Somatoform pain disorders

ICD-11 will largely assign persistent somatoform pain disorders to the interpretation-neutral category of “primary chronic pain,” abandoning the earlier concept of a “monocausal psychogeny”-an introduction to the clinical picture.

According to ICD-10, persistent somatoform pain disorders are medical conditions that cause persistent, severe, and excruciating pain that cannot be explained, or cannot be fully explained, by physical injury. ICD-11 will largely assign such pain disorders to the interpretation-neutral category of “primary chronic pain,” abandoning the earlier concept of a “monocausal psychogeny” [1].

Pathophysiology

Chronic pain in patients with somatoform pain disorder is associated with functional changes in pain perception and pain processing, which underlie different pathophysiological mechanisms [2]. Neuroanatomically, bottom-up pain sensitizing processes at the level of the peripheral free nerve terminal, spinal cord, thalamus, somatosensory cortex as well as the limbic system. In addition, top-down pain modulating influences of the frontal brain on the limbic system, periaqueductal gray, and spinal cord are known from placebo/nocebo research [3].

Etiology: biography and biology

Environmental stimuli can alter pain physiology insidiously or accidently. Acute pain amplification often starts with an accident or a surgical procedure, events that interact with a corresponding vulnerability. However, the severity of the somatic-nociceptive pain trigger does not predict the severity of the subsequent somatoform pain disorder.

A common vulnerability factor is a significant life history stress level, which may also contribute significantly to the maintenance of the pain disorder [2]. The association with aversive childhood experiences was described early on as “pain proness” [4]. The working term “action proness” [5] refers to increased vulnerability following aversive influences in adulthood and often manifests clinically in pain-disposing overactive behavior with neglect of physical needs (stress-induced hyperalgesia).

Involuntary migration and war experiences may also contribute to pain sensitization [6].

Pain history

Patients with somatoform pain disorders frequently report burning, pulling, or pressing pain of high to very high intensity (VAS >6 on the NRS scale). Common accompanying symptoms include increased sensitivity to touch, numbness in the acras, or tingling dysesthesias. Accompanying symptoms indicating considerable central nervous stress are sleep disturbances, disturbances of comprehension, short-term memory, and concentration, as well as drowsiness and premature exhaustion. In addition to hyperalgesia, reports of generally increased somatosensory sensitivity to stimuli (noise, light, crowds) and increased emotional irritability (impatience, aggressiveness, anxiety) point to the mechanism of stimulus amplification.

Frequently spontaneously mentioned pain-increasing factors are physical strain, prolonged persistence in a body position, or pressure bearing. When asked, many patients additionally confirm strain, stress, time and expectation pressure, increased demands on the ability to concentrate, and physical and mental exhaustion as pain amplifiers. While relaxation, heat, or distraction are often found to relieve pain, analgesic therapies typically do not have a resounding effect.

Clinical findings in the physical examination

A careful neurological and rheumatological body status is the basis of a clinical examination in somatoform pain disorders. Irrespective of any existing lesions, functional changes of the musculoskeletal system are often seen with little spontaneous motor activity, poor posture, relieving postures, pain-related movement limitations, cautious gait, and halting or slowed movements. Manual clinical examinations often reveal myogelosis, usually in the form of a hard muscle in the shoulder-neck region. Many patients with myofascial pain patterns show corresponding trigger points, and many patients with generalized pain disorders often show hyperalgesia of the tender points (pressure-dolent tendon insertions according to the former Fibromyalgia Criteria 1990). Since somatoform pain disorders are usually associated with lowered pain thresholds to pressure stimuli or increased NRS values [7], pain sensitivity should always be tested with algometric methods.

Psychiatric comorbidity

Since somatoform pain disorders are regularly accompanied by psychological symptoms, there is a risk of a simplistic causal interpretation of pain symptoms as the result of “somatization processes”. Approximately two-thirds of pain patients at our university tertiary center for somatoform pain disorders concurrently meet formal criteria for depression, and approximately one-third report suicidal ideation at admission. Because depressive symptoms can occur as a consequence, co-cause, parallel symptom, or alternate with chronic pain, careful long-term consideration of presumed causality is necessary. Often, psychiatric symptomatology is based on the same formative influences as the pain disorder (e.g., early childhood deprivation, years of distress, traumatization). Fittingly, a large proportion of patients exhibit lowered thresholds for both pain, anxiety, and stress stimuli. Accordingly, very many pain patients report greatly increased anxiety and sensory overload, e.g., in department stores, public transportation, along with increasing avoidance of such situations. Trauma sequelae disorders are also very common comorbidly, associated flashbacks are often somatosensory in nature and may have a presumed causal relationship with the pain experience [8]. Likewise, a considerable proportion of somatoform pain patients can be found to have an insecure attachment style and more severe interpersonal problems, which can often be classified as personality disorders. Likewise, comorbid addiction problems (opiates, benzodiazepines, nicotine, alcohol) are common, with iatrogenic opioid dependence being a particular unresolved problem.

Personalized Multimodal Pain Management

Unlike lesional forms of pain, peripheral infiltrative interventions or conventional analgesic therapies are not effective in somatoform pain disorders. Coanalgesic agents such as tricyclic antidepressants or SSRIs may be used, depending on the disorder profile, in a manner analogous to fibromyalgia treatment guidelines [9].
“Relearning” pain processing is the essential goal of multimodal pain management [10]. Neurobiologically, this means a positive modulation of somatosensory, affective-limbic, cognitive-mnestic and behavioral brain areas. This process of relearning should be promoted in personalized multimodal pain management through a broad spectrum of therapeutic interventions involving different disciplines in individual and group settings. Occupational and physical therapy interventions involve, among other things, the planning and implementation of measured reconditioning, relaxing, and pleasurable activating interventions. The creation of a profile of psychological stress and resources leads to targeted interventions for individual changes in pain-relevant behavior and experience in the sense of psychoeducation. The main psychological goals of change are emotional relief, reduced pain catastrophizing, regaining perspectives for action, more successful stress management and an increase in the experience of competence, control and self-efficacy. For some patients, personalized multimodal pain therapy can be the first step toward deepening clarification and coping processes begun in outpatient psychotherapy.

Assessment of somatoform pain disorders

The medical assessment of somatoform pain disorders underwent a long-awaited paradigm shift in Switzerland with the leading judgment 9C_492/2014 of the Federal Supreme Court in 2015. In particular, the construct of the “willful surmountability presumption” was discarded, which from 2004 to 2015 was to a certain extent the blanket argument for rejecting pension applications for this type of illness. Today, adequate medical assessment guidelines for somatoform pain disorders are available (www.sappm.ch/ueber-uns/begutachtung), which should lead to a more open-ended and case-by-case assessment. The guideline catalog offers the expert reviewer a comprehensive orientation grid in which relevant characteristic patterns (indicators) for diagnosis, prognosis, and the weighting of possible disability consequences are systematically illuminated.

Take-Home Messages

Patients with somatoform pain disorders show significant changes in pain perception and central nervous pain processing.
Somatoform pain disorders are by no means to be regarded as exclusion diagnoses, but are characterized by characteristic trait patterns.
Somatoform pain components often occur comorbidly with nociceptive-lesional pain.
Appropriate treatment of chronic pain disorders requires targeted detection of clinical evidence of somatoform pain components.
The assessment of somatoform pain in the context of assessing the patient’s ability to work is performed according to current guidelines in relation to positive indication criteria.

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