1.The spectrum of elderly myopathies in an Asian population
Shereen Ng ; Kum-Thong Wong ; Khean-Jin Goh
Neurology Asia 2013;18(2):177-181
Myopathies, although presenting more commonly in the younger age group, can occur and contribute
signifi cantly to disability in the elderly. To describe the spectrum of elderly myopathies, we reviewed
52 elderly patients (> 65 years) from the University of Malaya Medical Centre muscle biopsy databank,
constituting 6.8% of 759 adult patients (> 18 years) who underwent muscle biopsy between 1992 and 2012.
Commonest were the infl ammatory myopathies (41/52, 78.8%), of which 43.9% had dermatomyositis;
23.9% polymyositis; 14.6% sporadic inclusion body myositis; 9.8% undifferentiated myositis and 2.4%
overlap myositis. Seven patients (13.4%) had genetic myopathy; 2 muscular dystrophy and 5 chronic
progressive external ophthalmoplegia, while 4 patients (7.7%) had drug-associated myopathy, 3 with
statins. Malignancies were seen in 9.8% of infl ammatory myopathies at diagnosis. Both acquired and
genetic myopathies are seen in elderly Malaysians of all ethnicities and should not be misdiagnosed
as some are potentially treatable and/or associated with malignancy.
2.Single mitochondrial DNA deletions in chronic progressive external ophthalmoplegia (CPEO) and Kearns-Sayre syndrome (KSS) patients from a multiethnic Asian population
Jia-Woei Chong ; Azlina Ahmad Annuar ; Kum-Thong Wong ; Meow-Keong Thong ; Khean-Jin Goh
Neurology Asia 2014;19(1):27-36
Mitochondrial DNA (mtDNA) deletions are a major cause of chronic progressive external ophthalmoplegia
(CPEO) and Kearns-Sayre syndrome (KSS). We analyzed single mtDNA deletions in 11 CPEO and
one KSS patients by means of Southern blot and long polymerase chain reaction (PCR) assays. The
deletion sizes ranged from 3.4 kb to 6.9 kb whereas the heteroplasmy level varied from 18.8% to
85.5%. Two unique deletions sized 4320 bp and 4717 bp were found. This study represents the first
genetic screen of mtDNA disorders in Malaysia, and it follows the data seen in other published reports
on CPEO and KSS genetic aetiology.
3.Cold allodynia as the presenting symptom in a case of acquired neuromyotonia (Isaacs syndrome) with multiple autoantibodies
Khean-Jin Goh ; Suhailah Abdullah ; Won Fen Wong ; Swan-Sim Yeap ; Nortina Shahrizaila ; Chong-Tin Tan
Neurology Asia 2014;19(4):409-412
We report a patient who presented with severe cold-induced allodynia and hyperhidrosis, and found to
have acquired neuromyotonia (Isaacs syndrome) with high voltage-gated potassium channel (VGKC)
antibody titre,positive contactin-associated protein 2 (CASPR2) and leucine-rich glioma-inactivated
1 (LGI1) antibodies. The patient also had positive anti-dsDNA and acetylcholine receptor (AChR)
antibodies without clinical features of SLE or myasthenia gravis, suggesting a strong underlying
autoimmune tendency. CT thorax showed no thymoma. Her symptoms improved with intravenous
immunoglobulin infusion but recurred despite maintenance oral corticosteroids and carbamazepine.
She has since been on regular IVIG infusions. Cold allodynia is an unusual presentation in acquired
neuromyotonia.
4.MRI findings of orbicularis oculi hypertrophy due to heavy resistance training on the inferior orbital rim
Hasyma Abu Hassan ; Norlisah Mohd Ramli ; Kenneth CS Fong ; Khean-Jin Goh
Neurology Asia 2013;18(4):427-429
Increase in cross-sectional muscle area of major muscle groups associated by heavy resistance training
has been well documented. However, there has been no published article of changes in the inferior
orbicularis oculi muscle when heavy resistance training is applied. We present a case of inferior
orbicularis hypertrophy detected on MRI in a gentleman who practised heavy resistance training
using his lower eyelids.
5.Late-onset Nipah virus encephalitis 11 years after the initial outbreak: A case report
Suhailah Abdullah ; Li-Yen Chang ; Kartini Rahmat ; Khean Jin Goh ; Chong Tin Tan
Neurology Asia 2012;17(1):71-74
Nipah virus infection is known to cause late-onset and relapsed encephalitis, in addition to an acute
encephalitic illness. This is a report of a 35 years old woman, who had exposure to the Nipah virus
infection during the 1999 Malaysian outbreak, was positive for Nipah IgG by immunofl uorescence, and
had multiple small hyperintense lesions in brain MRI typically seen in acute Nipah encephalitis patients,
indicating asymptomatic Nipah virus infection. She subsequently developed acute encephalitis after
11 years, manifesting as diplopia, internuclear opthalmoplegia and epileptic seizures with pleocytosis
in cerebrospinal fl uid examination. She had another episode of relapsed encephalitis a year later, with
seizures, memory impairment, chorea and new lesions in MRI brain. This patient is unusual in the
long incubation of 11 years before manifesting with late-onset Nipah encephalitis.
6.Ultrasonography in the evaluation of carpal tunnel syndrome: Diagnostic criteria and comparison with nerve conduction studies
Kok-Yu Chan ; John George ; Khean-Jin Goh ; Tunku Sara Ahmad
Neurology Asia 2011;16(1):57-64
Ultrasound criteria for carpal tunnel syndrome (CTS) may vary in different populations. To determine
the ultrasonographic criteria for CTS in a Malaysian population and compare its usefulness with nerve
conduction studies (NCS), we studied patients clinically diagnosed with CTS and normal controls
by ultrasonography. All patients also underwent standard NCS. Median nerve Cross-Sectional Area
(CSA) and Flattening Ratio (FR) at 3 different levels – proximal to tunnel inlet, at tunnel inlet and
tunnel outlet were measured. Receiver operator characteristic (ROC) analyses were used to calculate
the optimal discriminatory threshold values for CTS. Of 54 CTS hands, NCS was positive in 85.2%.
Median nerve CSA at all 3 levels, were signifi cantly greater in CTS hands.FR was signifi cantly
greater at tunnel inlet. A CSA threshold of 0.1 cm2
proximal to and at tunnel inlet had sensitivities
of 70.4% and 63% and specifi cities of 85.2% and 88.5 % respectively. CSA at tunnel outlet had
lower specifi city. If CSA of 2 levels (viz. proximal to or at tunnel inlet) were considered together,
sensitivity and specifi city improved to 81.5% and 83.3%. Qualitative loss of fascicular discrimination
of the nerve proximal to the inlet had sensitivity and specifi city of 77.8% and 96.3%. The most useful
ultrasonographic parameter was median nerve CSA either proximal to or at tunnel inlet. However,
the sensitivities were lower compared to NCS. Qualitative appearance of the median nerve is a useful
adjunct to diagnosis. In conclusion, ultrasonography play an important complementary role to NCS
in the diagnosis of CTS.
7.Persistent effect on neuromuscular transmission in patients with primary hemifacial spasm treated with repeated botulinum toxin injections
Khean-Jin Goh ; Chiu-Wan Ng ; Letchumy P Ramanaidu ; Mohamed Azly Yahya ; Chong-Tin Tan
Neurology Asia 2009;14(2):115-119
Botulinum toxin injection is an effective treatment for hemifacial spasm by causing pre-synaptic
block at the neuromuscular junction. Its effects are temporary and repeated injections are required
to maintain benefi t. Mild, permanent facial weakness is often thought to be due to prolonged nerve
compression. To investigate the possibility of a chronic and persistent effect of botulinum toxin on
neuromuscular transmission, we carried out stimulated single-fi bre electromyography to compare
jitter of the affected orbicularis oculi in previously treated and treatment naïve hemifacial spasm
patients. Previously treated patients were studied when the acute effects of the last botulinum toxin
injection had worn off. We found mean jitter was signifi cantly higher in previously treated patients.
Although, treated patients had longer duration of hemifacial spasm, mean jitter was dependent only
on the number of previous botulinum injections and independent of the duration of hemifacial spasm
and time from the last injection. This suggests a persistent and cumulative effect of botulinum toxin
on neuromuscular transmission in patients treated for hemifacial spasm.
8.Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis: A series of ten cases from a university hospital in Malaysia
Suhailah Abdullah ; Shen-Yang Lim ; Khean Jin Goh ; Lucy CS Lum ; Chong Tin Tan
Neurology Asia 2011;16(3):241-246
Objective: To report on the incidence, and the clinical and laboratory features of patients seen at the
University of Malaya Medical Centre with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis.
Methods: The charts of all patients admitted to the adult neurology ward with encephalitis over an 18-
month period from January 2010 to June 2011 were reviewed. Diagnosis of anti-NMDAR encephalitis
was based on the presence of encephalitis plus antibody against the NMDAR. Two other paediatric
patients with anti-NMDAR encephalitis seen over the same period were also included in this report.
Results: There was a total of 10 patients with anti-NMDAR encephalitis seen over the study period.
The mean age was 18.1 years (range 9-29 years). Eight patients were female, two male. Five were
Malay and fi ve were Chinese. All patients had prominent psychiatric symptoms, followed by epileptic
seizures. Nine patients had a movement disorder, orofacial dyskinesia being the commonest, and all
had autonomic involvement. None had an underlying tumour. Treatments consisted of corticosteroid,
plasma exchange and intravenous immunoglobulin (IVIG). The clinical outcome was variable, with
full recovery (2), substantial recovery (3), partial recovery (4), and mortality (1) seen. Remarkably,
the eight adult cases of anti-NMDAR encephalitis accounted for 50% of the 16 cases of encephalitis
seen during the study period.
Conclusion: Anti-NMDAR encephalitis may be a relatively common cause of adult encephalitis among
certain Asian groups. None of our cases was paraneoplastic in origin.
9.Karaoke, power failure and carbon monoxide poisoning
Chiun-Hian Chai ; Shen-Yang Lim ; Khairul Azmi Abdul Kadir ; Khean-Jin Goh ; Chong-Tin Tan
Neurology Asia 2011;16(3):255-257
Accidental carbon monoxide poisoning in countries with cold climates is commonly related to indoor
heating. This condition appears to be relatively uncommon in tropical Asian countries and therefore
the diagnosis may be unsuspected. We report a case of a Malaysian patient who presented with a
severe, and ultimately fatal, delayed (biphasic) neuropsychiatric syndrome due to carbon monoxide
poisoning. The diagnosis was made only when a history compatible with carbon monoxide poisoning
subsequently surfaced, and neuroimaging demonstrated the typical pallidal lesions, associated with
marked leukoencephalopathy, seen in this condition. Our case is unique because the poisoning occurred
in the setting of indoor operation of a portable electricity generator in a karaoke centre because of
power failure. Karaoke is a highly popular form of entertainment in many parts of Asia and we suggest
that a high index of suspicion of carbon monoxide poisoning is required in this setting.
10.The frequency of common mitochondrial DNA mutations in a cohort of Malaysian patients with specifi c mitochondrial encephalomyopathy syndromes
Jia-Woei Chong ; Azlina Ahmad Annuar ; Kum-Thong Wong ; MeowKeong Thong ; Khean-Jin Goh
Neurology Asia 2011;16(4):321-327
A cohort of Malaysian patients with clinico-pathological diagnosis of three specifi c mitochondrial
encephalomyopathy syndromes comprising of mitochondrial encephalomyopathy, lactic acidosis
and stroke-like episodes (MELAS), myoclonus epilepsy with ragged-red fi bers (MERRF) and Leigh
syndrome were studied to determine the frequency of their common mitochondrial DNA mutations. The
‘hot-spot’ point mutations for MELAS, MERRF and Leigh syndrome were screened. In the absence
of common point mutations, screening of large-scale deletions as well as sequencing of tRNALeu and
tRNALys genes were performed. Of 22 patients studied, nine m.3243A>G mutations, four m.8344A>G
mutations, one m.8993T>G mutation and one deletion were identifi ed (65% detection rate). While the
m.3243A>G mutation was closely associated with MELAS, the m.8344A>G was more heterogenous,
being seen in one MERFF, two isolated mitochondrial myopathies and one Leigh syndrome patient.
Screening for m.8993T>G in Leigh syndrome has a low yield as unsurprisingly Leigh syndrome has
considerable genetic heterogeneity.