Displaying publications 1 - 20 of 54 in total

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  1. Zhong Yang L, Ngoo QZ, Viswanathan S, Sudarno R
    Cureus, 2024 Mar;16(3):e56268.
    PMID: 38623103 DOI: 10.7759/cureus.56268
    We report a case of isolated left abducens nerve palsy accompanying a right thalamic infarct. The patient, a 43-year-old Malay male with newly diagnosed hypertension, diabetes mellitus, and dyslipidemia, initially reported binocular diplopia on left lateral gaze persisting for five weeks. Subsequently, he experienced acute left-sided body weakness and slurred speech for over one day. Clinical examination revealed restricted left eye lateral gaze (-3) with no relative afferent pupillary defect. Additionally, decreased power (4/5) was noted in the left upper and lower limbs. Brain magnetic resonance imaging (MRI) revealed restricted diffusion in the right thalamus extending to the right posterior internal capsule, left anterior cingulate gyrus, and left caudate nucleus. The patient was initiated on antiplatelet, antihypertensive, and oral hypoglycemic agents, resulting in symptom improvement. This rare neuroophthalmological finding has not been reported previously.
  2. Viswanathan S, Wah LM
    Mult Scler, 2019 10;25(11):1452-1461.
    PMID: 30113245 DOI: 10.1177/1352458518792430
    OBJECTIVES: This study looked at observed crude prevalence/incidence of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) in Malaysia and identified any inter-ethnic differences for MS/NMOSD.

    METHODS: This was a nationwide tertiary hospital-based retrospective cross-sectional study using the capture-recapture method. It looked at the estimated crude prevalence of confirmed MS and NMOSD and annual incidence on 29 December 2017. Recapture of data was done between February and March 2018 on 1 March 2018. Public and referring private institutions were accessed.

    RESULTS: The survey identified 767 MS and 545 NMOSD subjects, with crude prevalence rates of 2.73 per 100,000 (95% confidence interval (CI): 2.53; 2.92 per 100,000 population) and 1.94 per 100,000 (95% CI: 1.77; 2.10 per 100,000 population) with observed crude annual incidence of 0.55 (95% CI: 0.43; 0.58) for MS and 0.39 per 100,000 (95% CI: 0.35; 0.47) for NMOSD. The MS:NMOSD ratios were 1.4:1.0. The capture-recapture method revealed 913 MS (95% CI: 910; 915.9) and 580 (95% CI: 578.8; 581.2) NMOSD with prevalence per 100,000 of 3.26 (95% CI: 3.05; 3.47) and 2.07 (95% CI: 1.90; 2.24), respectively. In the MS group, 59.4% were Malay, 16.6% Chinese, 20.5% Indian, and 3.5% were from indigenous groups. In the NMOSD group, 47.3% were Malay, 46.9% Chinese, 3.5% Indian, and 2.3% were from other indigenous groups. The ratio of NMOSD to MS among the Chinese was 2:1, but the ratio of MS to NMOSD among the Malays was 1.8:1, and that in Indians was 8.3:1.

    CONCLUSION: There is a modest increase in the prevalence of MS and NMOSD in Malaysia with inter-ethnic differences for MS/NMOSD.

  3. Viswanathan S, Botross N, Rusli BN, Riad A
    Mult Scler Relat Disord, 2016 Nov;10:112-115.
    PMID: 27919476 DOI: 10.1016/j.msard.2016.10.001
    Acute disseminated encephalomyelitis (ADEM) complicating dengue infection is still exceedingly rare even in endemic countries such as Malaysia. Here we report two such cases, the first in an elderly female patient and the second in a young man. Both presented with encephalopathy, brainstem involvement and worsening upper and lower limb weakness. Initial magnetic resonance imaging (MRI) of the brain was normal in the first case. Serum for dengue Ig M and NS-1 was positive in both cases. Cerebrospinal fluid (CSF) showed pleocytosis in both with Dengue IgM and NS-1 positive in the second case but not done in the first. MRI brain showed changes of perpendicular subcortical palisading white matter, callosal and brainstem disease mimicking multiple sclerosis (MS) in both patients though in the former case there was a lag between the onset of clinical symptoms and MRI changes which was only clarified on reimaging. The temporal evolution and duration of the clinical symptoms, CSF changes and neuroimaging were more suggestive of Dengue ADEM rather than an encephalitis though initially the first case began as dengue encephalitis. Furthermore in dengue encephalitis neuroimaging is usually normal or rarely edema, haemorrhage, brainstem, thalamic or focal lesions are seen. Therefore, early recognition of ADEM as a sequelae of dengue infection with neuroimaging mimicking MS and repeat imaging helped in identifying these two cases. Treatment with intravenous steroids followed by maintenance oral steroids produced good outcome in both patients.
  4. Sobri Muda A, Kwah YG, Al-Edrus SA, Wong SL, Norzaini MZ, Viswanathan S
    Neuroradiol J, 2010 Nov;23(4):443-6.
    PMID: 24148636
    We describe a rare case of multiple dilated Virchow-Robin spaces in the brainstem in a patient presenting initially with blepharospasm with subsequent spread to involve the face and neck. On magnetic resonance imaging (MRI), these lesions demonstrated an isointense signal to cerebrospinal fluid on all sequences with no mass effect or enhancement. Although rare, this condition should be considered part of the differential diagnosis when evaluating cystic abnormalities in the brainstem. This is the first reported case of blepharospasm with subsequent orofacial and neck dystonia caused by dilated Virchow-Robin spaces. The imaging findings and differential diagnoses are discussed.
  5. Yan Hung SK, Hiew FL, Viswanathan S
    Ann Indian Acad Neurol, 2019 1 30;22(1):102-103.
    PMID: 30692769 DOI: 10.4103/aian.AIAN_232_18
    Multiple co-infections can predispose a patient to autoimmune encephalitis. Out of thirty cases of N-methyl-D-aspartate receptor (NMDAR) encephalitis seen at a single tertiary referral center, only two cases of co-infection with NMDAR encephalitis were identified. One of these cases was highly interesting due to the presence of more than one co-infections along with the presence of cortical dysfunction, seizures, and orofacial dyskinesias at the onset in a male in the absence of tumors, which was refractory to initial treatment.
  6. Ooi HS, Viswanathan S, Botross NP, Eow GB, Chin YT, Kanesalingam R, et al.
    Neurol India, 2020 8 30;68(4):850-855.
    PMID: 32859827 DOI: 10.4103/0028-3886.293469
    Background: The association between appendectomy and multiple sclerosis (MS) is unknown. In this study, we explored the association between appendectomy and MS and neuromyelitis optica spectrum disorder (NMOSD).

    Patients and Methods: MS and NMOSD patients older than 40 were identified from neurology records from hospitals in Malaysia. The diagnoses were based on the Revised McDonald (2010) and Wingerchuk (2015) criteria. Controls were sampled from Malaysia's normal population. Individuals were interviewed telephonically or face-to-face. The age inclusion criterion (over 40) differentiated high or low lifetime risk of appendicitis, as appendicitis incidence is rare after 40.

    Results: 49 MS, 71 NMOSD, and 880 controls met the inclusion criteria. Seventy-two individuals (9 MS, 4 NMOSD, 59 control) had undergone appendectomy. Appendectomy rates were 18.37% in the MS group (95% CI 7.5-29.2%), 5.6% in the NMOSD group (0.3%, 11%), and 6.7% among controls (5.1%, 8.4%), (MS vs NMOSD P = 0.036, MS vs controls P = 0.007). Binary regression analysis showed that MS was an independent risk factor for appendectomy (OR 2.938, 95% CI 1.302, 6.633, P = 0.009). NMOSD showed no association with appendectomy.

    Conclusion: MS is positively associated with appendectomy, unlike ulcerative colitis, which is negatively associated. We hypothesize that there is a commonality in the microflora in persons who have had these two illnesses.

  7. Ching YM, Viswanathan S, Mohamed Nor N, Shuib S, Kamarudin B, Mansor S, et al.
    Auto- immunity highlights, 2019 Dec;10(1):13.
    PMID: 32257069 DOI: 10.1186/s13317-019-0123-7
    Background: Multiple sclerosis is an immune mediated disease targeting the central nervous system. Association of non-human leukocyte antigen gene, CD58, with multiple sclerosis has been reported in several populations but is unclear among Southeast Asians. This pilot study was conducted to explore the association between CD58 polymorphism and multiple sclerosis among the Malay population in Malaysia.

    Methods: Blood samples were collected from 27 multiple sclerosis patients, and compared with 58 age- and gender matched healthy individuals. All patients were tested negative for anti-aquaporin 4. DNA was extracted from the blood and genotyped for 3 single nucleotide polymorphisms rs12044852, rs2300747 and rs1335532 of gene CD58 by real-time PCR.

    Results: The majority of multiple sclerosis patients were female (85.2%). The general mean age of onset was 30.5 years. Genotyping results showed that frequencies of the alleles were between 40 and 50% for MS patients and healthy individuals. Association (allelic model) between multiple sclerosis and CD58 gene polymorphism alleles rs12044852 (p = 0.410), rs2300747 (p = 0.881) and rs1335532 (p = 0.407) were indistinct.

    Conclusions: The impact of the CD58 gene polymorphism was not prominent in this pilot study, implying that genetic composition contributing to multiple sclerosis may be different between different populations, thus results in a heterogeneity of disease manifestation and distribution.

  8. Lim JL, Ng EY, Lim SY, Tan AH, Abdul-Aziz Z, Ibrahim KA, et al.
    Neurol Sci, 2021 Oct;42(10):4203-4207.
    PMID: 33559030 DOI: 10.1007/s10072-021-05056-x
    BACKGROUND: Genome-wide association studies (GWAS) have shown that variants in the 3-methylcrotonyl-CoA carboxylase (MCCC1)/lysosome-associated membrane protein 3 (LAMP3) loci (rs10513789, rs12637471, rs12493050) reduce the risk of Parkinson's disease (PD) in Caucasians, Chinese and Ashkenazi-Jews while the rs11248060 variant in the diacylglycerol kinase theta (DGKQ) gene increases the risk of PD in Caucasian and Han Chinese cohorts. However, their roles in Malays are unknown. Therefore, this study aims to investigate the association of these variants with the risk of PD in individuals of Malay ancestry.

    METHODS: A total of 1114 subjects comprising of 536 PD patients and 578 healthy controls of Malay ancestry were recruited and genotyped using Taqman® allelic discrimination assays.

    RESULTS: The G allele of rs10513789 (OR = 0.83, p = 0.001) and A allele of rs12637471 (OR = 0.79, p = 0.007) in the MCCC1/LAMP3 locus were associated with a protective effect against developing PD in the Malay population. A recessive model of penetrance showed a protective effect of the GG genotype for rs10513789 and the AA genotype for rs12637471. No association with PD was found with the other MCCC1/LAMP3 rs12493050 variant or with the DGKQ (rs11248060) variant. No significant associations were found between the four variants with the age at PD diagnosis.

    CONCLUSION: MCCC1/LAMP3 variants rs10513789 and rs12637471 protect against PD in the Malay population.

  9. Palace J, Wingerchuk DM, Fujihara K, Berthele A, Oreja-Guevara C, Kim HJ, et al.
    Mult Scler Relat Disord, 2021 Jan;47:102641.
    PMID: 33310418 DOI: 10.1016/j.msard.2020.102641
    BACKGROUND: Antibodies to the aquaporin-4 (AQP4) water channel in neuromyelitis optica spectrum disorder (NMOSD) are reported to trigger the complement cascade, which is implicated in astrocyte damage and subsequent neuronal injury. The PREVENT study demonstrated that the terminal complement inhibitor eculizumab reduces adjudicated relapse risk in patients with anti-AQP4 immunoglobulin G-positive (AQP4+) NMOSD. The objective of this analysis was to evaluate the efficacy of eculizumab in reducing relapse risk and its safety in AQP4+ NMOSD across clinically relevant subgroups in PREVENT.

    METHODS: In the randomized, double-blind, time-to-event, phase 3 PREVENT trial, 143 adults received eculizumab (maintenance dose, 1200 mg/2 weeks) or placebo (2:1), with stable-dose concomitant immunosuppressive therapy (IST) permitted (except rituximab and mitoxantrone). Post hoc analyses of relapses and adverse events were performed for prespecified and post hoc subgroups based on concomitant IST and prior rituximab use, demographic and disease characteristics, and autoimmune comorbidity.

    RESULTS: The significant reduction in relapse risk observed for eculizumab versus placebo in the overall PREVENT population was consistently maintained across subgroups based on concomitant IST and previous rituximab use, age, sex, region, race, time since clinical onset of NMOSD, historical annualized relapse rate, baseline Expanded Disability Status Scale score, and history of another autoimmune disorder. The serious infection rate was lower with eculizumab than placebo regardless of rituximab use in the previous year, concomitant IST use, or history of another autoimmune disorder.

    CONCLUSION: Across a wide range of clinically relevant AQP4+ NMOSD patient subgroups in PREVENT, eculizumab therapy was consistently effective versus placebo in reducing relapse risk, with no apparent increase in serious infection rate.

    TRIAL REGISTRATION: NCT01892345 (ClinicalTrials.gov).

  10. Ahuja A, Tyagi PK, Kumar M, Sharma N, Prakash S, Radha, et al.
    Cells, 2022 Sep 07;11(18).
    PMID: 36139367 DOI: 10.3390/cells11182792
    Stem cells are a well-known autologous pluripotent cell source, having excellent potential to develop into specialized cells, such as brain, skin, and bone marrow cells. The oral cavity is reported to be a rich source of multiple types of oral stem cells, including the dental pulp, mucosal soft tissues, periodontal ligament, and apical papilla. Oral stem cells were useful for both the regeneration of soft tissue components in the dental pulp and mineralized structure regeneration, such as bone or dentin, and can be a viable substitute for traditionally used bone marrow stem cells. In recent years, several studies have reported that plant extracts or compounds promoted the proliferation, differentiation, and survival of different oral stem cells. This review is carried out by following the PRISMA guidelines and focusing mainly on the effects of bioactive compounds on oral stem cell-mediated dental, bone, and neural regeneration. It is observed that in recent years studies were mainly focused on the utilization of oral stem cell-mediated regeneration of bone or dental mesenchymal cells, however, the utility of bioactive compounds on oral stem cell-mediated regeneration requires additional assessment beyond in vitro and in vivo studies, and requires more randomized clinical trials and case studies.
  11. Tai MS, Viswanathan S, Rahmat K, Nor HM, Kadir KA, Goh KJ, et al.
    Sci Rep, 2016 12 13;6:38802.
    PMID: 27958312 DOI: 10.1038/srep38802
    Tuberculous meningitis (TBM) causes significant morbidity and mortality. The primary objective was to re-examine the concept of "TB zone" and "ischaemic zone" in cerebral infarction in patients with tuberculous meningitis. The secondary objective was to evaluate cerebral infarction, vasculitis and vasospasm in tuberculous meningitis infections. Between 2009 and 2014, TBM patients were recruited. Neuroimaging was performed and findings of cerebral infarction, vasculitis and vasospasm were recorded. Infarcts were classified based on arterial supply and Hsieh's classification. Fifty-one TBM patients were recruited of whom 34 patients (67%) had cerebral infarction. Based on Hsieh's classification, 20 patients (59%) had infarcts in both "TB zone" and "ischaemic zones". 12 patients (35%) had infarcts in "ischaemic zone" and two (6%) patients had infarcts in "TB zone". In terms of vascular supply, almost all patients (35/36) had infarcts involving perforators and cortical branches. 25 patients (73%) and 14 patients (41%) had infarcts supplied by lateral lenticulostriate and medial lenticulostriate arteries respectively. 15 patients (37%) had vasculitis. Vasospasm was present in six patients (15%). 29 patients (85%) with cerebral infarction also had leptomeningeal enhancement (p = 0.002). In summary, infarcts involved mainly perforators and cortical branches, rather than "TB zone" versus "ischaemic zone".
  12. Botross NP, Riad AA, Viswanathan S, Nordin RB, Lock HN
    Scott Med J, 2014 May;59(2):e1-6.
    PMID: 24671628 DOI: 10.1177/0036933014529868
    Gaucher's disease is a lysosomal storage disorder caused by the deficiency of glucocerebrosidase. Gaucher's disease has three clinical types: non-neuronopathic (Type 1), Acute Neuropathic (Type 2) and chronic neuronopathic (Type 3). The chronic neuronopathic (Type 3) is characterised by a variety of disease variants with onset in childhood with hepatomegaly, skeletal lesions and later slow horizontal saccades, treatment-resistant generalised tonic-clonic and myoclonic seizures, dementia, progressive spasticity, cognitive deterioration, ataxia and death in the second or third decade of life.
  13. Krishnan D, Viswanathan S, Rose N, Benjamin HSN, Ong AM, Hiew FL
    BMC Neurol, 2021 Sep 21;21(1):366.
    PMID: 34548039 DOI: 10.1186/s12883-021-02394-3
    BACKGROUND: Spinal AVF (SAVF), a potentially treatable cause of myelopathy, remains a challenging diagnosis. Its rarity and non-specific imaging findings often result in misdiagnosis despite a high index of clinical suspicion. The classically described high T2 signal in the spinal cord or prominent vascular flow voids in the intradural space were not infrequently missed on initial imaging, only to be picked up at follow-up imaging after progression of symptoms. Additionally, small sized fistulas(
  14. Hiew FL, Thit WM, Alexander M, Thirugnanam U, Siritho S, Tan K, et al.
    J Cent Nerv Syst Dis, 2021;13:11795735211057314.
    PMID: 35173510 DOI: 10.1177/11795735211057314
    Therapeutic plasma exchange (TPE) is an effective and affordable treatment option in most parts of Southeast Asia (SEA). In 2018, the SEA TPE Consortium (SEATPEC) was established, consisting of regional neurologists working to improve outcome of various autoimmune neurological diseases. We proposed an immunotherapeutic guideline prioritizing TPE for this region. We reviewed disease burden, evidence-based treatment options, and major guidelines for common autoimmune neurological disorders seen in SEA. A modified treatment algorithm based on consensus agreement by key-opinion leaders was proposed. Autoimmune antibody diagnostic testing through collaboration with accredited laboratories was established. Choice of first-line immunotherapies (IVIg/corticosteroid/TPE) is based on available evidence, clinicians' experience, contraindications, local availability, and affordability. TPE could be chosen as first-line therapy for GBS, CIDP, MG (acute/short term), IgG, A paraproteinemic neuropathy, and NMDAR encephalitis. Treatment is stopped for acute monophasic conditions such as GBS and ADEM following satisfactory outcome. For chronic immune disorders, a therapy taper or long-term maintenance therapy is recommended depending on the defined clinical state. TPE as second-line treatment is indicated for IVIg or corticosteroids refractory cases of ADEM, NMOSD (acute), MG, and NMDAR/LGI1/CASPR2/Hashimoto's encephalitis. With better diagnosis, treatment initiation with TPE is a sustainable and effective immunotherapy for autoimmune neurological diseases in SEA.
  15. Hung SKY, Hiew FL, Viswanathan S, Puvanarajah S
    J Peripher Nerv Syst, 2018 Sep;23(3):183-189.
    PMID: 30027593 DOI: 10.1111/jns.12282
    Intravenous immunoglobulin (IVIG), corticosteroids and therapeutic plasma exchange (TPE) are evidence-based conventional treatments for chronic inflammatory demyelinating polyneuropathy (CIDP). In many centres, unconventional treatments are frequently used as alternatives. We evaluated the outcome of conventional and unconventional therapies in 31 CIDP patients. Overall response rate with conventional first-line immunotherapies was 77% (20/26), comparable between IVIG and corticosteroids (80% vs 70%). Use of TPE was limited. Treatment response among typical and atypical CIDP were comparable (76 vs 80%). Non-responders were patients with progressive form of typical CIDP and DADS. Majority (21/26, 81%) of patients with persistent neurological deficits received maintenance therapy. Two subgroups of patients frequently treated with maintenance immunosuppressants were those with improving or stable disease following first-line treatment (12, 57%) and those with progressive form of CIDP (2, 10%). Primary indications for immunosuppressant use were corticosteroids-sparing and additional immunosuppression effects. Nine (64%) patients with improving or stable disease given azathioprine were taken off corticosteroids after a median duration of 14 months (range 12-108). Two (14%) eventually achieved cure or clinical remission without treatment. Maintenance IVIg was given to 6 (29%) relapsing CIDP patients; none of achieved cure or remission after similar median duration of treatment. Less potent immunosuppressant drugs (azathioprine, mycophenolate mofetil, and methotrexate) were frequently used, with moderate adverse effect profiles. In resource limited setting, unconventional treatments were commonly used among CIDP patients with different clinical course of progression. In most cases, careful risk-benefit re-assessment is required to justify its further use.
  16. Pittock SJ, Berthele A, Fujihara K, Kim HJ, Levy M, Palace J, et al.
    N Engl J Med, 2019 08 15;381(7):614-625.
    PMID: 31050279 DOI: 10.1056/NEJMoa1900866
    BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing, autoimmune, inflammatory disorder that typically affects the optic nerves and spinal cord. At least two thirds of cases are associated with aquaporin-4 antibodies (AQP4-IgG) and complement-mediated damage to the central nervous system. In a previous small, open-label study involving patients with AQP4-IgG-positive disease, eculizumab, a terminal complement inhibitor, was shown to reduce the frequency of relapse.

    METHODS: In this randomized, double-blind, time-to-event trial, 143 adults were randomly assigned in a 2:1 ratio to receive either intravenous eculizumab (at a dose of 900 mg weekly for the first four doses starting on day 1, followed by 1200 mg every 2 weeks starting at week 4) or matched placebo. The continued use of stable-dose immunosuppressive therapy was permitted. The primary end point was the first adjudicated relapse. Secondary outcomes included the adjudicated annualized relapse rate, quality-of-life measures, and the score on the Expanded Disability Status Scale (EDSS), which ranges from 0 (no disability) to 10 (death).

    RESULTS: The trial was stopped after 23 of the 24 prespecified adjudicated relapses, given the uncertainty in estimating when the final event would occur. The mean (±SD) annualized relapse rate in the 24 months before enrollment was 1.99±0.94; 76% of the patients continued to receive their previous immunosuppressive therapy during the trial. Adjudicated relapses occurred in 3 of 96 patients (3%) in the eculizumab group and 20 of 47 (43%) in the placebo group (hazard ratio, 0.06; 95% confidence interval [CI], 0.02 to 0.20; P<0.001). The adjudicated annualized relapse rate was 0.02 in the eculizumab group and 0.35 in the placebo group (rate ratio, 0.04; 95% CI, 0.01 to 0.15; P<0.001). The mean change in the EDSS score was -0.18 in the eculizumab group and 0.12 in the placebo group (least-squares mean difference, -0.29; 95% CI, -0.59 to 0.01). Upper respiratory tract infections and headaches were more common in the eculizumab group. There was one death from pulmonary empyema in the eculizumab group.

    CONCLUSIONS: Among patients with AQP4-IgG-positive NMOSD, those who received eculizumab had a significantly lower risk of relapse than those who received placebo. There was no significant between-group difference in measures of disability progression. (Funded by Alexion Pharmaceuticals; PREVENT ClinicalTrials.gov number, NCT01892345; EudraCT number, 2013-001150-10.).

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