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Workers' Compensation

Are Chronic Pain Syndromes and Drug Dependency Ratable Under the AMA Guides? If So, How?

By Robert G. Rassp, Esq.

© Copyright 2014. Excerpted from The Lawyer’s Guide to the AMA Guides and California Workers’ Compensation, 2014 Edition (LexisNexis).

Reminder to Calif. Workers' Compensation Judges: You have access to this publication on Lexis Advance. References below to The Lawyer's Guide within brackets link to Lexis Advance.

How to Rate Chronic Pain Syndromes

“Impairment due primarily to intractable pain may greatly influence an individual’s ability to function” [AMA Guides 5th Edition, Section 13.8, page 343]. To some medical practitioners, pain is the “fifth vital sign” and besides checking blood pressure, heart rate, respiration, and temperature of a patient, it is becoming common practice for physicians to also ask patients to rate themselves on a visual analog scale (VAS) for pain.

The International Association of the Study of Pain has defined pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.” Pain is a subjective symptom with both psychological and sensory components – there does not have to be tissue damage for pain to occur [see IASP 2013, and go to the IASP Taxonomy section on the home page].

One of the most vexing issues that we see in our cases is whether or not chronic pain conditions can be rated under the AMA Guides when an injured worker becomes MMI or permanent and stationary. The first issue is to determine whether or not a person has a chronic pain condition and if so which kind. Then a determination has to be made as to whether the injured worker has received all reasonable medical treatment to address the chronic pain condition so that it reasonably can be considered to be stabilized and ready for WPI ratings. If the treating or evaluating physician is convinced that the chronic pain condition is stabilized with treatment, then and only then can the injured worker be declared MMI/permanent and stationary and WPI ratings can be assigned. But how are physicians to utilize the AMA Guides to rate chronic pain syndromes?

[Editor’s Note: Citations link to Bracketed citations link to Lexis Advance.]

An ancillary issue is, can a physician rate drug addiction or dependency that is caused by an industrial injury? We see significant cases in which an injured worker is placed on opioids, benzodiazepines, and hypnotics (sleep medications) and becomes dependent on them on a long term, if not permanent, basis. See the discussion of medication side effects in Ch. 5, § 5.125.12], of The Lawyer’s Guide to the AMA Guides and California Workers’ Compensation. Remember, drug addiction or dependency is a separate and distinct issue from any impairment associated with the side effects of medication in general.  In fact, case law has supported the fact that an injured worker’s drug dependency along with his or her physical limitations rendered the injured worker presumptively permanently and totally disabled based on the fact pursuant to Labor Code section 4662 [LC 4662]. See the discussion of the Boatright case in Ch. 5, § 5.285.28], of The Lawyer’s Guide to the AMA Guides and California Workers’ Compensation.

There are different types of chronic pain conditions that once diagnosed and stabilized can form the basis for WPI ratings using the AMA Guides. There are basically two types of chronic pain cases—ones that have a physiologic explanation and those that do not.

Physiologic chronic pain cases have two different types within that category—nociceptive and neuropathic pain. Nociceptive pain involves actual tissue damage that causes pain receptors (nociceptor nerves) to fire along neural pathways. The nociceptors cells do not stop firing, and the bio-chemical result is that the local region tells the dorsal spine that the local area is in pain and the spine then tells the pain receptors in the brain and the injured worker feels sharp, aching or throbbing pain in the local area of tissue damage. Nociceptive pain can be caused by an otherwise benign pathology. Neuropathic pain on the other hand is caused by actual nerve damage, and injured workers describe pain along a nerve distribution as burning, a “heavy sensation,” or numbness along the nerve pathway. Many injured workers also complain of weakness of an involved extremity. Neuropathic pain can be caused by direct trauma to a nerve (a “pinched” nerve), malnutrition, alcoholism, diabetic polyneuropathy, inflammation, or an infection.

The physiologic chronic pain cases involve such conditions as failed lumbar syndrome that can be caused by many factors, including scar tissue formation around nerve roots, multi-level spinal pathology, arachnoiditis, and spinal instability. Other physiologically based chronic pain conditions include complex regional pain syndrome (CRPS) either in the form of Type I RSD or Type II Causalgia. This condition can occur in an upper extremity, lower extremity, or combination of them.  See Ch. 5, § 5.165.16], of The Lawyer’s Guide to the AMA Guides and California Workers’ Compensation, for a discussion of the diagnosis of CRPS.

On the other hand, there is non-physiologically based chronic pain, which is essentially referred to as “somatic symptom disorders” that involve pain as the primary symptom but where there is no known bio-physiological explanation of the source of the pain. Somatic pain related disorders can be as debilitating as physiologically based pain, but the frustration of physicians, attorneys, claims examiners, and in most cases, the injured worker himself or herself is that there is no medical explanation for the existence of the pain. There is no longer any tissue or nerve damage, or there was not any to begin with at the time of injury, but there is a perception of severe debilitating pain where the injured worker lives his or her life around the pain as the center of his or her universe. The important reminder here is for these injured workers, any underlying physical injury has long ago healed by objective medical standards and there is no longer a physical explanation for these injured workers’ complaints of intractable pain.

The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, IV-Text Revised (DSM-IV TR) included Pain Disorder as a diagnosis for these patients. The DSM-5, adopted by the APA in May 2013 eliminated Pain Disorder as a diagnosis and instead subsumed it into a new section called Somatic Symptom and Related Disorders [see DSM-5 page 309]. The now obsolete DSM-IV TR Pain Disorder required as part of the diagnostic criteria that there be no underlying medical explanation for the painful condition. Under the DSM-5, the APA has eliminated that as a required part of the diagnostic criteria. The authors of the DSM-5 recognize that [see DSM-5 pages 309-310]:

[S]omatic symptom disorders can also accompany diagnosed medical disorders. The reliability of determining that a somatic symptom is medically unexplained is limited, and grounding a diagnosis on the absence of an explanation is problematic and reinforces mind-body dualism. It is not appropriate to give an individual a mental disorder diagnosis solely because a medical cause cannot be demonstrated. Furthermore, the presence of a medical diagnosis does not exclude the possibility of a co-morbid medical disorder, including a somatic symptom and related disorder. Perhaps because of the predominant focus on lack of medical explanation, individuals regard these diagnoses as pejorative and demeaning, implying that their physical symptoms were not “real.” The new classification defines the major diagnosis, somatic symptom disorder, on the basis of positive symptoms (distressing somatic symptoms plus abnormal thoughts, feelings, and behaviors in response to these symptoms).

In the DSM-5, diagnoses in the DSM-IV of somatization disorder, hypochondriasis, pain disorder, and undifferentiated somatoform disorder (used by some physicians to rate fibromyalgia in the past) have been removed and substituted with the new category of Somatic Symptom and Related Disorders [see DSM-5 pages 812-13].


> The first step to rate WPI for chronic pain syndromes is to identify any permanent objective medical findings.

The difficulty in all of these types of chronic pain cases is how to rate them accurately in accordance with current case law. The first rule is to recognize the diagnosis and whether there are permanent objective medical findings.

> The second step is to identify the primary parts of body injured and to rate them in accordance with the strict application of the AMA Guides.

The Court of Appeal in Milpitas Unified School District v. Workers’ Comp. Appeals Bd. (Guzman) “Guzman III” 187 Cal. App. 4th 808, 75 Cal. Comp. Cases 837 [75 CCC 837] mandates that in establishing the most accurate rating is to utilize the applicable chapter, tables, and methods in the Guides and determine the strict WPI ratings for each part of body injured. See Chapters 5 through 8 of this guidebook for a discussion of the Guzman III case. So if you have a lumbar, cervical, or thoracic spine case, you utilize Chapter 15 of the AMA Guides; if you have a shoulder, hand, elbow, or wrist case you utilize Chapter 16 of the AMA Guide; if you have a knee, ankle, hip, or leg case, you utilize Chapter 17; if you have a heart or hypertension case, you utilize Chapters 3 and 4, and so on.

> The third step is to determine whether the strict WPI ratings are the most accurate ratings in a given case and, if not, what alternative rating method produces the most accurate ratings.

If a case evolves into a chronic pain case, the treating and evaluating physician and common sense will indicate that the injured worker has not recovered from an industrial injury. In so many of our cases, secondary gain is not a primary motivating factor—most injured workers are motivated to get better and return to work. Regardless of how cynical you may be, the epidemiology of work injuries indicate the vast majority of injured workers nationwide want to get better and return to work and to productive lives, and most people do. It is easy for claims administrators, employers, and defense counsel to become cynical when we see so many failures.

Attorneys who practice social security disability law see the same phenomenon in their clients, regardless of whether or not an illness or injury is work related—most people who get sick or injured are motivated to get better and return to productivity in their lives.

That being said, the AMA Guides provides a framework for evaluating WPI ratings in cases that evolve into chronic pain syndromes. Much of the discussion of these conditions are scattered throughout the Guides, but there are many different ways to rate chronic pain cases. As stated above, it starts with a diagnosis with permanent objective medical findings.

> If there is a chronic pain syndrome, the fourth step is to identify how the strict or alternative WPI ratings can be adjusted to account for the chronic pain syndrome as opposed to a 3% WPI add-on for pain related impairment pursuant to Pages 1-12 of the 2005 PDRS.

The key to this is to differentiate between a 3% pain add-on to a strict WPI rating and evaluating a chronic pain syndrome separately as its own ratable entity. The difference between the two is that a chronic pain syndrome usually arises out of a separate diagnosis such as complex regional pain syndrome (RSD or causalgia), post-traumatic neuralgia, thoracic outlet syndrome, fibromyalgia, or what used to be called a psychiatric “pain disorder”, which is now more accurately called a somatic symptom disorder. For a detailed discussion about fibromyalgia and how to rate it, see The Lawyer’s Guide to the AMA Guides and California Workers’ Compensation, Ch. 5, § 5.245.24], and for a discussion of the 3% WPI pain related add-on, see The Lawyer’s Guide to the AMA Guides and California Workers’ Compensation, Ch. 5, § 5.255.25].

In certain cases, we see applicants who have a fairly routine injury, such as the development of carpal tunnel syndrome or a herniated lumbar disc, surgery is performed, and then all heck breaks loose and the applicant becomes severely disabled. These cases, fortunately, are rare in clinical medical practices. The diagnosis and treatment of chronic pain syndromes have developed into a medical specialty in its own right and some discussion is in order here.

In clinical medical practice, it is not so much what the chronic pain syndrome is called; rather, it is more relevant as to what the presenting symptoms are and what are the best ways to treat them. The AMA Guides refer only once to independently ratable chronic pain syndromes in Chapter 13, The Central and Peripheral Nervous System, Section 13.8, page 343.

Do not confuse a diagnosis of a chronic pain syndrome that is discussed as a ratable permanent impairment in Section 13.8 of the AMA Guides and the up to 3% WPI add-on for pain that has a greater than expected effect on a person’s ADL functioning as indicated in AMA Guides, Chapter 18, and page 1-12 of the 2005 PDRS. In order to have a ratable permanent WPI impairment for a stand-alone diagnosis of a chronic pain syndrome, there must be one of the three diagnosis mentioned in Section 13.8: CRPS-RSD; CRPS Causalgia; or “posttraumatic neuralgia.” The instructions in AMA Guides, Chapter 13, Section 13.8, page 343, state:

To rate an impairment for causalgia, posttraumatic neuralgia, and RSD in an upper extremity, see Table 13-22. If a lower extremity needs to be rated for causalgia, posttraumatic neuralgia, or RSD, use the station and gait impairment criteria in Table 13-15.

“Posttraumatic neuralgia” is not defined in the AMA Guides, so counsel needs to rely on the clinical expertise of the diagnosing physician to determine if this criteria can be used to rate a condition as a “chronic pain syndrome.” Bear in mind, “neuralgia” is defined as severe, stabbing, throbbing, or burning pain along a nerve distribution. So there has to be neuropathic or nociceptor pain for a chronic pain syndrome to be ratable as a stand-alone impairment. Counsel must develop the record to determine the nature of the chronic pain syndrome and its origin.

An interesting anomaly in the AMA Guides is that a neuropathic chronic pain syndrome affecting a lower extremity can rate up to a 60% WPI under AMA Guides, Chapter 13, Table 13-15, at page 336, but an amputated leg rates a 40% WPI under AMA Guides, Chapter 17. The only explanation of this disparity is that a neuropathic chronic pain syndrome affects more than just the injured lower extremity.

Rating Chronic Pain in the Absence of Objective Medical Evidence

Can a chronic pain syndrome case be rated under the AMA Guides despite the absence of permanent objective medical evidence for the pain? The answer depends upon the physician’s diagnosis and the legal restrictions under Labor Code section 4660.1 [LC 4660.1] that prohibits a psychiatric impairment rating for a psychiatric diagnosis that is caused by a physical injury in the absence of a violent act or catastrophic injury. See Chapter 6 of this guidebook for a discussion of SB 863 and how permanent disability is now established for injuries occurring on or after 1/1/13.

In some cases, the only explanation for an injured worker’s chronic pain syndrome is that of a psychiatric origin. If that is the case, then the restrictions of Labor Code section 3208.3 [LC 3208.3] apply and the analysis of WPI shifts to the GAF score and associated WPI rating that is mandated by the 2005 PDRS. The fact that the DSM-5 published in May 2013 eliminates the GAF score along with Axis I through Axis V (the GAF score was Axis V), may not affect our rating these cases. This is because the use of the GAF score is mandated by regulation. Remember, the 2005 PDRS itself is a regulation adopted by the DWC Administrative Director and no changes to the 2005 PDRS on rating psychiatric impairment are on the horizon.

This raises an interesting question. Since the GAF score has been eliminated from the DSM-5, can counsel make the case that alternative and more accurate ratings for psychiatric injuries, including chronic pain, in the absence of any remaining physical objective medical findings can be accomplished within the AMA Guides to rebut a WPI rating based on a GAF score? So far, there is no published DCA case that supports using the AMA Guides to rebut a GAF based WPI rating. However, there are WCAB panel decisions that do. The purpose of this discussion is to raise the issue here since the DSM-5 has been adopted by the American Psychiatric Association and no one currently knows what psychiatrists and psychologists will do with the application of prior editions of the DSM to determine WPI ratings. Labor Code section 3208.3 [LC 3208.3] is vaguely written, and an argument can be made that prior editions of the DSM no longer apply and since there is no longer a GAF score, the 2005 PDRS ratings for psychiatric impairment are obsolete. We will see how psychiatrists, psychologists, and the WCAB react to this.

However, in the context of chronic pain in the absence of a physical diagnosis, the AMA Guides may provide an alternative framework for physicians to evaluate these cases and apply WPI ratings within the four corners of the Guides. This rubric might apply in any psychiatric claim and not just chronic pain cases.

An alternative rating method for chronic pain cases that do not have an underlying physical explanation may be analyzed as follows:

> What is the cause of the chronic pain syndrome?

> Rate ADL functioning using Table 1-2 on page 4 utilizing the severity classes set forth in Table 14-1 on page 366(?)

> Rate workplace function using the four categories listed on page 365 of the AMA Guides and also evaluate them in the context of severity classes set forth in Table 14-1 on page 366

>> Understanding and memory, such as following instructions and carrying out procedures

>> Sustained concentration, productivity, and persistence to task completion

>> Social interaction with the public, co-workers, and management

>> Adaptation to changes in work place duties and responsibilities

> Utilize Table 13-8 on page 325 for Class 1 through Class 4 for Rating Impairment Due To Emotional or Behavioral Disorders

> Explain how and why an injured worker falls within a class and how a specific WPI rating is established within a class

> Establish how and why the overall impairment is permanent

What is elegant about this method is that all of the criteria are within the four corners of the Guides. There seems to be a much more logical correlation between using ADL and work function impairment assessments that are clearly delineated in the Guides with an impairment rating schedule that is also within the Guides. The GAF scores associated with WPI ratings in the 2005 PDRS are not based on any kind of scientific research or consensus of psychiatrists or psychologists. It is based on a consensus of DEU raters and the former manager of the DEU who in 2005 developed this rubric.

The severity index in Table 14-1 while not providing any direct WPI ratings, does provide a psychiatrist or psychologist with a way of assessing severity of impairment with a list of functions, both ADL and work, that he or she can assess and then apply logically to the classes of emotional and behavioral WPI ratings listed in Table 13-8. The conclusions of the evaluating or treating physician must constitute substantial evidence so that there has to be strong evidence of the level of severity of impairment of function with ADLs, work functions, or both, along with a proper DSM diagnosis of a mental disorder that is causing the impairment of function that is permanent.

This method of evaluating and rating WPI for mental and behavioral impairment for a chronic pain case is elegant because it follows the law. In Guzman III, the DCA clearly upheld the WCAB in its conclusion that physicians can rebut a strict WPI rating, provided that the conclusions of the physician as to why a strict rating is not accurate and an alternative one is constitute substantial evidence.

Rating Narcotic Addiction and Dependency

One of the saddest facts of life is that many injured workers fall from being productive members of society to becoming fully dependent on narcotic medication, losing a quality of life that we all expect and hope for. Substance abuse is a national problem and not just among injured workers. Even the AMA Guides speak about these people in Chapter 14, section 14.4e on page 365:

Chronic substance abuse and personality disorders can coincide. The effects of chronic substance abuse include impairments in concentration, attention, impulse control, judgment, etc, which often last for the duration of the dependency. These behaviors can also occur with personality disorders. To evaluate the severity of the impairment, the examiner needs to assess whether there are (1) restrictions in activities of daily living; (2) difficulties in maintaining social functioning; (3) difficulties in completing tasks in a timely manner because of deficiencies in concentration, persistence and pace; and (4) repeated episodes of decompensation and loss of adaptive functioning, averaging three times per year, with each episode lasting 2 or more weeks.

The typical case starts with an industrial injury and evolves into an injured worker’s dependency on opioids, benzodiazapines, and hypnotics. The opioids are the narcotic pain relievers, the benzodiazapines are the anti-anxiety medications, and the hypnotics are the sleep medications. Dependency can occur for any one of these medications or a combination thereof. You do not need to go too far beyond the FDA mandated warnings about side effects of these drugs that accompany each prescription in order to establish how they can affect a person’s ADL and work functioning. See The Lawyer’s Guide to the AMA Guides and California Workers’ Compensation , Ch. 9, §§ 9.06[26] and 9.07 [§§ 9.06, 9.07], for a detailed description of these medications.

If an injured worker with chronic pain syndrome becomes drug dependent, can the drug dependency be rated by itself? In some cases, yes, if within reasonable medical probability the drug dependency is permanent at the time of MMI. There are probably three ways such a case can be rated:

> Using the 2005 PDRS for GAF and WPI due to substance abuse disorder that is within all versions of the DSM

> Using the alternative rating method under Table 13-8 described above as an alternative psychiatric rating method that uses the AMA Guides to rebut a GAF-WPI rating method

> Using Tables 13-5 (Clinical Dementia Scale), 13-6 (Rating impairment based on mental status), and Table 13-4 for sleep and arousal disorders

There is a detailed description of how to use Tables 13-5 and 13-6 in the context of a stroke case in Ch. 3, § 3.133.13] of The Lawyer’s Guide to the AMA Guides and California Workers’ Compensation.

The rationale for rating drug dependency is based on the notion that the cause of the dependency is iatrogenic—caused by the treating physician, who in recent times, is supposed to be an employer’s physician under a sanctioned MPN. The problem, for example, is how cheap it is to get a person hooked on a Schedule II narcotic. A 90 day supply of hydrocodone 750 ES (an opioid with acetaminophen, brand name Vicodin) costs about $68.00. An office visit to a physician to get the prescription for it costs about $98.32. So the injured worker is happy because the pain goes away if he takes the drug as prescribed, which is up to 4 tablets a day. The claims administrator is happy because it only costs them under $200.00 every 45 days for medical treatment, and the doctor is happy because the patient stops whining about being in pain all the time. On a national scale, this is a recipe for substance abuse and narcotic dependency. It is true now as it was 50 years ago when doctors prescribed a lot of Valium to nervous patients. It is an epidemic in the United States, and the FDA is taking steps to reduce the public’s dependency on these drugs.

However, we are faced with the requirement that all industrially caused permanent impairment result in accurate WPI ratings. Drug dependent injured workers should be entitled to benefits based on this problem if drug dependency is permanent, attempts at detoxification do not work, detoxification is not offered by the claims administrator, or the services are refused by the injured worker due to the underlying dependency.

Tables 13-5 and 13-6 must be utilized together. The evaluating physician scores each impairment under the Clinical Dementia Scale for memory, orientation, judgment and problem solving, community affairs (including work—“independent function at usual level in job,…”), home and hobbies, and personal care. The scoring system applies, and then the WPI is determined by the physician’s use of Table 13-6. Table 13-4, commonly used to this point in time for sleep disorders, also can be used to determine impairment due to being under the influence of these medications, which all can cause drowsiness if taken during the day time.

Some attorneys are advocating use of Tables 13-5 and 13-6 in regular psychiatric cases instead of the GAF-WPI method mandated in the 2005 PDRS or the alternative method using Tables 14-1, ADLs and work function analysis and Table 13-8 described above in this guidebook. Case law will have to be developed to see whether the WCAB accepts these methods as either rebuttal to a strict GAF-WPI rating or as a stand-alone rating for drug dependency due to an industrial injury.

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