ACNR VOLUME NUMBER MAYJUNE Alan Carson Series editor Alan Carson is a Consultant Neuropsychiatrist - PDF document

ACNRVOLUME 11 NUMBER 2 MAY/JUNE 2011 Series editor Alan Carson is a ConsultantNeuropsychiatrist and Part-time Senior Lecturer. Heworks between the Neurorehabiltation units of theAstley Ainslie Hospital and the Department of ClinicalNeurosciences at the Western General Hospital inEdinburgh. He has a widespread interests in neuropsychi-atry including brain injury, HIV and stroke. He has long-standing research and teaching collaboration with JonStone on functional symptoms in neurology. Mark J Edwards PhD, is an NIHR Clinician Scientist atthe Sobell Department forMotor Neuroscience andMovement Disorders at theInstitute of Neurology and anHonorary Consultant neurologist at the NationalHospital for Neurology and imb injury, particularly minor injury that doesnot cause nerve damage, is very common. Suchinjuries usually cause no more than minorannoyance, but in a small group of people suchinjuries trigger severe disabling symptoms which are elcome to the sixth in a series of articles in ACNRexploring ACNRMJ11:Layout 1 27/4/11 22:08 Page 22 ACNR VOLUME 11 NUMBER 2 � MAY/JUNE 2011 � request nerve conduction studies of theaffected limb to exclude any possibility ofnerve injury that might have occurred at thetime of the original trauma. Small fibreneuropathy is often suggested as a possibilesource of the pain in fixed dystonia/ CRPS1, butthere are a number of arguments to suggest thisis unlikely to be the case,and I would notgenerally request thermal thresholds. So, withnormal imaging, blood tests and nerve conduc-tion studies combined with a typical history ofminor injury followed swiftly by severe painand fixed posture, I would feel fairly comfort-able with the diagnosis of fixed dystonia. What Iwould want to find on examination would be afixed postured limb with (paradoxically) littleactivation of muscles at rest despite the posture(if you feel the limb gently the muscles areoften relaxed when no attempt is being madeto alter the posture), but with clear resistance topassive movement of the limb. There is usuallylittle or no voluntary movement possible, andmuscles opposing the posture tend not even tobe activated by the patient when requested todo so: this is very different from typicaldystonia. Other signs are often present, forexample a co-contraction type tremor, give wayweakness. Additional history taking may reveala history of other functional symptomsincluding non-epileptic attacks, weakness,sensory loss and fatigue.What has been tried already, and arethere other therapies available?Conflict continues to rage in the movementdisorder world as to the aetiology of thisdisorder. There is a somewhat unhelpful dual-istic battle between those who feel this is anorganic condition and those who would preferto call it psychogenic. Both are probably right,and certainly the argument does little to helppatients. On the organic side there is evidenceof abnormal reflex sensitivity,corticalexcitabilityand the occurrence of contracturesin some patients, indicating the maintenance ofpostures even when unobserved. On thepsychogenic side there is evidence of high ratesof affective and dissociative symptoms inpatients,response to a multidisciplinary inter-vention based on psychotherapy,cleardramatic placebo response in some patientsand the common co-occurrence of morewidely accepted functional disorders such asnon epileptic seizures.Not surpsingly there is asimilar battle regarding the pathophysiology ofThe literature suggests a bleak therapeuticpicture for those with fixed dystonia.Forexample in one follow-up study, 77% of patientswere either the same or worse after a meanfollow-up of 7.6 years.However, this need notnecessarily be the case. Simply being honestwith the patient regarding the disorder is ofgreat importance. Often patients are relieved tohear that they have a problem that is ‘recog-nised’ rather than constantly being told howunusual they are. I would typically try to putforward a holistic model to the patient thatencompasses the role of the injury in sensitisingthe motor and sensory system, the deleteriouseffect of simply maintaining a posture for a longtime (giving the example of limb immobilisa-tion for fractures where quite severe pain, poormotor control and feelings of ‘disconnection’from the limb are common), and the role ofemotions in creating vulnerability to the effectsof the initial injury and an abnormal attentionalfocus on the limb maintaining symptoms.Contrary to expectations, discussion in a sensi-tive way of the role of psychological factors intriggering and maintaining symptoms in thisway can be met with understanding andacceptance. This can be helped by collabora-tion with a good pain team where a structuredpain control program will usually include asignificant amount of cognitive work whichoften spills over into helpful improvements inthe abnormal posture. The key therapeutic aimswould be to desensitise the limb, get it movingeven if only passively at first, and to use psycho-logical techniques to remove focus on symp-toms, block out pain and explore, if the patientis willing, any longer term psychological issues.This rehabilitation approach is good in theory,but it requires a lot of collaboration betweendifferent teams which is difficult in manysettings. Recently, botulinum toxin injectionsgiven following an explanation of the patho-physiology as above have been shown toproduce a dramatic immediate effect,which,given that botulinum toxin takes days to startworking, is clearly a placebo effect. Long termbenefits and pitfalls of this approach are notcertain, but in some patients I have found this auseful way to get the limb moving and to makesubsequent physiotherapy more effective.Examination under anaesthetic can also have arole in convincing you and the patient thatthere are no significant contractures (as rarelythese can occur). Videoing this procedure andshowing it to the patient afterwards can helpbring home the fact that the limb can move outof its fixed position. In the right hands, abreac-tion may also occasionally be worth trying,particularly to rescue an otherwise desperatesituation. One centre suggests intrathecalbaclofen for such patients, but in my mind it isstill uncertain whether sufficient blinding of thetherapy occurred to cover for the possibility ofa placebo effect in the published placebocontrolled trial.What am I going to advise about Whatever one’s views on aetiology, it is clearthat fixed dystonia is a potentially treatable,even completely reversible, disorder. In view ofthis, an irreversible invasive procedure such asamputation seems unadvisable. But what is theevidence?It is surprisingly unusual (at least in terms ofpublished reports) for patients with organicneurological disorders causing abnormal limbpostures and/or pain to request amputation.contrast, there is quite a large literature onamputation for CRPS1 with at least 70 casesreported.The descriptions of patients in thesereports indicate that it is likely that some hadadditional fixed dystonia. Recently a case seriesof five patients with fixed dystonia who soughtor achieved amputation has also beenpublished.The clear and unequivocal messagefrom these reports is that amputation in thesetting of CRPS1 with or without fixed dystoniacarries a very high risk of causing harm to thepatient. For example, in the largest case series of34 patients with CRPS1 and amputation,had periproceedural complications and 85%developed phantom limb pain. Only two casesreported benefit in pain reduction. Of the threecases of fixed dystonia reported by myself andcolleagues who had achieved amputation,twodeveloped phantom limb pain and the otherdeveloped fixed dystonia in the un-amputatedarm and is now requesting a further amputa-tion. From a pathophysiological point of view itis of interest that this group of patients appearsmore willing to seek amputation than patientswith other causes of limb posture and pain.There might even be similarities to those withbody integrity identity disorder – people withnormal limbs who seek amputation.leaving aside such speculation, the clear adviceto the GP and patient in this case would be toavoid amputation at all costs. This is a problemwith its origin in the brain, and amputating alimb is not going to alter that. In fact I would goso far as to say that on the current evidence,such a procedure would be unethical, as thechance of benefit is so low and the chance ofsignificant harm so high. CLINICALDILEMMASINNEUROPSYCHIATRY 1.Schrag A, Trimble M, Quinn N, Bhatia KP. syndrome of fixed dystonia: an evaluation of 103Brain 2004:127;2360-72.2.Oaklander AL, Fields HL. Is reflex sympatheticdystrophy/complex regional pain syndrome type 1 asmall-fiber neuropathy? Ann Neurol 2009:65(6);629-3.Lang AE, Chen R. Dystonia in complex regional painsyndrome type 1.Ann Neurol 2010:67(3);412-4.4.Espay AJ, Morgante F, Purzner J, Gunraj CA, Lang AE,Chen R. Cortical and spinal abnormalities inAnn Neurol. 2006 ;59:825-34. 5.Edwards MJ, Cordivari C, Bhatia KP. Immediate responseto botulinum toxin in patients with fixed dystonia.Dis 2011 (in press).6.Ibrahim NM, Martino D, van de Warrenburg BP, QuinnNP, Bhatia KP, Brown RJ,Trimble M, Schrag A. The prog-nosis of fixed dystonia: a follow-up study.ParkinsonismRelat Disord. 2009 Sep:15(8);592-7.7.van Hilten BJ, van de Beek WJ, Hoff JI, Voormolen JH,Delhaas EM. Intrathecal baclofen for the treatment ofdystonia in patients with reflex sympathetic dystrophy. Engl J Med. 2000 Aug 31:343(9);625-30.8.Edwards MJ, Alonso-Canovas A, Schrag A, Bloem B,Thompson PD, Bhatia KP. Limb amputation in fixeddystonia: a form of body integrity identity disorder? Dis 2011 (in press). 9.Dielissen PW, Claassen AT, Veldman PH, Goris RJ.Amputation for reflex sympathetic dystrophy. Joint Surg Br. 1995:77;270-3. ACNRMJ11:Layout 1 27/4/11 22:08 Page 23