For debateTime to put “cot death” to bed?Not time to put cot death to bed
(Published 11 September 1999)
Cite this as: BMJ 1999;319:697
The increased awareness of deliberate harm to infants by parents and carers has prompted debate on the terminology used for “cot deaths.” These two papers give historical context of the debate and consider whether the use of “sudden infant death syndrome” should be abandoned.
Time to put “cot death” to bed?
- M A Green, emeritus professor ()
- Department of Forensic Pathology, University of Sheffield, Sheffield S3 7ES
- Foundation for the Study of Infant Deaths, London SW1X 7DP
In a recent editorial in the Journal of Clinical Pathology I argued that pathologists should approach sudden and unexpected death in the first year of life with greater caution than may have been applied in recent years.1 In consequence of the increased awareness of deliberate harm by parents and carers reported by Meadow and so graphically captured on video recordings by Southall and Banks,2–4 I said that the term “not ascertained” should be used much more widely than it is at present. I am fully aware of the distress that such an approach may cause to recently bereaved and totally innocent parents. I am also old enough to recall the “bad old days” of the 1960s, when deaths were wrongly attributed to unsuitable bedding or inappropriate care, leading to unnecessary inquests and pillorying of the parents in the local press. At the other end of the spectrum we used to invent meaningless diagnoses such as “acute interstitial pneumonitis” and “viral bronchiolitis.”
Until late 1971 the registrar general would not accept the sudden infant death syndrome or any of its synonyms as a cause of death. This refusal had two undesirable consequences. Firstly, we had no idea of the true incidence of such deaths in the United Kingdom (or any other society) until reports such as that of Banks gave an indication of the size of the problem.5 Secondly, we focused our attention on an ever enlarging battery of laboratory investigations, rather than closely scrutinising the child's and the parents' histories, especially in those cases where a previous similar death had occurred. Indeed, such serial deaths tended to reinforce the hypothesis that some cot deaths were due to an inborn error of metabolism or other congenital anomaly.
In 1969, when Beckwith proposed the now universally accepted definition of the sudden infant death syndrome,6 there were around 1200 sudden infant deaths in England and Wales each year. Through the 1970s and 1980s this annual total remained at about 1000 until the “back to sleep” campaign at the beginning of this decade.7 This campaign was reinforced by the death of the child of a well known and popular TV presenter and its attendant publicity. Since then, the annual totals, although they vary slightly from year to year, now hover around the 400 mark.
Child homicide, especially by the mother, is by its very nature difficult to detect; we can only hazard guesses at its incidence. Nor should we direct our suspicions solely to the mother. Meadow has recently reported a series in which there was of involvement the father (or male cohabitee) in 15 cases of deliberate harm.8 Wilczyniski, in her retrospective studies, has said that the number of cases where adult harm has led or contributed to death stands at over 100 per year rather than the 50 or so cases classified as homicide by the Office for National Statistics.9 I am inclined to agree with her. In private conversation, many paediatric pathologists and forensic pathologists say that parental or adult intervention may have occurred in 20-40% of the cases of so called sudden infant death syndrome with which they are involved. If we assume (and to me it seems a reasonable assumption) that the numbers of adults who harm their children have remained fairly constant over the years, then in the relatively low number of baby deaths currently occurring, the proportion of “suspicious” cases is increased accordingly. It follows that all of us involved in such deaths should approach them with suspicion, albeit cautiously expressed. The advice given in a recent Canadian investigative protocol to “Think Dirty,” although a little graphically phrased for my liking, sums it up.10
Recent research in Sheffield University's department of forensic pathology has highlighted the importance of careful assessment of the histology of the lungs in every case, along with a review of any previous cases from the same family unit.11 We found that in many cases where there was fresh bleeding within a relatively small number of the alveoli (8% or more) we had to revise our previous diagnosis of the sudden infant death syndrome and replace it with “not ascertained.” There was a broad correlation, and I put it no higher than that, between the extent of the bleeding and the possibility, sometimes subsequently admitted by the perpetrator, of deliberate upper airway obstruction.
Furthermore, the observation by Becroft and Lockett of iron laden pulmonary macrophages in the lungs of so called sudden infant death syndrome cases, and their suggestion that these may be markers of previous mechanical airway obstruction,12 has inspired retrospective and prospective research studies currently being undertaken in Bristol and Sheffield, as well as in other centres overseas.13 The importance of the number and distribution of siderophages is still not entirely certain. We know that difficult delivery, viral infection, and rare congenital diseases such as idiopathic pulmonary haemosiderosis may all lead to their deposition. However, so far the indications are that siderophages are rarely, if ever, seen after full term normal delivery; that they clear within a matter of weeks; and that, if present in moderate to large numbers, they act as a marker of possible previous partial asphyxia. I reiterate the caution that they are markers, not proof, of inappropriate activity.
Pathologists should not confine themselves entirely to pathological observation. An adequate history is just as important to them as it is to clinicians. Meadow14 and Southall3 have clearly set out lists of maternal and child risk factors which should raise suspicion of deliberate harm. I always ask coroners' officers and their police colleagues to particularly address these issues. If I find fresh bleeding or siderophages within the lungs, I initiate further and even more detailed inquiry.
Most importantly, even if my necropsy and ancillary investigations are completely negative, I do not give the sudden infant death syndrome as a cause of death if three or more of the documented risk factors are present. This may seem to many to be a “hard line” approach. I believe that the pathologist has a place in any “care of next infant” scheme. It is a chastening experience to perform a frank homicide necropsy on a child whose elder sibling was signed off as a cot death a few years previously. I should know—I have done it.
Competing interests MAG has given evidence (for either prosecution or defence) in several criminal cases where smothering was alleged. The fees earned were all surrendered to the University of Sheffield.
Not time to put cot death to bed
- Sylvia Limerick, vice chairman ()
- Department of Forensic Pathology, University of Sheffield, Sheffield S3 7ES
- Foundation for the Study of Infant Deaths, London SW1X 7DP
- Accepted 5 July 1999
Is the clock being turned back 30 years?1 The views of a few authors highlighting the small numbers of unnatural infant deaths that have been misclassified as sudden infant death syndrome have been widely publicised.2–6 Some views risk returning us to a time when there was no registrable nomenclature for identifying natural unexplained sudden infant deaths, no mechanism for supporting bereaved parents, and no research base for elucidating preventive measures.7
The number of deaths due to infant homicide is a matter of conjecture.8 Some estimates derive from the experience of individual clinicians, and extrapolations from these need to be treated with caution. Other figures are based on studies in defined geographical areas. One multicentre study (1976-9) of 988 deaths from all causes in infants aged between 1 week and 2 years found that only 9 (1%) deaths were the result of infanticide and in a further 15 (1.5%) there was unproved suspicion.9
Official statistics comprise recorded cases and form an essential basis for comparison. A study of Home Office criminal statistics in England and Wales published in 1993 found that the annual rate of infant homicide (45 per million population) had remained relatively constant since the Homicide Act 1957, while infant mortality had fallen.10 Home Office records for 1982-8 indicated that infants were most at risk on the first day of life, when 21% of deaths occurred, that 13% of victims were aged between 1 day and 1 month old, and that 23% were aged between 2 and 3 months. For the year 1997, when there were 642 000 live births, 29 infant homicide deaths would be predicted.
Combining the Office for National Statistics' postneonatal figures in England and Wales for homicide and injury purposely inflicted (ICD-10, E960-9) and for injury undetermined whether accidentally or purposely inflicted (ICD-10 E980-9) for 1986-96 provides a mean of 26 (range 15 to 33) deaths per year.11 12 Postneonatal deaths certified as sudden infant death syndrome fell from 1292 to 343 over this period. The combined deaths from homicide and injury accounted for 1% of all deaths in the postneonatal period in 1968-78 and 1979-91 and for 1.8% of deaths in 1992-6.
The most recent estimates of the number of deaths certified as sudden infant death syndrome that may, in fact, have been the result of maltreatment come from the confidential inquiries into stillbirths and deaths in infancy study of sudden unexpected deaths in infancy carried out between 1993 and 1996 in three regions of England.13 After scrutinising the circumstances and available records, expert panels of health professionals had to assign each death to a category of causation, one of which was “maltreatment by carers.” This category encompassed a wide spectrum of abuse ranging from deliberate action such as smothering to extremely poor care or negligence. The study concluded that maltreatment was probably the main cause of death in 22 of the 346 (6%) cases of sudden infant death syndrome examined and a secondary or alternative cause in a further 28 (8%)—totalling concern in 14% of deaths attributed to sudden infant death syndrome. The evidence shows that the incidence of infant homicide is small. At least 86% of the sudden infant death syndrome cases studied did not arouse any degree of suspicion, even when the national rate for sudden infant death syndrome had fallen to 0.6 per 1000 live births.
Investigation—the coroner's inquiry
It is in the best interest of bereaved families and everyone concerned to determine asaccurately as possible the circumstances and cause of death. The discrepancy between the number of deaths certified as infant homicides and the number certified as sudden infant death syndrome judged suspicious by an expert panel indicates that there should be better ways of providing pathologists and coroners with information from health professionals about the circumstances of the death (including the baby's medical history) and the later findings of a local case discussion.14 15
The registrar must report deaths of unnatural or unknown cause to the coroner, who has to hold an inquest where there is reason to suspect “a violent or an unnatural death” or “a sudden death the cause of which is unknown.”16 A coroner is able to order a postmortem examination if he has reason to believe that a natural cause may be discovered and, if the report of the examination confirms this, to issue a form notifying the registrar that he does not intend to hold an inquest, on which he certifies the cause of death as reported by the pathologist.17
Practice varies among coroners, but contact with general practitioners, police, and the child protection register, and arranging for a skeletal survey and other tests, assists in distinguishing between natural and unnatural death (E Thomas, Her Majesty's Coroner, personal communication). The Brodrick report of 1971 states that “in the investigation of a ‘cot death’, a good clinical history is almost as important as a good postmortem examination.”18 It recommends that “a coroner should consider with the greatest care whom he should ask to visit the home and attempt to obtain from the parents relevant information about the history of events leading to the death.”
The coroner normally receives information from the coroner's officer or police acting on his behalf. However, many bereaved families value an early visit from an experienced healthcare professional.19–21 This not only provides parents with an opportunity to ask questions but also enables the health professional to give them support and to gather information about the circumstances of the death that could assist both pathologist and coroner.
A paediatric pathologist or a general pathologist with special training, working with a forensic pathologist if necessary, should undertake histological, toxicological, and bacteriological tests to an agreed national standard. This should ensure the utmost scrutiny in determining whether an inquest is necessary and, most importantly, identifying the more rare causes of sudden infant deaths.
Because the annual number of postperinatal infant deaths referred to coroners is now less than 750 (A McKenzie, personal communication; based on Office for National Statistics data for 1997), it is practical to introduce a mandatory procedure after each unexpected death in infancy—holding a local case discussion after the necropsy.14 15 This discussion should include the general practitioner, health visitor, paediatrician, and pathologist. Parents could be given a provisional cause of death such as sudden infant death syndrome “subject to further investigation”22 and told that a more precise cause will be given by the coroner after tests. Most parents will accept a reasonable delay if the reason for it is explained and they are supported meanwhile (Foundation for the Study of Infant Deaths, personal communication). This procedure, if routine, would avoid any need for the pathologist to use the term “cause unascertained” and would prevent any stigma being attached prematurely where there is unproved suspicion.
Certification of cause of death
Since most sudden unexpected infant deaths are natural deaths, there is no case for abandoning the term “sudden infant death syndrome.” It should be used correctly, after comprehensive investigation, as defined in the ICD-9 code 798.0: “Sudden Infant Death Syndrome, SIDS or cot death or sudden death of non-specific cause in infancy.” This category was created only in 1979 as a subdivision of the ICD-9 code 798, “Sudden death, cause unknown,” which previously in ICD-8 had the subtitle “Sudden death, known not to be violent but with cause otherwise unknown.”
In Britain, since 1971,2 use of the term sudden infant death syndrome or equivalent term, which excludes explained unexpected infant deaths, has reduced the inflated death rates for respiratory disease and enabled research to focus on an identifiable group of deaths. This has led to the successful identification of infant care practices—for example, supine sleeping—which have reduced sudden infant deaths by a remarkable 70% since 1988.23 It has also facilitated study of infants born after a cot death, which has provided important evidence that even recurrence of sudden infant death syndrome in the same family is not necessarily suspicious.24
Sudden unexplained infant death is still the largest category of death in infants aged over 1 month. However heterogeneous the aetiology of these deaths, a collective term is still needed for identification, for explanation, and as a basis for expert study and sensitive support to bereaved families.
Competing interests None declared.