Biomedical subjects
Publications and source records attributed to S N Wong.
A Chinese boy with glycerol kinase deficiency is reported. His presentation with severe hypernatraemia secondary to hypodipsia and glycerol-induced osmotic diuresis is unusual and not previously described in the literature.
BACKGROUND: The idiopathic photodermatoses have been reported to be rarer in tropical Singapore than in countries of higher latitude, with photoaggravated dermatoses and systemic phototoxicity making up most of the photodermatoses seen here. This study aims to reassess the spectrum of photodermatoses seen at the National Skin Centre, Singapore, compared with almost a decade ago, and analyse the clinical and photobiological characteristics, as compared with other countries. MATERIALS AND METHODS: We reviewed the clinical data of 141 patients phototested from January 2000 to December 2001, and analysed the epidemiological, clinical and photobiological features. RESULTS: Photosensitive dermatoses were diagnosed in 88% (124/141) of patients phototested. In those diagnosed with photodermatoses, polymorphic light eruption (PMLE) (28%) was the most common diagnosis, followed by photoaggravated dermatoses (26%), chronic actinic dermatitis (CAD) (15%), systemic phototoxicity (15%), solar urticaria (SU) (7%), actinic prurigo (AP) (5%) and photoallergic contact dermatitis (4%). Ethnic Indians appeared to be more predisposed to PMLE; AP was diagnosed only in ethnic Chinese. The other photodermatoses occurred proportionally in all racial groups. AP differed from that found in Caucasians, being of adult onset and persistent. Abnormal phototest results were obtained in all patients with CAD, SU and AP, but only in 56% and 49% of systemic phototoxicity and PMLE, respectively. CONCLUSION: Idiopathic photodermatoses are more commonly diagnosed in Singapore than a decade ago, while the incidence of systemic phototoxicity has remained stable. The spectrum of photodermatoses in our Asian population now approximates that seen in Caucasian cohorts.
The current study investigated the immunomodulating effect of CKBM on cytokine induction in peripheral blood mononuclear cells (PBMCs) isolated from 20 healthy volunteers. Cytometric Bead Analysis (CBA) was used to study IL-2, IL-4, IL-6, IL-10, TNF-alpha and IFN-gamma. TNF-alpha and IL-6 were significantly increased in a CKBM dose- and time-dependent manner. Flow cytometry analysis showed an increased intracellular staining of IL-6 but not of TNF-alpha in CKBM treated PBMCs. In addition, MTT cell cytotoxicity assay showed that CKBM concentrations below 5% did not significantly affect the metabolic activities of PBMCs. The current study indicated that CKBM may modulate the immune response by inducing the secretions of TNF-alpha and IL-6, which are cytokine mediators of innate immunity and inflammation preparing or "priming" the body to combat diseases.
Tolosa-Hunt syndrome is characterized by a dull, persistent pain around the affected eye, ophthalmoplegia and, sometimes, involvement of other cranial nerves passing through the cavernous sinus. Corticosteroid administration is valuable in the treatment and frequently has a dramatic effect. We report a boy with Tolosa-Hunt syndrome who fails to respond to the initial steroid treatment. The role of the MRI in the management of this condition is discussed.
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There have been a few reports in the literature of chronic actinic dermatitis (CAD) associated with HIV infection, mostly in African--Americans of skin type VI, where photosensitivity predated the diagnosis of HIV infection. We report three cases, all Chinese males with skin type III or IV, who presented to our centre with CAD, and in whom advanced asymptomatic HIV infection was subsequently diagnosed. All had CD4 cell counts less than 100 cells/ micro L, with no evidence of AIDS-related complex. They were treated conservatively with photoprotection and topical steroids with mild to moderate improvement. A comparison with nine previously reported cases is made. The pathogenesis of CAD is unclear, but predominance of CD8 cells in severe cases and reversal of the CD4 : CD8 ratio in lesional skin and peripheral blood of HIV-negative CAD patients has been observed. CAD may be consequent to, and a presenting feature of, advanced HIV infection.
Moyamoya syndrome has been reported in association with Down syndrome. In paediatric patients, the usual presentation is that of ischaemic stroke. We report a 9-year-old boy with Down syndrome and moyamoya syndrome who presented with acute-onset left hemiparesis. This is the first such reported case in Hong Kong. There is growing evidence that the chromosomal abnormalities in patients with Down syndrome may contribute to a vulnerability for the development of moyamoya syndrome. A high index of suspicion is necessary to make the correct diagnosis. Medical and surgical management strategies for this disease are discussed. Surgical intervention should proceed without delay, if indicated, to prevent further neurological deterioration. A multidisciplinary approach is recommended for the rehabilitation of these patients.
Thrombotic thrombocytopenic purpura is a rare but serious condition in childhood. It can be idiopathic or a complication of other diseases or drug therapy. We report on a 12-year-old Chinese girl who presented with fulminant systemic lupus erythematosus with progressive renal failure, pancytopenia, and cerebral dysfunction due to thrombotic thrombocytopenic purpura. The patient also had Pneumocystis carinii pneumonia, Pseudomonas septicaemia, and Herpes zoster infections as a result of immunosuppressive treatment. She responded to combined therapy with pulse methylprednisolone, cyclophosphamide, plasmapheresis, and intensive care support, and completely recovered renal and neurological function. A review of the English-language medical literature since 1968 identified 20 other paediatric cases of systemic lupus erythematosus and thrombotic thrombocytopenic purpura. Clinical features, treatment, and outcome of these cases are presented and discussed. Early recognition is important, and although plasmapheresis is not of proven benefit in severe cases of systemic lupus erythematosus, it is life-saving in lupus-related thrombotic thrombocytopenic purpura and must be instituted early to avoid a poor outcome.
BACKGROUND: The subepidermal immunobullous disorders (SEIBDs) comprise bullous pemphigoid (BP), cicatricial pemphigoid (CP), epidermolysis bullosa acquisita (EBA), linear IgA disease (LAD), dermatitis herpetiformis (DH), pemphigoid gestationis (PG) and bullous systemic lupus erythematosus (BSLE). They are thought to be rarer in the Far East than in western Europe. OBJECTIVE: This 2-year retrospective study investigates the spectrum seen at our centre and the minimum estimated incidence of each. PATIENTS AND METHODS: A total of 67 patients seen at the National Skin Centre (NSC), Singapore between January 1998 and December 1999 were diagnosed as having an SEIBD. Fifty-nine (88%) had BP, four (6%) had EBA, two (3%) LAD and two (3%) BSLE. There were no cases of CP, DH or PG diagnosed during this period. The minimum estimated incidence in our local population was 7.6, 0.5, 0.26 and 0.26 per million population per year, respectively. The mean age of onset was 77, 68, 65 and 31 years, respectively. RESULTS: BP is the commonest SEIBD seen locally, with an incidence at least equal to that in western Europe. It is diagnosed at our centre three times more frequently than pemphigus. There is a predilection for ethnic Chinese but not Indian. EBA is twice as common as in western Europe and shows a predilection for ethnic Indians. LAD is rare here compared to China, despite the predominant Chinese population. BSLE is also rare. In contrast to western Europe, CP, DH and PG are very rare in Singapore. CONCLUSIONS: This is the first study from this region to show that certain SEIBDs are not rarer in the Far East, as previously thought.
OBJECTIVES: We studied the false-positive rate of bag urine cultures in diagnosing bacteriuria in infants and examined the factors responsible for contamination. METHODS: One hundred asymptomatic patients with previous urinary tract infections (UTI; age range 5-23 months; sex ratio M : F 73:27) were screened by bag urine cultures and confirmed by suprapubic aspiration or catheterization. Those producing contaminated and clean samples were interviewed with a standard questionnaire. RESULTS: Sixty patients had insignificant growth and 40 had doubtful or mixed growth. After further interview and instructions, the latter group produced a second bag urine sample with negative results in 23 and positive results in 17. Among the latter, UTI was confirmed in five and excluded in 12 cases. The false-positive rate of first urine collection was 36.8%. Comparing patients with contaminated urine to those with negative urine samples, we found the former were associated with waiting for more than one void to complete urine collection, and with uncircumcised boys. Other factors did not reach statistical significance. Proper counselling and repeating a second culture reduced the overall false-positive rate to 12.6%. CONCLUSION: In our population, the contamination rate of one bag urine culture was 36.8%, which is unacceptable and alternative methods need to be sought. Contamination was associated with improper collection procedures and with uncircumcised boys. Proper instructions and doing a second urine culture reduced the overall rate to 12.6%, but at the expense of delaying diagnosis and treatment.
UNLABELLED: The aim of this study was to investigate the behavioural problems and parenting stress of enuretic children in the local Chinese community. The study recruited 89 children with primary nocturnal enuresis (PNE) from the paediatric clinics of 9 regional hospitals in Hong Kong, and 131 age- and gender-matched control children without PNE from the Student Health Centres. After adequate instruction, the parents completed the Child Behaviour Checklist (CBCL) and Parenting Stress Index (PSI). A trained interviewer interviewed the parents and children and rated the children on the Global Assessment of Functioning (GAF). The PNE group had worse overall scores in both the Problem and Competence scales of CBCL; in particular, they had more attention problems and aggressive behaviours, and lower social competence and school performance than the control group. Their parents demonstrated more parenting stress as shown by higher PSI scores. CONCLUSION: In the local Chinese population, PNE was associated with more childhood behavioural problems and greater parenting stress. Attention to the psychosocial functioning of the child and parents may be important in the management of enuresis.
UNLABELLED: To determine the optimal method of suprapubic aspiration (SPA), the success rates of real-time ultrasound-guided SPA were compared with those of conventional SPA, and factors associated with success were studied. Thirty infants were randomly allocated to group A (for real-time ultrasound-guided SPA) and 30 infants to group B (for blind SPA with a prehydration protocol). The results showed that the overall success rates for all attempts were similar (26/30 or 87% in group A vs 24/30 or 80% in group B, p > 0.05). The first attempts in both groups were equally successful (both 18/30 or 60%). In comparison with failed attempts, successful ultrasound SPA attempts were associated with a greater bladder depth (mean +/- SD: 28 +/- 11 vs 21 +/- 5 mm, p < 0.01), length (32 +/- 12 vs 23 +/- 9 mm, p < 0.05) and volume (17 +/- 13 vs 8 +/- 6 ml, p < 0.01), but similar width (33 +/- 9 vs 29 +/- 5 mm, p > 0.05). In blind SPA, successful attempts were associated with the presence of bladder dullness on percussion (odds ratio 29). CONCLUSION: This study confirms that ultrasound-guided SPA has a high success rate. Blind SPA could also be equally successful with appropriate preparation. Ultrasound-guided SPA is recommended when the bladder depth exceeds 3 cm, or the bladder length exceeds 3.7 cm. If an ultrasound machine is not available, blind SPA may be an alternative, with attention being paid to prehydration and the demonstration of bladder dullness by percussion.
UNLABELLED: D-2-Hydroxyglutaric aciduria (D-2-HG) is a rare metabolic disorder. First reported in 1980, it does not have any well-recognized presentation or specific treatment regimen. Neuroimaging findings are heterogeneous. Subdural haemorrhage has not been a feature of any of the reported cases. This report presents a boy with bilateral subdural haematoma in whom non-accidental injury was initially suspected and subsequent metabolic investigation led to a diagnosis of D-2-HG. CONCLUSION: In the management of childhood subdural haemorrhages, it is very important that potentially treatable metabolic disorders are detected and that parents are not wrongly accused of injuring their children.
INTRODUCTION: Bullous pemphigoid (BP) is the most common immunobullous disorder in Western Europe, affecting mainly the elderly. Previous reports have suggested that it is rarer in the Far East. We report on the clinico-epidemiological features of BP seen at our centre. MATERIALS AND METHODS: This is a 2-year retrospective study of patients seen at the National Skin Centre who were diagnosed to have BP. RESULTS: Fifty-nine patients were newly diagnosed with BP over a 2-year period between January 1998 and December 1999. The minimum estimated incidence was 7.6 per million population per year, with mean age of onset of 77 years, and a male to female ratio of 1:2. There was a predilection for Chinese but not Indian. Localised disease was found in 34% and mucosal involvement in only 1.7%. Direct immunofluorescence was positive in almost all patients, and 94% of those tested had positive indirect immunofluorescence. 'Roof' pattern was present in 95.8% and 'roof and floor' pattern in 4.2%. Prednisolone was the treatment of choice in most patients (78%). Anti-inflammatory agents were more commonly used than a decade ago (13.5%). CONCLUSIONS: BP is the most common immunobullous disease locally, with an incidence at least equal to that in Western Europe. There was a predilection for ethnic Chinese rather than Indian. Apart from the rarity of mucosal involvement, the clinical features are similar to those of Western nations.
The present study describes the characteristics of epilepsy in a cohort of Chinese epileptic children. All children with active epilepsy who were under 15 years of age and residing in the catchment area of Tuen Mun Hospital, Hong Kong were monitored. Etiology, seizure types, and epilepsy syndromes were classified according to the recent guidelines of the International League Against Epilepsy. A total of 309 children were recruited into the study. The etiology of epilepsy was idiopathic in 42% of the children, cryptogenic in 16.8%, and remote symptomatic in 40.8%. Perinatal factors were the most frequently found cause of epilepsy. Seizure types were partial in 48.5% of the children and generalized in 46.9%. Epilepsy syndromes could be classified in all but seven patients, with 48.2% localization related and 49.5% generalized. Generalized seizures were more prevalent in children less than 5 years of age. Additional neuroimpairments affected 36% of our epileptic children. Sixty-nine percent of patients were seizure free for more than 1 year. The authors conclude that the International League Against Epilepsy can be applied successfully to a population-based cohort of Chinese epileptic children. A larger, longitudinal epidemiologic study is needed to answer questions concerning the true prevalence, incidence, types, and etiologies in the Chinese population.
Hydroa vacciniforme (HV) is a rare blistering photodermatosis that heals with vacciniform scarring, with onset usually in childhood and spontaneous resolution by early adulthood. We report two cases of HV seen at the National Skin Centre, Singapore, both with a late onset at 20 years of age, during compulsory military service, and one with a less typical non-vesicular presentation, that initially caused some diagnostic difficulties.
We report on a newborn boy, who was delivered at 26 weeks' gestation by emergency caesarean section because of a prolapsed cord and breech presentation. Grade IV hyaline membrane disease subsequently developed, for which a surfactant was given. On day 8, there were frequent apnoeic attacks, and on day 30, marked irritability developed, as did intermittent stiffening of all four limbs. The anterior fontanelle was bulging and tense, and the cerebrospinal fluid was found to be turbid. Gram staining of the cerebrospinal fluid and blood revealed Gram-positive bacilli. Subsequent culturing yielded Bacillus cereus, which was sensitive to amikacin and vancomycin. Severe cerebral oedema developed, however, and computed tomography of the brain showed bright cortical sulci, suggestive of meningitis. The baby died on day 37, and post-mortem histological examination of the brain showed extensive liquefactive necrosis with abundant neutrophilic infiltration. Since infection with Bacillus cereus is rapidly fatal, early recognition of infection by this organism is important.
INTRODUCTION: We describe a case illustrating a rare but increasingly recognised association of chronic actinic dermatitis (CAD) with human immunodeficiency virus (HIV) infection. CLINICAL PICTURE: A 40-year-old Chinese man of skin type III presented with a photodistributed rash of 3 years' duration. Histology, phototesting and subsequent clinical course were consistent with CAD. HIV serology was positive. CD4 count was 26 cells/microL, with absence of acquired immunodeficiency syndrome (AIDS)-defining illnesses. TREATMENT: Topical steroids, sun-protection and trimethoprim-sulphamethoxazole prophylaxis were prescribed. OUTCOME: Improvement was documented over the arms, but the facial plaques persisted. CONCLUSION: CAD may be a presenting feature of advanced HIV infection.