eLetters

118 e-Letters

  • 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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  • Cortical foot

    Letter to the editor; 14th February 2021

    RE: Cortical foot

    Fox R,Sztriha L. Pract Neurol 2021, 21:73-74

    Dear Editors,

    We read the above article (like all highly educational articles of Practical Neurology) with interest.

    As the authors pointed out the clinical picture is highly suggestive of peroneal nerve lesion. There was no mention of NCS and EMG had been undertaken in this case. If NCS were carried out then it is prudent to stated that Nerve Conduction Studies excluded Common Peroneal nerve lesion, to make the case water tight and credible.

    It is known that elderly would wake up with foot drop due to Peroneal nerve lesion and not necessarily indicate a stroke. In this case an ischaemic lesion was noted at the top of the motor strip and not in the depth of central sulcus where the foot is located. As the homunculus illustrates in Figure 2, the lesion is at the Knee area at best). Parasagittal meningiomas in the depth cause the foot weakness(also suggesting that the well-known ‘homunculus illustration is probably accurate’!) and we teach medical students practical neuroanatomy and localization using such examples. Thus it would be helpful for the paper to document all claims as accurately as possible.

    Dr S Wimalaratna, Neurologist, Kettering General Hospital

    Dr S Alagoda, Clinical Neurophysiologist, Musgrove Park Hospital, Taunton

  • Fasciculation anxiety syndrome in clinicians: The dreams in the witch house

    To the Editors,

    Being a sufferer of Benign Fasciculation Syndrome (BFS) for more than a year, I read with great interest Professor Kiernan’s editorial (1), as well as Dr. Vercueil’s personal account of his encounter with the syndrome (2). I was relieved to see how much the “clinical course” of my case corresponded to that described by Professor Kiernan and Dr. Vercueil. They surfaced during a period of stress and sleep-deprivation, and has since kept going.

    As Professor Kiernan writes, anything that increases central excitability can trigger fasciculations. This includes the fear that they form part of a prodrome to motor neuron disease (MND); a defining characteristic of Fasciculation Anxiety Syndrome in Clinicians (FASICS). Even though my diagnosis of BFS have been “confirmed” by an EMG and a neurologist, I still suffer from occasional episodes of FASICS exacerbations, surfacing like a recurrent nightmare according to its own inner logic. In other words, FASICS undoubtedly shares a quality with health anxiety, namely a jumbled relationship between symptoms and belief. The opening lines of H.P Lovecraft’s “The dreams in the witch house” captures this poetically; “Whether the dreams brought on the fever, or the fever brought on the dreams, Walter Gilman did not know”.

    After years of working in hospitals you will have encountered some rare cases where the etiology of a disease have followed a non-standard pathway. These can unconsciously skew your wo...

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  • Response to: Beyond the hummingbird - Deer Drs...

    Dear Editor,

    We read with great interest the recent article by Drs Page & Gaillard describing neuroradiology signs and their variable utility [1].

    We recently attempted to bring science to the art of descriptive radiological signs by conducting a randomized controlled trial to assess the utility of these signs for medical student radiology education [2]. We found that ‘Metaphoric Signs’ (linking radiology resemblance to an object or concept which is not actually present in an image) increased descriptive and diagnostic ability as well as students’ lesson enjoyment, when compared to teaching with normal anatomy comparators.

    The importance of diagnostic accuracy of commonly used signs was similarly emphasised in our discussion. In addition to being diagnostically accurate, the success of a metaphoric sign also relies on how well it resonates with each individual learner, based on their perception of the real-world similarity alluded to in the radiology image and their prior experiences[3,4]. This is aptly exemplified by Author FG’s stronger association of the pontine appearance in osmotic demyelination with a blockbuster sci-fi trilogy than classical mythology.

    An interesting observation in our study was that several students used incorrect wording for the name of the signs yet identified the correct diagnosis. Students who correctly diagnosed agenesis of the corpus callosum from a coronal MRI image containing the ‘Moose head sign’ [5] varia...

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  • Response to Weydt et al

    We thank Dr Weydt and colleagues for their interest in our review. We are aware of the subjective benefit of cannabinoids reported by some living with multiple sclerosis, and a trial of THC:CDB spray is also approved by the UK’s National Institute for Health & Care Excellence (NICE). The CANALS study mentioned, in which PLS patients were well represented (28% of treatment arm and 20% of placebo arm), was a Phase 2 study powered to consider safety and tolerability. Adverse events were reported in 76% of the treatment group versus 27% in the placebo group. A reduction in the clinician’s Modified Ashworth Spasticity scale score was noted, and in the patient’s numeric rating scale score for pain, but not their scores for spasm or spasticity. In the discussion, the authors note that muscle cramping was not alleviated in a prior randomised trial of THC in ALS (1). We agree with their call for further evaluation, through a Phase 3 study of the benefit of cannabinoids over the licensed therapies for spasticity outlined in our review.

    Reference:

    1. Weber M, Goldman B, Truniger S. Tetrahydrocannabinol (THC) for cramps in amyotrophic lateral sclerosis: a randomised, double-blind crossover trial. J Neurol Neurosurg Psychiatry. 2010 Oct;81(10):1135-40. doi: 10.1136/jnnp.2009.200642. PMID: 20498181.

  • Cannabinoids for spasticity in primary lateral sclerosis (PLS)

    To the editor

    We greatly enjoyed the excellent recent review on the diagnosis and management of primary lateral sclerosis (PLS). Turner and Talbot emphasize the importance of controlling spasticity as the most troublesome symptom, which is often associated with pain, discomfort and physical disability [1].
    As the authors point out, the current standard of care (baclofen, tizanidine, benzodiazepines and botulinum toxin) is frequently complicated by side effects, difficulties in titration and a lack of well controlled clinical studies [2]. We were thus surprised that the authors omitted the option of medicinal cannabis from the discussion of this very important topic.
    A study by Riva and colleagues offers clear evidence on the efficacy of the cannabinoid preparation Nabiximol for the control of spasticity in ALS and PLS patients [3], which is further supported by Meyer and colleagues providing compelling real world evidence of this effect [4].
    The THC:CBD oromucosal spray (nabioximols, brand name Sativex) became approved in European Union countries in 2010. Although only approved for people with moderate to severe spasticity in multiple sclerosis, who have not responded adequately to other anti-spasticity regimes, THC:CBD is increasingly being used off-label for spasticity in patients with motor neuron diseases. In addition, the patients themselves have self-medicated with recreational cannabis for many years [5].
    The multicenter, double-blind,...

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