T. F. Fok

Natural history and predictors for progression of mild childhood obstructive sleep apnoea

Aims: The natural history of mild childhood obstructive sleep apnoea (OSA) was examined and factors associated with disease progression were identified. Methods: Subjects were recruited from an epidemiological study which examined the prevalence of OSA in Chinese children aged 6–13 years. The first 56 consecutive children identified with mild OSA (apnoea-hypopnoea index 1–5) were invited for a repeat assessment 2 years after the diagnosis. Results: 45 children participated in the follow-up study, in 13 of whom (29%) the OSA was found to have worsened. Compared with those in whom OSA had not worsened, the worsened OSA group had a greater increase in waist circumference, a higher prevalence of large tonsils (occupying ⩾50% of the airway) at both baseline and follow-up, and a higher prevalence of habitual snoring at both baseline and follow-up. The presence of large tonsils had a positive predictive value of 53% and a negative predictive value of 83% for worsening OSA over a 2-year period. Multivariate linear regression analysis showed that the change in obstructive apnoea-hypopnoea index was associated with age at baseline (β (SE)u200a=u200a−0.92 (0.34), pu200a=u200a0.009), gender (maleu200a=u200a1; femaleu200a=u200a0) (β (SE)u200a=u200a4.69 (1.29), p<0.001), presence of large tonsils at baseline (β (SE)u200a=u200a4.36 (1.24), pu200a=u200a0.001), change in waist circumference (β (SE)u200a=u200a0.30 (0.09), pu200a=u200a0.002) and persistently large tonsils (β (SE)u200a=u200a5.69 (1.36), p<0.001) over the 2-year period. Conclusions: Mild OSA in the majority of children does not resolve spontaneously. Subjects with tonsillar hypertrophy, especially boys, should be closely monitored to allow early detection of worsening OSA. Weight control should be stressed in the management of childhood OSA.

Cardiac remodelling and dysfunction in children with obstructive sleep apnoea: a community based study

Background: Childhood obstructive sleep apnoea (OSA) is suggested to be associated with cardiac structural abnormalities and dysfunction but existing evidence is limited and the treatment effect on echocardiographic outcome remains controversial. Objective: To examine the presence of subclinical cardiac abnormalities in childhood OSA and the effects of treatment on cardiac changes. Methods: Polysomnography (PSG) and echocardiographic examinations were performed in 101 children aged between 6 and 13 years who were invited from a community based questionnaire survey. They were classified into a reference group (apnoea–hypopnoea index (AHI) <1, nu200a=u200a35), mild OSA group (AHI 1–5, nu200a=u200a39) and moderate to severe group (AHI >5, nu200a=u200a27) based on the PSG results. Treatments, including adenotonsillectomy or nasal steroids, were offered to the mild and moderate to severe OSA groups. Results: The moderate to severe OSA group had greater right ventricular (RV) systolic volume index (RVSVI), lower RV ejection fraction (RVEF) and higher RV myocardial performance index (RVMPI) than the reference group. They also had more significant left ventricular (LV) diastolic dysfunction and remodelling with larger interventricular septal thickness index (IVSI) and relative wall thickness than those with lower AHI values. The moderate to severe OSA group had an increased risk of abnormal LV geometry compared with the reference group (odds ratio 4.21 (95% CI 1.35 to 13.12)). Log transformed AHI was associated with RVSVI (pu200a=u200a0.0002), RVEF (pu200a=u200a0.0001) and RVMPI (p<0.0001), independent of the effect of obesity. Improvement in RVMPI, IVSI and E/e′ were observed in those with a significant reduction in AHI (>50%) comparing 6 month with baseline data. Conclusions: OSA is an independent risk factor for subclinical RV and LV dysfunction, and improvement in AHI is associated with reversibility of these abnormalities.

Lesson from performing SCORADs in children with atopic dermatitis: Subjective symptoms do not correlate well with disease extent or intensity

Backgroundu2002 Atopic dermatitis (AD) is a distressing disease associated with pruritus and sleep disturbance. It is not known how well these symptoms correlate with the extent and intensity of eczematous involvement. We evaluated whether: (i) the level of sleep loss correlates with pruritus and (ii) the level of pruritus correlates with the extent or severity of AD in children according to the SCORing Atopic Dermatitis (SCORAD) index.

Inhalant Allergens as Risk Factors for the Development and Severity of Mild-to-Moderate Asthma in Hong Kong Chinese Children

Sensitization to aeroallergens has been found to be a dominant risk factor for asthma in population-based studies. Similar results in asthmatic children being managed in hospital-affiliated outpatient clinic have not been established. We therefore conducted a case-control study on asthmatic children attending a university hospital-based outpatient clinic to investigate the pattern of aeroallergen sensitization, and to assess the correlation between asthma control and the presence of allergen-specific IgEs. Asthmatic patients underwent a questionnaire assessment of their asthma control, skin prick tests (SPT) for allergen sensitization, and spirometric evaluation. Peripheral blood was collected from all subjects for in vitro serum specific IgE assay (RAST) to common aeroallergens. One hundred and seventy asthmatics (aged 9.8 ± 3.7 years) and 57 age-matched control subjects were enrolled. Our patients had a median of two asthmatic attacks within 6 months prior to evaluation, and their median Disease Severity Score was 13. The median FEV1 in our asthmatic children was 98%, whereas serum logarithmic total IgE concentrations in patients and controls were 2.57 and 2.09, respectively (p<0.0001). More than 85 % of our asthmatic children were sensitized to house-dust mite (HDM), and sensitization to HDM and cat, as well as elevated serum total IgE concentration, was a significant risk factor for the development of asthma in this cohort. Several objective measures of asthma severity, as well as FEV1, correlated significantly with sensitization to HDM, pets, and cockroaches. In conclusion, indoor aeroallergens are one of the risk factors for the development and severity of mild-to-moderate asthma in Chinese children in Hong Kong.

Use of Anthropometric Indices to Reveal Nutritional Status: Normative Data from 10,226 Chinese Neonates

Background: Measures of body size at birth are widely used for the evaluation of prenatal growth but limitations exist in their interpretation. Objective: To establish the percentile curves for the six common anthropometric indices (PI: ponderal index, BMI: body mass index, THR: thigh circumference/head circumference ratio, MAC/OFC: mid-arm circumference/head circumference, W/OFC: weight/head circumference, and W/L: weight/length) and determine the best anthropometric index for evaluating intrauterine nutritional status in Chinese neonates. Methods: A prospective cross-sectional anthropometric study was carried out. The anthropometric measurements were performed according to the Hall’s guidelines within 48 h of birth. Results: 10,226 infants (5,422 males, 4,804 females) with gestation 28–42 weeks from 12 hospitals were included for analysis. All of the six anthropometric indices correlated well with total skinfold thickness (T-SF, the sum of triceps skinfold thickness and subscapular skinfold thickness; p < 0.0001). Among the six anthropometric indices, W/L showed the highest correlation coefficient with T-SF (r = 0.622; p < 0.0001 in whole group, r = 0.653; p < 0.0001 in preterm infants, r = 0.612; p < 0.0001 in term infants). Conclusion: The present study establishes the gender-specific reference curves for the six important anthropometric indices in Chinese infants. W/L is a readily available index at birth that reflects the intrauterine nutritional state.

Brief case series: montelukast, at doses recommended for asthma treatment, reduces disease severity and increases soluble CD14 in children with atopic dermatitis.

Background: The choice of oral therapeutic agents for the treatment of atopic dermatitis (AD) in children is limited. Montelukast, a specific cysteinyl leukotriene (LT) receptor antagonist, may be useful in alleviating AD symptoms. Objective: To evaluate the clinical and immunological effects of montelukast in children with AD. Methods: After a 2‐week run‐in, children with AD were started on oral montelukast 5u2005mg once‐daily for children <12 years of age and 10u2005mg for older children. The clinical severity of AD as indicated by the SCORing Atopic Dermatitis (SCORAD) score, and serum soluble CD14 and urinary leukotriene E4 (LTE4) concentrations were evaluated at baseline and the end of a 3‐month treatment period. Results: Four boys and three girls, with a median (range) age of 12 (3–16) years, participated in the study. The total SCORAD was reduced in five patients (by 30–84%) and remained similar in two patients. Their median (range) SCORAD scores before and after treatment were 34.7 (16.5–54.8) and 17.0 (6.9–36.9) (pu200a=u200a0.046). The intensity component of SCORAD also decreased from 5 (2–10) to 3 (1–7) (pu200a=u200a0.042). Serum sCD14 levels increased significantly from 5533 (4575–6452) ng/ml to 6259 (5617–8988) ng/ml (pu200a=u200a0.028), whereas urinary LTE4 levels remained the same (pu200a=u200a0.735). Conclusions: Montelukast, at doses recommended for asthma treatment, resulted in over 30% reduction in the total SCORAD in some children. Treatment with montelukast may also be associated with deviation of the immune system towards the Th1‐specific pathway.

Recurrent and Novel Mutations of GCDH Gene in Chinese Glutaric Acidemia Type I Families

Glutaric acidemia type I is caused by mutations of the glutaryl‐CoA dehydrogenase (GCDH) gene resulting in loss of GCDH enzyme activity. Patients present with progressive dystonia and lesions in basal ganglia. Dietary treatment, when instituted from the early neonatal period, markedly reduces dystonia and morbidity. Early diagnosis and prenatal diagnosis will be facilitated by knowledge of locally prevalent GCDH mutations. Several common GCDH mutations have been found in different ethnic groups. GCDH mutations were studied in 5 Chinese glutaric acidemia type I families. We detected two novel recurrent mutations (A219T and IVS10‐2A>C) which were found in two unrelated families. An asymptomatic carrier of IVS10‐2A>C was also found on screening of 120 individuals. Other mutations were identified, including two other novel (R386G & IVS3+1G>A) and two known mutations (G178R & R355H). Fibroblasts from patients carrying the novel mutations were confirmed to be deficient for GCDH activity. This is the first report of GCDH mutations describing recurrent mutations in Chinese patients. The carrier rate of IVS10‐2A>C may be particularly high in Chinese.

Resting energy expenditure, oxygen consumption and carbon dioxide production during sleep in children with atopic dermatitis

Background: Pruritus and scratching are cardinal symptoms of atopic dermatitis (AD). Sleep and growth may also be affected in children with moderate‐to‐severe AD. We evaluated whether resting energy expenditure (REE), oxygen consumption (VO2) and carbon dioxide production (VCO2) in various stages of sleep were influenced by the disease severity. Methods: Disease severity was evaluated by the scoring atopic dermatitis (SCORAD) index. All‐night polysomnography was performed and REE, VO2 and VCO2 were measured. Results: Twenty children (13 boys and seven girls) with AD and eight controls were recruited. The median overall SCORAD for our AD patients was 36.8. The total sleep efficiency was lower in patients with severe AD than that obtained in the control group (median: 72% versus 88%; pu200a=u200a0.039). When compared with mild‐to‐moderate disease (SCORAD⩽40) and controls, REE, VO2 and VCO2 in patients with severe AD (SCORAD>40) did not differ in sleep stages I and II combined, stages III and IV combined or the rapid eye movement (REM) stage. REE, VO2 and VCO2 in these sleep stages did not show significant correlation with the overall and the three components of the SCORAD scores. Conclusions: Children with AD do not appear to have significant disturbance in their resting energy consumption, oxygen consumption and carbon dioxide production during sleep. These parameters do not appear to correlate with the symptomatology of pruritus and sleep disturbance. We speculate that deranged metabolism during sleep is unlikely in children with AD.

Reasons for new referral non‐attendance at a pediatric dermatology center: A telephone survey

Background: Non‐attendance at pediatric dermatology outpatient clinics is a significant problem. Aim: To determine the reasons and predictors for non‐attendance. Methods: New referral non‐attenders to the pediatric dermatology clinic of a university teaching hospital were contacted by telephone and reasons for non‐attendance enquired about. Results: Sixty‐three patients (20%) did not attend the first appointment over a 15‐month study period. The mean±SD waiting time between attenders and non‐attenders was 99±46 days and 113±41 days (pu200a=u200a0.029). A total of 49% of attenders and 60% of non‐attenders were males. Telephone contact of non‐attenders who did not schedule any re‐appointment spontaneously (nu200a=u200a54), found that the mother was the informant in 85% of cases. Approximately 80% of informants gave one reason for non‐attendance; approximately 20% gave two or more reasons. The most common reasons for non‐attendance were ‘skin condition already improved’ (46%) and ‘forgot appointment’ (25%). ‘Long waiting time’ did not appear to be a common reason for non‐attendance. There was no significant association between age of patient, urgency of booking and non‐attendance. Conclusions: We confirm that there is a significant non‐attendance rate in pediatric dermatology new referrals. Many of the skin conditions reportedly resolve spontaneously. As there is no identifiable predictor for non‐attendance apart from a longer waiting time, any maneuvers or interventions to improve attendance rate are unlikely to be significantly fruitful.

Overview of common inherited metabolic diseases in a Southern Chinese population of Hong Kong

BACKGROUNDnThe Joint metabolic clinic at the Prince of Wales Hospital was established in January 1997 to provide a comprehensive multi-disciplinary care to patients with inherited metabolic diseases (IMDs). Patients are referred from both within and outside our hospital. Until July, 2000, more than 40 patients and families with 20 different biochemical diagnoses attend the clinic for regular follow up. A pattern of more common IMDs among Hong Kong Chinese emerged from our case registry. In order to advance the understanding of Chinese metabolic diseases, we examined the molecular basis of those diseases with unique features in Chinese or were locally prevalent. Mutations were found in patients with primary carnitine deficiency, ornithine transcarbamylase deficiency, X-linked adrenoleukodystrophy, glutaric aciduria type I, and galactosemia. We also analyzed the mutations in multiple carboxylase deficiency and Niemann-pick type C on four families.nnnCONCLUSIONSnAlthough IMDs are a significant cause of mortality and morbidity among pediatric patients, with a better understanding of the molecular genetics of these diseases, prenatal diagnosis of these common IMDs will be facilitated, which is currently the most effective way of controlling IMDs.