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Recent eLetters

Displaying 1-10 letters out of 78 published

  1. Re:Letter to Practical Neurology: comment on MG: ABN's management guidelines (Sussman et al. Practical Neurology 2015 )

    I am grateful to Drs Wong and Plant for their invaluable comments, based on their enormous experience of patients presenting with suspected ocular myasthenia. The Guidelines are intended to offer non-specialists an approach to management that will work, safely, in the majority of patients. Within them, we stressed repeatedly the need to seek specialist opinion when in any doubt, and their letter emphasises the benefit of seeking such help. Their views, by and large, don't contradict our basic approach, except with respect to the timing of the introduction of azathioprine. With respect to the specific issues that they raise: Thyroid function should be assessed in all patients. We agree that if the diagnosis of myasthenia is not secure, then it is appropriate to look for evidence of thyroid ophthalmopathy, which would include antibody testing and imaging studies. Some patients seronegative for acetylcholine receptor antibodies may be seropositive using other techniques, as they describe. However, if the clinical diagnosis is of purely ocular myasthenia then the result will not affect the immediate management as proposed in the Guidelines We are not enthusiasts for the Tensilon? test and don't mourn its non- availability! We have seen numerous patients incorrectly diagnosed as having myasthenia on the basis of a test performed by somebody without appropriate experience. We agree that other forms of anti-cholinesterase testing may occasionally be helpful, and are grateful for their detailed proposals. However, we have doubts about these being undertaken by non- specialists. We agree that physical treatments (e.g. eye patches and prisms) have their place both acutely and in some patients with persisting diplopia despite optimal drug treatment, but of course they become unnecessary inn the majority of patients who respond extremely well to drug therapy. We also agree that the evidence base for using alternate-days steroids, in terms of reducing long-term side-effects, is minimal. At very high doses, as may be needed in generalised myasthenia, steroid-induced myopathy may be difficult to differentiate from myasthenic weakness. We have never seen steroid-induced myopathy on an alternate day regime. In patients with marked symptomatic fluctuation between steroid and non-steroid days, and those with diabetes, we would often have a preference for a daily steroid regime. In the past, thymectomy has not been used widely for non-thymomatous ocular myasthenia, perhaps largely because sternotomy represents major surgery, with unacceptable cosmetic consequences, particularly for the dominant young-female population. However, if the less invasive technique of video-assisted thymectomy reduced the risk of generalisation, and for some negated the need for immunosuppressant drug therapy, then it would potentially be very valuable. Unfortunately, the International Thymectomy Trial will not address these issues, and a further trial, at least in the foreseeable future, seems unlikely. We think it is an option that is appropriate to discuss with the patient. Although azathioprine is often considered a relatively safe drug, and its steroid-sparing effect potentially valuable to the patient, our experience suggests that many patients have their myasthenia controlled on a modest dose of prednisolone and that azathioprine is unnecessary. We are concerned by long-term side-effects, particularly cutaneous malignancies, increased risk of infection (including shingles) and the occasional case of late-myelosuppression. The points raised by Drs Wong and Plant emphasise the lack of data concerning the treatment of MG and should encourage us to design studies to help answer the really important questions in MG, such as whether it is possible to determine initial optimal treatment requirements from clinical or immunological features.

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  2. Letter to Practical Neurology: comment on MG: ABN's management guidelines (Sussman et al. Practical Neurology 2015 )

    Dear Sirs, Myasthenia gravis: Association of British Neurologists' management guidelines We read with interest the ABN's management guidelines on Myasthenia Gravis[1] and commend the authors for putting toget her guidelines for this condition where the evidence base is limited. The comments here reflect our experience of managing a large number of patients with ocular myasthenia gravis (OMG). Moor fields Eye Hospital is thelargest and only 24-hour eye casualty in London and as such patients with OMG often present early to us.

    Diagnostic tests In addition to thyroid function, we also routinely test for thyroid antibodies, as thyroid eye disease (TED) may coexist with OMG. Thyroid function may benormal in such circumstances, and the presence of TED may affect the response to treatment. There are two reasons for this. Firstly the presence of thyroidantibodies is circumstantial evidence for an autoimmune phenotype. Secondly patients with thyroid antibodies may be euthyroid and still have dysthyroid eyedisease. The coexistence of TED and OMG is important to recognize as the two conditions are managed differently. Approximately 50% of OMG patients are seronegative to anti-AChR antibodies[2]. In addition to anti-MuSK antibodies (MuSK+ MG can present as OMG only[3]), newer tests using the cell-based assays can be helpful, and willlikely become more widely available, which include:clustered anti-AChRantibodies (positive in up to 50% of seronegative OMG[2]) and LRP4 antibodies(which is part of the MuSK complex) [3]. At the time of writing, edrophonium (Tensilon) test is no longer available. Alternative methods of performing an anti-cholinest erase test may includeneostigmine or pyridostigmine: Neostigmine adminis tered intramuscularly has a long duration of action that allows pre- and post -test comparison and careful documentation of ocular motility; a trial of oral pyridostigmine can also be useful as a diagnostic test. We tend to perform the pyrid ostigmine challenge in the following manner: For in-patients, we start with a single oral dose of 30mg pyridostigmine and examine the patient one hour later. A sequential increase by30mg is administered every 4 hours, i.e. up to a single dose of 120mg. With the four hour interval between each dose, the test may therefore take two days to complete. This method also allows observation of any dose-related adverse effects e.g. diarrhoea. For the out-patient setting, pyridostigmine challenge is performed over 8-12 weeks, with 2-3 cycles of two-weeks on, two-weeks off pyridostgmine. The patient keeps a careful diary comparing their symptoms during the two weeks on pyridostigmine, and the two weeks off pyridostigmine. We prescribe a dose of 30mg three times daily, which is increased over days to 120mg three times daily, and continue the pyridosti gmine challenge on 120mg three times daily if tolerated by the patient.

    Treatment of ocular myasthenia gravis In addition to symptomatic treatment with pyridostigmine, other symptomatic treatments potentially useful include monocular occlusion (use of an eye patch, or frosting of one lens on the spectacles) and prisms (usually more useful if the deficits become more fixed after long term OMG). We prefer a daily dose of corticosteroid compared to alternate day dosing, as is the preference or recommendations by other MG experts[4]. The evidence for a better risk profile for alternate day dosing is limited. The literature on this seems to come predominantly from renal transplant in children, with regards to growth, although the evidence for this is mixed[5,6 ]. In our experience, dailydosing can help with medication compliance At present, we do not routinely refer our patients with OMG for thymectomy, unless imaging suggests that a thymoma may be present. This is an area that has unresolved questions. Some recent retrospective studies suggest that early thymectomy in non-thymomatous OMG could potentially improve outcome, but this question remains to be addressed in a randomised controlled trial [3]. The MGTX trial studied the effect of thymectomy in MG, is due to be reported in January 2016, but excluded patients with OMG[7].

    It is also our practice to start azathioprine early (i.e. approximately 1-2 months) in patients who have response to corticosteroids. In our experience, patients often relapse below 15-20mg prednisolone, and there fore find the relatively early introduction of azathioprine may help weaning off prednisolone earlier. One argument against starting azathioprine early is that some patients will be able to come off prednisolone and remain in remission. In our experience this is an unusual eventuality. After our patients have been in remission, we then start to consider weaning off the corticosteroid-sparing agent such as azathioprine if they have been on this alone for approximately two years. The ABN guidelines by Sussman et al are a useful resource for practicing neurologists, and we hope that our experience in the management of large numbers of patients with OMG described above could also be of value.

    References 1 Sussman J, Farrugia ME, Maddison P, et al.Myasthenia gravis: Association of British Neurologists' management guidelines. Practical Neurology2015;15 :199-206. doi:10.1136/practneurol-2015-001126 2 Jacob S, Viegas S, Leite MI, et al.Presence and pathogenic relevance of antibodies to clustered acetylcholine receptor in o cular and generalized myasthenia gravis. Arch Neurol 2012;69:994-1001.doi:10.1001/archneurol.2012.437 3 Wong SH, Huda S, Vincent A, et al. Ocular myasthenia gravis: controversies and updates.Curr Neurol Neurosci Rep 2014;14:421. doi:10.1007/s11910-013-0421-9 4 Kumar V, Kaminski HJ. Treatment of myasthenia gravis.Curr Neurol Neurosci Rep 2011;11:89-96. doi:10.1007/s11910-010-0151-1 5 Feldhoff C, Goldman AI, Najarian JS, et al. A comparison of alternate day and daily ster oid therapy in children following renal transplantation. Int J Pediatr Nephrol 1984;5:11-4. 6 Diethelm AG, Sterling WA, Hartley MW, et al. Alternate-day prednisone therapy in recipients of renalallografts. Risk and benefits. Arch Surg 1976;111:867-70. 7 Aban IB, Wolfe GI, Cutter GR, et al.The MGTX experience: challenges in planning and executing an international, multicenter clinical trial. J Neuroimmunol 2008;201-202:80- 4. doi:10.1016/j.jneuroim.2008.05.031

    Conflict of Interest:

    None declared

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  3. A need to increase understanding of brain injury in professionals carrying out DoLS assessments

    I read the article "Brain Injury and deprivation of liberty on neurosciences wards" with interest - it is well-timed and provides a helpful introduction to the the recent changes to deprivation of liberty safeguarding criteria. Working in a residential neurorehabilitation centre I am very familiar with the DoLS process as the majority of our client group are admitted under this safeguard. As mentioned in the article, the recent changes have led to an increase in the number of requests for DoLS assessment, as many of our clients lack the capacity to consent to their admission and meet the "acid test", but are not actively seeking to leave. The local authority has been overwhelmed by requests and as such it can take considerable time for the assessment to be completed, as the article mentions.

    A particular concern for the service is the lack of brain-injury specific knowledge in DoLS assessors. In my experience the professionals sent out to complete assessments are frequently from either a mental health or learning disability background. They can require considerable support in understanding the complexity of acquired brain injury, particularly with relation to individuals who have impairments that are not immediately apparent at a first meeting. It is frustrating that DoLs assessors are required to give a "diagnosis" of a mental disorder (frequently "organic personality disorder" is the only available label) as part of the DoLS process when commonly the reason for referral is a cognitive impairment (i.e. impaired insight, attention or memory) rather than a psychiatric condition. Understandably these teams have a colossal workload but I would suggest that it is to their advantage to make contact with local brain injury services and seek consultation and training. This can enable DoLs professionals to feel confident to meet the needs of a population from whom they are likely to now receive ever increasing referrals.

    Conflict of Interest:

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  4. Undiagnosing neurological disease

    With great interest I read Coebergh et al. piece on how to undiagnose neurological disease. 1 My experience as a neurologist with subspecialty training in epilepsy has taught me that diagnostic labels such as seizure disorder or epilepsy once attached are very hard to purge either from the patient's medical records or his memory. I frequently encounter patients carrying a diagnostic label of epilepsy in whom continuous video-EEG monitoring reveals non-epileptic events. The record shows no interictal epileptiform features and I feel reasonably confident in undiagnosing their seizure disorder. Taking away their diagnosis of epilepsy is though easier said than done as frequently an abnormal EEG has been reported in the past. Maybe the patient suffers from epileptic as well as non- epileptic events. Maybe I should continue the anticonvulsant to be on the safe side. My patient too is apprehensive and not keen on shedding his diagnostic label. Status quo is maintained.

    References

    1. Coebergh JA, Wren DR, Mumford CJ. Undiagnosing' neurological disease: how to do it, and when not to. Pract Neurol 2014;14:436-439.

    Conflict of Interest:

    None declared

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  5. Re:The article by Zanette et al (2014;14:351-353). T

    We thank Dr. Davenport for his interest in our case report [1] and the opportunity to better explain our clinical reasoning. In his e-letter Dr. Davenport argues that there is a discrepancy between the distribution of the pain, which appeared more suggestive of L2 and perhaps a contribution of L1 and L3, and the involvement of L4 root as documented by clinical neurophysiology and neuroimaging. The patient was asked to draw the distribution of pain on a body diagram with no suggestion from any of us,[2] and some degree of inaccuracy in drawing pain distribution cannot be completely ruled out. However, the most likely explanation for the discrepancy between the reported pain distribution and the anatomical dermatome charts is the presence of referred pain and central sensitization, two phenomena that are known to contribute to the presence of non-anatomical and/or enlarged distribution of neuropathic pain.[3] A pain duration longer than 2 years, as in our case, strongly supports the view of central sensitization. The second point raised by Dr. Davenport concerns the notion that a depressed knee jerk mainly suggests L3 instead of L4 damage. The knee jerk is mediated by the L3 and L4 roots, and its depression, as in the present case, might be secondary to L4 radiculopathy.[4]

    With best regards, Giampietro Zanette MD, Francesca Magrinelli MD, Stefano Tamburin MD

    References 1. Zanette G, Magrinelli F, Tamburin S. Periodic thigh pain from radicular endometriosis. Pract Neurol 2014;14:351-3. 2. Magrinelli F, Zanette G, Tamburin S. Neuropathic pain: diagnosis and treatment. Pract Neurol 2013;13:292-307. 3. Zanette G, Cacciatori C, Tamburin S. Central sensitization in carpal tunnel syndrome with extraterritorial spread of sensory symptoms. Pain 2010;148:227-36. 4. Mumenthaler M. Neurologic Differential Diagnosis; translated and annotated by Otto Appenzeller, 2nd ed. New York, NY: Thieme Publishing Group. 1992:26-27.

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  6. The article by Zanette et al (2014;14:351-353). T

    I thoroughly enjoyed the article by Zanette et al (2014;14:351-353). The authors are to be congratulated for their skilful history taking skills, specifically the key observation that the pain coincided with menses, suggesting the diagnosis, and thus confirming that a neurology opinion, far from being "the last resort", should have been the "first resort". I am troubled by the distribution of the pain however; the authors' thesis, elegantly supported by the neurophysiology and exquisite imaging, is that the pain was due to endometriosis affecting the left L4 root. However, the distribution of the pain appears more suggestive of mainly L2, and perhaps a contribution from L1 and L3 - they also mentioned a depressed knee jerk, which is mainly L3. Most of us regard the L4 dermatome as being below the knee and medial. Whilst I do not dispute the diagnosis of endometriosis, I am intrigued by this, and wonder how the authors explain the dermatomal discrepancy?

    With kind regards Richard J Davenport DM FRCP Edin Consultant Neurologist rjd@skull.dcn.ed.ac.uk Voicemail: 0131 537 3590 NHS PRACTICE Department of Clinical Neurosciences Western General Hospital Edinburgh EH4 2XU Secretary telephone: 0131 537 2072 Fax: 0131 537 1132 Royal Infirmary of Edinburgh MOPD 2 51 Little France Crescent Old Dalkeith Road Edinburgh EH16 4SA Secretary telephone: 0131 242 1487 PRIVATE PRACTICE Spire Murrayfield Hospital 122 Costorphine Road EDINBURGH EH12 6UD Telephone: 0131 334 0363 Spire Shawfair Park Hospital 10 Easter Shawfair Edinburgh EH22 1FE Telephone: 0131 654 5600

    Conflict of Interest:

    None declared

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  7. CSF Evaluation

    Is there any reason you can think of when the CSF protein and the CSF glucose should be evaluated from different tubes of CSF and not the same tube?

    Conflict of Interest:

    None declared

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  8. How I start a new patient consultation-view from across the pond

    I read with interest Allen et al. approach to starting a new patient consultation1. Apart from a few minor differences the basic methodology employed by all four physicians is essentially the same. Across the pond, I start a new patient consultation in much the same way. I walk into the reception area, call out the patient's name and upon acknowledgement ("right here" or "yes" is the usual response, rarely "yo" and I have still to hear someone say "present); I introduce myself to the patient and then proceed to walk the patient and the accompanying caregiver or friend to the examination room assigned to me for that day. During the short walk I may exchange a few brief pleasantries, the weather or the traffic always are safe bets to elicit an answer from even the most stoic of patients! ("It sure is hot today" or "did you have a tough time driving into the city today?"). This helps to break the ice and my next question after everyone is seated comfortably in the room is "So Ms Watson what brings you in to see my today?" I then allow the patient or the caregiver (both at times) to speak uninterrupted for the next few minutes as I record their words verbatim on a piece of paper. I make it a point to look up at the patient from time to time to acknowledge that he or she has my rapt attention. This is contrary to some of my colleagues who prefer to type the history into the electronic health record (EHR) at the same time. I feel this makes the encounter rather aseptic (with the physician typing vigorously into the computer at times with his back to the patient) and so I prefer to type my notes into the EHR either immediately after the conclusion of the patient encounter or at the end of the day. I then ask a few direct questions frequently to clarify some aspects of the patient's history and then move on to the relevant past medical history, list of current medications, social and family history and finally a brief review of the systems. Then follows the neurological examination and it is not infrequent that I may ask a few direct questions at this stage too ("does it hurt here" "where does the pain radiate?"). I devote the last 10-15 minutes of a new patient consultation (a new patient consultation is typically an hour in duration) to explain my assessment and plan and answer any questions. I end the encounter by walking the patient over to my secretary so that she can help schedule the tests ordered and a follow up consultation if warranted.

    References

    1. Allen C, Scolding N, Mumford C, Smith P, Fuller G. How I start a new patient consultation. Pract Neurol 2013; 13:254-7.

    Conflict of Interest:

    None declared

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  9. HIV testing in a patient presenting with cognitive impairment-to test or not to test

    I read with interest the debate between Nightingale el al. and Schott about whether we should routinely test for HIV in patients presenting with cognitive impairment 1,2 . I assume that while the authors have taken rather polarized views to state their point, the correct answer lies somewhere in between. Testing for HIV shall not be the foremost in my mind in a 75-year-old male presenting with slowly progressive cognitive impairment for the past few years accompanied with typical features of a cortical dementia (aphasia, apraxias and agnosias). In such a patient I shall rather harness my clinical and diagnostic skills to differentiate between Alzheimer's disease, frontotemporal dementia and Lewy body dementia. On the other hand a 45-year-old male presenting with cognitive impairment accompanied by a movement disorder, certainly HIV testing shall be included in my diagnostic armamentarium. One must though not forget that positive HIV serology is not synonymous with HIV encephalopathy or AIDS dementia complex which is a clinical syndrome comprising of a combination of cognitive, behavioral and motor dysfunction. Testing a patient with cognitive impairment for HIV shall have a high positive predictive value only when the test is carried out after taking the patient's age at presentation, history (not just of risk factors but also of the rate of progression of symptoms) and examination findings into consideration.

    References

    1. Nightingale S, Michael BD, Defres S, Benjamin LA, Solomon T. Test them all; an easily diagnosed and readily treatable cause of dementia with life-threatening consequences if missed. Pract Neurol. 2013;13:354-6.

    2. Schott JM. HIV testing in dementia: test some, perhaps more, but not all. Pract Neurol. 2013;13:357-8.

    Conflict of Interest:

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  10. aetiology of myoclonus

    sir/madam,

    Can myoclonus involve large muscles like the trunk muscles giving out just one jerk with a duration of a fraction of a second?Would it be justified to term this phenomena as a myoclonic seizure or a complex myoclonus when there is LOC for that fraction of a second;happening while falling asleep only.Or can it be a sleep disorder,a hypnic jerk?

    Conflict of Interest:

    without reading the entire text how can I declare any competing interests.

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