eLetters

27 e-Letters

published between 2018 and 2021

  • Pain in locked-in Guillain-Barré syndrome: pathophysiological and therapeutic thoughts

    I read with great interest the excellent paper by Kumta and colleagues1 and the accompanying editorial2 concerning a patient with severe Guillain-Barré syndrome (GBS) requiring mechanical ventilation, who provided his experiences during the 31-day period of locked-in syndrome. I wish to open up some insights on the reported pain.
    Physical therapy, in particular the passive stretching of calf and masseter muscles, provoked him intense pain, the patient’s description being very impressive: “It felt like they were trying to tear the muscles off the bone … I’ve never known pain like it” 1. Pain due to peripheral nerve damage is basically divided into two major types: dysesthetic pain and nerve trunk pain, the distinction between them being based upon clinical observation and experience3. Reported aching characteristics in the current patient (excruciating, deep, and provoked by nerve stretch) points to nerve trunk pain.
    Pain is an integral manifestation of GBS. In a series of 55 consecutive GBS patients, Moulin and colleagues analysed pain features4, which could be summarised as follows: i/ 49 (89%) patients described pain during the course of their illness; ii/ in around half of them, it was described as excruciating; and iii/ pain preceded weakness by a mean of 5.3 days in 14, and both symptoms appeared simultaneously in seven. Furthermore, in “pure” motor GBS syndromes, usually classified as acute motor axonal neuropathy (AMAN), nerve trunk pain may occur in a h...

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  • Phenytoin in trigeminal neualgia

    Your artclce mentions phenytoin as a treatment that has been tried in open label studies. When I began as a neurologist I'd not heard of its use but was put on to it by a senior colleague. I do use carbamazepine as first line but have found phenytoin far superior to other second line agents. I draw the interested reader to the excellent article by Hellelink and Schatman (J Pain Res. 2017; 10: 1663-6 doi: 10.2147/JPR.S141896) which puts a case for phenytoin being considered first line.

  • Response to Response by A Lees

    To the Editor,

    We agree with Andrew Lees on the value of the applause sign (i.e. ask a PSP patient to clap 3 times, and they typically perseverative by clapping more than 3 times) and a lack of decrement on hypokinesia tests (e.g. sequential finger tapping or in micrographic writing, without a progressive reduction in amplitude) to differentiate Progressive Supranuclear Palsy from Parkinson’s disease. Both are very useful, easy bedside tests.

    We also agree that there are cases where one is unsure. A diagnosis of Progressive Supranuclear Palsy is not to be given lightly, as for any other disease. But, patients with Progressive Supranuclear Palsy have suffered disproportionately from delays and diagnostic hesitation, often long past any reasonable doubt. It does not help a patient or family to live with a wrong diagnosis, or no diagnosis, for a large part of their illness. Across many countries, the diagnosis of PSP is made at around three years from symptom onset (Murley et al, 2021; Cosseddu et al 2017; Mamarabadi et al, 2018). In other words, halfway from onset to death. This is unnecessarily long. Greater awareness and simple clinical skills can reduce the diagnostic delay by more than a year (Mamarabadi et al, 2018). Through our article, we hope our colleagues can become more confident, early and accurate in making the diagnosis of PSP as a gateway to better care.

    James Rowe, Tim Rittman and Negin Holland

    References

    Mamarabadi M, R...

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  • Response to article by Rowe et al

    To the editor

    Although Rowe and colleagues make it clear that the most important purpose of their review is to cover the neglected aspect of management of Progressive Supranuclear Palsy (1) they also describe the disorder’s clinical symptoms and signs and its differential diagnosis in some detail. In this section of the article they fail to mention two simple bedside tests which I have found particularly useful over the years in making me more certain about my diagnosis. In those patients where Parkinson’s disease is the main differential diagnosis sequential finger tapping for 20 seconds is frequently informative. A progressive reduction in speed and amplitude ( ‘the sequence effect’) is a sine qua non for Parkinson’s disease but is rarely found in Progressive Supranuclear Palsy where marked reduction in amplitude of finger taps without decrement and preserved speed of movement is much more usual (2). Utilisation and imitation behaviour (3, 4) and the applause sign (5), all indicative of prefrontal lobe dysfunction, are very common in fully established Richardson’s syndrome but I have also found them to be sometimes present early on particularly when abulia or behavioural abnormalities are presenting complaints. The grasp reflex on the other hand is not commonly observed
    The diagnosis of Progressive Supranuclear Palsy is difficult and uncertainty is common particularly in the early stages. To retract a diagnosis of Progressive Supranuclear Palsy is tri...

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  • A world in which neurologists and clinical neurophysiologists work well side by side for the benefit of patients

    I read your article (Neurology and clinical neurophysiology: an artificial divide. Kieran MC. Pract Neurol 2021;21:274-275) with interest.
    Clinical neurophysiology is primarily a diagnostic specialty concerned with recording electrical activity from the nervous system to aid the diagnosis, classification and management of neurological disease (clinical neurophysiology curriculum: www.jrcptb.org.uk/specialties/c;inical-neurophysiology). One of the attractions of the specialty is precisely this: the breadth of the specialty and the interaction with a wide variety of specialties. Although nerve conduction studies (NCS) and electromyography (EMG) form a big part of our work, most clinical neurophysiologists, at least in the UK do a lot more. We record and report electroencephalography (EEG) studies including long term recordings and video EEG telemetry, a variety of evoked potential studies (EPs), electroretinography (ERG) studies and sleep studies, among others. The specialty is about more than NCS and EMG. Even within the area of NCS/ EMG, although a proportion of our referrals are from neurology teams, we frequently see patients referred by orthopaedic, oncology and rheumatology teams.
    I suppose there could be a world in which neurologists perform NCS / EMG as well as EPs, EEGs, sleep studies on all their patients; hand surgeons and shoulder specialists perform NCS /EMG on their patients...

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  • Diplopia due to idiopathic orbital myositis can mimic cellulitis or infectious orbitopathy

    We were delighted to read the article on orbital myositis heralding herpes zoster ophthalmicus (HZO) [1], highlighting the importance of considering an underlying infectious aetiology in cases of painful complex ophthalmoplegia.

    Infections are a common cause of neurological complications in our setting, although unique cases continue to remind us about broader differentials. We encountered a case of a 55-year-old female with an unremarkable past medical history who was on holiday in Mombasa but presented to a local ophthalmologist with acute-onset diplopia and a painful swollen left eye. She was commenced on oral and topical antibiotics for a presumed pre-septal orbital cellulitis, but did not improve so was transferred urgently to our tertiary regional referral centre in Nairobi. Further social and travel history were non-revealing. On physical examination her blood pressure and temperature were normal, and she had no signs of thyroid disease. On full neurological examination she only had a left lateral rectus palsy with no other signs, and mild left peri-orbital swelling with erythema.

    Comprehensive investigations (including metabolic, inflammatory, auto-immune, vasculitic and infective blood tests panels) as well as magnetic resonance imaging (MRI) of the brain with venography and angiography were all normal except for modestly raised C-reactive protein of 13 mg/dL (normal range 0-5). MRI of the orbits revealed enlargement of the left lateral rectus with...

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  • Caudate head atrophy in FTLD-FUS

    Dr Gowell and his colleagues, in their detailed and vivid description of a young-onset case of frontotemporal dementia (FTD) associated with FUS pathology, have missed a trick. They point out the frontal atrophy that is evident in the patient’s brain MRI (figure 1), but have not commented on the bilateral caudate head atrophy that is also present. This is best appreciated in the third image from the left in the upper row of images (coronal, T1-weighted). This MRI characteristic is a tell-tale sign in FUS-associated FTD (ref). The differential for the presence of caudate head atrophy in brain MRI scans is not wide (also present in Huntington’s disease and neuroacathocytosis), so its presence in the context of progressive dementia with predominant frontal lobe dysfunction in the absence of movement disorder should alert the clinician to this possibility. Having a “second look” at the imaging is always worth doing!

    Ref.
    Josephs KA, Whitwell JL, Parisi JE, et al. Caudate atrophy on MRI is a characteristic feature of FTLD-FUS. Eur J Neurol 2010;17(7):969-975.

  • Uncovering the fixation suppression of peripheral nystagmus - poor man’s solutions.

    I agree with Dhonde et al. (1) that a pair of humble 20 dioptre lens spectacle is often sufficient and less cumbersome than Frenzel glasses for routine bedside use at acute neurology and emergency wards. I have been using such glasses for more than 10 years to help distinguish peripheral from central nystagmus. Video 1 shows a lady with acute left vestibular neuronitis. Her right beating primary position nystagmus is more pronounced when visual fixation is removed using above-mentioned spectacles. Another trick is to ask the patient to gently shut the eye lids, Video 2. Some patients, like this man with acute left vestibular neuronitis, do have thin enough eyelids to discern the enhancement of nystagmus from the removal of visual fixation.

    Reference:
    1. Dhonde P, Khadilkar S. Frenzel glasses: an affordable alternative. Pract Neurol. 2020 Dec;20(6):504.
    Legend for video:
    a. VIDEO1-Peripheral nystagmus, more obvious with removal of visual fixation using modified Frenzel glasses: https://cloud.degoo.com/share/IKZ3Xj6YlnbMZ1Xe16ui0A

    b. VIDEO2-Peripheral nystagmus, worse on eye closure: https://cloud.degoo.com/share/FyVfA144V6oHsULRgUOuIQ

  • Comment on: Nathoo N, Naik S, Rempel J, et al. Superficial siderosis treated with dural tear repair and deferiprone. Pract Neurol 2021;21(1):71-72.

    Comment on: Nathoo N, Naik S, Rempel J, et al. Superficial siderosis treated with dural tear repair and deferiprone. Pract Neurol 2021;21(1):71-72.

    Dear Colleagues

    Concerning “superficial siderosis” I would like to emphasize that we have to distinguish two different types regarding localization and pathophysiology: 1) The infratentorial type that was described in the case report [1]. Patients present with a triad of sensorineural hearing loss, ataxia and myelopathy [2]. Treatment is based on staunching recurrent bleeding and elimination of toxic iron deposits with deferiprone. The latter is not without some risk: neutropenia with sepsis [3]. – 2) The supratentorial type is a manifestation of cerebral amyloid angiopathy in the vast majority of cases [4], and there is no known cure. Cortical superficial siderosis – of the supratentorial type – is the cause of transient focal neurological episodes that can mimic transient ischaemic attacks, migraine auras or simple partial seizures [5].

    Yours sincerely,

    Daniel Eschle, MD, MSc
    Consultant Neurologist
    Kantonsspital Uri, 6460 Altdorf (Switzerland), Telephone: ++41 41 875 51 51
    E-Mail: deschle@hotmail.com or daniel.eschle@ksuri.ch

    Conflicts of interest and ethics
    The author declares that there are no conflicts of interest, in particular none with a manufacturer of pharmaceutical products...

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  • Response to letter to the editor dated 14th February 2021, from Drs Wimalaratna and Alagoda, regarding the article “Cortical Foot”.

    Thank you for your interest in our case report.

    To address your first point, we did not carry out nerve conduction studies or electromyography. The patient was seen as a part of a hyperacute stroke service and we made the diagnosis within 48 hours of symptom onset. After finding an explanatory central lesion, we did not look further peripherally. It would seem to be highly unlikely the patient had developed a simultaneous acute stroke in a relevant area of cortex and peroneal nerve lesion. It is interesting you mention teaching medical students in your response - we teach our students about Occam's razor! As you will no doubt be aware, neurophysiology conducted this soon after symptom onset will be unlikely to contribute in any case, and we are not in the habit of recalling patients at a later date for additional investigations for purely academic value, and we are sure many would share our view this is not appropriate given the current pressure the NHS is under. A stroke diagnosis changes management in terms of secondary preventative medications, hypothetically diagnosing a co-existent compressive neuropathy does not add.

    Secondly, we would argue that the location of this lesion does explain the neurological signs quite satisfactorily. As we know, the ankle dorsiflexors are in fact located in the anterior compartment of the lower leg, just below the knee and not actually in the foot itself. Furthermore, there is likely to be considerable individual var...

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