Original Article

YK Lim, TYT Tan, R Zuzarte, ML Daniel, GSH Yeo
Correspondence: Dr Tony Tan, tonytan@kkh.com.sg

ABSTRACT
Introduction To determine the perinatal outcomes of monochorionic (MC) pregnancies complicated by the twin-twin transfusion syndrome (TTTS) that were managed in a specialised twin clinic at the KK Women's and Children's Hospital.
Methods This was a 21-month retrospective study carried out from January 2002 to September 2003. MC pregnancies were followed up every two to three weeks with regular ultrasonographical and Doppler studies from the time monochorionicity was diagnosed. Standard criteria used for the diagnosis of TTTS are the presence of oligohydramnios/polyhydramnios sequence on ultrasonography. The severity of TTTS was staged according to Quintero's system.
Results There were 77 sets of MC pregnancies in our database. 11 sets were diagnosed with TTTS, hence the incidence was 14.3 percent. The median gestation at diagnosis of TTTS was 17.4 (16.4 to 26) weeks. At first presentation, five were stage I, two were stage II, three were stage III and one was stage IV. Three pregnancies were terminated in the second trimester and one was lost to follow-up. Of the other seven, two were treated expectantly or delivered, four with amnioreduction/ septostomy and one with cord occlusion. The median gestation at delivery is 30.8 (26.7 to 36.9) weeks. Four (57 percent) were delivered before 32 weeks and these same four pairs required neonatal intensive care. The overall perinatal survival was 78 percent (11/14) and the median diagnosis to delivery interval was 10.7 (3.1 to 17.5) weeks.
Conclusion TTTS occurs in a significant proportion of MC pregnancies. The perinatal survival outcome of this group of patients managed in this clinic is comparable to that of other good centres.

Keywords: monochorionic pregnancy, perinatal outcomes, perinatal survival, twin-twin transfusion syndrome, ultrasonography
Singapore Med J 2005; 46(8): 401-406

W Liu, CC Loo, JW Chiu, HM Tan, HZ Ren, Y Lim
Correspondence: Dr Yvonne Lim, yve16@hotmail.com

ABSTRACT
Introduction Etoricoxib is a second generation cyclooxygenase-2 inhibitor with a rapid-onset time and a long duration of action. It is ideal for providing pre-emptive analgesia for ambulatory surgeries. We hypothesised that pre-operative etoricoxib can decrease the use of fentanyl post-operatively, when compared with placebo in patients undergoing termination of pregnancy. We also compared their pain scores, time to discharge, side effects and satisfaction with analgesia post-operatively.
Methods After approval by the hospital research ethics committee and receipt of informed written consent, we recruited 40 American Society of Anesthesiologists Physical Status Classification I and II patients scheduled for elective first trimester termination of pregnancy. Patients were randomly allocated to receive either oral etoricoxib 120 mg (Group E, n=20) or placebo tablet (Group P, n=20) pre-operatively. A blinded observer evaluated the post-operative pain scores, need for supplementary analgesia, side effects and satisfaction scores. Sample size was calculated (power of 0.8 and alpha=0.05) to detect a 20 percent difference in fentanyl usage. Amount of fentanyl used, pain scores and satisfaction scores were analysed using non-parametric tests. The incidence of side effects was analysed using chi-squared test.
Results Etoricoxib 120 mg significantly decreased the amount of fentanyl required after termination of pregnancy compared to placebo (0 microg/patient, interquartile range [IQR] 0-25 versus 50 microg/patient, IQR 0-50, p-value is less than 0.05). Patients who received etoricoxib 120 mg also had significantly lower pain scores than the placebo group at time of discharge (8 +/- 11 versus 1 +/- 3, p-value is less than 0.05) and at six hours post operation (8 +/- 12 versus 0 +/- 0, p-value is less than 0.01). There was no difference in their side effects, and time to discharge and overall satisfaction were similar in both groups.
Conclusion Pre-operative administration of oral etoricoxib 120 mg decreased the use of fentanyl and pain scores after minor gynaecological surgery without significant side effects.

Keywords: ambulatory surgical procedures, analgesia, cyclooxygenase inhibitors, etoricoxib, non-steroidal anti-inflammatory drugs
Singapore Med J 2005; 46(8): 397-400

Y Lim, S Jha, AT Sia, N Rawal
Correspondence: Dr Yvonne Lim, yvel6@hotmail.com

ABSTRACT
Introduction Good analgesia is important after a caesarean section but there are no studies to date that compared intrathecal (IT), epidural (EP) and intravenous patient-controlled analgesia (IV PCA) morphine for post-caesarean section analgesia. In this study, we compared the differences in the quality of analgesia and side effects rendered by IT, EP and IV PCA morphine for post-caesarean section analgesia.
Methods We systematically collected and reviewed the data of 949 women who received IT, EP or IV PCA morphine for post-caesarean analgesia during a six-month period. We reviewed the patients 24 hours after surgery and recorded the type of analgesia, the use of adjuncts, pain scores, side effects and degree of satisfaction with the mode of analgesia. The data was captured in an electronic database and analysed.
Results IT morphine was the predominant method of post-caesarean analgesia, accounting for 89.5 percent of the cases. Non-steroidal anti-inflammatory drugs (NSAIDs) were more commonly used in the IT and EP group (IT 76 percent, EP 80 percent and IV PCA 49 percent, p-value is less than 0.05). IT morphine group had a significantly lower pain score at rest (p-value is less than 0.001) and on movement (p-value is less than 0.05) when compared with IV PCA group. EP morphine also resulted in a lower pain score than IV PCA on movement (p-value is less than 0.05). There was no difference in pain scores between EP and IT morphine. In the subgroup analysis of patients who did not receive NSAIDs, IT and EP morphine group also registered lower pain scores at rest and on movement than IV PCA group (p-value is less than 0.05). There was no difference in the satisfaction scores among the three groups.
Conclusion The use of IT and EP morphine was associated with lower pain scores than IV PCA morphine at rest and on movement in the first 24 hours after caesarean section. No severe side effects were found.

Keywords: caesarean section, epidural anaesthesia, morphine, patient-controlled analgesia, spinal anaesthesia
Singapore Med J 2005; 46(8): 392-396

NY Boo, S Selvarani
Correspondence: Professor Nem Yun Boo, nyboo@imu.edu.my

ABSTRACT
Introduction This study aimed to determine the proportions of normothermic infants who remained normothermic, and hypothermic infants who became normothermic following the use of a heated water-filled mattress (HWM) in the labour room.
Methods A prospective observational study carried out in the labour room over a 2.5 month period on 228 well term infants delivered by lower segment caesarean section (LSCS) in the operating theatre (environmental temperature 18 degrees Celsius). Upon arrival in the labour room, the infants were placed on a HWM in a nursing cot. The axillary temperature was measured using a mercury thermometer for three minutes. Each infant was then wrapped with a large piece of linen, and covered with a blanket. Just before transfer to postnatal wards, the axillary temperature was re-measured.
Results 52.2 percent (119/228) of infants were hypothermic (temperature less than 36.5 degrees Celsius) upon arrival in the labour room. Before leaving the labour room, the median increase in axillary temperature of the initially hypothermic infants was significantly higher (0.2 degrees Celsius, interquartile range 0.5) than those initially normothermic infants (0.0 degrees Celsius, interquartile range 0.3) (p-value is less than 0.00001). Among the initially hypothermic infants, 40.3 percent (48/119) became normothermic before transfer to postnatal wards. The significant independent risk factors associated with persistent hypothermia were lower birthweight (p-value equals 0.02), lower gestational age (p-value equals 0.02) and shorter duration on the warming mattress (p-value equals 0.08). Among 109 initially normothermic infants, 17.4 percent became mildly hypothermic (mean axillary temperature 36.2 degrees Celsius, standard deviation 0.2) before leaving the labour room.
Conclusion The HWM is a reasonably effective simple device for the prevention and treatment of hypothermia in the labour room.

Keywords: heated water-filled mattress, labour room, neonatal disorders, neonatal hypothermia
Singapore Med J 2005; 46(8): 387-391

MK Thong, TL Soo
Correspondence: Dr Thong Meow Keong, thongmk@um.edu.my

ABSTRACT
Introduction Beta-thalassaemia major is one of the commonest genetic disorders in South East Asia. The strategy for the community control of beta-thalassaemia major requires the characterisation of the spectrum of beta-globin gene mutations in any multi-ethnic population. There is only a single report of mutation analyses of the beta-globin gene in an isolated Kadazandusun community in Kota Belud, Sabah, Malaysia, which showed the presence of a common 45 kb deletion.
Methods To confirm the observation that this large deletion is the commonest beta-globin gene mutation among the Kadazandusun and other indigenous populations in Sabah, Malaysia, we performed polymerase chain reaction (PCR) analysis of the beta-globin gene in ten children with beta-thalassaemia major attending the Thalassaemia Centre, Queen Elizabeth Hospital, the major paediatric referral centre in Kota Kinabalu, Sabah.
Results The 45 kb deletion was confirmed to be the commonest mutation found in the Kadazandusun, Bajau and Murut populations, whereby it was detected in 19 out of the 20 (95 percent) alleles analysed. The other mutation was due to an IVS-1 position 1 G > T mutation.
Conclusion This finding confirmed the deletion in the homozygous state was associated with a severe phenotype. The reason for the predominance of this mutation in Kota Kinabalu is most likely to be due to founder effects and possibly intermarriages between the various ethnic groups. Prenatal diagnosis using PCR for this common mutation is feasible in this community. Medical workers and scientists at molecular diagnostic centres serving large South East Asian populations should incorporate a diagnostic strategy for this deletion in the appropriate population. Future studies on these indigenous ethnic groups in other areas and other groups in Sabah are required.

Keywords: beta-thalassaemia, gene deletion, genetic disorder, mutation, thalassaemia
Singapore Med J 2005; 46(7): 340-343

NC Tan, SL Cheah
Correspondence: Dr Ngiap-Chuan Tan, Tan.Ngiap.Chuan@singhealth.com.sg

ABSTRACT
Introduction Asymptomatic chronic hepatitis B virus (HBV) carriers, followed-up in primary care, present a challenge to primary care physicians as they encounter problems in monitoring this group of patients. The study aims to explore the barriers faced by primary care physicians in the management of patients with chronic hepatitis B infection in primary care.
Methods Qualitative analysis of eight focus group discussions with 43 primary care physicians in Singapore was conducted.
Results Primary care physicians highlighted the HBV carriers' poor compliance to disease monitoring as a major hurdle, attributing to their lack of understanding of the disease, state of denial, fear of stigmatisation in society, failure to perceive benefits, costs and reluctance of investigations due to physical discomfort. The carriers' health-seeking behaviour, such as doctor hopping and the use of traditional medication, were other barriers. The investigators noted that the physicians placed emphasis on passive disease monitoring, focusing on the investigation results when they reviewed the carriers. They were less proactive in explaining the disease's natural history nor discussing the possibility of definitive anti-viral treatment for suitable carriers. These physicians varied in their approaches in disease monitoring of chronic HBV infection. The fees-for-service healthcare system allowed the carrier to seek consultation from different doctors, which could result in disruption of disease surveillance. This was further compounded by the differential cost of investigations in private practices and government-aided polyclinics. The absence of a national HBV registry and recall system and waiting time for referral to specialist clinics in restructured hospitals, were other barriers.
Conclusion The management of HBV carriers in primary care could be enhanced by measures that eliminate the barriers involving the patient, doctor and healthcare system.

Keywords: chronic hepatitis B infection, hepatitis, primary care physicians
Singapore Med J 2005; 46(7): 333-339

W Lee, CL Ong, CCL Chong, WS Hwang
Correspondence: Dr Wickly Lee, wickly_lee@nni.com.sg

ABSTRACT
Introduction Omental infarction is a rare occurrence in the paediatric population. It often presents as an acute abdomen that can mimic acute appendicitis and cholecystitis.
Methods Six cases of omental infarction in children, proven on histopathology, were retrospectively reviewed for their clinical presentation and imaging findings on ultrasonography and computed tomography.
Results These cases revealed clinical and imaging findings on computed tomography that were suggestive and helpful in the pre-operative diagnosis of omental infarction. Findings on ultrasonography were less specific. Histopathological specimens revealed findings of vasculitis in all cases.
Conclusion There are clinical and imaging features that will help in the pre-operative diagnosis of this uncommon condition. We also postulate vasculitis as a possible underlying pathology for omental infarction.

Keywords: acute abdomen, computed tomography, omental infarction, ultrasonography, vasculitis
Singapore Med J 2005; 46(7): 328-332

A Eisenman, V Rusetski, D Avital, J Stolero, T Snitkovsky
Correspondence: Dr Arie Eisenman, eisenman@naharia.health.gov.il

ABSTRACT
Introduction Cardiac-specific troponins (cTn) are recently-introduced, sensitive and specific markers of myocardial injury, and their absence should allow to safely exclude a coronary event. Various assays are commercially available but the relative advantage of each is not clear. Our objective was to compare the reliability of the two most commonly used troponin assays (cTnI and cTnT), in the emergency department (ED) for clinical decision when myocardial infarction (MI) or acute coronary syndrome (ACS) is suspected.
Methods This prospective study included all patients arriving at the ED over a six-month period with chest pain or symptoms suggesting MI or ACS, in which diagnosis could not be confirmed due to absence of characteristic ECG features. All patients were tested with at least one of the two troponin assays available at the ED.
Results Of the 54 included patients, ten (19%) were eventually diagnosed with MI/ACS. Qualitative assays for cTnI and cTnT identified the MI/ACS patients by both assays (respective positive predictive values of 0.5 and 0.7, and negative predictive values of 1.0 and 0.9). However, these assays were only partially correlated (R equals 0.49) and differed significantly. The quantitative assay for cTnI, but not for cTnT, discerned those who had MI/ACS (group A) from those who had other condition (group B) by their troponin levels (MI/ACS - 17.2 plus or minus 23.8 ng/ml versus others - 0.37 plus or minus 0.91 ng/ml, p is less than 0.001).
Conclusion In the ED, bedside assays of troponins are invaluable tools for the clinician, and their use is cost-effective. However, in the recommended cutoffs levels, only troponin I but not troponin T allowed the safe discharge of patients not requiring acute hospital care.

Keywords: acute coronary syndrome, myocardial infarction, troponin I, troponin T
Singapore Med J 2005; 46(7): 325-327

M Mahboob, MF Rahman, P Grover
Correspondence: Dr Mohammed Mahboob, mahboob@ins.iictnet.com

ABSTRACT
Introduction The depletion of defensive body chemicals called antioxidants may increase the risk of complications from the most common form of diabetes mellitus. This study aims to evaluate blood serum lipid peroxidation product (malondialdehyde), an antioxidant, in non-insulin dependent male and female type 2 diabetic patients.
Methods Blood serum samples were collected from the diabetic patients and non-diabetic healthy controls. Malondialdehyde (MDA) level, which is an index of endogenous lipid peroxidation, reduced glutathione and protein content of the serum were estimated.
Results A significant elevation in MDA level and decrease in glutathione and protein content was observed in both male and female diabetic patients in comparison to non-diabetic controls.
Conclusion Our findings indicate that the increase in the lipid peroxidation product MDA and decline in glutathione-dependent antioxidant defences may appear early in non-insulin dependent type 2 diabetes mellitus patients before the development of secondary complications.

Keywords: antioxidant, diabetes mellitus, malondialdehyde, non-insulin dependent type 2 diabetes mellitus, oxidative stress
Singapore Med J 2005; 46(7): 322-324

SC Ong, DCE Ng, FX Sundram
Correspondence: Dr Seng Chuan Ong, gnmosc@sgh.com.sg

ABSTRACT
Introduction This study aims to examine the usefulness of fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in thyroid carcinoma patients with elevated serum thyroglobulin (Tg) but negative iodine-131 (I-131) whole body scans.
Methods 17 patients with differentiated thyroid carcinoma who underwent FDG PET/CT scans were reviewed retrospectively over a period of one year from July 2003 to June 2004. All these patients had completion thyroidectomy and subsequently presented with elevated serum Tg but negative post-therapy I-131 whole body scans. Nine of these patients underwent FDG PET/CT in a hypothyroid state, while the remainder underwent FDG PET/CT while on thyroxine replacement.
Results 15 out of 17 PET/CT scans revealed lesions consistent with metastases, giving a sensitivity of 88.2 percent. Four of these patients were amendable to surgical treatment. Two scans were negative.
Conclusion FDG PET/CT is a sensitive diagnostic tool to detect radioiodine-negative recurrences/metastases in patients with thyroid carcinoma. Our preliminary results are comparable with published results based on PET.

Keywords: computed tomography, fluorine-18-fluorodeoxyglucose, positron emission tomography, thyroglobulin, thyroid cancer
Singapore Med J 2005; 46(6): 297-301