Concentrations of antimony in infants dying from SIDS and infants dying from other causes

BACKGROUND—A patient with cystic fibrosis (CF) and repeated calcium oxalate renal stones prompted us to investigate other children for risk factors for this recognised complication of CF.
METHODS—Twenty four hour urinary excretion of calcium, oxalate, and glycolate was measured in children with CF and no symptoms of renal tract stones. Normal diet and treatments were continued.
RESULTS—In 26 children (aged 5-15.9 years) oxalate excretion was correlated with age; 14 of 26 children had oxalate excretion above an age appropriate normal range. There was a positive correlation between oxalate excretion and glycolate excretion. Mean calcium excretion was 0.06 mmol/kg/24 h with 21 of 24 children having calcium excretion below the normal range.
CONCLUSIONS—Hyperoxaluria may reflect malabsorption although correlation between excretion of oxalate and glycolate suggests a portion of the excess oxalate is derived from metabolic processes. The hypocalciuria observed here may protect children with CF from renal stones.

     

Gluconeogenic enzymes in fibroblasts from infants dying of the sudden infant death syndrome (SIDS)

The activities of mitochondrial phosphoenolpyruvate carboxykinase (PEPCK), pyruvate carboxylase (PC), and total malic enzyme (ME) were determined in cultured fibroblasts from 74 infants diagnosed as having died from the Sudden Infant Death Syndrome (SIDS) and 36 infants who died from known causes. In addition, the glycemic state of infants was measured by determining the 'maximum' glucose present in plasma and cerebral spinal fluid (CSF) based on the following formula: glucose (maximum) = glucose + 1/2 (lactate). There were no statistical differences between SIDS and control infants in any of the three enzymatic activities measured in fibroblasts or in the estimated 'maximum' glucose values in plasma or CSF. The present results do not support the involvement of hypoglycemia as a cause of death in SIDS.     

Neonatal jaundice in full-term infants. Role of breast-feeding and other causes

Serum bilirubin determinations were performed on 264 term infants who were consecutively delivered via the vaginal route. Forty-one infants (15.5%) had serum bilirubin concentrations greater than 12 mg/dL. No cause for this was found, initially, in 23 (56%) of these infants. On the third hospital day, the mean (+/- SD) serum bilirubin level was 6.9 +/- 3.6 mg/dL in breast-fed infants and 6.5 +/- 3.2 mg/dL in bottle-fed infants. Of the 23 infants without obvious cause for hyperbilirubinemia, eight (four bottle-fed and four breast-fed infants) had serum bilirubin concentrations greater than 12 mg/dL on the third hospital day, whereas in 15 (14 breast-fed infants and one bottle-fed infant), the elevated serum bilirubin level occurred on day 4 or 5. Breast-feeding does not seem to affect the total serum bilirubin level in the first three days of life but may be associated with an increased incidence of hyperbilirubinemia subsequently. In a normal full-term population, routine investigations do not disclose a cause for hyperbilirubinemia in about half of the patients.     

Sudden infant death syndrome: risk factors for infants found face down differ from other SIDS cases

OBJECTIVE: To test the hypothesis that infants with sudden infant death syndrome (SIDS) found face down (FD) would have SIDS risk factors different from those found in other positions (non-face-down position, NFD). STUDY DESIGN: We used the New Zealand Cot Death Study data, a 3-year, nationwide (1987 to 1990), case-control study. Odds ratios (univariate and multivariate) for FD (n = 154) and NFD SIDS (n = 239) were estimated separately, and statistical differences between the two groups were assessed. RESULTS: Of 12 risk factors for SIDS, there were 8 with a statistically significant difference between FD and NFD infants. After adjustment for the potential confounders, younger infant age, Maori ethnicity, low birth weight, prone sleep position, use of a sheepskin, and pillow use were all associated with a greater risk of SIDS in the FD than the NFD group. Sleeping during the nighttime, maternal smoking, and bed-sharing were associated with a risk of SIDS only in the NFD group. Pacifier use was associated with a decreased risk for SIDS only in the NFD group, whereas being found with the head covered was associated with a decreased risk for SIDS for the FD group. CONCLUSIONS: Infants with SIDS in the FD position appear to be a distinct subgroup of SIDS. These differences in risk factors provide clues to mechanisms of death in both SIDS subtypes.     

Sleep apnea in infants and the risk of SIDS

The examination of the respiratory function in 184 sleeping infants gave evidence of a significant difference in several parameters between the so-called SIDS risk group and the control group. The risk group (97 babies) consists of 60 infants with frequent prolonged apneas, 30 infants with postnarcotic apneas and 7 near miss infants. Polygraphic registration during sleep showed significantly more apneas in the risk group. These apneas often appeared more frequently during certain periods. The average respiratory deficit expressed as the MA-value (MA = average apnea duration) in the risk group was significantly higher than in control infants. Besides that we were able to prove a more frequent pathological gastroesophageal reflux in the risk infants than in control infants.     

Sleep phase and gastro-oesophageal reflux in infants at possible risk of SIDS.

The association between gastro-oesophageal reflux and sleep state in 24 infants with confirmed or suspected gastro-oesophageal reflux was studied by monitoring both the pH in the lower oesophagus and polygraphic tracings made during sleep at night. Gastro-oesophageal reflux during the night was confirmed in 20 infants. Three hundred and sixteen precipitous drops of more than one unit of pH were recorded during the studies, 186 during periods of wakefulness. Of 130 drops in pH during sleep, 62 (48%) began during active sleep and 62 during indeterminate sleep. Of the latter, 56 (90%) were associated with brief gross body movements. Only five of the drops in pH (4%) began during quiet sleep. Gastro-oesophageal reflux stopped during active sleep on 56 occasions (43%), in indeterminate sleep in 62 (47%), and in quiet sleep in 12 (9%). Episodes of gastro-oesophageal reflux starting or ending in quiet sleep were uncommon. The occurrence of gastro-oesophageal reflux during active sleep may partly explain why reflux during sleep is a risk factor for pulmonary disease.     

Higher incidence of SIDS at weekends, especially in younger infants.

BACKGROUND: An increased incidence of sudden infant death syndrome (SIDS) at weekends has been previously noted, although it has not been found in all studies. Where a weekend effect has been found it is most prominent on Sundays. AIM: To identify the magnitude of this effect in British data before and after the fall in prevalence associated with the "back to sleep" campaign. METHODS: Aggregated data from England Wales, Scotland, and Northern Ireland for the years 1986-98 during which there were 12,762 deaths from SIDS were examined. RESULTS: Comparing the periods before (1986-90) and after (1993-98) the fall in incidence associated with the "back to sleep" campaign, the percentage of infants dying at the weekend in the later period (32.24%) was slightly greater than for the earlier period (31.30%), although this difference was not statistically significant. In both periods the observed weekend incidences were significantly higher than the expected weekend percentage of 28.6%. Although the proportion of infants aged < or =4 months and > or =5 months at death did not change between the two periods, the weekend effect was more marked in the younger infants, particularly in the 1993-98 period. There was no consistent Saturday effect. In 1993-98 deaths appeared to be more evenly distributed throughout the week for infants > or =5 months. CONCLUSION: The excess of SIDS at weekends still appears to be present despite the overall fall in prevalence associated with the "back to sleep" campaign. Increased risks at weekends might have implications for support to high risk families.     

Higher incidence of SIDS at weekends, especially in younger infants

Background: An increased incidence of sudden infant death syndrome (SIDS) at weekends has been previously noted, although it has not been found in all studies. Where a weekend effect has been found it is most prominent on Sundays. Aim: To identify the magnitude of this effect in British data before and after the fall in prevalence associated with the "back to sleep" campaign. Methods: Aggregated data from England & Wales, Scotland, and Northern Ireland for the years 1986–98 during which there were 12 762 deaths from SIDS were examined. Results: Comparing the periods before (1986–90) and after (1993–98) the fall in incidence associated with the "back to sleep" campaign, the percentage of infants dying at the weekend in the later period (32.24%) was slightly greater than for the earlier period (31.30%), although this difference was not statistically significant. In both periods the observed weekend incidences were significantly higher than the expected weekend percentage of 28.6%. Although the proportion of infants aged ⩽4 months and ⩾5 months at death did not change between the two periods, the weekend effect was more marked in the younger infants, particularly in the 1993–98 period. There was no consistent Saturday effect. In 1993–98 deaths appeared to be more evenly distributed throughout the week for infants ⩾5 months. Conclusion: The excess of SIDS at weekends still appears to be present despite the overall fall in prevalence associated with the "back to sleep" campaign. Increased risks at weekends might have implications for support to high risk families.     

Sudden infant death syndrome (SIDS) in South Australia 1968-97. Part 2: the epidemiology of non-prone and non-covered SIDS infants

OBJECTIVE: To identify the risk factors for infants who die suddenly and unexpectedly, but whose deaths are not related to prone position, or having the head covered. METHODOLOGY: A case-control study was designed in which the cases were infants who had died of sudden infant death syndrome (SIDS) in South Australia between January 1974 and December 1997, who were found not prone, not bed sharing and with the head not covered. The controls were two infants for each case, born in the same year and found in the prone position (again not bed sharing and with the head not covered). RESULTS: Sudden unexpected death infancy is rare in non-prone infants with the head not covered. occurring on average twice a year in South Australia, where there are 18,000-21,000 births per year. In this group there was a higher percentage of infants with features associated with low socio-economic groups (teenage pregnancies and maternal smoking), sibling SIDS, suspicion of non-accidental injury and the presence of minor congenital anomalies, especially cardiac anomalies. CONCLUSIONS: The majority of unexpected deaths in infancy can be prevented by not allowing infants to be unobserved in prone position, and by preventing them from getting their faces covered. For the few infants not found in these positions, a careful investigation should be made for malformations or non-accidental injury.     

Brain maturation and damage in infants dying from chronic pulmonary insufficiency in the postneonatal period

The changes in the brains of 11 infants who survived from 29 days to 13 months after severe chronic pulmonary insufficiency are described.Brain maturation as assessed by myelination and gyral formation was within normal limits. In 5 infants the brain weight was less than normal if age was used in the comparison, but greater than normal if body weight was used.In addition to hypoxic or ischaemic damage, which was found in some degree in all cases except one, there were several other local lesions. These included periventricular leucomalacia 7, periventricular haemorrhage 1, hydrocephalus 2, and cystic encephalomalacia 3. Though the last is almost certainly due to vascular occlusion, this could not be shown. The possibility of cerebral embolism after umbilical vein catheterization is considered but not proven.     

A critical comparison of the history of sudden-death infants and infants hospitalised for near-miss for SIDS

To determine whether significant historical differences distinguish the near-miss for Sudden Infant Death from the infants who died of SIDS, we analysed the histories and clinical data from two groups of infants seen in our University Hospital and from collaborative research group. The data were obtained with the use of a standardised questionnaire and consultation of all available medical data.Sixty-five infants were identifed as near-miss for SIDS after they had suffered a severe cardiorespiratory incident during sleep for which no cause could be found despite a complet medical examination. After an autopsy had failed to reveal a cause for the unexpected death 95 cases of SIDS were retained in the study. A series of 353 variables were collected from the parents, the gynaecologists, neonatologists and attending physicians.After statistical analysis, only 15 of the 353 items studied significantly differentiated between the two groups. A stepwise discriminant analysis performed on these items led to the identification of six independent variables: the time of the incident; the circumstances leading to the observation of the child; the child's sleep position; previous minor intestinal problems; the size of the family and the mother's coffee consumption. Most variables indicate that the near-miss infants were discovered and rescued earlier than the infants who died. No other historical information appeared significantly to differentiate between the two groups of infants. These data need confirmation from a prospective epidemiological survey.Abbreviation SIDS Sudden Infant Death Syndrome     

Estimating infant mortality from human immunodeficiency virus and other causes in breast-feeding and bottle-feeding populations.

This paper discusses the literature dealing with breast-feeding in women with human immunodeficiency virus (HIV) infection. This review is used to develop a background for a quantitative assessment of factors determining whether breast-feeding or bottle-feeding will result in a lower overall mortality in areas of different HIV prevalence. An algebraic formula is presented that enables calculation of the mortality that would result in any population if the following variables are known or capable of estimation: portion of childbearing women infected with HIV, portion of newborns infected with HIV at birth, relative mortality of breast-fed and bottle-fed infants that are not HIV infected, and transmissibility of HIV during breast-feeding. The information available for estimating these variables is incomplete. Nevertheless, boundaries can be set for each variable, based on information obtained locally or from the literature, to aid in objective evaluation of the risks of promoting bottle-feeding or breast-feeding in populations with different risk characteristics. Consideration of these factors indicates that the benefits of breast-feeding over bottle-feeding can substantially outweigh any putative risk of HIV transmission during breast-feeding unless the prevalence of HIV infection is quite high or the difference in mortality of breast-fed and bottle-fed infants is very low.     

Surfactant abnormalities in ALTE and SIDS.

Abnormalities in the relative concentrations of the components of surfactant have been implicated in prolonged expiratory apnoea (PEA) and sudden infant death syndrome (SIDS). Controversy has, however, surrounded these findings, as they may be secondary to terminal life events. In this study the physical properties of surfactant were measured in children with recurrent apparent life threatening events (ALTEs), PEA, and SIDS. Bronchial lavage samples were obtained from 21 children with recurrent ALTEs, two SIDS victims, and 26 control patients. Lipid components were immediately elutriated from these samples with liquid chloroform. The physical properties of the extracted surfactant were studied on a Langmuir trough in which the area (A) of the monolayer was cycled continuously as the surface tension (gamma) was measured by the Wilhelmy method using a platinum 'flag'. The investigators performing these tests were unaware of the clinical diagnosis. Twenty one of 23 patients displayed abnormal physical properties while seven of 26 controls displayed similar abnormalities. These abnormalities were partially inverted hysteresis (figure of eight) loops and inverted (anticlockwise) loops that also generally exhibited less hysteresis. Of the 26 controls 20 exhibited a wide hysteresis pattern that cycled in a normal (clockwise) direction. These differences were significantly different. It is concluded that children with recurrent ALTEs have definable abnormalities in the physical properties of surfactant and that these findings may provide a sensitive means of identifying those at risk of recurrent ALTEs and SIDS.     

Retrospective study of incidents of sudden death (SIDS) in 80 infants

The parents of 80 victims of SIDS (Sudden Infant Death Syndrome) participated in this retrospective study. The semistructured interview included questions concerning events preceding infants' death and the situation at the discovery of the death. Fifty-eight of the 80 SIDS victims were male, twenty-two were female. Fourty-four of the babies underwent a postmortem examination. There was a high incidence of death during the winter months and concerning the hour of the day in the morning hours. Most families (91%) had no socioeconomic difficulties--in contrast to reports of other authors. In 34% of the SIDS cases the parents reported about stress or irregularities of the daily family life cycle (journey, mayor family events, quarrels) immediately before the death of the baby. About 20% of the victims were not in the usual surrounding at the time of death. In about 30% of the SIDS victims an infection was observed. Since between the 2nd and 4th month of life a major neuronal reorganization in the central nervous system is assumed (Prechtl, 1984), stress during this period may be particularly effective and dangerous for the baby. This would explain the high incidence of SIDS during this vulnerable phase (60%) in which the baby, apparently, is unable to react properly.     

Diagnostic categories in infants referred for an acute event suggesting near-miss SIDS

Among 857 infants admitted between 1977 and 1984 for a life-threatening apnoeic event a definite pathologic condition was found in 576 (66%). In 32 (6.5%) of the latter the polysomnogram was abnormal. The major clinical diagnostic categorics were, with decreasing frequency: digestive (n=263), vasovagal (n=95), neurological (n=78), respiratory obstructions (n=33), and respiratory infections (n=27); miscellaneous causes were found in 80 infants. No obvious cause could be traced in the remaining 281 infants. According to those caring for them the episode was severe in 77 (27%) of these infants, 57 (74%) of which had an abnormal polysomnogram, and minor in 204 (73%), 36 (18%) of which had an abnormal sleep study. Home monitoring was performed for 145 patients: all those with an abnormal polysomnogram and the 20 infants with an unexplained severe episode associated with a normal sleep study. We conclude from our experience that when an infant is referred for an acute event suggesting nearmiss sudden infant death syndrome (SIDS), a large array of diagnoses can be found and that an electric monitoring device will ultimately be advocated for only 17% of all infants presented, but for all those with an unexplained severe episode, irrespective of the results of the sleep study.Abbreviation SIDS sudden infant death syndrome