Original Article

Na-ChiangMai W, Pojchamarnwiputh S, Lertprasetsuke N, Chitapanarux T
Correspondence: Dr Wittanee Na-ChiangMai, wnachian@mail.med.cmu.ac.th

ABSTRACT
Introduction The diagnosis of tuberculous peritonitis is still challenging and very important. Early and accurate diagnosis leads to an effective therapy and good survival rates. With the widespread use of computed tomography (CT) in the abdomen, it is important to be familiar with the spectrum of CT appearances seen in tuberculous peritonitis. Our retrospective study aims to describe the common CT features of this disease.
Methods Abdominal CT images in 17 patients with tuberculous peritonitis in our institution from January 2002 to December 2005 were retrospectively reviewed. CT findings were evaluated for the presence of ascites, the abnormal patterns of mesentery, omentum and peritoneum.
Results Ascites and mesentery involvement were present in all patients. The most common pattern of mesenteric changes was thickened soft tissue strands with crowded vascular bundles (65 percent). The involvement of the omentum was present in 15 patients (88 percent), and the most common type was smudged pattern (82 percent). Peritoneal involvement was present in 15 patients (88 percent). Smooth uniform thickening pattern was the most common type (76 percent).
Conclusion Common features in the patients with tuberculous peritonitis include the combination of free ascites, thickened strands with crowded vascular bundles within the mesentery, smudged pattern of the omental involvement and smooth uniform thickening of the peritoneum.

Keywords: computed tomography, mesentery, omentum, peritoneum, tuberculous peritonitis
Singapore Med J 2008; 49(6): 488-491

Chong YY, Caballero MR, Lukawska J, Dugue P
Correspondence: Dr Pierre Dugué, pierre.dugue@kcl.ac.uk

ABSTRACT
Introduction Anaphylaxis during general anaesthesia is a major concern. Early recognition and management of anaphylaxis, as well as its future prevention, remain a challenge for the anaesthetists, while for the allergists, the elucidation of the causal agents may be difficult. We aimed to describe our experience in our drug allergy clinic.
Methods We retrospectively reviewed 23 consecutive adult patients who presented with anaphylaxis during anaesthesia from March 1, 2005 to February 28, 2006.
Results Out of the 23 patients (12 females, 11 males) with mean age (+/- SD) of 53.1 +/- 15.8 years, 15 patients were found to have a positive skin test to at least one neuromuscular blocking agent (NMBA); all of them showed cross-sensitivity with one or more NMBA(s). Three patients had a positive skin test to opioids, two patients to gelofusine, two patients to penicillin, and one patient each to povidone-iodine and chlorhexidine. Two patients had negative test results to agents used during their anaesthesia. Four patients had double positive skin tests to different families of drugs/agents. 18 patients had severe reaction-grade 3, and 15 of them tested positive for NMBA(s). Serum tryptase levels were known in nine patients. We did not encounter any latex or hypnotics sensitisation.
Conclusion NMBA was the commonest cause of anaphylaxis during general anaesthesia, occurring in 65% in our series.

Keywords: anaphylaxis, drug allergy, general anaesthesia, neuromuscular blocking agents
Singapore Med J 2008; 49(6): 483-487

Díaz-Quijano FA, Martínez-Vega RA, Villar-Centeno LA
Correspondence: Dr Fredi Alexander Díaz Quijano, fre_diazq@yahoo.com

ABSTRACT
Introduction Spontaneous haemorrhage is an important cause of hospitalisation in dengue patients. Early predictors of these complications could help to make opportune decisions.
Methods We prospectively evaluated 51 febrile patients (without previous spontaneous haemorrhage), including 32 cases of dengue fever. Initial evaluation was performed during the first 96 hours after the onset of fever and included complete blood cell count and coagulation tests. Participants were followed-up daily until the seventh day of the disease.
Results Overall, 15 patients developed spontaneous haemorrhage during the follow-up. Tourniquet test and dengue infection were not associated with haemorrhage (p-value is greater than 0.2). In a logistic regression analysis, platelet count (odds-ratio [OR] 0.78; 95 percent confidence interval [CI] 0.65-0.94) and partial thromboplastin time (OR 1.78; 95 percent CI 1.06-2.99) were independently associated with spontaneous haemorrhage.
Conclusion Early alterations in platelet count and coagulation test could predict spontaneous bleeding in the acute febrile syndrome.

Keywords: acute febrile syndrome, dengue fever, dengue haemorrhagic fever, platelet count alteration, spontaneous haemorrhage
Singapore Med J 2008; 49(6): 480-482

Lye DC, Chan M, Lee VJ, Leo YS
Correspondence: Dr David Lye, david_lye@ttsh.com.sg

ABSTRACT
Introduction Approximately 80 percent of all notified cases of dengue infections in Singapore were hospitalised from 2000 to 2005. We aimed to determine if hospitalised dengue patients had significant morbidity and mortality, and if admissions were in accordance with previously-published admission criteria.
Methods The medical records of the first 20 patients with laboratory-confirmed dengue from two consecutive months in three time periods were retrospectively reviewed. Demographical, clinical and laboratory data on admission, during hospitalisation and on discharge, were compared.
Results There were 120 patients with a mean age of 35 years. Males comprised 77 percent and foreign workers 51 percent. Of the published admission criteria, 33 percent had vomiting, 22 percent diarrhoea, 13 percent abdominal pain, 18 percent bleeding and one patient had hypotension. 30 percent were above the minimum platelet threshold of 80,000/microL, but 50 percent had safe levels of platelets between 50,000 and 80,000/microL. Dengue haemorrhagic fever occurred in 4 percent with no death. After admission, platelet nadir was below 20,000/microL in only 9 percent and below 10,000/microL in only 2 percent of cases. Bleeding did not correlate with platelet count. Medical referral to the hospital was significantly associated with thrombocytopenia, while self-referral was significantly associated with vomiting.
Conclusion Severe adverse outcome among young adults with uncomplicated dengue fever is rare. Instead of hospitalisation, daily outpatient monitoring with symptomatic treatment and medical leave may be a safe and feasible alternative.

Keywords: dengue fever, dengue haemorrhagic fever, dengue infection, platelet count, thrombocytopenia, uncomplicated dengue fever
Singapore Med J 2008; 49(6): 476-479

Najafi M
Correspondence: Dr Mahdi Najafi, najafik@sina.tums.ac.ir

ABSTRACT
Introduction Fast-track is a method proposed to decrease medical costs through the reduction of patients' length of stay in the hospital. This study was carried out to assess the risks and benefits of conducting the fast-track method in cardiac anaesthesia and to evaluate the role of continuous infusion of short-acting anaesthetics in a successful fast-track protocol.
Methods 100 cases were divided into two groups. In the fast-track group, fentanyl and propofol infusions were started at induction time and atracurium one hour later. No bolus drug was administered during the operation. Fentanyl infusion was continued up to 12 hours after surgery. The conventional extubation group received fentanyl and pancuronium as bolus doses. The two groups were evaluated for time of alertness and extubation in the intensive care unit, total analgesic dosage administered during the 24 hours after operation, arterial blood gas and peripheral saturation of oxygen before and after extubation.
Results Time period between intensive care unit admission and alertness was significantly different in the fast-track (1.3 hours) and control (3.3 hours) groups (p-value is less than 0.001) as well as total time of intubation in the intensive care unit (4.3 hours vs. 7 hours) (p-value is less than 0.001). No patient of the fast-track group experienced low pressure of arterial oxygen, low saturation of arterial oxygen, high pressure of arterial carbon dioxide or need for reintubation in the first 24 hours after surgery.
Conclusion Continuous infusion of drugs in the fast-track method facilitates earlier extubation. It maintains continuous sedation and analgesia without increasing respiratory complications.

Keywords: coronary artery bypass, fast-track, general anaesthesia, intensive care unit, length of stay, postoperative complications
Singapore Med J 2008; 49(6): 470-475

Ambulkar R, Tan AYH, Chia NCH, Low TC
Correspondence: Dr Tan Yong Hui Addy, addytanyh@yahoo.co.uk

ABSTRACT
Introduction The intubating laryngeal mask airway (ILMA) is a specially-designed airway device that can be used for endotracheal intubation without direct laryngoscopy. The advantage of this device is that it allows blind endotracheal intubation with a predictably high success rate. The use of neuromuscular blocking agents in facilitating the use of the ILMA has been investigated in the Western population with a quoted successful intubation rate of 88-96 percent. This randomised, double-blind study aimed to see if the use of neuromuscular blocking agent is necessary for successful intubations.
Methods A total of 150 patients, rated categories 1 and 2 on the American Society of Anesthesiology Physical Status Classification System, were induced with propofol 2.5 mg/kg and fentanyl 2 microg/kg. After insertion of the ILMA, the patients received either saline or 0.6 mg/kg of rocuronium. After 90 seconds, tracheal intubation was attempted using the specially-designed silicon endotracheal tube. In addition to the success rate of intubation, the incidence of complications was also recorded.
Results The success rate for tracheal intubation within three attempts was 93.3 percent for the saline group and 92.0 percent for the rocuronium group; this was statistically insignificant. The time to securing the airway was 11.5 seconds for the saline group, compared to 10.0 seconds in the rocuronium group, but this was statistically insignificant. The incidence of coughing during insertion of the endotracheal tube was 42.7 percent in the saline group as compared to 1.3 percent in the rocuronium group (p-value is less than 0.001). 12 percent of the patients in the saline group moved during intubation, while none was reported to move in the rocuronium group (p-value is 0.003). These results compared favourably with rates quoted in studies conducted on Western populations.
Conclusion The intubating laryngeal mask airway-assisted intubation yields a high success rate, which was similar between the paralysed and non-paralysed patients, with no statistical significance. However, the non-paralysed patients were prone to coughing and movements during intubation, requiring supplemental propofol.

Keywords: intubating laryngeal mask airway, intubation, laryngeal mask airways, laryngeal masks, neuromuscular blocking agents
Singapore Med J 2008; 49(6): 462-465

Poulose V
Correspondence: Dr Vijo Poulose, vijo_poulose@cgh.com.sg

ABSTRACT
Introduction Severe community-acquired pneumonia is a major cause of mortality and morbidity worldwide. This study looked at the clinical characteristics of these patients admitted to a Singaporean community hospital and the prognostic impact of age, bacteraemia and logistic organ dysfunction score (LODS) on intensive care unit mortality.
Methods Retrospective analysis of 80 severe community-acquired pneumonia patients admitted to the intensive care unit over a 20-month period was conducted. The Mann-Whitney U and chi-square tests were used for statistical analysis and a p-value of less than 0.5 was considered as significant.
Results There were 55 male and 25 female patients, with a median age of 62 years. The median LODS was 5. The intensive care unit mortality was 30 percent. The median LODS of intensive care unit survivors was 5 and of non-survivors, 8. The overall hospital mortality was 37.5 percent. A microbiological aetiology was identified in 38 percent of patients. Three of four patients with melioidosis died. Between intensive care unit survivors and non-survivors, there was a significant difference in the LODS, but no significant difference in the age and incidence of bacteraemia.
Conclusion Severe community-acquired pneumonia is a highly fatal disease which requires early initiation of appropriate empirical antibiotic therapy, which should include coverage for melioidosis in the local context. The microbiological workup should include testing for tuberculosis. The LODS system may be an appropriate tool in estimating the severity of illness.

Keywords: intensive care unit, logistic organ dysfunction score, melioidosis, severe community-acquired pneumonia
Singapore Med J 2008; 49(6):458-461

Thevarajah TM, Nadarajah S, Chew YY, Chan PC
Correspondence: Dr Malathi T Thevarajah, tmalathi@um.edu.my

ABSTRACT
Introduction We report the results of a laboratory evaluation of the BioRad Urinary Metanephrines Reagent Kit. The test was designed for the quantitative measurement of normetanephrine and metanephrine in urine by high performance liquid chromatography. The kit was evaluated in view of improving assay reliability and specificity as compared to the manual method based on cation exchange chromatography and spectrophotometry.
Methods Performance was evaluated for precision, linearity, accuracy, sensitivity and detection limit based on National Committee on Clinical Laboratory Standards (NCCLS) protocols. Analytical precision was evaluated using commercial controls and patient sample. Accuracy was evaluated by assessing recovery. Linearity was determined using aqueous standards.
Results The within-run coefficient of variation (CV) for metanephrine and normetanephrine were 1.9 percent and 2.4 percent (low control); 4.2 percent and 3.5 percent (high control); 3.8 percent and 3.3 percent (patient sample), respectively. The between-day precisions were 3.8 percent and 4.3 percent (low control); and 5.5 percent and 3.7 percent (high control) for metanephrine and normetanephrine, respectively. The linearity curve showed metanephrine and normetanephrine to be linear with concentrations, to at least 1,600 microgramme per litre and 2,000 microgramme per litre, respectively. Analytical recovery averaged 102 percent for metanephrine and 95 percent for normetanephrine. Levels as low as 23 microgramme per litre normetanephrine and 10 microgramme per litre metanephrine were measured with this method. The detection limit was 3.3 microgramme per litre for metanephrine.
Conclusion The performance characteristics of automated sample preparation and auto-injection facilitate handling of larger number of samples as well as improve assay reliability.

Keywords: automated method reagent kit, high performance liquid chromatography, urinary metanephrine, urinary normetanephrine
Singapore Med J 2008; 49(6): 454-457

Lim GH, Shabbir A, So JBY
Correspondence: Dr Lim Geok Hoon, ghlimsg@yahoo.com.sg

ABSTRACT
Introduction Acute appendicitis is the commonest cause for right lower abdominal pain. Clinical features, laboratory and imaging investigations are either not very sensitive or specific, and neither is therapeutic. We aimed to define the role of diagnostic laparoscopy in patients with right lower abdominal pain.
Methods Data was collected retrospectively from January 1, 2005 to December 31, 2005. Patients admitted to the Emergency Department and subsequently transferred to the Department of Surgery, National University Hospital, Singapore, with right lower abdominal pain and who eventually underwent diagnostic laparoscopy were evaluated.
Results 691 patients with right lower abdominal pain were admitted with suspected diagnosis of appendicitis. Diagnostic laparoscopy was undertaken in 103 patients aged 17-71 years old. Of the 83 females, 78 (94 percent) were premenopausal . Histology-proven acute appendicitis was diagnosed in 78 (75.7 percent) patients. Interestingly, within this group, 25.6 percent had other concomitant pathologies found on laparoscopy. 25 patients had a normal appendix; gynaecological causes accounted for pain in 15 of these 25 (60 percent) cases. In four (3.9 percent) patients, no pathology was found. Complication rate was 1.9 percent, which included ileus in two patients. In 32 (31.1 percent) patients, diagnostic laparoscopy altered the management plan, requiring either intervention or care by a subspecialty.
Conclusion Diagnostic laparoscopy is useful in evaluating patients with right lower abdominal pain, especially in those with equivocal signs of acute appendicitis. It also has the additional benefit of being therapeutic. Premenopausal women benefit the most from this procedure.

Keywords: acute appendicitis, diagnostic laparoscopy, laparoscopic surgery, right lower abdominal pain
Singapore Med J 2008; 49(6): 451-453