Biomedical subjects
Publications and source records attributed to D T Cass.
An infant who presented with Hirschsprung's disease was found to also have the clinical features of persistent Müllerian duct syndrome and on testing to have Müllerian inhibiting substance deficiency. This association has not been previously reported. While this may be a coincidence, recent reports indicate intersex conditions can be associated with Hirschsprung's disease.
The etiology of aganglionosis of the bowel remains controversial. Initial embryological studies in chicks, mice, and humans suggested the defect was in the migratory capacity of the vagal neural crest cells. This traditional theory has recently been challenged by the demonstration of a defect in the local microenvironment and the suggestion that neural crest cells migrate normally until they reach the terminal defective segment of bowel which then excludes them. To contribute to this debate we studied three rodent animal models using histological, "in vivo" (kidney capsule), and "in vitro" (tissue culture) techniques. The results suggest that there is no discernible difference between mutant and normal embryos in the early migration from the vagal neural crest to the stomach. Migration through the small bowel is normal in mutant mice, but is slowed in the rat. In both strains of mice the migration of enteric precursors into the mutant colon is slowed over an extended period of time, such that a difference between normal and mutants is evidenced well before the final aganglionic region is reached. Aganglionosis is the result either of a defect in vagal neural crest migration or in the microenvironment over an extended area of the bowel and not just in the terminal aganglionic colon. There are changes in the appearance of mutant enteric neurons in tissue culture and some alterations in the gut mesenchyme; it remains to be determined which is the primary event.
Paediatric drownings in New South Wales during the years 1987-1990 are reviewed to document the current pattern. Over these three years we have registered 250 paediatric deaths by physical injury. Sixty-one (24%) of these deaths were by drowning. Twenty-nine of the 61 drownings (47%) occurred in domestic pools; 25 of these were in unfenced or inadequately fenced pools. Of the remaining four cases, one was associated with a chair being used to gain access and the other three remain unexplained. Thirty-three of the 61 drownings occurred in country areas; of these 10 were in pools, eight in rivers or creeks, six in boating accidents, four in the surf and three in dams. A changing trend identified by this study is the increasing percentage of drownings (44%) occurring in nominally "fenced" pools in which the fencing was not functioning because the gate was open or the fencing was in disrepair. Legislation must be supported by public education and council inspection if the full benefit of isolation fencing is to be realised. With respect to all drownings there is a continuing need for education about the dangers that bodies of water, even in the bath or a bucket, pose to young children, and the need for parents to strive for optimal supervision.
The recent increase in skateboard injuries is causing concern. Over a 30-month period there were 80 admissions (69 children) to Westmead Hospital because of skateboard injuries. Among children most injuries were minor, involving fractures to the upper limbs (47) or minor head injuries (8). The only serious injuries were a ruptured urethra and a closed head injury. Over the same time period skateboard riding caused five deaths in New South Wales. These all involved head injuries and in four instances collisions with cars. The data strongly support other studies that show skateboard riding is particularly dangerous near traffic and should be proscribed. However, in parkland and around the home the skateboard is an enjoyable toy with an acceptable risk of minor injury. Helmets should be worn and would have prevented all the head injury admissions in this series. Children under 10 have a higher risk of fractures and head injuries due to insufficient motor development to control the boards and the resultant falls. Skateboard injuries are an example of injuries caused by a "fad epidemic". To cope with these types of periodic events up-to-date data collection is needed, followed rapidly by an intervention programme so that serious injuries can be kept to a minimum.
Post-mortem studies of the normal infantile pylorus have demonstrated an asymmetrical structure with the mucosa protruding under the circular muscle at the lesser curve but not on the anterior surface. In addition the circular muscle was often discontinuous at the pyloroduodenal junction with only longitudinal fibres or even fibrous tissue separating the mucosa from the serosa. In a further specimen in which a pyloromyotomy had been performed 10 weeks previously, this asymmetry was more pronounced. This anatomy suggests that in pyloric stenosis it may be safer to site the caudal part of the pyloromyotomy incision on the anterior surface, rather than on the anterosuperior surface as most authors recommend. Perforation of the mucosa is predicted to be less likely.
Thirty-five patients with significant fetal hydronephrosis detected on antenatal ultrasound had postnatal investigations which included ultrasound, 99mtechnetium diethylenetriamine pentacetic acid (99mTcDTPA) renal scans and micturating cystourethrograms. Antenatal and postnatal ultrasound were unable to determine reliably the level of obstruction causing the hydronephrosis. The 99mTcDTPA renal scan was useful in determining the necessity and timing of surgery, but could not exclude vesico-ureteric reflux. Seven patients required surgery in the neonatal period and a further seven children had surgery because of deterioration of the scan appearance on follow-up studies performed at 3, 6 and 12 months of age and then at longer time intervals. Twenty patients (almost 60%) have been managed conservatively for a mean of 28 months (range: 12 months-7 years) with no deterioration in renal function.
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In order to determine the preventable factors in fatal accidents, a retrospective review of paediatric deaths after admission to a suburban teaching hospital was conducted. The medical records and coroners' reports for 64 consecutive cases over a 68-month period were reviewed. The main causes of death were pedestrian injuries (42% of deaths), drowning (20% of deaths) and injuries to vehicular passengers (17% of deaths) and cyclists (13% of deaths). There was a male predominance (64%). Children who were aged less than five years were at greatest risk at home, with death by drowning (46% of deaths) predominating. For children who were over five years of age, accidents on the roadway as pedestrians (58% of deaths) and pedal-cyclists (20% of deaths) were the most-common causes of death. Analysis of the accidents showed that preventive strategies were underutilized. Thirty per cent of deaths could have been avoided by the wearing of restraints in motor vehicles, the wearing of cycle-helmets and the proper use of swimming-pool barrier equipment. Adequate supervision of children who were less than 10 years of age at road crossings could have prevented a further 17% of deaths. In comparison, even the most-optimal postinjury care would have salvaged only 5% of the cases. Therefore, while the ideal organization of services after injury is a logical aim in the management of childhood trauma, if lives are to be saved, the main emphasis must be on prevention.
In patients with a past history of pyloric stenosis, swallowed foreign bodies may not pass out of the stomach. Not only is this clinically relevant, but it also suggests that, even after apparently successful surgery, pyloric function may not be completely normal. A case history is presented and the literature is reviewed.
Bicycle injuries are an important cause of trauma. Approximately 75% of such accidents occur in children and involve difficult decisions in the areas of education, engineering and legislation. A prospective 3-year study was undertaken to understand the range of injuries and in particular to concentrate on severe injuries. In all, 251 children were admitted to Westmead Hospital after receiving bicycle injuries. Most injuries were minor but there were 37 serious injuries and six deaths. Head injuries predominated, especially in the seriously injured. The rate of wearing helmets was low, with less than 10% of all admissions wearing a helmet. None of the seriously or fatally injured wore a helmet. Helmet-wearing remains the single most important preventative measure to be instituted if the serious morbidity and mortality rates associated with bicycle injuries are to decrease.
Over a 2-year period 1,116 children admitted to an urban teaching hospital were studied prospectively. The overall group was analysed as to the nature of the injury and a subgroup of seriously injured children was identified and further analysed. All deaths were examined as to their cause and possible preventable as well as salvageable factors. The predictive value of the Trauma Score (T.S.) and Method of Injury (M.O.I.) were evaluated for their prospective prediction of serious injury as determined by the Injury Severity Score and outcome. Most of the children were not seriously injured, with the most common injury being due to a fall (57%) and involving a single injury to the upper limb. With the subgroup of 143 children (13% of the total) who suffered serious injuries, the cranial cavity (90%) was the most common site of injury, occurring most often in pedestrians (31% of the total injured). There were 16 deaths in the series, representing 1.4% of all paediatric trauma admissions and 11% of the admissions who were seriously injured. All deaths were related to motor vehicle accidents and associated with serious head injury. A Trauma Score less than or equal to 12 accurately included all deaths but when correlated with the I.S.S., the Trauma Score had a specificity of 99% and a positive predictive value of 86%; its sensitivity was only 27%. The Method of Injury was associated with an overtriage rate of 300% in relation to the I.S.S.. Of children admitted following pedal cycle accidents only 9% were wearing helmets. Of car occupants injured, 39% were unrestrained.(ABSTRACT TRUNCATED AT 250 WORDS)
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The distributions of nerve cells and fibers with immunoreactivity for the peptides enkephalin, gastrin-releasing peptide, neuropeptide Y, somatostatin, substance P, and vasoactive intestinal peptide were examined in specimens of myenteric plexus and external muscle from the pylorus of 20 infants with hypertrophic pyloric stenosis. These were compared with peptide distributions in pyloric samples from unaffected infants and adults. In the normal pylorus the circular muscle was richly supplied with fibers reactive for enkephalin, neuropeptide Y, substance P, and vasoactive intestinal peptide. In pyloric stenosis, these immunoreactive fiber bundles were either missing or less than 5% of normal. In contrast, there were reactive cell bodies and nerve fibers in the myenteric plexuses of both normal and affected specimens. In the samples from cases of stenosis, swollen nerve fibers that appeared to be in the process of degeneration were frequently encountered. It is concluded that infantile hypertrophic pyloric stenosis is associated with a loss of peptide immunoreactivity in nerve fibers in the circular muscle, although the same peptides are still revealed in fibers and in nerve cell bodies in the myenteric plexus.
This study is based on a 12 month prospective analysis of 598 paediatric trauma admissions, drawn principally from an urban environment. The spectrum of trauma is described, highlighting the minor nature of most injuries and the rarity of penetrating trauma. A subgroup of seriously injured children was identified and further analysed. All deaths were examined. The predictive value of the Trauma Score (TS) and Method of Injury (MOI) were assessed in terms of eventual injury severity using the Injury Severity Score (ISS), and morbid outcome. Most of the patients were not seriously injured, and sustained single system injury only. The injuries were related principally to falls (62%). Seventy-nine children (13%) were identified as seriously injured (ISS greater than or equal to 16). In this group pedestrian injuries were the major cause of injury (29%). Amongst seriously injured children, cranial injury was identified in 91%, followed by abdominal injury in 33%. There were nine deaths in the series, representing 1.5% of all paediatric trauma admissions, and 11% of seriously injured patients. All deaths were associated with a significant head injury. Although the TS had a specificity of 99% in predicting serious injury and a positive predictive value of 94%, its sensitivity was only 26%. The MOI was associated with an overtriage rate of 200%. Of children admitted following pedal cycle accidents, 86% of the total and 91% of seriously injured children were not wearing a helmet. Of passengers in a motor car, 37% of the total number were unrestrained. The results suggest triage in children requires more than a physiological measure (TS) or MOI.(ABSTRACT TRUNCATED AT 250 WORDS)
We report the case of a nine-month-old girl with acquired oesophageal stricture and tracheo-oesophageal fistula after the ingestion of a mercury button-battery. In any child with suspected button-battery ingestion an x-ray examination should be carried out to exclude oesophageal impaction which necessitates immediate removal of the battery, as tissue necrosis may occur within hours.
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