Conversion Disorder After Implant of a Spinal Cord Stimulator in a Patient with a Complex Regional Pain Syndrome

Abstract

Spinal cord stimulation has been widely used and reported to be effective in complex regional pain syndrome (CRPS) (1,2). However, careful patient selection and adequate evaluation of the patient’s psychosocial history are key to the success of this therapy because psychological factors can limit the effectiveness of this procedure (1,3,4). Thus , all patients should have careful assessment of the relative role of physical, psychological, and environmental factors including evaluation of any psychopathology. Although the rate of complications of spinal cord stimulation is approximately 50% in some studies, most of these complications have been benign, related to minor displacement of electrodes, and requiring only noninvasive manipulations (5–7). Complications should be described to patients before performing the procedure. Conversion disorder, classed as a somatoform disorder, and once known as “conversion hysteria,” occurs infrequently. The cardinal feature of a conversion disorder is the loss or alteration of a function. However, the occurrence of the disorder seems related to psychological rather than physical mechanisms. Conversion disorders consist of a single motor or neurological symptom (e.g., blindness or paralysis). Strong psychological evidence is required for this diagnosis. Often the conversion is medically impossible. As an example, hemibody paralysis, in which the paralysis extends from one side of the face to the same side of the body, is biologically impossible, but it conforms to the layperson’s perception of the nervous system. Criteria for conversion disorder described in the Diagnostic and Statistical Manual for Mental Disorders (DSM IV) (8) also include that the symptom or deficit causes clinically significant distress or impairments in function. The exclusion of symptoms that are deliberately feigned, produced by a substance or a culturally sanctioned symptom, is also required. In addition, the symptom or deficit is not limited to pain or sexual dysfunction and does not occur during the course of a somatization disorder. A computer-generated search for case reports and literature reviews (Medline) found no reports of conversion disorder after implantation of a spinal cord stimulator. This report describes the management of a case in which psychopathology interfered with the outcome of a frequently used procedure for an otherwise well-defined chronic pain condition. Case History This left-handed, 43-yr-old man was referred to our clinic in 1999 5 yr after a work-related injury in which he hit the ulnar side of his left wrist against the sharp edge of a chair. His presenting complaint was left forearm and hand pain. The patient had experienced multiple injuries to his left wrist. In 1976, he fractured both wrists in a motorbike accident. During the next 2 yr, he required two operations for arthrodesis of his left wrist and additional surgery to release the ulnar nerve. His arthrodesis did not initially result in either pain or neurological deficit. In 1984, he fell while roller-skating, fracturing the lower end of the left ulnar bone, which required surgical excision. Surgery left him with increased mobility and no further symptoms. In 1994, the patient, who was a biomedical engineer, suffered a blow to the left wrist when using a spanner at work. From the time of his fourth injury (1994), his problems with pain began. Numerous investigations, including nerve conduction study, computed tomography scan, and ultrasound studies, revealed no specific cause for his continuing pain. The patient perceived pain described as constant, sharp, stabbing, and burning on the ulnar side of the left wrist consistent with an ulnar sensory distribution in the hand and medial aspect of the left arm, as well as the left shoulder. Pain disturbed his sleep, was exacerbated when he used his hand, and improved with rest, transcutaneous electrical nerve stimulation, and medication. There were also some dysesthesias over the ulnar distribution of the left hand and occasional swelling over his left hand and forearm. At the time of first assessment, the patient was taking dextropropoxyphene napsylate 300 mg, valproic acid 500 mg, and gabapentin 1200 mg/d. On examination, he was unable to flex or extend his left wrist and had decreased range of pronation and supination of the left forearm without significant wasting of the intrinsic musculature of his left hand. Power in the left arm was essentially normal apart from slight weakness of the flexion/extension/abduction of his left little finger. Upper limb reflexes were symmetrical. Poor peripheral circulation in his left hand with clinically colder temperature was noted; however, there was no edema. Other features included a thoracic scoliosis concave to the left, depressed posture of the left scapula and shoulder and poor muscle tone around the left deltoid and supraspinatus muscles. The patient had diet-controlled type 2 diabetes mellitus and gastroesophageal reflux. He was a nonsmoker and nondrinker and the adopted son of scientist parents whom he described as kind. His parents later had a biological son. He felt that he was strikingly different in appearance from his parents and brother and that he did not quite belong. He described the important status of his adopted parents in the scientific community and, when questioned, frequently used medical and scientific terminology, sometimes inappropriately. As an example, he noted that his parents had decided not to conceive children of their own because both were Rh negative (an unlikely reason that scientists would use not to conceive). It seemed important to him to impress the interviewer with the status of his father, noting that when he had died (in a manner similar to the death of Marie Curie), the event had been front-page news. However, even when describing aspects of his life that might have produced emotion, his affect was colorless and bland. He was divorced and had remained out of touch with his former wife and his son, who was now 10 yr old, and spoke of them without emotion. He did not express emotion over difficulties in his work as an electrical engineer, although he noted that there had been a great deal of unhappiness in the work setting during the past 6 mo because of recent staff cutbacks. He had been living with a new partner for less than 1 yr. His partner had “three different kinds of epilepsy,” and was experiencing daily uncontrollable epileptic seizures. The patient brightened somewhat as he spoke of his partner’s illness, yet noted that because of the medications he was taking for his pain, he was unable to engage in sexual intercourse and that this was troubling his partner considerably. Thus, during the interview, his affect was generally inconsistent with the themes he was discussing. After our initial multidisciplinary assessment, the patient was given the diagnosis of CRPS type II of the left arm (Code 203.X1h) (9). We recommended cognitive behavioral therapy and a trial of the opioid Physeptone (methadone) to assist in tapering his use of opioids. We also discussed the possibility of a trial of a dorsal column stimulator (DCS). At 6-mo follow-up, the patient had failed to obtain significant improvement in his pain and his ability to function with medication. He had refused to attend the cognitive behavioral pain management program, citing his inability to take time away from work without jeopardizing his job. We considered carefully the patient’s unwillingness to attend a cognitive behavioral pain management program, and after weighing the advantages and disadvantages of proceeding with the implant of a DCS, we decided that the patient’s psychological history and preference not to undergo a cognitive behavioral program should not preclude the surgical procedure. Although we believed that psychological therapy preceding the implant would have been optimal, we felt that his lack of willingness to pursue this option did not justify denial of surgery. Thus, as a result of his lack of pain control, we undertook a trial of DCS. A single array of four electrodes was positioned spanning the C5 vertebral body. Stimulation was continued for 3 days, resulting in a marked reduction in pain and improved circulation to the left hand and permitting a significant improvement of left upper limb function. However, his shoulder pain persisted. It was decided to use a dual four-channel system to provide adequate pain relief for the whole area. The patient was readmitted for a 5-day period 3 mo after the initial trial (the delay was because of the lack of an available bed) for implant of a dual dorsal column electrode system at the C2-5 level. This provided good pain relief over all the painful areas and improved function. Postoperatively, he remained afebrile, and both abdominal and cervical wounds seemed to be healing well. An area of allodynia around the abdominal pocket was noted early on that was thought to be an exaggerated response to postoperative wound pain (possibly neuropathic). The patient was discharged on an antineuropathic drug regimen (tricyclic antidepressant and anticonvulsant) for the abdominal pocket symptoms, with slow release formulation of oxycodone as well as some oxycodone (short-acting formulation) for breakthrough postoperative pain. We reviewed the patient on the 10th day after the implant for suture removal and started him on clindamycin (known allergy to penicillin and cephalosporin) for an inflamed and tender cervical spine wound. He was afebrile and had no new neurological signs at that time. He presented at the hospital emergency room on the same night feeling unwell and complaining of headache and photophobia. Heart rate and blood pressure were increased. A low-grade temperature of 37.7°C was noted. Neurological examination revealed a moderate weakness involving his entire left lower limb, with decreased sensation to pinprick over the left leg. Reflexes were normal. An urgent brain and cervical spine computed tomography scan and microbiology consult were obtained. No signs of an epidural collection or of meningitis were found. However, IV antibiotic therapy was instituted as a precautionary measure. The next morning, the patient reported some funny feelings in his left leg, some difficulties in passing urine, and tenderness over his cervical wound. On examination, he was found to be afebrile with normal blood pressure and slightly increased heart rate (107 bpm). A staff specialist in neurology who was asked to examine the patient found neither a consistent neurological syndrome nor any deficit in power or reflexes. Thirty-six hours after admission, the patient felt generally better with less pain in the cervical wound. He was able to walk almost normally. He was afebrile, the wound looked less inflamed, and there was only a minor degree of weakness in the left lower limb. He was continued on the same regimen of antibiotics. Two days after admission, the patient reported a sudden onset of lightheadedness and right arm and leg weakness with right facial numbness but without alteration of consciousness. On neurological examination, he was oriented and normally responsive with normal cranial nerve function, although there was some decrease of sensation to pinprick over the V2 and V3 divisions of his right trigeminal nerve. Tone was symmetrically normal and power was 0 of 5 on the right upper and lower limb and 5 of 5 on the left hemibody. Sensation to pinprick was reduced over the right hemibody with normal sensation on the left. Proprioception was normal on both sides. Right lower limb reflexes were absent with normal reflexes on the left. Urine retention required catheterization. Taken together, these symptoms and signs were not consistent with a spreading CRPS. Cardiopulmonary examination revealed no abnormality. We requested a magnetic resonance image (MRI) of the brain and the spinal cord after turning off the spinal cord stimulator. The MRI showed that spinal cord stimulator leads were well positioned. No epidural collection, thecal enhancement, nor abnormal cord signals were noted. A further neurological review was requested. A second examination performed 2 h later by the neurologist revealed a rapid recovery of normal function of the right arm with some remaining weakness of the right leg and bilateral decrease of knee and ankle reflexes. The neurologist could not explain this presentation on anatomical or pathophysiological grounds and noted some behavioral inconsistencies. He recommended a bolus of steroids (500 mg IV of methylprednisolone) as a precaution to deal with possible implantation in the and requested day there was an almost of the patient’s lower limb symptoms. He was able to after An initial showed normal response in both upper and lower The was days later and the of neurological over the next days remained blood remained normal with a in the normal was only related to the bolus of A second bolus of 500 mg was given IV were and he was on for a of The a and As this program he reported improved and of in review was after the occurrence of the patient’s hemibody paralysis and after medical and surgical found no reason for his symptoms. We noted the patient’s to his symptoms and his that even one side of his was he could with the The neurologist also on his The noted that a significant of had in the patient’s the he had found his biological who was living in and had to to his partner’s remained by and his work remained He continued to these and his recent paralysis with He also noted with the first to have had an MRI with an implant in factors were in the patient’s he seemed to to be medically He seemed to have little for and to have a with medical symptoms to the exclusion of any of feelings or His while describing symptoms that might normally be to or was Thus, his presentation a by which included a lack of a to be and a of his presentation was of a conversion The possibility of a disorder was We were that symptoms were not for his behavioral symptoms were thought to be absent because the patient had for his We believed that or psychological factors were to his symptoms and were his Conversion symptoms a patient’s either from experiencing painful or (the of and from This patient’s inability to his own a of is by seemed to be the cause for the of a conversion disorder. included the he as a included the of his partner’s sexual and of a work to IV was as Conversion CRPS and first with biological of difficulties at work and in The patient was discharged a later with no neurological and a good of the over his cervical spine wound. His medications included clindamycin mg four a gabapentin mg a mg two a mg at mg two a and mg a this patient’s inability to his pain and evidence of psychological factors this our multidisciplinary felt that the patient would from an cognitive behavioral pain management generally used to the patient’s psychological status before the program that he was not that he felt and that his in his ability to his life with chronic pain was His was and he continued to his hemibody paralysis as a During the program, he continued to as he and his partner were for psychological therapy during the cognitive behavioral His partner reported which believed problems for described the patient as unable to an sexual the end of the program, the patient had in of and cognitive He had improved the management of his and was less pain medications were and he had improved on a of physical showed improvement in symptoms, a marked in and a significant decrease in perceived and We reviewed the patient on different over the next 6 He increased his of and work. He continued to use psychological to his pain and reduced the use of his spinal cord stimulator from 6 h to 2 h day with no additional pain medication. after the patient remained in was taking no and was using the stimulator on only 1 assessment was and 1 yr after the cognitive behavioral pain management were by from a of patients the Pain The were and The is a with the of the of and while the range of symptoms of of these It was by and at the of and of 3 to the negative of and in a single The is similar to the and to IV but with the The is similar to the but is The to all IV and of these most The of the as a whole and for of the was in the and and The was not used in reported in and 1 yr After Pain The is a that both the and of a ability to a range of continuing pain. It was by in and is on of which in the face of and are asked to rate are that can of the 10 described pain by a on a not at all and 6 range from 0 to with In and Strong in a of patients with lower pain, the as and The was and as a to physical in patients with lower pain The patients to a it to them to the range from 0 pain related to pain related were initially from the a range of normal daily After were to by pain from by the of the included this used a of chronic pain was to the of to pain as a rather than pain This of the has been reported and found The of the have been well It has been found to be and to patients with chronic lower pain and chronic pain with of function or it has been and is generally considered a and The in the provided the for spinal cord stimulation The the that pain is and responsive to both and also described pain as Thus, assessment take than the or of The examination of one in to an assessment An of the of and to pain is also is a negative response not only by pain but also by psychological as and loss of As by occurs when the physical and psychological of the is This patient had a well-defined cause for his pain nerve and physical signs the diagnosis of CRPS. multidisciplinary assessment revealed some degree of and, from a psychosocial an to his He a to the management of his pain and In had we given to his psychological and continued to one of our or in his continuing we might have this case in a different or at the of his neurological Although most reviews complications of spinal cord stimulation most complications and and are related either to of electrodes or of electrodes found neurological related to spinal cord stimulator implantation in a of in which electrode by spinal cord also found complications related to the surgical as and pain at the of surgery. performed a of on and of spinal cord stimulation for patients with failed surgery syndrome the period from to case were time for these was one to with of patients reviewed 50% pain Complications in of patients were generally minor with complications to new neurological loss or The rate from to complications were with approximately of patients one or complications with the and complications reported in the referred this patient a outcome with good pain His increased temperature after the of the as had in a of reported postoperative was and it is possible that the patient’s response to was related to the of conversion symptoms. two of neurological complications after spinal cord stimulation, as are reported in the medical patients had spinal cord stimulator and Neurological symptoms over the of days and remained In both signs during surgery were of these were found at the of the of the and the electrode of the revealed neither nor of there is evidence in some patients of of a at the of spinal of both epidural and type these to be related to drug not the have that the conversion symptom has to the Although these patients are sometimes found to have Conversion symptoms at any but during or early are generally by an psychosocial and for days or and occur frequently in than in with reported from to occur frequently in from lower and be in that these symptoms rather than to the patients from the that has their ability to to them that to any that and to our patient, all these were used including performing MRI scan and to absent of therapy include or this patient’s rapid recovery when no medical reason for his symptoms could be we considered these of therapy the would important as a for were not an of an in the search for the ability to with this type of which is generally without the of a rapid and the willingness of the patient to undergo therapy A cognitive behavioral program for of chronic pain was We believed that this program, which was at that would this patient the he would have been to At a later time for this patient, the cognitive behavioral program was also to these Although our patient did not for were This patient required a great deal of from the medical staff and seemed to the Although we could not the conversion to a single there were He the for conversion disorder as with motor dysfunction a neurological condition. The neurological was with a however, inconsistent symptoms were as sensory including his face on the same side as in his lower body. were related to his with his and his his and the of his biological although it was to a time Although a disorder was of the we felt that his symptoms were and his The patient was with of his spine and brain as well as nerve conduction No his symptoms. His presentation continuing medical evaluation and would have in and areas of function had The deficit was not limited to dysfunction by pain. We this patient from CRPS with a multidisciplinary at and the different of his pain Although had been to the of this patient, we were with an presentation thought to be of psychological The of possible complications resulting from spinal cord stimulation, as well as the of to this case without removal of the DCS. We that the patient was to have a for his symptoms. the relief of his pain and the of the medical pain who were the patient an cognitive behavioral pain management his initial he the program the surgical he not have been to Thus, it is that for this patient, both of therapy to his This case a good of the to patients from a to provide the possible