Thermal balance and metabolic rate during upper respiratory tract infection in infants.

Sequential recordings were made in the first five months after birth of metabolic rate, environmental temperature, and body temperature during sleep at home in 17 infants, each with an older sibling. Further recordings were made whenever an older sibling developed an upper respiratory tract infection (URTI), again four to six days later, and again two weeks later, aiming to achieve recordings before, during, and after an URTI in the infant. The temperature of the room and wrapping of the infant were determined according to their usual practice by the parents. Parents added appropriate wrapping to achieve thermal neutrality based on our calculated values and the measured oxygen consumption. In five of the six infants who developed an URTI in the first three months after birth there was no change or a decrease in metabolic rate at the time of the infection; for infants older than 3 months the metabolic rate increased in three of the five episodes recorded. Peripheral skin temperature decreased at the time of URTI at all ages, though in the older infants it usually increased in parallel with rectal temperature during the latter part of the night, when pyrexia was most common. Infants thus respond to URTI by heat conservation. In the younger infants the lower metabolic rate and the further decrease in this rate with URTI means that fever is rare, and their temperature may decrease on infection. In the older infants the increase in metabolic rate (from an already higher baseline) may result in fever. These differences may contribute to the increased vulnerability of the older infants to heat stress, particularly at the time of acute viral infections.     

Sleep apnoea during upper respiratory infection and metabolic alkalosis in infancy.

Three to four hour polygraphic sleep studies were carried out in 10 infants, five with upper respiratory infection and five with metabolic alkalosis secondary to vomiting during and after recovery from illness. During upper respiratory infection, the main abnormality detected was brief (greater than 3 less than 6 seconds) or prolonged (greater than 6 seconds) attacks of obstructive apnoea. Other indices of apnoea were similar to recovery data. Gross body movements were also increased. In infants with metabolic alkalosis indices of central apnoea were significantly increased when compared with recovery or case control data. Prolonged (greater than 15 seconds) attacks of central apnoea and obstructive apnoea (greater than 6 seconds) were only observed during illness. Gross body movements and periodic breathing were also increased. These findings suggest that the functional consequences of apparently ''mild'' illnesses in young infants may be greater than is generally suspected and perhaps relevant to mechanism(s) of death in sudden infant death syndrome.     

Cardiorespiratory patterns occurring in infants during and after recovery from respiratory tract infection

During and after respiratory tract infections in 29 hospitalized infants, 12 cardiorespiratory measurements were performed on 24-hour recordings of ECG and respiratory activity. These measurements were compared with similar data obtained from 110 age-matched control infants without infection. Respiratory and heart rates during the state of regular breathing were increased during infection, as compared with recordings made after recovery. The numbers of short apneic pauses 3.6 to 6.0 seconds and greater than 6.0 to 12.0 seconds in duration, together with the duration of the overall longest apneic pause per recording, were reduced during infection compared with after recovery. The total durations of periodic breathing and of periodic apnea per recording were also reduced during infection compared with after recovery. These effects were consistent in 27 of the 29 cases, but in two, periodic breathing levels during infection exceeded the 90th percentile in age-matched controls and were reduced after recovery. Measurements made after recovery tended to conform more closely to values in the control infants. None of the 29 infants studied subsequently died or suffered chronic respiratory problems. This study suggests that prolonged apneic pauses or increased numbers of short pauses are not usually a consequence of respiratory tract infection in normal infants.     

Chlamydia trachomatis lower respiratory tract infection in infants

Chlamydia trachomatis may be an important cause of lower respiratory tract infection (LRTI) in infants born to mothers amongst whom there is a high prevalence of sexually transmitted disease. A study of 100 ambulatory infants with signs of LRTI in South Africa showed that 6% had C. trachomatis infection. The majority of the infected infants had received chloramphenicol eye ointment as prophylaxis. Half had previously visited a health facility for the same illness but the infection has been misdiagnosed. Infants with C. trachomatis infection were According to the Centers for Disease Control (CDC) guidelines, 85% were younger than uninfected infants (mean (SD) age of 3.8 weeks (3.2) vs 8.7 weeks (5.4); p=0.03). Clinical signs significantly associated with chlamydial infection were the presence of eye discharge (p = 0.02) or conjunctivitis (p = 0.01). There was a greater rate of rhinorrhoea (p = 0.06) and wheeze (p = 0.03) amongst patients without chlamydial infection. H. influenzae, M. catarrhalis, S. pneumoniae, S. aureus and N. gonorrhoeae were cultured from five different patients infected with chlamydia. The majority of infants with chlamydial infection had mild disease requiring only outpatient anti- biotic therapy.     

MxA protein in infants and children with respiratory tract infection

MxA protein—a stable product of cells stimulated by type I interferons—was examined prospectively for its ability to discriminate between viral and bacterial respiratory tract infections (RTIs) in 182 infants and children. The nasopharyngeal secretions (NPSs) of all of them were tested for MxA using enzyme-linked immunosorbent assay (ELISA), and the whole blood of 92. Seventy-three children undergoing elective surgery served as controls. These apparently healthy children had higher levels of serum MxA than adult controls. Using antigen detection and serology, a viral aetiology was diagnosed in 81/182 cases. The sensitivity and specificity of MxA ELISA were assessed at 92 and 76% for the blood test and at 40 and 91% for the NPS, respectively. The positive predictive value for a viral RTI was superior to a leucocyte count or C-reactive protein when determined only once.     

婴幼儿胃食管反流与呼吸道感染的关系探讨

目的探讨婴幼儿阶段胃食管反流与呼吸道感染的关系。方法用便携式24h食管pH监测仪记录食管下端pH值变化。观察组89例,平均年龄(10.5±0.9)个月,系因下呼吸道感染在呼吸科病房住院患儿,符合下述3条件之一①3个月内有下呼吸道感染史≥1次;②咳嗽喘息经过治疗≥半个月仍不愈;③溢乳史。对照组为26例健康儿,平均年龄(13.7±2.1)个月。结果观察组5项反流指标均高于对照组,差异有显著性(P均<0.001)。观察组病理性GER的检出率为79.8%(71/89例),显著高于对照组(χ2=49.554,P<0.01)。呼吸道感染合并GER的患儿在总反流次数、反流时间≥5min的次数和最长反流时间上婴儿高于幼儿,差异有显著性(P<0.01或<0.05);总pH<4时间百分比和综合评分也是婴儿较幼儿高(P<0.01)。呼吸道感染合并GER的患儿体重偏重眼体重大于第80百分位(P80)演占40.8%(29/71例)。婴儿GER患儿中体重偏重者占一半,与幼儿GER相比,差异有显著性。结论在婴儿期胃食管反流症状较幼儿期常见,溢乳和体重偏重有关;婴幼儿时期胃食管反流病与反复呼吸道感染、呼吸道炎症不愈以及部分哮喘有关。     

The clinical features of respiratory syncytial virus: Lower respiratory tract infection after upper respiratory tract infection due to influenza virus

BACKGROUND: Respiratory syncytial virus (RSV) and influenza virus are the primary pathogens of respiratory tract infection. However, epidemics of influenza virus infection have been observed to interrupt RSV epidemics (termed an epidemiological interference effect). METHODS: At a clinic in Tsuna county, Hyogo prefecture, Japan, a total of 1262 outpatients under 6 years of age with lower respiratory tract infection due to RSV (RSV-LRTI) and upper respiratory tract infection due to influenza virus (FLU-URTI) in three successive winter seasons (1999-2000, 2000-2001 and 2001-2002) were analyzed. RESULTS: The RSV-LRTI epidemic and FLU-URTI epidemic overlapped in each season, but the RSV-LRTI epidemic peak preceded that of the FLU-URTI epidemic. Epidemiological interference between RSV and influenza virus was observed in the second and third season; the number of patients with RSV-LRTI began to decrease after the start of the FLU-URTI epidemic and recovered to some extent after the FLU-URTI epidemic passed its peak. There were no differences in onset age, male-to-female ratio and severity of RSV-LRTI in outpatients before and after the start of the FLU-URTI epidemic in all the three seasons. CONCLUSION: An epidemiological interference between RSV and influenza virus was observed in Tsuna county in two of the three winter seasons. However, there was no difference between the clinical features of the patients with RSV-LRTI before and after the start of the influenza virus infection epidemic. The data suggest that the clinical severity of RSV infection is not changed by the epidemiological interference effect of influenza virus infection epidemics.     

Intermittent treatment with high dose nebulized beclomethasone for recurrent wheezing in infants due to upper respiratory tract infection

BACKGROUND: To investigate if high dose inhaled beclomethasone dipropionate started early after upper respiratory tract infection (URTI) could reduce recurrent wheezing in infants. METHODS: Twenty-six ambulatory infants, 7-12 months of age, with recurrent wheezing during upper respiratory tract infection participated. All experienced at least three wheezing attacks. Those with underlying lung or systemic disease were excluded. Infants were divided into two groups in an open unblinded manner, until 13 patients had been recruited for each group. The groups were similar in risk factors for recurrent wheezing. Four treatment periods of 5 days were planned for group 1. The dose regimen was nebulized beclomethasone 400 mg by mask tid for 5 days. Treatment was started at the very first sign of URTI prior to any sign of wheezing. Group 2 did not receive any preventive treatment and constituted the control group. Symptoms scores were recorded. The number of emergency room visits, hospital admissions and short courses with oral steroids was also noted. RESULTS: Twelve infants completed 48 treatment periods. Five visited the emergency room, only one during beclomethasone therapy. Six received oral steroids, two receiving beclomethasone. No patient was admitted to the hospital. Symptom scores were significantly lower during beclomethasone treatment (p<0.05). No apparent adverse events were reported. CONCLUSIONS: The infant with recurrent wheezing during URTI is a therapeutic challenge. Most of these infants have prodromal symptoms for about 24 hours before wheezing starts. In the present study we observed favorable results, decrease in the number the child wheezed and the number of acute attacks, when high dose inhaled beclomethasone is administered during this critical time.     

Subacute zinc deficiency in children with recurrent upper respiratory tract infection

Serum, urine and hair zinc levels in 20 patients with recurrent upper respiratory tract infection are compared with those of age- and sex-matched controls. Lower hair zinc (1.44 vs 2.00 mmol/g hair,P=0.004) and higher urinary zinc levels (2.2 vs 1.6 mmol/mol creatinine,P=0.05) were found, but no difference in serum zinc. The patients had lowernormal height for age (SD-score 0.2 vs 0.7,P=0.031), there was no difference in weight for height. No correlation was found between the zinc values and the duration of the complaints.     

Systematic review of the treatment of upper respiratory tract infection

OBJECTIVES: To assess the risks and benefits of antibiotic treatment in children with symptoms of upper respiratory tract infection (URTI). DESIGN: Quantitative systematic review of randomised trials that compare antibiotic treatment with placebo. DATA SOURCES: Twelve trials retrieved from a systematic search (electronic databases, contact with authors, contact with drug manufacturers, reference lists); no restriction on language. MAIN OUTCOME MEASURES: The proportion of children in whom the clinical outcome was worse or unchanged; the proportion of children who suffered complications or progression of illness; the proportion of children who had side effects. RESULTS: 1699 children were randomised in six trials that contributed to the meta-analysis. Six trials were not used in the meta-analysis because of different outcomes or incomplete data. Clinical outcome was not improved by antibiotic treatment (relative risk 1.01, 95% confidence interval (CI) 0.90 to 1.13), neither was the proportion of children suffering from complications or progression of illness (relative risk 0.71, 95% CI 0.45 to 1.12). Complications from URTI in the five trials that reported this outcome was low (range 2-15%). Antibiotic treatment was not associated with an increase in side effects compared with placebo (relative risk 0.8, 95% CI 0.54 to 1.21). CONCLUSIONS: In view of the lack of efficacy and low complication rates, antibiotic treatment of children with URTI is not supported by current evidence from randomised trials.     

Association of vitamin D supplementation with respiratory tract infection in infants

Vitamin D deficiency has been reported to be associated with respiratory tract infection (RTI). However, evidence regarding the effects of vitamin D supplementation on susceptibility of infants to RTI is limited. In this prospective birth cohort study, we examined whether vitamin D supplementation reduced RTI risk in 2,244 infants completing the follow‐up from birth to 6 months of age. The outcome endpoint was the first episode of paediatrician‐diagnosed RTI or 6 months of age when no RTI event occurred. Infants receiving vitamin D supplements at a daily dose of 400–600 IU from birth to the outcome endpoint were defined as vitamin D supplementation and divided into four groups according to the average frequency of supplementation: 0, 1–2, 3–4, and 5–7 days/week. We evaluated the relationship between vitamin D supplementation and time to the first episode of RTI with Kaplan–Meier plots. The associations of vitamin D supplementation with infant RTI, lower RTI (LRTI), and RTI‐related hospitalization were assessed using modified Poisson regression. The median time to first RTI episode was 60 days after birth (95% CI [60, 90]) for infants without supplementation and longer than 6 months of age for infants with supplementation (p < .001). We observed inverse trends between supplementation frequency and risk of RTI, LRTI, and RTI‐related hospitalization (p for trend < .001), with the risk ratios in the 5–7 days/week supplementation group of 0.46 (95% CI [0.41, 0.50]), 0.17 (95% CI [0.13, 0.24]), and 0.18 (95% CI [0.12, 0.27]), respectively. These associations were significant and consistent in a subgroup analysis stratified by infant feeding.     

Equal virulence of rhinovirus and respiratory syncytial virus in infants hospitalized for lower respiratory tract infection

Respiratory syncytial virus (RSV) and rhinovirus (RV) are predominant viruses associated with lower respiratory tract infection in infants. We compared the symptoms of lower respiratory tract infection caused by RSV and RV in hospitalized infants. RV showed the same symptoms as RSV, so on clinical grounds, no difference can be made between these pathogens. No relation between polymerase chain reaction cycle threshold value and length of hospital stay was found.     

Reflex apnoea response and inflammatory mediators in infants with respiratory tract infection*

The reflex apnoea response to water stimulation was evaluated in infants with respiratory syncytial virus (RSV) infection and compared to the response in non-infected infants who had sustained an apparent life-threatening event (ALTE) or were siblings of infants who had died of sudden infant death syndrome (SIDS). RSV-infected infants had a significantly (p < 0.05) reinforced reflex apnoea response compared with non-infected infants. There was a significant negative correlation between the concentration of interleukin 1β (IL-Iβ) in pharyngeal secretions and the duration of apnoea (p < 0.01). Increased clinical severity was, however, associated with high (>5.000 pg ml^-1) concentrations of IL-l/J. There was no correlation between apnoea and interleukin 6. These findings may be relevant for the understanding of why apnoea may be the presenting symptom of RSV infection, and offer an explanation of why a proportion of SIDS cases has a history of mild respiratory tract symptoms prior to death.     

新生儿机械通气并下呼吸道感染的相关因素分析

目的探讨新生儿机械通气(MV)并下呼吸道感染的临床特点。方法对68例92份下呼吸道分泌物进行培养及药敏试验，且对并发下呼吸道感染率与胎龄、体重、机械通气持续时间等因素进行分析。结果感染率为61．76％，MV时间越长，感染率越高，以鲍曼不动杆菌、铜绿假单胞菌、肺炎克雷伯杆菌为主要致病菌，药敏对大多数常用抗生素、甚至第3代头孢菌素多不敏感。结论感染率与出生体重和MV持续时间有关，与胎龄无关；革兰阴性杆菌为主要致病菌．耐药率高．应积极防冶．     

12例小儿急性上呼吸道梗阻的病因

目的：总结小儿急性上呼吸道梗阻的发生原因,以减少误诊率和病死率。方法：分析2007年3~12月该院儿科PICU住院的全部急性上呼吸道梗阻患儿(12例)的临床资料。全部病例均完成了胸部X线片、喉镜检查、喉部及肺部CT扫描及三维重建检查。结果：12例患儿院外诊断为先天性单纯性喉喘鸣（8例,67%）、急性喉炎等。入院后12例中4例(33%)经喉部CT扫描诊断为先天性甲状舌管囊肿, 1例(8%)为咽后壁脓气肿,1例(8%)为左颈部淋巴管瘤,2例(16%)为声门下狭窄,4例(33%)为急性喉炎。院外诊断与入院后诊断相比误诊率为67%。结论：小儿急性上呼吸道梗阻喉喘鸣非常容易误诊,尤其是婴幼儿,必须排除引起喉喘鸣的其他病理因素(如占位病变,先天性因素等)方可拟诊先天性单纯性喉喘鸣。甲状舌管囊肿是新生儿及婴幼儿喉喘鸣的常见原因之一,临床误诊率较高。因此,建议将喉镜检查作为新生儿及婴幼儿喉喘鸣的常规筛选手段,有条件者可进行喉部、肺CT扫描及三维重建检查。［中国当代儿科杂志,2009,11（2）：116-119］