Displaying publications 1 - 20 of 24 in total

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  1. Viswanathan S, Hiew FL
    J Clin Apher, 2019 Aug;34(4):434-444.
    PMID: 30829434 DOI: 10.1002/jca.21696
    There has been an increase in the use of therapeutic plasma exchange (TPE) in immune-mediated neurological disorders in recent years. However, accessibility and availability of TPE remains low and costly, especially for a country with limited healthcare funding like Malaysia. With expanding clinical indications in neurological disorders, and increasingly expensive conventional immunomodulatory treatment such as intravenous immunoglobulin and monoclonal antibodies, TPE remains an effective part of first or second-line treatment. In this article, we detailed the historical aspects of the use of TPE in neurological disorders in Malaysia over the last four decades and discussed the challenges behind the establishment of the first in-house neurology-driven TPE service in the country. Local TPE database from a national neurology centre in Kuala Lumpur over the past 20 years was analyzed. We observed a remarkable three folds increase in the use of TPE at our center over the past 10 years (total 131 TPE treatments) compared to a decade prior, with expanding clinical indications predominantly for central nervous system demyelinating disorders. Besides using membrane filtration method, centrifugal technique was adopted, providing new opportunities for other clinical beneficiaries such as a neurologist driven "in-house TPE unit". However, there were real world challenges, especially having to provide services with limited funding, human resources, and space. In addition, much has to be done to improve accessibility, availability, and sustainability of TPE services at our center and nationwide. Nevertheless, even with limited resources and support, it is possible with concerted efforts to work within the confines of these limitations to establish a safe, successful, and sustainable TPE service.
  2. Fu KS, Wong PY, Hiew FL
    BMJ Neurol Open, 2020;2(1):e000020.
    PMID: 33681775 DOI: 10.1136/bmjno-2019-000020
    Introduction: Therapeutic plasma exchange (TPE) for semi-critical neurological manifestations can be managed in non-acute setting instead of critical care unit. In 2014, we established a non-acute neurology TPE unit for semi-critical haemodynamically stable patients. In this study, we aimed to evaluate the technical and safety parameters from the first 3 years of service.

    Materials and methods: We analysed prospectively collected TPE data for patients treated with centrifugation TPE at our non-acute neurology TPE unit in Kuala Lumpur Hospital between May 2015 and June 2018.

    Results: A total of 245 TPE procedures were performed in 55 patients for nine neurological indications, predominantly the central nervous system (79%). Twenty four per cent (n=13) had category I and 73% (n=40) had category II indication (American Society for Apheresis (ASFA) 2019). Others (4%) were not in ASFA indications. Neuromyelitis optica spectrum disorders accounted for half (51%) of the total patients. Twenty-three (41.8%) patients experienced adverse events, with hypotensive episodes being the the most common (n=12/55, 21.8%). Five (9.1%) patients had catheter-related blood stream infection, correlating with higher exchange plasma volume (p=0.023). Symptomatic hypocalcaemia was less common (n=5/55, 9.1%) and allergic reaction to human albumin was rare (n=1/55, 1.8%). Four technical errors detected. Three involved centrifugation sets manufacturing defects and one involved error in centrifugation set installation. Seven (2.9%) procedures were terminated: 5 for adverse effects and 2 for technical errors.

    Conclusion: Performing TPE among semi-critical patients with neurology manifestations in basic non-acute set-up proved safe, with predictable complications. This set-up reduced the reliance on critical care services for TPE procedures.

  3. Tan JSH, Lee S, Hiew FL
    eNeurologicalSci, 2021 Mar;22:100321.
    PMID: 33553704 DOI: 10.1016/j.ensci.2021.100321
    Amyotrophic lateral sclerosis (ALS) is characterized by progressive onset motor deficits with heterogenous presentations ranging from dysarthria to foot drop. Approximately 20% of the patients present with focal bulbar symptoms, in which some may remain restricted to bulbar region (isolated bulbar palsy), and the remaining eventually spreads to involve other body regions (classical ALS). Without accompanying upper and lower motor neurons signs elsewhere, differential diagnoses for isolated bulbar symptoms are extensive, include ALS variants as well as potentially treatable mimics. Therefore, it is important to take heed on every possible aetiology that may disrupt the hypoglossal nucleus, nerve, or lingual muscle itself. Herein, we illustrated a rare presentation of Group A basilar invagination, which mimicked bulbar-onset ALS.
  4. 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.
  5. Chia PK, Hung SKY, Hiew FL
    J Clin Neurosci, 2019 Nov;69:114-119.
    PMID: 31416736 DOI: 10.1016/j.jocn.2019.08.016
    We determined the clinical progression, disability and outcome of 11 Multifocal Motor Neuropathy (MMN) patients from Malaysia. Mean patient age was 46.8 (SD 13.3), with mean disease duration of 108.0 months (SD 80.2). All reported unilateral limb weakness at onset. At diagnosis, after mean 49.9 months (SD 73.5) delay, 7 (63.6%) had more than 2 limbs involvement. Nine (90%) of 10 patients received induction IVIg dose of 2.0 gm/kg responded, demonstrated improvement in MRCSS of > 2 points or mRS score of > 1 point. We observed 38.5% drop in IVIg dose to mean 1.12 gm/kg/month after 12 months of treatment, and a further 34.8% drop upon 24th month treatment to mean dose of 0.73 gm/kg/month. This was in parallel with initial improvement in MRCSS and mRS, observed among 88.9% and 77.8% of the patients, and later further improvement (33.3%) or stabilization (66.7%) of mRS score toward 2nd year. During the same period, 50% of patients reported deterioration in ONLS, 33.3% in grip strength and 16.7% in MMN-RODS. Beyond 36th month, average annual IVIg dose increased at 0.12 gm/kg/year (SD 0.09) or 11.2%, up to the 84th months. Despite that, progressive deterioration was observed in term of number of limbs involvement, definite motor conduction blocks on electrophysiology study, and both clinical as well as functional scores. Although IVIg dose reduction for maintenance treatment in MMN is recommended, careful clinical assessment is required to prevent under-treatment. Use of reliable and responsive modern outcome measures is important to quantify clinically relevant change to guide therapy.
  6. Viswanathan S, Schee JP, Omar MA, Hiew FL
    Ther Apher Dial, 2021 Aug;25(4):513-532.
    PMID: 33029928 DOI: 10.1111/1744-9987.13595
    Evidence on the benefits of intermittent therapeutic plasma exchange (TPE) as maintenance therapy in neuromyelitis optica spectrum disorder (NMOSD) is limited. This study explores the possible effectiveness of sequential intermittent therapeutic plasma exchange (SITPE), a novel TPE protocol in the management of adult NMOSD patients. Through retrospective review of medical records in Kuala Lumpur Hospital, Malaysia, NMOSD patients who underwent SITPE, namely, an induction phase of monthly cycle of TPE (1 cycle = five exchange sessions) for three cycles with or without a subsequent maintenance phase of three-monthly cycle of TPE for three cycles, were included in this controlled historical cohort study. We explored their serial improvements in Expanded Disability Status Scale (EDSS), limb power, visual acuity, and annualized relapse rate following SITPE initiation. Statistical significance was set at P 
  7. Hiew FL, Ramlan R, Viswanathan S, Puvanarajah S
    Clin Neurol Neurosurg, 2017 Jul;158:114-118.
    PMID: 28514704 DOI: 10.1016/j.clineuro.2017.05.006
    OBJECTIVES: This study aimed to evaluate the clinical and electrophysiological characteristics of various distinctive classical and localised Guillain-Barré syndrome (GBS) subtypes.

    PATIENTS AND METHODS: Clinical characteristics and electrophysiological data of sixty-one consecutive patients admitted between 2012 and 2015 were systematically analysed and reclassified according to the new GBS clinical classification. Neurophysiology was evaluated with Hadden et al.'s vs recently proposed Rajabally et al.'s criteria. Functional severity and clinical outcome of various GBS subtypes were ascertained.

    RESULTS: All patients initially identified as GBS or related disorders can be sub-classified into having classical GBS (41, 67%), classic Miller-Fisher Syndrome (MFS) (6, 10%), Pharyngeal-cervical-brachial (PCB) (3, 5%), paraparetic GBS (4, 7%), bifacial weakness with paresthesia (3, 5%), acute ophthalmoparesis (AO) (1, 2%) and overlap syndrome (3, 5%): one (2%) with GBS/Bickerstaff brainstem encephalitis overlap and 2 (3%) with GBS/MFS overlap. Greater proportion of axonal classical GBS (67% vs 55%, p=0.372) seen with Rajabally et al.'s criteria and a predominantly axonal form of paraparetic variant (75%) independent of electrodiagnostic criteria were more representative of Asian GBS cohort. Classical GBS patients had lowest admission and discharge Medical Research Council Sum Score (MRCSS), greater functional disability and longest length of in-patient stay. Twenty (20/21, 95%) patients who needed mechanical ventilation had classical GBS. Patients required repeated dose of intravenous immunoglobulin (5/6, 3%) or plasma exchange (4/4, 100%) more frequently had axonal form of classical GBS.

    CONCLUSION: Phenotype recognition based on new GBS clinical classification, supported by electrodiagnostic study permits more precise clinical subtypes determination and outcome prognostication.

  8. 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.
  9. Verghese A, Krishnan D, Chia YK, Querol L, Hiew FL
    J Cent Nerv Syst Dis, 2021;13:11795735211039913.
    PMID: 34899003 DOI: 10.1177/11795735211039913
    Optic nerve demyelination is one of the clinical features of combined central and peripheral demyelination (CCPD), an entity with heterogenous immunopathogenesis and clinical characteristics, overlapping between multiple sclerosis (MS) and chronic inflammatory demyelinating polyneuropathy (CIDP). Of interest, earlier studies among patients with CIDP prior to discovery of antibodies against paranodal protein neurofascin 155 (anti-NF 155) also reported optic nerve dysfunction. We aimed to evaluate optic nerve demyelination among anti-NF 155 CIDP patients. We studied 2 patients with anti-NF 155 CIDP using visual-evoked potentials (VEP) and optical coherence tomography (OCT). Both patients had distal acquired demyelinating symmetric (DADS) subtype CIDP. Other common features were prominent sensory ataxia, hand tremors, significantly elevated cerebral spinal fluid protein, high titre anti-NF 155 antibodies and poor response to corticosteroid and intravenous immunoglobulin (IVIg). No central nervous system neuroradiological abnormality detected. Both had normal visual acuity and colour vision, but one had subclinical right relative afferent pupillary defect (RAPD). VEP of both showed bilateral prolonged P100 latencies. OCT for patient with RAPD demonstrated moderate to severe retinal nerve fibre layer (RNFL) thinning. Identification of optic nerve demyelination among subclinical CIDP with anti-NF 155 antibodies expanded the spectrum of demyelination within the subset of CCPD.
  10. Hiew FL, Ong JJ, Viswanathan S, Puvanarajah S
    J Clin Neurosci, 2018 Apr;50:203-207.
    PMID: 29398193 DOI: 10.1016/j.jocn.2018.01.018
    Long-term outcome in Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) is very limited, especially from Asian countries. We aimed to determine the outcome of our cohort of CIDP patients and to define the relevant clinical, electrophysiological and laboratory determinants of disease activity, progression and treatment response. We retrospectively reviewed records of 23 CIDP patients attending our Neurology service at Kuala Lumpur Hospital, Malaysia between January 2000 and December 2016. We analysed data on neurological deficits, electrophysiological and laboratory parameters to determine diagnostic characteristics, correlation with disease activity and clinical outcomes following treatment. Included were 15 (65%) males and 8 (35%) females with a mean age of 42.7 years (SD 14.4). Mean duration of follow-up visit was 66 months (range 6-134 months). The cohort consists of 19 classical (sensory-motor) CIDP and 4 MADSAM. Large majority of patients (66%) had either stable active disease (CDAS 3, 44%) or were in remission (CDAS class 2, 22%) following treatment with standard immunotherapies (Intravenous Immunoglobulins, steroids or immunosuppressants). The proportion of CIDP patients in each CDAS class was comparable to published cohorts from North America and Europe. Medical Research Council (MRC) sum score was the only clinical score that differed across CDAS classes (p = .010) with significant inverse correlation (Spearman's rho -0.664, p = .001). In conclusion, treatment outcomes of our CIDP cohort was comparable to those of published series. Further studies with larger cohort of patients from other parts of Asia are important to determine the long-term outcome of this heterogenous disease in this region.
  11. Ahmad NS, Chan MY, Hiew FL, Sharif SA, Vijayasingham P, Thayaparan T, et al.
    Med J Malaysia, 2003 Oct;58(4):526-32.
    PMID: 15190628
    The cornerstone of asthma management is achieving adequate symptom control and patient education. We studied in our local population of asthmatic patients how well their symptoms were controlled with currently prescribed treatment and their insight into the disease and its management. Over a 6-month period, 93 asthmatics recruited from two local government health clinics and a state hospital were interviewed using a standard questionnaire. Patients were classified into 4 groups based on the treatment they were on according to Global Initiative for Asthma (GINA) treatment guidelines. The number of patients in Step 1 (rescue medication alone), Step 2 (1 controller medication), Step 3 (2 controller medications) and Step 4 (at least 3 controller medications) were 8, 39, 34 and 12, respectively. Except for day symptoms in Step 1 group, fewer than 50% achieved minimum day or night symptoms and no restriction of daily activities. Questions on patient insight were only available for 50 patients. Weather change (74%), air pollution (66%) and physical stress (46%) were the three highest ranked common asthma triggers. More than half correctly recognized the important symptoms of a serious asthma attack but fewer than 15% were familiar with the peak flow meter and its use or with the asthma self-management plan. Most patients perceived that their treatment had helped reduce disease severity and exacerbations. We conclude that symptom control and some aspect of patient education are still lacking in our local asthmatics.
    Study site: Hospital Tuanku Jaafar, Seremban, Negeri Sembilan; Klinik Kesihatan Seremban; Klinik Kesihatan Ampangan, Malaysia
  12. Lau YH, Mohd Unit H, Lee LP, Loh WK, Hiew FL
    Clin Neurophysiol Pract, 2020;5:112-117.
    PMID: 32613149 DOI: 10.1016/j.cnp.2020.05.001
    Objective: We detailed the electrophysiological patterns of peripheral nerve temporal dispersion across spectrum of POEMS syndrome and Castleman disease (CD).

    Methods: Compound muscle action potentials (CMAP) duration of 3 patients with POEMS syndrome and 2 with hyaline vascular type CD without clonal plasma cell dyscrasia were retrospectively analysed.

    Results: Median and ulnar nerves distal CMAP duration were prolonged in all patients irrespective of plasma cell dyscrasia or M protein. All lower limbs distal CMAP responses were absent. Greatest distal CMAP duration prolongation was observed in median nerves for POEMS syndrome (17.0 ms, 158% upper limit normal) and in ulnar nerves for CD (9.8 ms, 47% upper limit normal). Distal/proximal CMAP duration ratio of <0.7 were seen in 33% of median and ulnar nerves studied among POEMS syndrome. Among nerves with ratio >0.7, all had distal CMAP duration prolongation (Range 7%-158% of upper limit normal).

    Conclusions: Abnormal distal CMAP dispersion is not uncommon in POEMS syndrome and CD without clonal plasma cell dyscrasia or M protein. POEMS syndrome has greater distal CMAP duration in median and ulnar nerves, particularly in median nerve that can reach up to 150% of upper limit normal, compared to <50% in CD.

    Significance: Detailed electrophysiological analysis of distal CMAP duration may help in distinguishing POEMS syndrome and CD.

  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. Pinzon RT, Schellack N, Matawaran BJ, Tsang MW, Deerochanawong C, Hiew FL, et al.
    J Assoc Physicians India, 2023 Jul;71(7):11-12.
    PMID: 37449697 DOI: 10.59556/japi.71.0290
    INTRODUCTION: Peripheral neuropathy (PN) is an insidious disease that is often asymptomatic during the early stages but which can have a significant impact on quality of life at later stages when nerve damage occurs. There is currently no guidance on the use of neurotropic B vitamins (B1, B6, and B12) for the management of asymptomatic and symptomatic PN.

    OBJECTIVE: To provide guidance to primary care physicians on an integrated approach to managing PN with neurotropic B vitamins (B1, B6, and B12).

    MATERIALS AND METHODS: A multidisciplinary panel of eight experts participated in an iterative quasi-anonymous Delphi survey consisting of two rounds of questions and a virtual meeting. A literature review formed the basis of the survey questions. The first round included multiple select, qualitative, and Likert Scale questions; the subsequent round consisted of 2-point scale (agree or disagree) questions that sought to develop consensus-based statements refined from the first round and recommendations derived from discussions during the virtual expert panel meeting.

    RESULTS: Clinical recommendations for the use of neurotropic B vitamins (B1, B6, and B12) have been developed for the prevention of PN progression or to delay onset in patients at high risk of developing PN. Recommendations have also been provided for the assessment of PN etiology and considerations for the use of loading dose (high dose) and maintenance dose (lower dose) of these neurotropic B vitamins (B1, B6, and B12).

    CONCLUSION: These clinical recommendations provide an initial step towards formulating comprehensive guidelines for the early and long-term management of PN with neurotropic B vitamins (B1, B6, and B12) and move beyond addressing only neuropathic pain associated with the late stages of PN.

  15. Viswanathan S, Hung SKY, Goyal V, Apiwattanakul M, Thirugnanam UN, Abdullah S, et al.
    J Clin Apher, 2018 Oct;33(5):559-568.
    PMID: 29626354 DOI: 10.1002/jca.21630
    In December 2017, 79 delegates attended the 2nd regional plasmapheresis conference and workshop for Southeast Asia (SEA) on the immunomodulatory role of plasma exchange in central and peripheral nervous system disorders in Kuala Lumpur, Malaysia. This meeting featured 6 plenary lectures, interactive sessions dedicated for experience sharing, case presentations, and a practical session for paramedics. Clinical experts and researchers from 7 SEA countries and India shared experience and challenges in treating autoimmune neurological disorders. While the spectrum of diseases and neurology practice remained largely similar, there was great disparities in accessibility of therapeutic plasma exchange (TPE) within SEA countries and between urban or rural settings. Costs, human resources, and healthcare policies are common challenges in providing sustainable TPE services. Novel techniques and innovative ideas in performing TPE were explored. A working consortium comprising of key opinion leaders was proposed to improve standards of TPE and enhance future research.
  16. 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.
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