Tracheomalacia-Lethal Factor in a 17-month-Old Child

A case is reported of a child who died at age 17 months after having repeated respiratory incidents, probably related to mild infections. After a fatal respiratory episode, tracheomalacia was detected at necropsy. No other abnormalities were found. This condition, unless suspected clinically, could easily be overlooked at necropsy.

Effect of parental smoking on cotinine levels in newborns

BACKGROUND

Smoking is a major risk factor for cot death. Many infants smoke passively as a result of parental smoking. This paper reports on infants exposed to a smoking environment and how they accumulate metabolites of cigarette smoke, such as cotinine, which may be physiologically harmful.

AIM

To assess cotinine levels in infants of smoking parents.

METHOD

Cotinine excretion in urine was assessed in 104 infants, of whom 71 had smoking parents and 33 had non-smoking parents. All cotinine levels were measured at approximately 12 weeks of age. The subjects were selected from a database of infants in developmental physiological studies which assessed the impact of various factors on early postnatal development.

RESULTS

On average babies with at least one parent who was a current cigarette smoker excreted 5.58 (95% CI 3.4 to 9.5) times as much cotinine in the urine as did the babies of non-smoking parents. Maternal smoking was the largest contributing factor. Co-sleeping (p = 0.037) and the minimum room temperature (p = 0.028) were significant contributory factors.

CONCLUSION

Infants from smoking households accumulate cotinine, a metabolite of nicotine, which may have a detrimental effect on the cardiorespiratory system.

Participation of disadvantaged parents in child care research

AIM

To assess the level to which parents from deprived and socially dysfunctional families collaborate in complex and time-consuming research.

DESIGN

Home-based study, of early physiological development in infants from a severely deprived area. Overnight continuous recordings of deep-body temperature with twice daily urine collection, parental daily diary of life-events and completion of child care social and psychological assessment by interview questionnaire. Measurements taken between age 6-12 weeks, each lasted 8-12 h per night, averaging four nights per baby. Level of parental participation assessed in relation to ongoing lifestyle pressures. Setting Home based. Inner city deprived estate.

PARTICIPANTS

Random sample of mothers with newborn healthy infants.

MEASUREMENTS

A total of 87 overnight deep body temperature recordings were made on 22 infants each lasting 8-12 h; 174 urine samples were taken; and 22 sets of questionnaires were completed.

RESULTS

Of 62 inner city deprived parents, 39 (62%) agreed to participate. 22 (35%) completed the study. Ongoing lifestyle pressures were high including incidents of burglary, fire and family violence. Family and partner pressures and life crises overwhelmed 10 non-participations.

CONCLUSIONS

Research partnerships can be developed with underprivileged families facing severe life-events. Parents were highly motivated to complete what they perceived as important infant care research.

Early physiological development of infants with intrauterine growth retardation

OBJECTIVES

To assess the patterns of early postnatal physiological adaptation and maturation in intrauterine growth retarded (IUGR) infants by measuring changes in sleeping deep body temperature, heart rate, and concentrations of urinary cortisol.

SETTING

At home.

PATIENTS

Sixty five IUGR babies and 127 controls matched for sex, social class, and levels of parental smoking.

RESULTS

Night time sleeping deep body temperature, heart rate, and cortisol excretion fell with age, eventually establishing an adult type diurnal rhythm of physiological function. Minimum overnight temperature showed a linear decline with age (p < 0.001), but the IUGR infants and the controls had significant differences in intercept (p = 0.007) and slope (p = 0.02). The estimated rate of decline per week was 0.020 degrees C for IUGR infants and 0.031 degrees C for controls. Maximum temperature did not show similar changes. IUGR infants had a mean (SE) age adjusted minimum overnight heart rate that was 4.2 (1.5) beats/min (p = 0.005) higher than controls. Overnight cortisol/creatinine ratios declined with age at a rate of 4.1% per week (log ratio -0.421 (0.0165), p = 0.01), but the ratio for IUGR infants was on average 42% higher (log ratio 0.35 (0.11), p = 0.002) than for controls of the same age. Morning cortisol concentrations did not show a similar pattern.

CONCLUSIONS

Postnatal physiological adaptation and maturation of IUGR infants is slower than normal and therefore they remain in a physiologically immature state for longer. The higher heart rates and greater cortisol excretion in such infants may be precursors to hypertension and cardiovascular disease seen in adults.

Overnight deep body temperature and urinary cortisol excretion in infants from economically deprived areas

OBJECTIVES

To assess the pattern of postnatal physiological maturation in economically deprived infants by measuring the age-related changes in deep body temperature during night-time sleep.

SETTING

Inner city Leicester, UK.

PARTICIPANTS

Forty-eight infants aged 6-21 weeks from economically deprived areas and 87 control infants from more affluent areas.

OUTCOME MEASURES

Average deep body temperature between 2 and 4 h after bedtime, overnight and early morning urinary cortisol excretion.

RESULTS

Both groups showed a decline in overnight deep body temperature with age that averaged 0.030 degrees C per week (SE = 0.003). Over the age range studied, the average age-adjusted overnight temperature in the infants from deprived homes was 0.090 degrees C (SE = 0.028) higher than that for the affluent group (P = 0.001). Deprived infants had on average 51% higher overnight urinary cortisol and 80% higher morning cortisol. The differences remained when the effects of room temperature, clothing, smoking, birthweight and gestational age were taken into account.

CONCLUSION

These indicators of postnatal physiological maturation suggest that infants from economically deprived homes mature less quickly. This might increase their vulnerability to illness.

Prolonged hypothermia following respiratory syncytial viral infection in infancy

Following proven respiratory syncytial viral infection, a previously healthy 2 year old boy displayed notable persistent hypothermia-the lowest temperature being 34.2 degrees C. No obvious ill effects were observed.

Sleeping O2 saturation levels in infants

Longitudinal recording of O2 saturation during night-time sleep of 82 infants show significantly more falls below 93% in females and infants of mothers who smoke. Implications are discussed.

Deep body temperature changes in twins

Twins show differences in physiological maturity within and between twin sets; where one infant is 5-weeks later than its sibling; while one pair may both be slow but develop together. Zygosity, birth weight and sex may be contributory but not causative factors. How vulnerability to illness may be affected, is discussed.

Child care decisions: parental choice or chance?

AIM

A study of the context of child care decision making by inner city and suburban mothers, using parents to help develop and administer a semi-structured questionnaire.

METHODS

A total of 131 mothers were interviewed (73 inner city and 58 suburban) at home.

RESULTS

Inner city mothers were more likely to bottle feed, smoke and adopt risky infant sleeping positions, for example the settee. Virtually all babies (98%) were fully vaccinated and placed prone (95%) to sleep at night. Inner city mothers smoked (71%) despite the known health risks and continued postnatally (55%), mainly as a means of relieving stress. In total, 30% of inner city mothers wanted to breast feed; 19% had succeeded to 6-8 weeks postnatally. Bottle feeding helped both mother and baby to have uninterrupted nights of sleep. Suburban mothers (59%) succeeded in breast feeding, with others choosing bottle feeding mostly because of returning to work. The average weekly alcohol consumption, 32 units inner city and 15 units suburban, was taken in weekend binges by inner city parents, but in daily small amounts by suburban mothers.

CONCLUSIONS

The well-being of the baby was the prime concern of all mothers, irrespective of social background. However, inner city mothers made rational decisions to smoke and bottle feed to reduce the impact of stress and allow the mother much needed respite for the good of the entire family.

Changes in body temperature and urinary cortisol after routine immunization in babies with intrauterine growth retardation

AIM

To investigate whether infants with intrauterine growth retardation (IUGR) experience different changes in temperature and cortisol excretion after routine immunization compared with normal healthy infants.

METHODS

Overnight deep body temperature and urinary cortisol to creatinine ratios were measured on the night after immunization and a control night in normal and IUGR infants.

RESULTS

In 60 normal infants, first vaccination at about 10 wk of age led to a significant increase in minumum overnight temperature compared to the control night, mean rise 0.25 degrees C (95% CI, 0.12 to 0.38). In 35 IUGR infants the mean rise in temperature between immunization night and control night was 0.35 degrees C (95% CI, 0.15 to 0.55). The increases in minimum temperature did not differ significantly between the normal and IUGR infants (p = 0.11). Cortisol to creatinine ratios measured from overnight urine samples showed that 23 IUGR infants had consistently higher levels than 39 normal infants: control night medians 34 and 15 (p=0.01) and immunization night medians 56 and 26 (p = 0.02), respectively. However, the percentage increase did not differ significantly between the IUGR infants and the normal infants. A smaller number of second immunizations were studied, but no significant differences were found.

CONCLUSION

These results suggest that although the impact of immunization is the same for IUGR and normal infants, because IUGR infants are less mature and at greater stress before immunization, the absolute levels that they experience after immunization are higher than those for normal infants.

Relations between the development of patterns of sleeping heart rate and body temperature in infants

Overnight patterns of rectal temperature and heart rate were recorded from 119 normal infants at weekly intervals from 7 to about 16 weeks of age. All data were collected in the infants' own homes. As previously reported, different infants developed an adult-like night time rectal temperature pattern abruptly at different ages. When heart rate data were collated by age, there was an apparently gradual fall in sleeping heart rate from 7 to about 14 weeks of age. This was, however, an artefact of data collation. Individual infants showed abrupt falls in heart rate at the time that the adult-like body temperature pattern appeared, but this occurred at different ages in different babies, so when data were collated cross sectionally, an apparently gradual fall resulted. The relation between the developmental changes in sleeping heart rate and rectal temperature was different in boys and girls, with girls showing a more abrupt and greater change in heart rate at the time of development of the adult-like body temperature pattern. Infants whose parents smoked had significantly lower heart rates once the adult-like body temperature pattern had appeared.

Higher rectal temperatures in co-sleeping infants

The effect on deep body temperature of infants co-sleeping (with either or both parents) is investigated in this case control study. Overnight continuous recordings of rectal temperature were made from 34 babies co-sleeping with one or both parents throughout the night and 34 infants matched for age, feeding regimen, parental smoking, thermal environment, sleeping position, and sex who slept alone. The co-sleeping infants had significantly higher rectal temperatures from two hours after bedtime, when the initial fall in sleeping body temperature was complete. The mean rectal temperature of co-sleeping infants between two and eight hours was 0.1 degree C higher than that of infants sleeping alone (p < 0.04). Given the very small variance in rectal temperature this probably reflects a considerable physiological difference between the two groups.

Factors affecting rectal temperature in infancy

The recordings of 1197 overnight rectal temperatures from infants of up to 24 weeks of age have been analysed with respect to 12 variables, including a number of risk factors for sudden infant death syndrome. Multivariable regression was used to identify if parental smoking, bottle feeding, sleeping position, and birth weight affect the overnight rectal temperature of infants. The rectal temperature, averaged over the period from three to five hours after the infants were put to bed, correlated well (R = 0.36) with the collected variables. An increase in the infant's age, birth weight, and the supine sleeping position all decreased the night time rectal temperatures. However, an increase in the night time room temperature, weight, and the combination of bottle feeding and parental smoking produced an increase in rectal temperature. The individual effects of bottle feeding and parental smoking were not significant. The results show that some of the major risk factors have the effect of raising the rectal temperature of sleeping infants.

Prone sleeping infants have a reduced ability to lose heat

The heat loss coefficients of a group of infants have been calculated and compared to see if there is a difference in the ability to lose heat between prone and non-prone sleeping infants. For a group of 43 infants aged 4-29 weeks, a simple mathematical model of exponential cooling in a body has been fitted to the fall in rectal temperature which occurs in infants at bedtime. One of the parameters yielded by the fitting process is the coefficient of thermal heat loss. After validation against the estimated heat loss from supine sleeping infants, the heat loss coefficient was compared at different sleep positions and gender. The mean heat loss coefficient, measured from the non-prone sleeping infants (0.269 W/degrees C, S.D. 0.197) agreed well with the value calculated for supine sleepers with the same tog levels (0.4 W/degrees C). Prone sleeping infants were found to have a considerably smaller heat loss coefficient which was approximately 60% of the value for non-prone sleeping infants (P = 0.000097). Female infants were found to have a heat loss coefficient that was approximately 70% of that of male infants but this gender difference was only significant (P = 0.025) for non-prone sleeping infants. These results suggest that infants sleeping in the prone position may be unable to lose heat as rapidly as those infants sleeping non-prone.

Urinary excretion of cortisol after immunisation

Urinary cortisol excretion and rectal temperature were measured in 66 infants before and after immunisation against diphtheria, tetanus, pertussis, and Haemophilus influenzae type b. Immunisation produced a significant increase of rectal temperature the next night at all ages. Infants without an adult-like night time body temperature pattern had a significant increase in urinary cortisol excretion night and morning after immunisation. Once an adult-like night time body temperature pattern developed immunisation no longer significantly raised urinary cortisol output.

Lower body temperature in sleeping supine infants

Night time rectal temperature recordings were made from 103 infants sleeping in their own home in different sleeping positions. In most cases sleeping position was verified by video monitoring throughout the night. In the period before an adult-like night time body temperature pattern appeared there was no significant effect of sleeping position upon night time body temperature, in line with previous reports. Once an adult-like night time temperature pattern appeared, infants sleeping supine reached significantly lower rectal temperatures than those sleeping prone or lateral. Babies sleeping supine moved significantly more during the night and were more likely to uncover their hands and arms. These findings suggest that supine sleepers are in a different physiological condition from those sleeping prone or lateral, which may be associated with their lower vulnerability to sudden unexpected infant death.

Interactions between infant care practices and physiological development in Asian infants

Asian infants are less likely to suffer cot death despite apparently higher prevalence of some risk factors. This paper compares the development of night time body temperature patterns in a small sample of Asian babies with the pattern already established for white infants, where babies who develop an adult-like night time temperature pattern later than usual share characteristics with victims of SIDS. The Asian infants had similar body temperature patterns to whites, but tended to develop the adult-like pattern later, not earlier as might have been expected. More Asian infants than white in our sample slept in the parental bed, and, before the adult-like body temperature patterns appeared, co-sleeping infants had higher body temperatures than those in their own cots. Asian infants slept in significantly warmer rooms than whites, but under similar amounts of bedding. These studies do not therefore reveal any physiological difference between Asians and whites which might account for low vulnerability to cot death, indeed, if anything the reverse.

Body temperature changes before minor illness in infants

This study aimed to examine the overnight temperature pattern of babies during the prodromal phase of minor illnesses. The overnight rectal temperature pattern of 123 babies was recorded weekly from about 6 to at least 16 weeks old, while parents maintained detailed records of signs of illness. By analysis of patterns of signs and visits to the general practitioner, 86 periods of minor illness were identified, mostly upper respiratory tract infections, though it was not usually possible to identify the infection by conventional virology. Data were analysed separately for babies who had developed an adult-like night time temperature pattern and those who had not. In both groups, obvious signs of illness were preceded by a disturbance of night time temperature pattern. Temperature was significantly raised over control weeks, though few babies were clinically febrile. The greatest temperature disturbances were seen in the three days before illness, though some disturbances were seen up to seven days before. A similar disturbance of temperature was seen the night after diphtheria, pertussis, and tetanus immunisation, and individual responses to natural infection and immunisation were well correlated, suggesting that the temperature change is more a function of the host response than the infecting agent.

Factors affecting the development of night time temperature rhythms

The rectal temperature of 26 infants between 6 and 16 weeks old was monitored continuously for one night each week. Rectal temperature always decreased with sleep but the minimum temperature attained changed with age. Some time between 8 and 16 weeks old the minimum sleeping rectal temperature decreased abruptly from around 36.8 degrees C to around 36.4 degrees C. This change was complete within one week and did not normally revert unless the infant became ill. Some infants changed as early as 8 weeks old, others not until 16 weeks. Breast fed infants changed significantly earlier than bottle fed infants. Girls changed significantly earlier than boys. First born infants changed significantly earlier than second or subsequent infants. Early changes were significantly more likely to be sleeping lateral or supine, and to have older mothers. They tended to come from more affluent families. There was no association between the time of change and the thermal environment in which the infant slept or the number of episodes of minor illness in the early weeks of life.

Sleeping position and rectal temperature

The effects of sleeping position upon body temperature were assessed by continuous monitoring of rectal temperature in 137 babies sleeping at home under conditions chosen by their parents. There were three groups of subjects: (1) normal babies aged 12-22 weeks whose temperature rhythms were developed, (2) normal babies aged 6-12 weeks who were developing their night time temperature rhythms, and (3) babies the night after diphtheria, pertussis, and tetanus immunisation, whose temperature rhythms were disturbed. Sleeping in the prone position was not associated with higher rectal temperatures at any time of night in young babies, nor did it exaggerate the disturbance of rectal temperature rhythm after immunisation. In older normal babies the prone position did not disturb rectal temperature in the first part of the night, though prone sleepers warmed a little faster prior to walking, especially in warm conditions. Prone sleepers were, however, born earlier in gestation and tended to be of lower birth weight. Normal babies can therefore thermoregulate effectively whatever their sleeping posture, even in warm conditions, though the prone position may make it slightly more difficult to lose heat. It is difficult to see how the prone position, even interacting with warm conditions, could induce lethal hyperthermia in otherwise normal babies. Perhaps the prone position is associated with other risk factors for sudden infant death syndrome.

Development of night time temperature rhythms over the first six months of life

Continuous recordings of night time rectal temperature were made at regular intervals over the first six months of life in 49 babies. In the first two weeks of life rectal temperature changed little overnight, but by 6 weeks of age rectal temperature at bedtime was significantly higher than later in the night. By around 12 weeks of age sleeping deep body temperature fell below 36.5 degrees C, and by 16 weeks of age all babies exhibited a consistent rhythm of rectal temperature. This fell by about 0.8 degrees C within two hours of bedtime, and then remained low until an hour or two before waking. As babies got older the mean interval between bedtime and first disturbance of parents got longer. Sleeping rectal temperature fell below 36.5 degrees C at about the time babies slept for seven hours. From 6 weeks of age, as individual baby's rectal temperatures fell more with sleep, sleep got longer.

Rectal temperature of normal babies the night after first diphtheria, pertussis, and tetanus immunisation

Continuous rectal temperature recordings were made from 32 babies the night after their first diphtheria, pertussis, and tetanus immunisation and compared with recordings made before immunisation. Tog values of clothes and wrapping and room temperatures were also recorded. We found that immunisation the day before disturbs the normal night time rhythm of deep body temperature. The rectal temperature of immunised babies was significantly higher than non-immunised babies from two hours into the night. We also found that there were considerable individual variations in the extent of disturbance of temperature rhythm. They were not correlated with thermal environment. There is no reason to suppose that these mild physiological responses to immunisation are in any way harmful.

Factors influencing the body temperature of 3-4 month old infants at home during the day

Continuous recordings of rectal temperature were made from 40 normal infants, aged 3-4 months, at home during two days of normal activities. We found that the rectal temperature of a normal, healthy baby may vary from 36.0 degrees C at night to 37.8 degrees C during active periods of the day. During daytime sleep rectal temperature fell, but to a lesser extent, and for less time than during night time sleeps. Feeds raised the temperature unless the baby slept, when they reduced the rate of fall of temperature. Bottle feeds affected temperature more quickly than breast feeds. The changes in temperature during sleep and after feeds were independent of the room temperature or thermal insulation of clothing and wrapping.

Use of thermographic imaging to study babies sleeping at home

Two 3 month old infants sleeping under different thermal conditions were found to maintain similar deep body temperatures. Thermographic imaging suggested that though the uncovered head is the main source of heat transfer, other parts of the body such as the hands may be used when necessary.

Disturbed nights and 3-4 month old infants: the effects of feeding and thermal environment

Parents completed a prospective diary of a night's sleep for 87, 3-4 month old infants at home whose body temperatures were continuously recorded. We found that about half of the babies disturbed their parents in the night. Breast fed babies were more likely to wake parents in the middle of the night. The babies who disturbed their parents in the middle of the night were significantly more heavily wrapped in significantly warmer rooms. We suggest that discomfort from efforts at active thermoregulation in warm environments may lead some babies to disturb their parents at 'unsocial hours'.

Keeping babies warm: have we got it right?

Concern has recently centred on the risks of babies overheating in their cots at night. We review the conditions under which babies sleep at home, and their effects on body temperature. Parents do not choose room heating, clothing and wrapping at random, but according to a 'formula' based on perceived risk to the infant of cooling. This formula allows 95 per cent of 3-4 month babies to produce controlled fall in body temperature at night, but most have to cooly by active thermoregulation, which relies heavily on the head as a route of heat loss. We conclude with some general recommendations about room heating and wrapping of babies which may reduce the risk of thermal stress during sleep.

Sleeping body temperatures in 3-4 month old infants

Rectal, skin, and ambient temperatures were continuously recorded overnight from 3-4 month old normal infants in their home cots under conditions of room temperature and wrapping chosen freely by parents. It was found that rectal temperature was above 37 degrees C when infants were put down, but fell rapidly to 36.4 degrees C within one and a half hours, then stabilised for a few hours before rising steadily. This pattern was tied more closely to the time of putting down than time of day. The extent and rate of temperature fall did not correlate with any feature of the thermal environment. We also found that skin temperature changed much less than rectal temperature over the night, and for the first two hours in the cot there was no relation between skin and rectal temperature. There is therefore a well organised, endogenous rhythm of temperature in 4 month old infants.

The thermal environment in which 3-4 month old infants sleep at home

The thermal insulation of clothing and wrapping (tog value), room temperature, and body temperature was measured for 3-4 month old infants sleeping in their home cots under conditions chosen freely by parents during a cold winter. We found that ambient temperature averaged 18.4 degrees C when infants were put down, but fell by an average of 4.4 degrees C during the night. Minimum room temperature correlated with outside temperature, but most rooms were heated to some degree; smaller babies were kept in warmer rooms. The tog value of clothing before putting the baby down averaged 5.1, supplemented by 9.6 tog units of wrapping in the cot--a 188% increase for a 4.4 degrees C drop in temperature. Total tog of clothing and wrapping correlated negatively with minimum room temperature; smaller born babies tended to be more heavily wrapped. Despite the large increase in insulation in the cot, most babies maintained normal body temperatures.

Severe failure to thrive and diarrhoea caused by laxative abuse

We report a case of chronic administration of Epsom salts leading to diarrhoea and severe weight loss in 7 month old girl.

Tonsillar enlargement and failure to thrive

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Pattern of illness in babies discharged from a special care unit

Babies discharged from special care are three times as likely to be readmitted to hospital with common acute illnesses, and to stay longer than other babies. Apnoeic episodes occurred exclusively in those infants who had not received special care, and half of all hospital admissions required less than 48 hours hospital stay, with no specific medical treatment.

Normal growth and development of the trachea

A quantitative study of the trachea has been made in 452 children with apparently normal tracheas ranging from 28 weeks' gestation to 14 years. In the neonatal period the trachea is funnel shaped with the upper end wider than the lower end. It becomes cylindrical with increasing age. The ratio of cartilage to muscle remains constant throughout childhood. The trachea appears to grow at a greater rate, in relation to crown-rump length, during the age of 1 month to 4 years than in utero or around puberty. Normal measurements for formalin-fixed tracheas related to crown-rump length are presented.

The trachea in children with tracheo-oesophageal fistula

Forty tracheas from children with tracheo-oesophageal fistulae were histologically analysed for structural deformity. Thirty (75%) had a deficiency of cartilage; 24 (60%) showed an increase in the length of the transverse muscle, and 26 (65%) had a longer than average internal perimeter. Only six tracheas were entirely normal. The position of the fistula bore little relationship to the abnormalities found. Since in only nine patients were abnormalities restricted to the site of the fistula, we believe that careful examination of the whole length of the trachea is needed at the time of surgery to determine the extent of the anomaly and to anticipate tracheal problems. This is also relevant to autopsy studies and to elucidate the cause of death.