2005

PSD Yeo, L Pinheiro, P Tong, PL Lim, YY Sitoh
Correspondence: Dr Poh Shuan Daniel Yeo, daniel_yeo@ttsh.com.sg

ABSTRACT
Flaviviruses are among the most important emerging viruses known to man. Dengue is the most common flavivirus infection in Singapore, and is transmitted between humans by the Aedes mosquito. We report a 25-year-old man with dengue fever complicated by selective hippocampal involvement manifesting as amnesia. This has not been described in the literature previously. Dengue polymerase chain reaction and serology were positive. Magnetic resonance imaging of the brain showed bilateral hippocampal involvement.

Keywords: amnesia, dengue fever, encephalitis, hippocampus, neurological manifestation
Singapore Med J 2005; 46(11): 647-650

M Lim, HK Goh
Correspondence: Dr Hsin Kai Goh, hsin_kai_goh@ttsh.com.sg

ABSTRACT
We describe a 27-year-old man who developed prolonged myalgia and dark red-coloured urine following dengue virus infection. The patient was found to have raised serum creatine kinase levels, consistent with rhabdomyolysis. He was treated with intravenous hydration and recovered uneventfully. Despite dengue fever being endemic in Singapore and South-east Asia, this is the first case report of such complication in this region.

Keywords: Creatine kinase, dengue fever, myalgia, myositis, rhabdomyolysis
Singapore Med J 2005; 46(11): 645-646

KB Chua, IL Chua, IE Chua, KH Chua
Correspondence: Dr Chua Kaw Bing, chuakawbing@yahoo.com.sg

ABSTRACT
Introduction Dengue and dengue haemorrhagic fever are common and serious arboviral diseases endemic in a number of countries situated in both the tropical and subtropical belts.
Methods A prospective study was carried out to examine the environmental factors influencing the ovipositing behaviour of gravid female Aedes mosquitoes in a typical urbanised residential environment in Malaysia. This study reports the effect of the usual ultra-low volume fogging of insecticides carried out by public health officers on the collection of immature Aedes mosquitoes using ovitraps.
Results Throughout the study, no dead immature Aedes mosquitoes was noted in any of the ovitraps set up in all of the fogging and immediate post-fogging periods. The mean number of days of ovitrapping for immediate pre-fogging, fogging and post-fogging periods were 10.3, 10.1 and 10.4 days, respectively. There was no statistically significant difference in the mean duration of ovitrapping cycle among the immediate pre-fogging, fogging and immediate post-fogging periods. The total number of immature Aedes mosquitoes collected in the immediate post-fogging periods was more than the immediate pre-fogging periods, and both were more than the fogging periods. However, there was no statistically significant difference in the total number of immature Aedes mosquitoes collected at various periods. It was not unusual to find dead insects, spiders and even small animals collected in ovitraps or environment in the fogged locality within 48 hours of chemical fogging.
Conclusion In this study, the usual chemical fogging in natural environment was ineffective in breaking the reproductive lifecycle by eliminating gravid female Aedes mosquitoes.

Keywords: Aedes mosquitoes, chemical fogging, dengue fever, mosquitoes, ovitraps
Singapore Med J 2005; 46(11): 639-644

MA Khan, SF Mekan, Z Abbas, RA Smego, Jr
Correspondence: Dr M A Khan, mohammad.aslam@aku.edu

ABSTRACT
Introduction The precise incidence of concurrent malaria and enteric fever in most geographical areas is largely unknown, and no data on such an association exists in Asia. Because both malaria and enteric fever are hyperendemic in Pakistan, we sought to determine the frequency, epidemiology, and clinical and laboratory features of dual malaria and enteric fever in a tertiary care setting.
Methods We conducted a retrospective case-control study of 1,891 patients hospitalised with malaria over a ten-year period and identified 21 patients with concurrent culture-proven enteric fever.
Results Cases with dual infection had significantly more gastrointestinal symptoms at the time of admission, including nausea, vomiting, abdominal pain, and/or diarrhoea compared to matched control subjects with uncomplicated malaria (p-value is less than 0.006). Cases were more likely to have a continuous rather than intermittent fever (p-value is less than 0.0001), delayed defervescence in response to antimalarial treatment (p-value is less than 0.006), normal or low white blood cell counts (p-value is less than 0.04), relatively higher platelet counts among cases versus control (p-value is less than 0.05) and serum haemoglobin (p-value is less than 0.06), elevated alanine aminotransferase levels (p-value is less than 0.02), and a prolonged hospital stay (p-value is less than 0.03). The negative predictive values for gastrointestinal symptoms, continuous fever pattern and delayed defervescence were 80 percent, 72 percent and 74 percent, respectively.
Conclusion Patients with malaria who have marked gastrointestinal symptoms, continuous pattern of fever and persistence of fever for more than 24 hours after appropriate antimalarial therapy, should be investigated or empirically treated for concurrent enteric fever. The absence of the above clinical features in patients with uncomplicated malaria should reassure physicians that there is no concurrent typhoid fever.

Keywords: enteric fever, malaria, tropical infection, typhoid
Singapore Med J 2005; 46(11): 635-638

IH Garba, GA Ubom
Correspondence: Dr Ibrahim H Garba, ihgarba2002@yahoo.com

ABSTRACT
Introduction Lactate dehydrogenase (LDH) activity was assayed in the sera of 76 adult male and 76 adult female patients within the age group of 18-40 years presenting with acute, uncomplicated Plasmodium falciparum malaria infection and a control group of 80 healthy adults within the same age group.
Methods Patient selection and pre-qualification were done by simple random sampling of individuals presenting at the Bauchi Specialist Hospital Outpatient Department with a history of fever and malaise within a period of one to eight days, and who were confirmed to be infected with the P. falciparum malaria parasite by microscopical examination of Giemsa-stained thin blood slides.
Results The mean serum LDH activity in male patients was found to be 789.4 +/- 35.0 IU. This activity is significantly higher than the control LDH activity of 247.10 +/- 19.0 IU (p-value is less than 0.05). The mean serum LDH activity among female patients was 634.0 +/- 35.0 IU, which is a relatively higher activity compared to the control LDH activity of 247.10 +/- 19.0 IU (p-value is less than 0.05).
Conclusion The combination of acute hepatocellular injury and red cell haemolysis induced by the invading merozoites may account for the increase in serum LDH activity during this infection. Therefore serum LDH activity is a potentially valuable enzymatic marker of acute, uncomplicated P. falciparum malaria infection, especially in the absence of other complicating diseases known to be associated with the above normal serum LDH activities.

Keywords: lactate dehydrogenase, malaria, Plasmodium falciparum, serum enzymatic marker
Singapore Med J 2005; 46(11): 632-634

K Mamun, J Lim
Correspondence: Dr Kaysar Mamun, gdmkm@sgh.com.sg

ABSTRACT
Introduction Every year, a large number of patients with dysphagia are placed on feeding tubes to prevent aspiration pneumonia. This prospective study was planned to compare the incidence of aspiration pneumonia and death in patients with dysphagia who were either fed orally or through a nasogastric tube.
Methods All patients aged 65 years or older, at the point of discharge from the geriatric medicine ward of a hospital, were recruited over a six-month period with a two-month follow-up. Patients diagnosed with dysphagia by the speech therapist were recommended to have either oral feeding with modified diet or nasogastric tube feeding. The incidence of aspiration pneumonia and death among patients on oral feeding, nasogastric tube feeding and patients who refused nasogastric tube feeding were compared.
Results A total of 122 patients completed the study. The rate of aspiration pneumonia and death were, respectively, 31.2 percent in nasogastric tube-fed patients and 10.3 percent in orally-fed patients (Fisher's exact test, p-value equals 0.007). Multivariate analysis showed that the mode of feeding predicted outcome (p-value equals 0.03). The rate of aspiration pneumonia and death were 31.2 percent in nasogastric tube-fed patients and 11.5 percent in those who refused nasogastric tube feeding (Fisher's exact test, p-value equals 0.064). Nasogastric tube-fed patients were more cognitively- and functionally-impaired compared to those on oral feeding.
Conclusion In our study, patients on nasogastric tube feeding did not have a better outcome against aspiration pneumonia and mortality when compared to those who were on oral feeding. The poorer outcome of nasogastric tube-fed patients could be attributed to their worse cognitive and functional statuses. Larger studies are needed to refute or confirm the usefulness of nasogastric tube in elderly patients with dysphagia.

Keywords: aspiration pneumonia, elderly patients, enteral nutrition, nasogastric tube feeding, pneumonia
Singapore Med J 2005; 46(11): 627-631

VH Chong, HB Yim, CC Lim
Correspondence: Dr Chong Vui Heng, chongvuih@yahoo.co.uk

ABSTRACT
Introduction As the population ages, the incidence of biliary tract pathologies also increases, leading to an increase in the demand for endoscopic retrograde cholangiopancreatography (ERCP) interventions. Our aims are to assess the outcomes, safety and complications associated with ERCP performed in an elderly population.
Methods Patients aged 80 years or over referred for ERCP from January 1999 to September 2002, were identified and retrospectively reviewed.
Results 103 patients (68 females, mean age 84.6 +/- 3.9 years old) underwent 144 procedures (1-6 procedures/patient). The main indications were cholangitis (51.4 percent), choledocholithiasis (19.4 percent) and blocked stents (14.6 percent). Malignancies represented 5.6 percent of indications. The mean procedure time was 38 +/- 16 minutes. The overall success rate was 80.5 percent. Minor events occurred in 23 percent (tachycardia 13, desaturation six, transient hypotension six, self-limiting bleed four, extravasations three, and mild pancreatitis one). Major events were post sphincterotomy bleeding (five days post-procedure) one, duodenal perforation one (Billroth-II gastrectomy, survived after surgery), cholangitis two, and one death was probably procedure-related (acute myocardial event five days post-stenting in a patient with Klatskin tumour). Seven deaths occurred within one month of ERCP, due to advanced malignancies (four), sepsis (two) and acute myocardial infarction (one). Patients who died within one month had significantly higher serum urea (p-value equals 0.001), and creatinine (p-value equals 0.007) levels, and lower haemoglobin (p-value equals 0.014) level. More patients had an underlying malignancy (p-value less than 0.001). In addition, they were given significantly less conscious sedation (midazolam [p-value equals 0.002] and fentanyl [p-value equals 0.018]).
Conclusion Our study showed that ERCP is safe in an elderly Asian population. Minor complications are usually transient and related to sedation, and mortality is usually related to severity of illness and underlying malignancies.

Keywords: biliary tract diseases, elderly patients, endoscopic retrograde cholangiopancreatography, endoscopy complications
Singapore Med J 2005; 46(11): 621-626

JC Wang, AWT Tan, R Monatosh, PTK Chew
Correspondence: Dr Wang Jenn Chyuan, jennwang2003@yahoo.com

ABSTRACT
Introduction To evaluate the clinical efficiency, safety and subjective visual outcomes of multifocal intraocular lenses (IOL) in the Singapore population.
Methods This is a retrospective case series of 45 phacoemulsification with multifocal lens implantation performed in 27 patients for cataracts, over a two-year period. The efficacy, stability and safety of the lens were assessed up to six months of follow-up. A telephone interview enquiring about ratings of vision, spectacle independence, glare, driving difficulty and photic phenomena, was conducted and the results were compared with those published in the literature.
Results The best corrected distance Logmar acuity was 0.1 (0.1 and near visual acuity was N5 (range N5 to N8) at six months. The distance visual acuity stabilised by one month whereas near vision remained unchanged from day one post-surgery. Posterior capsular opacification was seen in 17 patients (38.6 percent) of which two patients (4.55 percent) required YAG capsulotomy. Total spectacle independence was achieved in 12 patients (54.4 percent). Among those who required spectacles, 50 percent required spectacles more than 50 percent of the time. Five patients (22.7 percent) reported glare usually at night (80 percent) as compared with daytime glare (20 percent). The most common photic phenomena report after surgery was halo.
Conclusion The Advanced Medical Optics ARRAY multifocal IOL showed good efficacy, predictability, stability and safety. The subjective visual outcomes in the Singapore population were comparable to those of their Western counterparts.

Keywords: ARRAY multifocal lens, cataract extraction, intraocular lens, presbyopia
Singapore Med J 2005; 46(11): 616-620

R Mahendran, HL Yap
Correspondence: Dr Rathi Mahendran, rathi_mahendran@imh.com.sg

ABSTRACT
The Ministry of Health Clinical Practice Guidelines for Depression were prepared and distributed to all doctors in Singapore in early 2004. This article highlights salient points and discusses pharmacotherapy, psychotherapy and psychoeducation in managing cases of depression. Assessment of suicide risk is elaborated upon, although this was not discussed in the guidelines. The learning points will be enhanced if this article is reviewed together with the Ministry of Health Clinical Practice Guidelines.

Keywords: clinical practice guidelines, depression, pharmacotherapy, psychotherapy
Singapore Med J 2005; 46(11): 610-615