2005

MK Leow, KC Loh
Correspondence: Dr Melvin Leow, mleowsj@massmed.org

ABSTRACT
The perilous potential of metoclopramide when used inadvertently in patients harbouring phaeochromocytomas goes largely under-recognised. Despite the rarity of phaeochromocytoma, clinicians should exercise caution in the use of metoclopramide among hypertensives and those with labile blood pressures, given the potentially life-threatening crisis it can readily evoke in those with this tumour. We report a series of three patients with phaeochromocytoma who developed acute crises from metoclopramide.

Keywords: catecholamines, dopamine antagonists, hypertensive emergency, metoclopramide, phaeochromocytoma
Singapore Med J 2005; 46(10): 557-560

R Ganesh, T Leese
Correspondence: Dr Trevor Leese, tbleese54@hotmail.com

ABSTRACT
Introduction In most parts of the world, acute parotid abscess is a rare pathology. It occurs mainly in elderly debilitated patients and patients with oral sepsis. In Singapore, this lesion appears to be more common.
Methods We retrospectively reviewed all patients admitted to our hospital over a three-year period with parotid abscess.
Results Ten patients were treated for parotid abscess. Only two of these patients were elderly and debilitated. The remaining patients were atypical in that they were relatively young and fit with no history of oral sepsis. All the abscesses responded to simple drainage and antibiotic therapy without the need to resort to the radical drainage techniques reported historically.
Conclusion Parotid abscess is seen in an unusually young cohort of patients in Singapore. The cause for this is unclear but it may be a result of chronic oral dehydration as a consequence of our climate.

Keywords: parotid abscess, parotitis, salivary gland, suppurative parotitis
Singapore Med J 2005; 46(10): 553-556

KH Tan, TYT Tan, J Tan, I Tan, SK Chew, GSH Yeo
Correspondence: Dr Kelvin Tan Kok Hian, khtan@kkh.com.sg

ABSTRACT
Introduction To study characteristics of birth defect cases among live births, stillbirths and abortions in Singapore between 1994 and 2000.
Methods Index cases for the National Birth Defects Registry (NBDR) were obtained from all neonatal nurseries in Singapore, all hospital discharge summaries, cytogenetic and pathology reports from all pathology laboratories in Singapore, and from the compulsory reporting of all termination of pregnancy cases and stillbirths delivered. Further information was obtained from case notes retrieved from the medical record offices, antenatal clinics, cytogenetic laboratories, pathology departments and the Registry of Births and Deaths. The notified cases (live births, stillbirths and abortions) between 1994 and 2000 were extracted from the NBDR and analysed with regard to ethnicity, maternal age, trend over the seven years and types of birth defects using the British Paediatric Association Classification.
Results Between 1994 and 2000, a total of 7,870 cases (6,278 births and 1,592 abortuses) were notified, giving a rate of 23.99 birth defect cases per 1000 live births. There was a decreasing trend in birth defect incidence (19.76 to 16.85 per 1,000 live births) among live births and stillbirths and an increasing trend of abortion (3.25 to 7.57 per 1,000 live births) for birth defects. Malays had a higher rate of congenital defects at birth (24.4/1,000 live births) compared to Chinese (18.4/1,000 births). The 25-29 years age group had the lowest overall rate (22.6/1,000 live births) compared to the 19 years and below group at 31.6/1,000 live births and the 45-49 years group at 126.6/1,000 live births. The five most common groups of anomalies (per 1,000 live births) were those of heart (9.07), musculoskeletal (4.98), chromosomal (4.35), urinary (3.12) and nervous systems (2.90). The five most common aborted anomalies (per 1,000 live births) were those of chromosomal (2.40), nervous (1.23), heart (0.95), musculoskeletal (0.85) and urinary systems (0.36).
Conclusion There was an increasing trend of abortion for birth defects, accompanied by a falling trend in the congenital anomalies of live births. Both extremes of maternal age were at higher risk of non-chromosomal birth defects while advanced maternal age was at higher risk of chromosomal defects.

Keywords: abortion, birth defect, chromosome disorders, congenital abnormalities
Singapore Med J 2005; 46(10): 545-552

A Ali, M Kurien, SS Mathews, J Mathew
Correspondence: Prof Mary Kurien, kurien_mary@hotmail.com

ABSTRACT
Introduction Complications of acute infective sinusitis are a therapeutic emergency. The purpose of this study was to determine the clinical presentation, microbiological pattern, treatment modalities and outcome of patients diagnosed to have acute rhinogenic orbital, intra- and extra-cranial complications from a developing country in Asia.
Methods A retrospective chart review from October 1999 to January 2004 was conducted.
Results Among 247 ENT surgical emergencies documented, 13 patients (5.3 percent) were diagnosed to have acute sinusitis with various complications either as in solitary or multiple forms. Orbital complications were the most common (61.5 percent) followed by acute subdural empyema (23.1 percent) and meningitis (15.2 percent). Subdural empyema was the most common intracranial complication. Staphylococcus was reported to be the most common offending organism (45.5 percent). Majority of the patients (84.6 percent) had surgical drainage of the affected sinuses, 38.5 percent being endoscopic drainage while external approach was done for those with coexisting osteomyelitis (30.8 percent). Two patients had combined approach, and one patient had post-operative facial paresis. There was no mortality in our series.
Conclusion Early detection, aggressive medical and prompt surgical treatment by multidisciplinary approach involving ophthalmological, neurosurgical and rhinological procedures, can successfully treat the complications with a significant reduction in the morbidity and no mortality.

Keywords: acute rhinosinusitis, infective rhinosinusitis, rhinosinusitis complications
Singapore Med J 2005; 46(10): 540-544

BYH Thong, KP Leong, HH Chng
Correspondence: Dr Bernard Thong Yu Hor, bernard_thong@ttsh.com.sg

ABSTRACT
Introduction To study the profile of patients with allergy to the venom of insect stings.
Methods 31 consecutive cases referred to our clinical immunology/allergy outpatient service from June 1, 1998 to June 30, 2002 were reviewed.
Results These patients comprised 3.5 percent of 889 cases referred during the study period. Their mean age was 28.8 +/- 10.5 (range 19-57) years and the majority were males (90.3 percent). Of these, 20 (64.5 percent) were Chinese, four (12.9 percent) were Malays and seven (22.6 percent) were of other races. 19 patients (61.3 percent) were men from the uniformed services including 12 (63.2 percent) full-time National Servicemen. 71 percent (22 patients) were stung for the first time. Urticaria (22 cases, 71.0 percent), dyspnoea (13, 41.9 percent), angioedema (12, 38.7 percent) and syncope (ten, 32.3 percent) were the most common manifestations of insect allergy. Anaphylaxis occurred in 22 (71.0 percent) cases, constituting 30.1 percent of all cases of anaphylaxis referred to our service during the study period. Although the causative insect was identified as honeybee (12, 38.7 percent), ant (four, 12.9 percent), wasp (three, 9.7 percent), and fire ant (two, 6.5 percent) by the majority of patients, ten (32.2 percent) patients were unable to identify the causative insect. The two patients stung by fire ants were Americans working in Singapore who had been stung while in the United States. Among those with anaphylaxis, honeybee, wasp and fire ant venom, for which specific immunotherapy is available, were identified as the cause in 40.9 percent, 4.5 percent, and 4.5 percent, respectively.
Conclusion Insect venom hypersensitivity made up 3.5 percent of allergy/immunology referrals and 32.8 percent of cases of anaphylaxis referred to our institution. The majority were military servicemen who developed allergic reactions during the course of duty. The inability to identify the causative insect in 50 percent with sting anaphylaxis limits the role of specific immunotherapy in our patients.

Keywords: anaphylaxis, insect venom, radioallergosorbent test, skin tests, specific immunotherapy
Singapore Med J 2005; 46(10): 535-539

BYH Thong, YK Cheng, KP Leong, CY Tang, HH Chng
Correspondence: Dr Bernard Thong Yu Hor, bernard_thong@ttsh.com.sg

ABSTRACT
Introduction To study the clinical features and causes of anaphylaxis in consecutive adult patients referred to a clinical immunology/allergy centre in Singapore.
Methods A retrospective review of 67 consecutive adults with anaphylaxis who presented from July 1, 1998 to February 28, 2002 was performed. Anaphylaxis was defined as a severe life-threatening systemic IgE-mediated hypersensitivity reaction. Non-steroidal anti-inflammatory drug-induced idiosyncratic reactions and other non-IgE mediated reactions were excluded. Hypotension and bronchospasm were not required to make a diagnosis. The aetiology was determined from clinical history followed by measurement of allergen-specific IgE levels, skin prick test with commercially-available allergen extracts or prick-prick test with the fresh/cooked/canned food products.
Results The mean age of patients was 32.9 +/- 10.9 (range 19-57) years. There were 44 (65.7 percent) males and 23 (34.3 percent) females. The main causes were food (44.8 percent), insect stings (32.8 percent) and idiopathic (22.4 percent). There were no cases due to drugs or natural rubber latex. Seafood (crustaceans and molluscs) comprised 66.7 percent of food-induced anaphylaxis. Honeybee and wasp stings together comprised 45 percent of insect venom anaphylaxis. The most common manifestations were dyspnoea (59.7 percent), urticaria (58.2 percent), angioedema (44.8 percent), and syncope (43.3 percent). Hypotension was documented in only 28.4 percent of cases.
Conclusion Food (crustaceans and molluscs) was the most common cause followed by insect stings or bites. The inability to identify the causative insect in 50 percent of cases with insect venom anaphylaxis limited the role of specific immunotherapy. Compared to other reported series, there were no cases of drug or latex anaphylaxis.

Keywords: hypersensitivity, radioallergosorbent test, skin tests, immunotherapy
Singapore Med J 2005; 46(10): 529-534

S Tavintharan, SC Lim, CF Sum
Correspondence: Dr S Tavintharan, tavintharan_subramaniam@alexhosp.com.sg

ABSTRACT
Clinical evidence indicates that a low level of high-density lipoprotein cholesterol (HDL-C) is a major risk of atherosclerosis. Raising HDL-C reduces this risk significantly, making HDL-C levels an important target of treatment for dyslipidaemia, especially in pre-existent atherosclerosis. HDL-C is protective against atherosclerosis, largely due to its function of reverse cholesterol transport. Additionally, some important roles include fibrinolysis, antioxidant functions, and reduction of platelet aggregability. A number of agents potentially modify HDL favourably. Niacin is the most potent HDL-C raising agent currently available in clinical practice, followed by fibrates. CETP inhibitors show greater HDL-C rising, but are still used in trial settings only. HDL mimetic agents are another group of agents that offer much promise. Clinical outcome data are awaited for these newer therapeutic agents.

Keywords: apolipoprotein A-l, atherosclerosis, high-density lipoprotein, hypoalphalipoproteinaemia
Singapore Med J 2005; 46(10): 519-528