the presence of pain.
Clinical Assessment of Pain
Because of the highly subjective and individual response to pain, pain is one of the most difficult symptoms to examine clinically. Tests and measurements have been developed to quantify pain and to attempt to objectify the pain experience. However, because the patient still provides the information, it still is considered to be “subjective” based on the patient’s perception of his or her pain. There are several individual factors that influence the patient’s pain experience including sex, age, and social, cultural, and genetic factors.
Nolan described five components of pain: physiologic, perceptual, affective, cognitive, and behavioral aspects. Table 114-1 defines each component. The pain behaviors observed in our patients represent the interaction among all five components. Observation of changes in a patient’s behavior, including how he or she reports pain, is the primary way clinicians evaluate the effectiveness of their intervention.
| Component | Explanation |
|---|---|
| Physiologic | The injury or tissue damage that serves as the source of the noxious stimuli or the source of the pain |
| Perceptual | The sensations conveyed by the nociceptors to the ascending pain pathways of the spinal cord to portions of the brain to alert the individual to respond to the painful stimuli; the brain is made aware of the pain and the individual responds by withdrawing from painful stimuli |
| Affective | Involves the individual’s emotional and psychological state, which can influence how the person responds to pain; the individual’s emotional status also may affect how he or she reports the pain |
| Cognitive | The patient’s knowledge about the cause of the pain; if the individual understands the nature or source of his or her pain, then he or she usually may respond more appropriately to the painful stimuli; lack of information or misinformation can heighten or depress the behavioral response to pain |
| Behavioral | The individual’s expression of the experience of pain, which involves interaction with the other components of pain |
All the established types of assessments for pain are essentially different forms of a common request that each therapist needs to ask of the patient as part of a thorough clinical examination. The request is “Describe your pain.” Pain often is reported as a chief symptom by hand therapy patients; therefore, it is an essential component of a therapist’s examination and intervention.
The reliability of the test can easily be influenced by the testing methodology, the affective and cognitive components of the patient’s pain, and the individual factors that may influence the patient’s pain perception. For example, the first time that a patient comes into the clinic with a fracture, tendon injury, or crush injury for early mobilization, he or she might be apprehensive about performing exercises and report high pain scores. The patient may think that it is too early to begin to exercise and that exercise may be painful or cause tissue damage. However, after the patient has experienced the first session, he or she is more likely to be relaxed during subsequent visits and report lower pain scores. Another example is that many patients with hand injuries or disease processes may undergo a subsequent secondary surgical procedure. Clinical experience has demonstrated that the patient’s reaction to the pain after the secondary procedure is usually less intense than after the primary procedure. The patient has an understanding of the rehabilitation process; therefore, less anxiety and pain behavior are expected.
Pain Threshold Versus Pain Tolerance
The threshold at which pain is detected is highly reproducible in different subjects within clinical pain experiments and in the same subject at different time periods. Threshold testing represents the sensory component of pain and determines whether a stimulus is painful. Conversely, pain tolerance is highly variable and correlates well with the affective and cognitive components of pain. Tolerance implies a question about how much pain an individual can take. Variables that affect pain tolerance include fatigue, lack of control, stress, and anxiety. During examination, therapists should determine whether any of the variables that modulate pain tolerance are present. Therapy interventions such as patient education about the rehabilitation process and positioning during hours of sleep can be extremely helpful in reducing some of the variables associated with pain tolerance.
Clinical Reasoning: Sources of Pain Mediation
As the therapist gathers information about pain, it is necessary to develop a hypothesis about the source of the patient’s pain mediation. Sometimes this is readily determined by the referral diagnosis, but in patients with longstanding pain, therapists often must carefully review the findings to determine the primary source of pain mediation. The International Association for the Study of Pain (IASP) has developed a classification system for pain that includes definitions for pain terms and descriptions of pain syndromes. Many of these pain terms are defined in Table 113-1 (online). This established taxonomy enhances communication in the scientific literature and clinic setting. Gifford and Butler have used the components of the IASP classification system to promote clinical reasoning among therapists about the primary source of pain mediation in patients with the chief symptom of pain. Understanding the source of the pain mediation allows therapists to effectively assess and manage pain symptoms.
Peripheral Nociceptive
Injured musculoskeletal tissues serve as the source of pain mediation. As discussed in Chapter 113 , tissues contain nociceptors that receive chemical, mechanical, or thermal stimulation and initiate impulses along nociceptive fibers (Aδ- and C-fibers) to the dorsal horn. These impulses are cortically registered as pain. This source of pain mediation is most commonly associated with acute inflammation and tissue damage (peripheral sensitization). Nociceptive pain usually relates to acute somatic pain, but it may be present in patients with chronic pain as well. As tissue healing occurs, pain is expected to subside. Common therapy interventions used to modulate pain such as physical agents, orthotic intervention, and graded exercise are usually effective. Patients with traumatic hand injuries or postoperative patients commonly have nociceptive pain.
Peripheral Neurogenic
The source of pain is a lesion or dysfunction in the peripheral nervous system. Lesions or areas of dysfunction are called abnormal impulse generator sites (AIGs). Pain is mediated by mechanical or chemical stimulation of injured neural tissue (i.e., AIGs). Examples of peripheral neurogenic pain in the upper quarter include cervical radicular pain and pain associated with peripheral nerve entrapment, such as carpal tunnel syndrome. Bogduk provides a description of the clinical differences associated with somatic versus neurogenic referred pain in the cervical spine. Structures at spinal levels C3 and lower can refer pain to the ipsilateral upper limb. Higher cervical levels refer pain only to the head and neck. Neurogenic referred pain is also associated with neurologic symptoms such as numbness, paresthesias, or weakness. These differences, illustrated in Table 114-2 , may help the therapist determine whether the primary source of pain mediation is peripheral neurogenic or nociceptive pain, or a combination of the two.
| Type of Referred Pain | Sources | Quality and Nature of Pain |
|---|---|---|
| Somatic | Any innervated cervical musculoskeletal structure including the following: zygapophyseal joint structures, ligaments, tendons/muscle, intervertebral disc, dura mater | Dull, diffuse, aching, poorly localized |
| Neurogenic | Caused by mechanical stimulation (compression) of spinal nerve or nerve root |
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Central Pain
Pain is mediated by a lesion or dysfunction within the central nervous system (CNS). It is theorized that an abnormal sensitivity or discharge of CNS neurons or synapses is associated with pain mechanisms. The nature of these pain symptoms is inconsistent and behaves differently from the peripheral sources of pain. There is usually little or no correlation with stimulus and response. Sudden stabs of unprovoked pain, pain “with a mind of its own,” or pain that comes out of nowhere may occur as a result of abnormal CNS nociceptor activity. Abnormal pain states such as allodynia and hyperalgesia are centrally mediated. Common therapy interventions usually are ineffective with this type of pain. Pharmacologic agents and behavior modification are key components to pain modulation in patients with central pain mediation.
Pain Related to the Sympathetic Nervous System
The primary source of pain is thought to be a function of the sympathetic nervous system. Both types of complex regional pain syndrome (CRPS), type I (causalgia) and type II (reflex sympathetic dystrophy), are linked to this source of pain mediation. Chapter 115 , Chapter 116 discuss the clinical examination, medical management, and appropriate therapist’s intervention for patients with this source of pain mediation.
Affective Pain
The source of pain is within the CNS and is related primarily to neurons or pathways concerned with affect or emotion. The limbic system is likely to be involved in this source of pain mediation. Other sources of pain mediation can be influenced or enhanced by changes in the patient’s emotional state. This is related to the concept of pain tolerance, as previously discussed. Therapy intervention must include patient education to modify the effect of affective variables on pain output.
Referred Pain
Referred pain is pain that occurs at a site remote from the source of the disease or injury. The onset, duration, and perception of pain largely depend on the primary cause of the pain. Referred pain occurs as a result of convergence of visceral and peripheral nociceptors on the same common nerve root of the spinal cord ( Fig. 114-1 ). In the upper quarter, referred pain is generally limited by visceral structures (organs) to the shoulder girdle region ( Fig. 114-2 ). An inflamed, infected, or obstructed heart, spleen, pancreas, or gallbladder may apply direct pressure to the diaphragm and refer pain to the shoulder. The gallbladder is on the right side of the diaphragm and would refer pain to the right shoulder. The heart and spleen would refer pain to the left shoulder. The location of the pancreas allows it to refer pain to either shoulder. The connection here is that the diaphragm is innervated by the phrenic nerve, which comprises cervical nerve roots C3 to C5. The shoulder cutaneous area is also innervated by nerve roots C4 and C5.
The other common type of referred pain in the upper quarter is radicular or neurogenic as discussed with peripheral neurogenic pain. The nerve roots of C5, C6, and C7 are most frequently involved and may refer pain to the shoulder, elbow, forearm, or hand on the ipsilateral side. Additional information on the examination and management of neurogenic referred pain may be found in Chapter 53 , Chapter 55 .
Tests and Measures for the Clinical Assessment of Pain
The selection of the appropriate measure for pain assessment depends on the aspect of pain the therapist is trying to capture. Table 114-3 classifies the pain measure with the appropriate dimension of pain. Most of the tools described subsequently assess only one dimension of pain. Multidimensional tools would be more helpful because they integrate pain and other symptoms with function.
| Dimension of Pain | Pain Measure(s) Used |
|---|---|
| Spatial (location) | Pain drawings or body diagrams |
| Intensity (how much) | Verbal or visual rating scales |
| Quality or nature | Patient interviews |
| Temporal | Pain diary, repeated rating scales or pain drawings |
| Functional impairment | Self-report or specific outcome questionnaires |
Pain Interview
The therapist can ask a series of questions regarding the patient’s perception of pain as part of the subjective portion of the clinical examination. Questions should elicit information regarding the intensity, quality, temporal aspects, and physical characteristics of pain. Intensity usually is described in terms of the severity of the pain. The quality of the pain may be described as a burning pain or a sharp, stabbing pain. The temporal aspects of pain include whether the pain is constant or intermittent. They also may include the time of day that the pain is better or worse and what activities seem to exacerbate the pain. The physical characteristics of pain refer to the location of the pain and whether the pain is radiating, localized, or diffuse. When conducting the interview, the therapist needs to be careful not to ask leading questions regarding pain. Broad-based questions (e.g., Do you have pain at all times?) also should be avoided. Box 114-1 reviews commonly asked questions during a pain interview.
Location of Pain
Where do you feel pain? (patient may point to painful areas)
Is your pain deep (within a joint) or superficial?
Nature of Pain
Is your pain constant or intermittent?
If constant, does it vary in intensity?
If intermittent, when do you have pain?
How long does your pain last?
What is the frequency of the pain? (frequent, occasional)
How long have you had this pain?
Do you have pain now? (during interview)
Behavior of Pain
Describe your pain (throbbing, aching, sharp, dull).
Does the pain move or spread to other areas?
Is pain aggravated by movement?
Is pain aggravated by certain postures?
Can you demonstrate the movement or postures that cause pain?
Do you have stiffness associated with pain?
Do you have pain at rest?
Do you have pain at night or in the morning?
Does the pain wake you from sleep?
Do you have pain during activity?
Do you have pain after activity?
What makes your pain worse?
What helps to ease your pain?
What do you do to relieve the pain?
Rating Scales
Many rating scales have been suggested in the literature as a way to measure the intensity of a patient’s pain. These rating scales are relatively quick and easy to administer. They can be presented in a verbal or visual format. Rating scales can be used as part of the initial assessment of pain as well as before, during, or after subsequent treatment sessions or procedures. The information obtained from the rating scales has been criticized as being too vague and not providing a true representation of the total pain experience. The information gained from the rating scales is momentary and therefore may provide the clinician with limited information regarding the effectiveness of a particular intervention in providing overall relief of pain. To administer a numerical rating scale, the therapist generally asks the patient to assign a number to his or her perception of pain or to “rate the pain” on a scale of 0 to 10, with 0 referring to no pain, and 10 being the worst pain that the patient has ever experienced. The visual analog scale (VAS) has several modifications ( Fig. 114-3 ). Commonly, it includes a 10-cm horizontal or vertical line that represents a range of levels of pain. The line may have no marks or descriptive words except at the ends of the line, which represent no pain at one end and the worst pain possible at the opposite end. Other visual scales may place more word descriptors along the continuum. The patient places a mark on the line to indicate his or her level of pain. A problem that may occur when using the rating scales is that the patient may initially start on the scale near or at the end of the scale, indicating the worst pain, and then the patient’s pain experience becomes worse. In this case, the patient’s response on the scale may exceed the upper limit.
