Pain Management in Persons With Traumatic Brain Injury

Nathan D. Zasler

INTRODUCTION

There is limited methodologically sound and evidence-based literature on the incidence, prevalence, epidemiology, etiology, assessment, and treatment of pain in persons with traumatic brain injury (TBI). Pain, as defined by the International Association for the Study of Pain, is “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage” [1]. Pain should be considered as a multidimensional subjective experience mediated by cultural, emotional, and perceptual influences, among other factors that affect patient perception and coping ability. Clinicians should always appreciate the context of the pain presentation and understand potential risk for both under- and over reporting of pain complaints.

PAIN GENERATORS IN PERSONS WITH TBI

There are often challenges with regard to accurately determining primary pain generators, particularly in patients early after more severe brain injury and/or polytrauma. Frequently, multiple pain generators can be identified in this population, many of which are not directly related to the brain injury itself. In the acute care phase, the primary pain generators are more likely to involve such phenomena as fractures, intra-abdominal injuries, peripheral nerve injuries, postsurgical pain, soft tissue injuries, and pain associated with invasive medical procedures such as central lines, IVs, lumbar punctures, and blood sampling, among other interventions [2]. In the chronic phase, spasticity/hypertonicity, myostatic contracture, myofascial pain, fibromyalgia, complex regional pain syndrome, shoulder subluxation, neuromusculoskeletal scoliosis, dystonias, central pain, central sensitization, skin breakdown, asymmetric joint wear, and tissue hypoxemia, among other phenomena, may be causes of pain [2].

Headache is probably one of the most common of all posttraumatic complaints in persons with TBI but is often related to other factors than the brain injury itself [3,4]. A good understanding of the differential diagnosis of posttraumatic headache or cephalalgia is essential to guide both assessment and treatment of this condition. Practitioners should strive to identify the specific causes of the headache disorder, which may often have multiple contributors including tension, cervicogenic dysfunction, and migraine, among others. The pharmacotherapy of posttraumatic headache has been discussed elsewhere; however, it should be realized that there are no FDA approved drugs specific to this class of headache [5,6] and that treatment normally is guided by approaches used for primary headache disorders such as tension and migraine headache.

In persons with disorders of consciousness (DOC), pain must be adequately assessed; however, controversies remain regarding the methods for assessment and management, including differentiation between reflex and conscious pain responses [7]. There are new assessment measures specifically designed to assess for evidence of conscious pain responses in persons with DOC [8], which should be part of any assessment battery in such patients. Practitioners should err on the side of providing pain modulating interventions including pharmacotherapy [7,8] in this patient group, given the unknowns regarding determination of degree of pain perception, if any, and/or suffering.

PAIN ASSESSMENT

History

The primary points to address in the context of taking a pain history include:

• Time of onset of pain.

• Progression of pain over time.

• Treatment history relative to pharmacological and nonpharmacological approaches that have either helped pain and/or made it worse.

• Frequency of pain.

• Severity of pain, typically rated using some type of pain scale (i.e., pain faces).

• “COLDER” mnemonic—character, onset, location, duration, exacerbation, relief.

• Functional consequences of pain (i.e., how this pain affects ability to perform work- and non–work-related activities). Pain, particularly when more chronic and more severe, may have adverse effects on cognition, sleep, mood, libido, and neuroendocrine function [9–11].

• In the context of assessing pain, it is always important to determine if the patient had similar pain complaints predating the injury and, if so, whether they have been altered by the injury in any way (i.e., better or worse).

• Review relevant medical records to increase understanding of potential pain generators [12].

• Interview corroboratory sources, as persons with TBI may not have adequate insight into, or memory regarding, their pain conditions and/or its functional consequences.

There are also a number of well-validated and reliable pain assessment batteries that can be considered for use to supplement information derived during the interview, including measures of behavioral and cognitive coping, measures of general health functioning, specific pain domain inventories, and/or general psychological measures; in particular, the Minnesota Multiphasic Personality Inventory (MMPI). There are also additional pain assessment measures with built-in response bias indicators [13]. Clinicians should also be familiar with nonorganic indicators on interview that may suggest the need for further assessment of functional contributors to the pain presentation, just as they should be attuned to response biases in pain reporting including both under- and over-reporting [14].

Examination

• Conduct a holistic evaluation including inspection, palpation, and appropriate neuromusculoskeletal examination. Adequate time must be taken to assess all potential relevant pain sources and strong examination skills are required in musculoskeletal medicine, orthopedics, and neurology [15].

• Evaluate for response bias as deemed relevant (e.g., MMPI-II validity scales, Word Memory Test, Pain Catastrophizing Scale), particularly when there are obvious secondary gain motivators such as personal injury litigation, disability benefits, or workers’ compensation [14], which would result in greater potential for pain symptom amplification. On the other hand, other populations may present with under-reporting of pain symptoms following concussion as has been noted in athletes and military personnel.

Diagnostic Assessment

The main clinical tests pertinent to assessment of pain that should serve to potentially complement the physical examination as previously described include imaging, electrophysiological testing, affective status testing, response bias testing, pain psychology and coping testing, and general functional assessment testing. Tests should only be ordered when it is anticipated that the results will have an impact on clarifying a diagnosis and/or treatment plan or facilitating prognostication [13,15], as the latter is requested and/or pertinent to management.

PAIN MANAGEMENT

Primary Goals in Pain Management

• Modulate and ideally negate physical and psychological signs and symptoms associated with the pain condition/disorder.

• Prevent chronicity and secondary complications thereof, such as central sensitization, chronic affective and maladjustment issues, dyssomnia, cognitive impairment, and neurohormonal adverse consequences.

• Reduce functional disability and facilitate productive activity including, as possible, return to work.

• Establish realistic treatment end points for the specific pain disorder.

• Educate regarding treatment options including risks versus benefits.

• The simplest, least invasive, lowest risk, and most cost-effective management approaches that allow for optimization of patient compliance and maximal functional restoration should be used whenever possible.

• When physical modalities can be used to ameliorate milder pain conditions then they should be attempted first before utilizing pharmacological agents; however, when pain is moderate to severe then concurrent pharmacological management may be appropriate.

• When pharmacological agents are used, analgesia should be delivered with minimal adverse effects and inconvenience to the patient, with clearly defined treatment expectations, including education regarding medication side effects.

• Proper communication should be maintained between the patient, the caregiver, and treater regarding response to individual pain treatment interventions.

• The treating clinician should maintain ongoing communication with any other clinicians involved with the patient’s health management to adequately coordinate clinical care.

• Try to avoid use of opiates to modulate pain unless other options have failed [16,17], and when used be aware of current standards of opiate therapy as well as long-term adverse risks for abuse, overdose, fractures, myocardial infarction, central sleep apnea, opioid induced hyperalgesia, dry mouth, constipation, dependence, tolerance, opioid endocrinopathy, and sudden death, among other conditions [18,19].

• Remember that not all pain is opiate sensitive; musculoskeletal pain generators tend to respond better to opiates than neurogenic/neuropathic pain generators.

• Institute appropriate screening (i.e., Opiate Risk Tool) and monitoring procedures (including use of opiate agreements and random urine toxicology screens) [18,19].

• If central pain is considered to be the etiology of the pain disorder, then appropriate nonpharmacological and pharmacological measures should be taken [20,21].

Pharmacological Methods of Treatment

General Guidelines

Pharmacological approaches should be hierarchically divided based on the intensity and type of pain being treated and where the patient is in the continuum of care, as some of the agents discussed in the following should only be used with close ongoing medical monitoring [6].

Mild

Only gold members can continue reading. Log In or Register to continue