Thalamic Pain Syndrome Lynn M. Wilton, RN, BSN This article was an entry in the annual Journal of Neuroscience Nursing writing contest sponsored by Kinetic Concepts. ABSTRACT: Though it occurs infrequently, thalamic pain syndrome (TPS) can be devastating Producing a sensation described as burning, TPS is activated by cutaneous stimulation and temperature changes. The syndrome can occur immediately, or even many months after stroke. The pain is unaffected by analgesics or narcotics and surgical intervention has demonstrated minimal success. Studies testing the efficacy of tricyclic antidepressants have shown a positive response. It is the goal of the nurse to maintain a tolerable pain level for the patient and promote the highest level of function and well-being Introduction C's pain except possible stereotaxic mesencephalotomy which she alamic pain evastating syndrome that can and her family refused. Mrs. C. remained with her daughter an pain isad g syndro hat ¢. d her family refused. Mrs. C d with her daugh d occur after a stroke. The syndrome occurs infre- continued to have intermittent episodes of pain until her death ap- : A ‘ ats proximately two years after discharge. quently but causes major setbacks in patient rehabili- tation. This article will describe thalamic pain syn- drome (TPS), its cause, effects and treatment regimes. This case is important in that it describes the phe- nomenon of TPS. It is an extremely frustrating occur- Case Study ence which limits the rehabilitation process and re- Mrs. C., a 62 year-old female, experienced a lacunar stroke in the sults in endurance of excruciating pain. left cerebral hemisphere. Right upper extremity flaccidity and ex- pressive aphasia were residual effects of the stroke. The initial course of rehabilitation was uneventful. By the third week she was Pathophysiology P functional, with minimal assistance, in performing activities of The thalamus is the major sensory relay between daily living such as dressing with set up and occasional cues. She the periphery and the cerebral cortex. Major pathways was able to transfer with supervision for safety. of sensation to the thalamus are:” It was during the third week Mrs. C. began complaining of pain on the right side. When anyone attempted to put her shoulder through range of motion she grimaced and cried, Radiographic films ¢ the lateral spinothalamic tracts which transmit sensations of pain and temperature; and physical examination demonstrated no subluxation or other * the spinoreticular tracts which transmit burning abnormality of the shoulder. A regime of analgesics and narcotics pain; and was used in an unsuccessful attempt to relieve the pain. Rehabili- © the anterior spinothalamic tracts which transmit tation continued but the right upper extremity pain remained, sensations of touch and pressure. Edema of the right hand necessitated use of an isotonic exerciser a si ae (isotoner glove) and maintenance of the extremity in an elevated The thalamus is also the relay for cerebellar, limbic position when lying or sitting. Each procedure was increasingly and basal ganglionic pathways. more agonizing until Mrs. C. refused to allow anyone to touch her Divisions within the thalamus are called thalamic arm and hand. She cradled the extremity and was unable to par- nuclei. These nuclei can be identified by their pat- ticipate in therapy during periods of highest pain, At times when terns of connection within the cerebrum and topo- the pain had subsided somewhat, she would elevate her hand to P A EOS 1 ‘ d graphical locations within the thalamus." Nuclei lecrease the edema. . F Eventually she was unable to make any further gains in ther- important in sensory relay are the ventral posterolat- apy and was discharged. During a follow-up visit a few weeks af- eral nuclei (VPL) which relay information from the ter discharge, she appeared much thinner, paler and exhausted. periphery and the ventral posteromedial nuclei (VPM) She was also developing contractures of the elbow, wrist and fin- which relay information from the head. Subcortical gers due to positioning in an attempt to protect them from pain. At the time, there was no other known treatment to relieve Mrs. thalamic nuclei, also known as reticular nuclei, set up a feedback system between the thalamus and the cerebral cortex." This feedback system influences Questions or comments about this article may be directed to the author at: Rush-Presbyterian-St. Luke's Medical Center, 1653 West the excitation ior inhibition of pain production. "* Congress Parkway, Chicago, Illinois 60612. She is a staff nurse in Reticular nuclei receive fibers from the spinothalamic the rehabilitation service. and trigeminothalamic tracts. The stimulus received Copyright ©American Association of Neuroscience Nurses 0047- is then regulated by either focusing or downgrading 2603/89/2106-0362$1.25 it at the brainstem and thalamic levels." The cortex 362 JOURNAL OF NEUROSCIENCE NURSING, DECEMBER, 1989, VOL 21, NO 6 363 similarly regulates the reticular and thalamic nuclei with corticothalamic fibers giving rise to the ability to tolerate pain at different thresholds." Generalized sensations can be felt at the level of the thalamus but cortical involvement is necessary for “re- finement of sensation, awareness of discriminative touch and proprioception” (p. 41). For example, if a person fell and twisted an ankle, the initial pain sen- sation and the position of the ankle would be inter- preted in particular areas of the cortex. The deep throbbing pain following injury would be interpreted by the thalamus. The presence of TPS is most often related to an in- farct within the thalamus or surrounding structures. Occasionally, it can occur from an abscess or tumor. Due to the deep nature of the structures involved, other forms of brain injury, ie, superficial or cortical head trauma would not necessarily produce the syndrome. A larger branch of the thalamogeniculate artery which supplies the lateral thalamus, the posterior limb of the internal capsule and the putamen is thought to be involved in TPS. Infarcts can be of lacunar, embolic or hemorrhagic origin causing ischemia of “fibers pass- ing from the medial and lateral portions of the thala- mus to the cortical sensory” (p. 963) area.’ Three rea- sons for the development of TPS after a stroke seem to exist: (1) remaining sensory fibers may be reor- ganized pathologically;'* (2) the feedback system of control, as previously described, may be lost; (3) col- lateral fibers may develop causing poor localization of sensation. Clinical Picture “La Syndrome Thalaminique,” first described be- tween 1903 and 1907 by Dejerine and Roussy, was characterized by the following: ¢ resolving mild hemiplegia; ¢ hemianesthesia with changes in deep pressure sensation; ¢ mild ataxia and complete astereognosis on the af- fected side; © severe paroxysmal pain that is very often intoler- able on the affected side; and * choreoathetoid movement of limbs on the affected side. One part of the Dejerine-Roussy syndrome is TPS. Thalamic pain syndrome does not usually present itself until a few weeks to months after the initial stroke. It often occurs as the patient is experiencing functional improvement. If the patient makes a com- plete recovery or has an extension of the stroke, the syndrome could be eliminated. Sensory transmission is restored with complete recovery, and an extension of the stroke would obliterate the three possible causes previously discussed. However, the syndrome can re- cur if a patient who makes a complete recovery suf- fers a stroke in the same area or if a stroke should occur in the same area on the opposite side. The primary symptom of TPS is pain. The pain is different from nociceptive pain because it is not caused by the stimulation of receptors but rather by the dis- ruption of fibers transmitting the pain. Thalamic syn- drome pain is described by patients as burning, tight, knife-like, crushing, stinging, a storm, a shock and in- describable.'*"’ Often patients also complain of hypersensitivity to temperature and touch, ie, warm air from a heater or pulling a sleeve up an extremity may produce an intolerable sensation. Treatment There are two forms of treatment used in TPS. Vari- ous surgical procedures are still used and have met with varying levels of success, while recent studies have identified drugs effective in treating TPS. Surgical Treatment Surgical interventions used to relieve the pain of TPS include: (1) extirpation of the postcentral gyrus (com- plete removal of the postcentral gyrus) to remove the ability to interpret pain as well as transmit pain to associated areas, thus eliminating the sensation of pain; (2) cervical cordotomy (division of a nerve tract in the spinal cord) to remove the tract’s ability to trans- mit a stimulus to the brain, thus removing the possi- bility of triggering TPS; (3) posteromedial hypothala- motomy to interrupt ability to interpret pain on an emotional level thus eliminating the ability to perceive pain; (4) stereotaxic mesencephalotomy to interrupt pain tracts which can trigger TPS. Although these sur- gical procedures can eliminate pain, they can also cause additional neurological damage, reducing func- tional ability or damaging other pathways unrelated to pain. Another surgical intervention, deep brain stimula- tion, involves implantation of electrodes in the thal- amic region or the periaqueductal gray matter of the midbrain. Deep brain stimulation which occurs when the electrodes are connected to an electrical source, causes the release of endorphins which in turn pro- duce analgesia." Pharmacologic Therapy The usual analgesics and narcotics are ineffective in the treatment of TPS due to the nature of their target receptors. Nonsteroidal anti-inflammatory analgesics prevent nociceptor activation of prostaglandin synthe- sis in the peripheral nervous system.' Most narcotics imitate neurotransmitters that activate receptors in the posterior horns of the spinal cord.' Neither of these mechanisms influences thalamic pain. Studies have shown that tricyclic antidepressants (TCA) have been effective in treating pain not only from peripheral nerve injury but also thalamic pain. The apparent effect of TCA is potentiation of descend- ing analgesic pathways by inhibiting re-uptake of serotonin and norepinephrine. They also appear to EE JOURNAL OF NEUROSCIENCE NURSING, DECEMBER, 1989, VOL 21, NO 6 A. Assessment 1, Character a. burning, stinging or knife-like 2. Location a. remains in one place, extends to other body areas 3. Duration 4, Intensity 5. Precipitating factors change in body position, touching the extremity or temperature change Il. Functional ability A. Assessment of physical 1. Strength 2. Endurance 3. Capabilities B. Assessment of psychological response 364 Table 1. Nursing Care Plan for the Patient with TPS Problem Intervention I. Pain A. Medication 1. Type a. analgesic b. narcotic c. tricyclic antidepressant d. combination of above 2. Lowest effective dose a. monitor effectiveness b. monitor adverse effects B. Behavior modification 1. Positive reinforcement for non-pain behavior to increase pain threshold* 2. Relaxation training to reduce stress, a protagonist to pain A. Therapies 1. Physical, occupational or vocational a. provide overall strengthening b. improve endurance c. maintain or increase ability to perform ADL and maintain bowel and bladder function d. provide gait training e. provide adaptive devices to help com- pensate for paresis or paralysis f. increase verbal and nonverbal commu- nication skills g. provide training for re-entry into the work force h. adapt the work environment B. Provide psychological support 1. Improve self-esteem 2. Decrease depression 3. Increase motivation Patient and Family Education A. Education about medication and pain control 1. Names of medications used, how they are effective, adverse effects 2. The impact of pain'* a. changes in lifestyle b. possible role changes A. Compliance 1. Have family members attend therapy sessions 2. Review information and tech- niques learned each day with patient and family 3. Give patients time needed to com- plete tasks learned B. Importance of maintaining a positive attitude 1. Encourage compliance with therapies 2. Allow patient to voice concerns and anger 3. Acknowledge patient's improvements JOURNAL OF NEUROSCIENCE NURSING, DECEMBER, 1989, VOL 21, NO 6 365 have an effect on the ascending monoaminergic sys- tem which is important in the perception of pain.' Tricyclic antidepressants which have been studied are clomipramine, imipramine and amitriptyline. Amitriptyline appears to be the most effective due to its analgesic effect, the low dose required and the least incidence of adverse effects.**'° A recom- mended dose for TPS is 75 mg daily in divided doses. Effectiveness is usually noted during the second week of administration.’ Nursing Implications Nursing is challenged in caring for TPS patients in neuroscience, rehabilitation and general medical- surgical settings. The patient not only suffers pain, but is also at high risk for developing depression, con- tractures of affected limbs and loss of function, all of which affect performance of activities of daily living (ADL). It is the goal of nursing to assist the patient in achieving the optimum level of function with the least amount of pain. The nurse, as an integral part of the multidisciplinary team, acts as moderator, medi- ator, controller and instructor to attain these goals. The nurse as moderator must assess the TPS patient on a continual basis. Areas to be assessed are func- tional ability and pain perception. Function is meas- ured by the progress, plateauing or regression made in ADL, transfers and ambulation. Pain perception is evaluated by observing overt motor behavior and by observing frequency of facial grimacing, rubbing of the painful area, guarding and sighing."* Subjec- tive pain may be measured by using a visual analogue scale, rating the pain on a scale of 0 to 10 with 10 be- ing the most severe.‘ The McGill pain questionnaire which measures intensity, perception and the affec- tive component of pain can also be helpful.’ As a mediator, the nurse assesses the patient's abil- ity to follow through and carryout instructions or skills. For example, in relation to safety, observe whether the patient locks the wheelchair before trans- ferring. Note whether the patient uses relaxation tech- niques taught by members of the health care team. The nurse as controller evaluates the effectiveness of plans implemented and, along with other team members, changes those plans when necessary. For ex- ample, if the patient continues to be incontinent, the bowel and bladder program may need to be changed. In the role of instructor, the nurse teaches the pa- tient and family the importance of medication in or- der to promote compliance, good body alignment while sitting or lying, performing ADL and preventing fur- ther complications. Table 1 is a more complete plan of care. Summary Though the exact cause and nature of thalamic pain syndrome is only postulated at this time, patients with TPS need not go untreated. Research has shown medications may reduce or eliminate the devastating pain so patients can live more productive and com- fortable lives. Nursing intervention for the patient with TPS fo- cuses on evaluating the pain and effects on functional ability, as well as administering medications, mon- itoring their effectiveness and educating the patient and family. References 1. Adams RD, Victor M: Principles of Neurology. McGraw-Hill Book Co., 1985. 2. 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