Diagnosis and classification of optic neuritis

There is no consensus regarding the classification of optic neuritis, and precise diagnostic criteria are not available. This reality means that the diagnosis of disorders that have optic neuritis as the first manifestation can be challenging. Accurate diagnosis of optic neuritis at presentation can facilitate the timely treatment of individuals with multiple sclerosis, neuromyelitis optica spectrum disorder, or myelin oligodendrocyte glycoprotein antibody-associated disease. Epidemiological data show that, cumulatively, optic neuritis is most frequently caused by many conditions other than multiple sclerosis. Worldwide, the cause and management of optic neuritis varies with geographical location, treatment availability, and ethnic background. We have developed diagnostic criteria for optic neuritis and a classification of optic neuritis subgroups. Our diagnostic criteria are based on clinical features that permit a diagnosis of possible optic neuritis; further paraclinical tests, utilising brain, orbital, and retinal imaging, together with antibody and other protein biomarker data, can lead to a diagnosis of definite optic neuritis. Paraclinical tests can also be applied retrospectively on stored samples and historical brain or retinal scans, which will be useful for future validation studies. Our criteria have the potential to reduce the risk of misdiagnosis, provide information on optic neuritis disease course that can guide future treatment trial design, and enable physicians to judge the likelihood of a need for long-term pharmacological management, which might differ according to optic neuritis subgroups.

A man in his fifties with variable weakness and difficulty in walking

BACKGROUND

An active man in his fifties was treated for atrial fibrillation with ablation. One week later he noticed variable weakness in his lower extremities. In the days that followed, his symptoms improved but could vary from day to day.

CASE PRESENTATION

On admission 3 months after the initial symptoms, he had spasticity and weakness in both lower extremities, with hyperreflexia and positive Babinski. Spinal fluid contained slightly elevated protein levels. Spinal MRI showed cord oedema and gadolinium enhancement over multiple spinal levels. Autoimmune myelitis was suspected, and he was treated with high dose steroids and rituximab. Due to lack of effect, repeated examinations were initiated. Information from his patient history regarding symptom exacerbation by walking or bending forward was emphasised. Repeated MRI showed unchanged spinal oedema and dilated peri- and intramedullary vessels. MRA and spinal digital DSA revealed a dural fistula at third lumbar level, with the left L3 radiculomedullary artery as the feed artery. The fistula was successfully ligated by the neurosurgeon.

INTERPRETATION

Spinal vascular lesions are rare and the diagnosis may be challenging due to atypical presentation. The case shows that detailed information from the patient history and thorough clinical investigation is of paramount importance to disclose this probably underreported condition.

Mutations in the J domain of DNAJB6 cause dominant distal myopathy

Eight patients from five families with undiagnosed dominant distal myopathy underwent clinical, neurophysiological and muscle biopsy examinations. Molecular genetic studies were performed using targeted sequencing of all known myopathy genes followed by segregation of the identified mutations in the affected families using Sanger sequencing. Two novel mutations in DNAJB6 J domain, c.149C>T (p.A50V) and c.161A>C (p.E54A), were identified as the cause of disease. The muscle involvement with p.A50V was distal calf-predominant, and the p.E54A was more proximo-distal. Histological findings were similar to those previously reported in DNAJB6 myopathy. In line with reported pathogenic mutations in the glycine/phenylalanine (G/F) domain of DNAJB6, both the novel mutations showed reduced anti-aggregation capacity by filter trap assay and TDP-43 disaggregation assays. Modeling of the protein showed close proximity of the mutated residues with the G/F domain. Myopathy-causing mutations in DNAJB6 are not only located in the G/F domain, but also in the J domain. The identified mutations in the J domain cause dominant distal and proximo-distal myopathy, confirming that mutations in DNAJB6 should be considered in distal myopathy cases.

Neurodegenerative Interplay of Cardiovascular Autonomic Dysregulation and the Retina in Early Multiple Sclerosis

Introduction: Autonomic nervous system (ANS) symptoms are prevalent in multiple sclerosis (MS) as is neurodegeneration. Our aim was to explore the occurrence of ANS symptoms and retinal neurodegeneration in a newly diagnosed MS population with tools available in a clinical setting.

Methods: Forty-three MS patients and 44 healthy controls took part in the study. We employed a bedside cardiovascular ANS test battery together with classical pupillometry, optical coherence tomography (OCT) evaluation of retinal neurodegeneration in eyes without previous optic neuritis (MSNON) and patients' self-report forms on fatigue, orthostatic and ANS symptoms.

Results: Half of the patients presented with ANS symptoms and a high level of fatigue. There was a significant difference in ganglion cell layer thickness (mean GCIPL) evaluated by OCT in MSNON compared to healthy control eyes. We found a negative linearity of mean GCIPL on group level with increasing disease duration. Three patients fulfilled the criteria of postural orthostatic tachycardia syndrome (POTS).

Conclusion: Our results demonstrate retinal neurodegeneration in MSNON, a high frequency of fatigue and a high prevalence of ANS symptoms in newly diagnosed patients. Whether neurodegeneration precedes ANS dysfunction or vice versa is still open to debate, but as unveiled by the presence of POTS in this MS population, differences in stress-response regulation add to the understanding of variation in onset-time of ANS dysfunction in early MS.

ULTRA-WIDE-FIELD FUNDUS IMAGING IN THE DIAGNOSIS AND FOLLOW-UP OF SUSAC SYNDROME

PURPOSE

To present the use of ultra-wide-field (UW) fundus imaging in the diagnosis and follow-up of a patient with Susac syndrome.

METHODS

Case report of a myopic patient presenting initially with rhegmatogenous retinal detachment. A significant portion of the retina was found to be avascular bilaterally at presentation. Surgery was performed with scleral buckle. Then, UW color and autofluorescent imaging and UW fluorescein angiography were obtained.

RESULTS

Successful retinal reattachment was obtained. Enlargement of the avascular area with neovascularization was observed at eight-month follow-up. In addition, the patient presented severe neurosensory hearing loss and clinical depression postoperatively. The results of UW fluorescein angiography revealed hyperfluorescent macular spots, arteriolar wall hyperfluorescence, leakage from retinal neovascularization, and confirmed the avascularity of two thirds of the retina, whereas the results of UW autofluorescence showed absence of the normal hypofluorescent retinal vessels outside the posterior pole. Findings of UW imaging in combination with systemic involvement led to the diagnosis of Susac syndrome. Appropriate treatment stopped the disease progress, ameliorated symptoms, and some of the occluded retinal vessels were reperfused.

CONCLUSION

In conclusion, UW fundus imaging is a valuable modality in the diagnosis and follow-up of patients with Susac syndrome. Early diagnosis and treatment is critical, particularly as it can lead to reperfusion of occluded retinal vessels.

Juvenile myasthenia gravis in Norway: HLA-DRB1*04:04 is positively associated with prepubertal onset

Background

Juvenile myasthenia gravis (MG) is a rare autoantibody mediated autoimmune disorder targeting the neuromuscular endplate. The clinical hallmark is muscle weakness and fatigability. Disease aetiology is complex, including both genetic and environmental factors. The involvement of genes in the human leukocyte antigen (HLA) is well established in adult MG. However, HLA associations in European juvenile MG have not been studied. This case-control study aimed to investigate and characterize genetic risk factors in prepubertal and postpubertal onset juvenile MG.

Methodology/Principal findings

A population based Norwegian cohort of 43 juvenile MG patients (17 with prepubertal onset, 26 with postpubertal onset) and 368 controls were included. Next generation sequencing of five HLA loci (HLA-A, -B, -C, -DRB1 and -DQB1) was performed, and a positive association was seen with HLA-B*08 (OR (95% CI) = 3.27 (2.00–5.36), P_c = 0.00003) and HLA-DRB1*04:04 (OR (95% CI) = 2.65 (1.57–4.24), P_c = 0.03). Stratified in postpubertal and prepubertal onset, HLA-DRB1*04:04 was only positively associated with the latter (P = 0.01). The HLA-B*08 allele (12.9% in the controls), previously described associated with early onset adult MG, was most frequently observed in postpubertal onset MG (40.4%, P = 0.0002) but also increased among prepubertal onset MG (23.5%, P = 0.05).

Conclusion

This study provides novel information about HLA susceptibility alleles in Norwegian juvenile MG where HLA-DRB1*04:04 was associated with prepubertal onset.

Juvenile myasthenia gravis in Norway: Clinical characteristics, treatment, and long-term outcome in a nationwide population-based cohort

BACKGROUND

This study aimed to characterize juvenile myasthenia gravis in a national population-based cohort in Norway, and to evaluate long-term outcome and potential differences correlated with prepubertal versus postpubertal disease onset.

PATIENTS AND METHODS

Patients with onset of myasthenia gravis aged ≤18 years were identified through multiple strategies. Retrospective clinical data were collected by means of medical charts. All patients had an updated clinical examination. Cases were divided into prepubertal and postpubertal onset using age 12 years as the cut off.

RESULTS

In total, 75 patients were identified of whom 63 were included in the study: 21 in the prepubertal and 42 in the postpubertal onset group. There was a female preponderance in both groups. In total, 59% presented with ocular symptoms, but the great majority of patients in both groups generalized during the two first years of the disease. Myasthenic crisis was more frequent in the prepubertal onset group. All patients were initially treated with pyridostigmine, 26 with steroids, and 17 with other immunosuppressive treatment. The postpubertal cases were more often treated with immunosuppressive therapy. Fifty patients (79%) underwent thymectomy. The general outcome was favourable: 57% became asymptomatic and only four subjects failed to attain clinical improvement. One-third had at least one additional autoimmune disease.

CONCLUSION

Despite frequent symptom generalization and a subgroup of prepubertal onset with severe disease, the long-term outcome was good, especially in the thymectomized prepubertal onset group. Polyautoimmunity occurred in both groups in one-third.

Fatigue and cognition: Pupillary responses to problem-solving in early multiple sclerosis patients

INTRODUCTION

In early multiple sclerosis (MS) patients, cognitive changes and fatigue are frequent and troublesome symptoms, probably related to both structural and functional brain changes. Whether there is a common cause of these symptoms in MS is unknown. In theory, an altered regulation of central neuropeptides can lead to changes in regulation of autonomic function, cognitive difficulties, and fatigue. Direct measurements of central neuropeptides are difficult to perform, but measurements of the eye pupil can be used as a reliable proxy of function.

METHODS

This study assesses pupil size during problem-solving in early MS patients versus controls. A difference in pupil size to a cognitive challenge could signal altered activity within the autonomic system because of early functional brain changes associated with cognitive load. We recruited MS patients (mean disease duration: 2.6 years, N = 41) and age-matched healthy controls (N = 43) without eye pathology. Neurological impairment, magnetic resonance imaging, visual evoked potentials, depression, and fatigue were assessed in all of the patients. In both groups, we assessed processing speed and retinal imaging. Pupil size was recorded with an eye-tracker during playback of multiplication tasks.

RESULTS

Both groups performed well on the cognitive test. The groups showed similar pupillary responses with a mean of 0.55 mm dilation in patients and 0.54 mm dilation in controls for all the tasks collapsed together. However, controls (N = 9) with low cognitive scores (LCS) had an increased pupillary response to cognitive tasks, whereas LCS MS patients (N = 6) did not (p < .05). There was a tendency toward a smaller pupillary response in patients with fatigue.

CONCLUSIONS

This is the first study to investigate pupillary responses to cognitive tasks in MS patients. Our results suggest that MS-related changes in cognition and fatigue may be associated with changes in arousal and the autonomic regulation of task-related pupillary responses. This supports the theory of a link between cognition and fatigue in MS.

Juvenile myasthenia gravis in Norway: A nationwide epidemiological study

BACKGROUND

The aim of this study was to assess the incidence rate and prevalence of autoimmune myasthenia gravis (MG) among children in Norway.

METHODS

This retrospective population-based study was performed in Norway from January 2012 to December 2013. Cases of juvenile MG (JMG) with onset < 18 years were identified through searches in coding systems of electronic patient records at the 15 main hospitals in Norway from 1989 to 2013. In addition, the acetylcholine receptor antibody database at Haukeland University Hospital and the clinical nationwide MG database at Oslo University Hospital were searched for cases of JMG. Diagnosis and age at onset were verified through medical records. Incidence and prevalence rates were calculated using the Norwegian population as reference.

RESULTS

In total 63 unique JMG cases were identified. This corresponds to an average annual incidence rate of 1.6 per million. Incidence rate was stable over the study period. Prevalence of JMG was 3.6-13.8 per million. Females constituted the majority of JMG cases (55 vs 8 males). The risk of JMG was higher among females both in the postpubertal and prepubertal group (p < 0.001 and p = 0.02, respectively).

CONCLUSION

This study confirms the rarity of JMG in Norway, especially among males, and shows a stable incidence rate over the last 25 years.

[Idiopathic intracranial hypertension as a cause of headache]

Idiopathic intracranial hypertension (IIH) is characterised by increased intracranial pressure with normal cerebrospinal fluid, and no evidence of space occupying process, meningeal pathology or venous thrombosis. The condition is associated with obesity, especially in women of childbearing age. IIH is a rare but serious cause of headache, and constitutes a differential diagnosis for sudden-onset headache, particularly if the patient has visual disturbances not related to migraine and reports pulsatile tinnitus, cranial nerve palsy or radiculopathy.

Severe inflammatory disease activity 14 months after cessation of Natalizumab in a patient with Leber's optic neuropathy and multiple sclerosis - a case report

BACKGROUND

Leber's hereditary optic neuropathy (LHON) co-occuring with multiple sclerosis-like disease (LHON-MS) is suggested to be a separate disease entity denoted Harding's disease. Little is known about the response to initiation and discontinuation of potent immunomodulatory treatment in LHON-MS.

CASE PRESENTATION

We describe a LHON-MS patient with 27 years disease duration who developed severe disease activity peaking 14 months after discontinuation of natalizumab, with extensive new inflammatory lesions throughout the brain and in the spinal cord resembling immune inflammatory reconstitution syndrome. She had previously been clinically and radiologically stable on natalizumab treatment for 6 years, and before that only experienced subtle clinical activity during 9 years on interferon beta1a.

CONCLUSION

This is the first report on severe exacerbation of inflammatory disease activity after discontinuation of natalizumab in LHON-MS, and suggests that late rebound activity can occur in these patients.

Contrast-enhanced ultrasound doppler examination of the retrobulbar arteries

Purpose: To evaluate the diagnostic usefulness of an ultrasound contrast agent in examination of the retrobulbar arteries.

Material and Methods: Ten healthy volunteers received a galactose-based echo-contrast medium (Levovist) by i.v. infusion. The ophthalmic, central retinal, the nasal and the temporal posterior ciliary arteries and the short ciliary arteries were studied in 19 eyes by color and spectral Doppler ultrasonography before and after contrast administration. Peak systolic and end diastolic velocities and spectral Doppler indices (pulsatility and resistive) were assessed. The quality of the spectral and color Doppler imaging of the arteries were visually graded on a 5-point scale.

Results: There were significant differences in pre- and post-contrast peak systolic velocities in the ophthalmic arteries ( p<0.05), but not in the other retrobulbar arteries, or in any of the spectral Doppler indices. After contrast administration the mean spectral Doppler score for vessels poorly visualized before contrast increased from 2.2 (±0.4) to 3.1 (±0.9). The number of short ciliary arteries with sufficient spectral Doppler quality increased from 7 prior to contrast to 14 following contrast. Prior to the infusion of Levovist, 62 (73%) out of 85 retrobulbar arteries could be evaluated with a sufficient spectral Doppler quality. Following the administration of contrast 66 (78%) arteries had sufficient spectral Doppler quality. However, by combining the results of the pre- and post-contrast examinations, sufficient spectral Doppler quality was obtained in 77 (91%) of the 85 retrobulbar arteries.

Conclusion: Contrast enhancement increased the number of detectable retrobulbar vessels. However, in the case of good quality pre-contrast imaging of the retrobulbar vessels, the use of Levovist did not add any substantial diagnostic information. The optimal spectral Doppler results were obtained when both pre- and post-contrast examinations were performed.

Pseudoperipheral palsy: a case of subcortical infarction imitating peripheral neuropathy

Background

Vascular damage in the central hand knob area can mimic peripheral motor nerve deficits.

Case presentation

We describe the case of a woman presenting with apparent peripheral neuropathy. Brain magnetic resonance imaging and computed tomography angiography revealed an infarct in the precentral hand knob area, with significant stenosis in the right proximal middle cerebral artery trunk. Subsequent 3-Tesla magnetic resonance imaging of the brain suggested cerebral angiitis. The patient experienced improved hand function following combined glucocorticoid and cyclophosphamide treatment.

Conclusion

Vascular damage in the hand knob area should be considered when evaluating peripheral motor nerve deficits in the presence of normal nerve conduction velocities. The diagnosis of cerebral angiitis remains a major challenge for clinicians.

A de novo Mutation in the SCN4A Gene Causing Sodium Channel Myotonia

We describe the case of a six year old boy with findings consistent with myotonia congenita: muscular hypertrophy, stiffness when commencing movements and typical warm-up signs. The most prominent symptom was myotonia of the eyelid muscles with apparent swelling around the eyes. Even though the pronounced warm-up phenomena in our patient suggested a chloride channel-associated myotonia congenita, the myotonia of his eyelid muscles indicated an involvement of sodium channels. Screening for mutations in the underlying CLCN1 gene was negative, however, in the SCN4A gene, we identified the missense mutation c.2108T>C; p.Leu703Pro for which there is strong evidence of pathogenicity because it arose de novo in the index patient.

[Posterior cortical atrophy]

BACKGROUND

Posterior cortical atrophy is a neurodegenerative condition with atrophy of posterior parts of the cerebral cortex, including the visual cortex and parts of the parietal and temporal cortices. It presents early, in the 50s or 60s, with nonspecific visual disturbances that are often misinterpreted as ophthalmological, which can delay the diagnosis. The purpose of this article is to present current knowledge about symptoms, diagnostics and treatment of this condition.

METHOD

The review is based on a selection of relevant articles in PubMed and on the authors' own experience with the patient group.

RESULTS

Posterior cortical atrophy causes gradually increasing impairment in reading, distance judgement, and the ability to perceive complex images. Examination of higher visual functions, neuropsychological testing, and neuroimaging contribute to diagnosis. In the early stages, patients do not have problems with memory or insight, but cognitive impairment and dementia can develop. It is unclear whether the condition is a variant of Alzheimer's disease, or whether it is a separate disease entity. There is no established treatment, but practical measures such as the aid of social care workers, telephones with large keypads, computers with voice recognition software and audiobooks can be useful.

INTERPRETATION

Currently available treatment has very limited effect on the disease itself. Nevertheless it is important to identify and diagnose the condition in its early stages in order to be able to offer patients practical assistance in their daily lives.

EFNS/ENS Guidelines for the treatment of ocular myasthenia

BACKGROUND AND PURPOSE

The symptoms of acquired autoimmune ocular myasthenia are restricted to the extrinsic eye muscles, causing double vision and drooping eyelids. These guidelines are designed to provide advice about best clinical practice based on the current state of clinical and scientific knowledge and the consensus of an expert panel.

SEARCH STRATEGY

Evidence for these guidelines was collected by searches in the MEDLINE and Cochrane databases. The task force working group reviewed evidence from original articles and systematic reviews. The evidence was classified (I, II, III, IV) and consensus recommendation graded (A, B or C) according to the EFNS guidance. Where there was a lack of evidence but clear consensus, good practice points are provided.

CONCLUSIONS

The treatment of ocular myasthenia should initially be started with pyridostigmine (good practice point). If this is not successful in relieving symptoms, oral corticosteroids should be used on an alternate-day regimen (recommendation level C). If steroid treatment does not result in good control of the symptoms or if it is necessary to use high steroid doses, steroid-sparing treatment with azathioprine should be started (recommendation level C). If ocular myasthenia gravis is associated with thymoma, thymectomy is indicated. Otherwise, the role of thymectomy in ocular myasthenia is controversial. Steroids and thymectomy may modify the course of ocular myasthenia and prevent myasthenia gravis generalization (good practice point).

Fatigue in myasthenia gravis: is it more than muscular weakness?

Background

Few studies have focused on fatigue in myasthenia gravis (MG), and fatigue in relation to the autonomic system has never been systematically explored in these patients. The study aimed to document the prevalence of MG-related fatigue in ethnic Norwegians and to examine whether MG severity is associated with symptoms of autonomic disturbance, which in turn is associated with fatigue and functional disability.

Methods

Eighty two of the 97 who fulfilled the study inclusion criteria participated in the study. Controls were 410 age- and sex-matched subjects drawn from a normative sample (n = 2136) representative of the Norwegian population. Bivariate analyses and multivariate linear regression analyses were used to assess associations between questionnaire-reported MG severity, symptoms of autonomic disturbance, fatigue (mental and physical) and functional disability.

Results

Forty-four per cent (36/82) of patients fulfilled the criteria for fatigue compared with 22% (90/410) of controls (odds ratio 2.0; p = 0.003). Twenty-one per cent of patients (17/82) met the criteria for chronic fatigue versus 12% (48/410) of controls (odds ratio 1.96; p = 0.03). MG patients had higher total fatigue scores than controls (p < 0.001) and a high prevalence of autonomic symptoms, especially poor thermoregulation and sleep disturbance. According to multivariate analyses controlled for MG score, symptoms of autonomic disturbances were independently positively associated with fatigue (p < 0.001), and fatigue was independently negatively associated with functional level (p < 0.001).

Conclusion

Norwegian ethnic patients with MG have higher levels of fatigue and a higher prevalence of chronic fatigue than controls, even in patients in full remission. MG severity is highly suggestive to be associated with symptoms of autonomic disturbance, which in turn is associated with fatigue and the level of functional disability.

[Drugs that may trigger or exacerbate myasthenia gravis]

Myasthenia gravis (MG) is an autoimmune disease causing muscle weakness due to impaired transmission at the neuromuscular junction. MG or a MG-like condition may be triggered or exacerbated by several drugs used for treatment of other diseases. Drugs may interfere with the neuromuscular transmission through several mechanisms, either by affecting pre- or postsynaptic ion channels or by affecting acetylcholinesterase. Based on a literature search in PubMed and the authors' own clinical experiences, we provide an overview focusing on the most frequently used drugs that may exacerbate weakness in patients with MG. In our experience, symptomatic MG-patients who have a generalised disease are especially vulnerable to drug-induced exacerbations, while stable MG patients with few symptoms more seldom are. Nevertheless, patients with MG must receive treatment for co-existing conditions. It is important to be aware of a possible increase in muscle weakness when introducing a new drug. If the patient deteriorates, the new treatment must be withdrawn or the dose reduced.

Is the brain water channel aquaporin-4 a pathogenetic factor in idiopathic intracranial hypertension? Results from a combined clinical and genetic study in a Norwegian cohort

PURPOSE

Idiopathic intracranial hypertension (IIH) is a condition of increased intracranial pressure of unknown aetiology. Patients with IIH usually suffer from headache and visual disturbances. High intracranial pressure despite normal ventricle size and negative MRI indicate perturbed water flux across cellular membranes, which is provided by the brain water channel aquaporin-4 (AQP4). IIH could be associated with malfunctioning intracerebral water homeostasis and cerebrospinal fluid (CSF) reabsorption based on functional or regulatory alterations of AQP4.

METHODS

Clinical data, blood and CSF samples were collected from 28 patients with IIH. Clinical characteristics were assessed, and a genetic association study was performed by sequencing the AQP4 gene on chromosome 18. Genetic data were compared with 52 healthy controls and matched by age, sex and ethnicity. Chi-square test and linear discriminant analysis (LDA) were used in the search of a genotype-phenotype association.

RESULTS

While the majority of patients responded to medical treatment, four required shunt application. All, except one, had a good visual outcome. The 24 AQP4 gene SNPs showed no association with IIH. Full cross-validation of the LDA modelling resulted in only 55.1% correct classification of the cases and controls, with a corresponding estimated p-value 0.37.

CONCLUSIONS

Our genetic case-control study did not indicate an association between AQP4 gene variants and IIH. However, the theory of an etiopathogenic link between IIH and AQP4 is tempting, and discussed in this article. Association studies with large sample size are difficult to perform owing is the rarity of the condition.

An unusual case of the syndrome of cervical rib with subclavian artery thrombosis and cerebellar and cerebral infarctions

Background

Cerebellar and cerebral infarctions caused by the syndrome of cervical rib with thrombosis of subclavian artery are very unusual.

Case presentation

We report the case of a 49-year-old male patient with a right cervical rib compression leading to subclavian arterial thrombosis and both cerebellar and cerebral infarctions secondary to retrograde thromboembolisation. Follow-up imaging revealed partial resolution of the thrombosis after combined anti-coagulant and anti-platelet therapy. The cervical rib and first costa were surgically removed to prevent additional events.

Conclusion

Cervical rib vascular compression should be promptly diagnosed and treated in order to avoid further complications, including cerebrovascular ischemic events.

Late onset myasthenia gravis is associated with HLA DRB1*15:01 in the Norwegian population

Background

Acquired myasthenia gravis (MG) is a rare antibody-mediated autoimmune disease caused by impaired neuromuscular transmission, leading to abnormal muscle fatigability. The aetiology is complex, including genetic risk factors of the human leukocyte antigen (HLA) complex and unknown environmental factors. Although associations between the HLA complex and MG are well established, not all involved components of the HLA predisposition to this heterogeneous disease have been revealed. Well-powered and comprehensive HLA analyses of subgroups in MG are warranted, especially in late onset MG.

Methodology/Principal Findings

This case-control association study is of a large population-based Norwegian cohort of 369 MG patients and 651 healthy controls. We performed comprehensive genotyping of four classical HLA loci (HLA-A, -B, -C and -DRB1) and showed that the DRB1*15:01 allele conferred the strongest risk in late onset MG (LOMG; onset ≥60years) (OR 2.38, p_c7.4×10⁻⁵). DRB1*13:01 was found to be a protective allele for both early onset MG (EOMG) and LOMG (OR 0.31, p_c 4.71×10⁻⁴), a finding not previously described. No significant association was found to the DRB1*07:01 allele (p_nc = 0.18) in a subset of nonthymomatous anti-titin antibody positive LOMG as reported by others. HLA-B*08 was mapped to give the strongest contribution to EOMG, supporting previous studies.

Conclusion

The results from this study provide important new information concerning the susceptibility of HLA alleles in Caucasian MG, with highlights on DRB1*15:01 as being a major risk allele in LOMG.

Good long-term efficacy of pallidal stimulation in cervical dystonia: a prospective, observer-blinded study

BACKGROUND AND PURPOSE

Deep brain stimulation of the internal globus pallidus (GPi-DBS) is established as an effective treatment of primary generalised dystonia in controlled studies. In cervical dystonia (CD), only one previous study has reported observer-blinded outcome assessment of long-term GPi-DBS, with 1-year follow-up.

METHODS

In this prospective, single-centre study, eight patients with CD (7 women:1 man, 4 focal:4 segmental) treated with bilateral GPi-DBS for median (range) 30 (12-48) months, were evaluated by the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS; Severity, Disability and Pain scores), the Short-Form Health Survey-36 (SF-36), and the Becks Depression Index in an open design. In addition, a blinded rater assessed the TWSTRS Severity score from videos obtained preoperatively and at the last follow-up.

RESULTS

In the blinded evaluation, median (range) TWSTRS Severity score improved from 25 (19-30) to 8 (4-23) (P = 0.028), thus a 70% (23-82) score reduction. In the open evaluation, median Severity score improvement at the last follow-up was 73%, representing a significant further improvement from 50% at 6 months. The Disability and Pain scores improved by median 91% and 92%, respectively, and the SF-36 subdomain scores improved significantly. A reversible right hemiparesis and aphasia occured in one patient 4 days postoperatively, because of reversible oedema around the left electrode. No other serious adverse effects and no permanent morbidity were observed.

CONCLUSIONS

This single-blinded study shows good long-term efficacy of GPi-DBS in CD patients and supports using this treatment in those who have insufficient response to medical treatment.

Static and pulsatile intracranial pressure in idiopathic intracranial hypertension

OBJECTIVE

The aim of this observational study was to characterize the static and pulsatile intracranial pressure (ICP) in conservatively (medically) treated idiopathic intracranial hypertension (IIH) patients in need of shunt surgery, and also in patients with chronic daily headache (CDH) without visual disturbances.

METHODS

The material includes 14 IIH patients and 7 CDH patients in whom ICP was monitored continuously over-night. Static ICP was characterized by mean ICP, pulsatile ICP was characterized by the wave amplitude, rise time, and rise time coefficient.

RESULTS

In the IIH group all 14 had headache and visual disturbances. Mean ICP was high (> 15 mmHg) in only 7 patients (50%), while mean ICP wave amplitude was high (≥ 4 mmHg) in all 14 (100%). All IIH patients were shunted and improved clinically thereafter (i.e., relief from visual disturbances and/or headache). None in the CDH group had high mean ICP or mean ICP wave amplitude, and none were shunted.

CONCLUSIONS

In this cohort of 14 conservatively treated IIH patients with lasting and shunt-responsive headache and visual disturbances, the mean ICP wave amplitude was elevated (≥ 4 mmHg) in all patients despite normal mean ICP (< 15 mmHg) in 7 patients (all but one on medication). Therefore, the pulsatile ICP may be more relevant than the static ICP in the diagnostic setting for patients with IIH. Further prospective standardized approaches are warranted.

Airway limitation and exercise intolerance in well-regulated myasthenia gravis patients

OBJECTIVES

Myasthenia gravis (MG) is an autoimmune disease of neuromuscular synapses, characterized by muscular weakness and reduced endurance. Remission can be obtained in many patients. However, some of these patients complain of fatigue. The aim of this study was to assess exercise capacity and lung function in well-regulated MG patients.

PATIENTS AND METHODS

Ten otherwise healthy MG patients and 10 matched controls underwent dynamic spirometry, and a ramped symptom-limited bicycle exercise test. Spirometric variables included forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and maximum voluntary ventilation (MVV). Exercise variables included maximal oxygen uptake (VO(2) max), anaerobic threshold (VO(2) AT) maximum work load (W), maximum ventilation (VE max), and limiting symptom.

RESULTS

Myasthenia gravis patients had significantly lower FEV1/FVC ratio than controls. This was more marked in patients on acetylcholine esterase inhibitors. On the contrary, patients not using acetylcholine esterase inhibitors had a significantly lower exercise endurance time.

CONCLUSION

Well-regulated MG patients, especially those using pyridostigmine, tend to have an airway obstruction. The modest airway limitation might be a contributing factor to their fatigue. Patients who are not using acetylcholinesterase inhibitor seem to have diminished exercise endurance in spite of their clinically complete remission.

[Neurofibromatosis type 2 and auditory brainstem implantation]

BACKGROUND

Neurofibromatosis type 2 (NF2) is a rare and severe autosomal dominant disorder caused by mutations in a tumour suppressor gene. This article reviews NF2 and its treatment with auditory brainstem implantation.

MATERIAL AND METHODS

The review is based on the authors' experience with the disease and literature identified through a non-systematic search of PubMed.

RESULTS

NF2 is caused by loss-of-normal function of the tumour suppressor protein merlin. Merlin normally suppresses cell growth and proliferation. The clinical picture is dominated by neurological symptoms, caused by multiple tumours - mainly schwannomas and meningeomas. The hallmark of the disease is development of bilateral vestibular schwannomas, and the most common presenting symptom in adults is progressive hearing loss. Presenile cataract, ocular motility disorders, peripheral neuropathy and skin tumours are other common findings. The majority of patients become deaf, many patients become severely disabled and life expectancy is reduced. The goal of management is conservation of function and maintenance of quality of life. Auditory brainstem implants stimulate the cochlear nucleus directly and provide substantial auditory benefits to patients with NF2.

INTERPRETATION

A multidisciplinary approach in specialty centres is recommended. Management by an experienced team reduces mortality and improves outcome after surgery. Auditory brainstem implantation is an important part of the hearing rehabilitation in these patients. Emerging knowledge of the molecular disease mechanisms offers hope for new therapeutic strategies.

A subhyaloid haemorrhage as the presenting symptom of bilateral optic neuropathy

A 28 year-old man with a spontaneous vitreous haemorrhage as the first sign of Leber's optic atrophy is presented. The blood collected in a central retrohyaloid area covering the left macula. The exact starting point of the haemorrhage was never positively identified, but it seemed to originate from an area of microangiopathy adjacent to the optic disc. For 8-10 months the vision of the left eye gradually decreased to counting fingers. A year later the visual acuity dropped to the same level on the right eye. The picture was compatible with Leber's optic atrophy. Other disorders causing bilateral optic neuropathy were excluded. A careful family history revealed several cases of visual problems for several generations. Vitreous haemorrhage as the first sign of Leber's optic atrophy has not previously been reported. Peripapillar microangiopathy, however, has been described in the asymptomatic stage of the disease.

[Primary and secondary dystonias]

BACKGROUND

Dystonia is a neurological syndrome, characterized by involuntary muscle contractions causing twisting, repetitive movements and abnormal postures. The aim of this brief review is to summarize the current state of knowledge as to the clinical, genetic, diagnostic and therapeutic aspects of dystonia.

MATERIAL AND METHODS

This article is based on own research, clinical experience and recent medical literature found by searching Medline.

RESULTS AND INTERPRETATIONS

Dystonia is the third most prevalent movement disorder in humans and is a common term for a group of primary (idiopathic) and secondary (symptomatic) movement disorders. For the primary types, tremor and myoclonus are the only symptoms in addition to the dystonia itself. Some primary dystonias have a hereditary component. Secondary dystonias are associated with other diseases with hereditary, metabolic, traumatic or exogen causes. There is still no curative treatment of dystonia, but new therapeutic methods increase the possibility of reducing involuntary movement, abnormal postures and pain, as well as improving function and quality of life for patients with dystonia.

Periodic abducens nerve palsy in adults caused by neurovascular compression

Unilateral abducens nerve palsy with periodic recurrences is a well-recognised finding in children, but is rare in adults. The underlying pathophysiological mechanism is unknown. Vascular compression of the nerve is suspected but never demonstrated. We describe an adult patient with, altogether, 11 periods of unilateral right-sided abducens palsy and arterial contact at the root exit zone of the symptomatic side.

Determinants and status of quality of life after long-term botulinum toxin therapy for cervical dystonia

The aim of this study was to assess health-related quality of life (HRQoL), using the Short Form Health Survey-36 (SF-36), in 70 cervical dystonia (CD) patients after long-term botulinum toxin (BTX) treatment (median 5.5 years), and to identify factors determining reduced HRQoL. We used combined patient-and physician-based measures to assess both CD severity [Toronto Western Spasmodic Torticollis Rating Scale, (TWSTRS)] and effect of long-term BTX treatment, and the Hospital Anxiety and Depression Scale (HAD) and General Health Questionnaire-30 to assess psychological distress. Mean SF-36 domain scores of the CD patients were reduced by <1 SD compared with age- and gender-matched population samples. High TWSTRS total scores and high HAD-depression (HAD-D) scores were the main factors associated with reduced scores in the physical and mental SF-36 domains, respectively. Patients evaluated to have a 'good effect' of long-term BTX treatment (n = 47), had significantly lower median TWSTRS total score, and a 3x lower frequency of high HAD-D scores, than those evaluated to an 'unsatisfactory effect' (n = 23). In conclusion, most CD patients enjoy a good HRQoL after long-term BTX therapy. Reduced HRQoL was associated with more severe disease and/or depressive symptoms.

[A 64-year old man with cognitive impairment and gait disturbance]

Intravascular lymphomatosis is a rare disease, characterized by occlusion of small arterioles and veins by malignant lymphoma cells. It often affects the central and peripheral nervous system and the skin. This case report illustrates the diagnostic challenge. Most patients develop rapidly progressive dementia combined with focal neurological symptoms. No relevant clinical, radiological or laboratory tests are available to diagnose the disease. Blood samples and bone marrow are usually normal. Diagnosis is often delayed and made post mortem. Brain biopsy could be diagnostic. The prognosis is poor, but early aggressive chemotherapy can potentially prolong the life span and in a few cases be curative. Intravascular lymphomatosis should be considered in patients with a combination of rapidly developing encephalopathy and focal neurological signs.

Microvascular decompression for hemifacial spasm: postoperative neurologic follow-up and evaluation of life quality

Microvascular decompression (MVD) is an effective and safe treatment in hemifacial spasm (HFS). Postoperative evaluations are usually made by neurosurgeons. Follow-up studies performed by neurologists and postoperative quality of life (QoL) investigations are lacking. All 25 HFS patients operated with MVD in our centre between 2000 and 2004 were evaluated with the recently validated HFS-7 scheme, extended with the item 'sleep disturbance due to HFS' (HFS-8). The patients underwent a careful neurological examination median 3 years after the operation. The evaluation focused on clinical aspects, changes in blood pressure and time until observable effect of MVD. The evaluation of HFS-7 questionnaire and the extended form (HFS-8) showed significant improvement in QoL after MVD. Neurological outcome was in almost all cases excellent or good. Eleven (44%) patients had no neurological deficits at all. Only one patient had serious complications with ipsilateral facial palsy, deafness, balance problems and vertigo. The other patients had minor neurological findings or symptoms. Eighteen (72%) patients experienced early effect within 3 months after MVD; seven (28%) patients had late effect between 6 and 14 months. Median age of the patients with late effect (62.6 years) was significantly higher than in those with early effect (52.7 years).

Apraxia of eyelid opening: clinical features and therapy

PURPOSE

Botulinum toxin injection is the treatment of choice in cases of benign essential blepharospasm. However, about 10% of the patients do not get sufficient effect from this treatment, and many of them have concomitant apraxia of lid opening.

METHODS

Over a 3-year period we treated 12 patients. Three had pure apraxia of lid opening and in the other nine it was associated with blepharospasm. All patients were initially treated with botulinum toxin injections with poor results. They underwent surgical treatment like blepharoplasty, limited myectomy, aponeurosis repair, and/or frontalis suspension. Some of them needed post operative botulinum toxin injections in the pretarsal part of orbicularis oculi muscles.

RESULTS

This combined therapy gave good functional and aesthetic results.

CONCLUSIONS

The specific causes of blepharospasm and apraxia of lid opening are unknown, but these two conditions coexist in some patients and can be difficult to treat. It is important to make a correct diagnosis, and a combined surgical and botulinum toxin treatment can be very effective.