At present, both the aetiology of hyaline membrane disease and a means of preventing it remain unknown. Recent studies indicate that a significant number of infants die of respiratory failure but there is no general agreement concerning the changes of pulmonary function which lead to this stage. Two approaches have been used in the treatment of respiratory decompensation. First it has been proposed that blood gas and acid base abnormalities which result from respiratory failure can be prevented by oxygen and intravenous alkali and secondly an attempt has been made to correct abnormal lung function itself by means of artificial ventilation. These methods are directed at different aspects of the problem and their efficacy is as yet not established. The application of artificial ventilation in particular must depend on the nature of any ventilation, diffusion or perfusion defect.

This study began in 1990 in the Burn Unit of The Red Cross War Memorial Children's Hospital (RCWMCH) in Capetown. It came to our attention that children in the Burn Unit developed respiratory problems. These were complications of fireburns, smoke inhalation, explosions and even hot water scalds. They presented with a wide and confusing array of symptoms and many failed to improve with the symptomatic treatment given. Greater understanding of the pathology was needed in order to investigate and manage these problems correctly. The ultimate aim of this study was to establish a treatment protocol that could be followed by junior staff.

The outcome of 121 children who underwent palliative cardiac surgery at the Red Cross War Memorial Children's Hospital over a 5 year period, 1980 1984, was retrospectively examined. 79 children had systemic artery to pulmonary artery shunt operations (SPS), 40 had pulmonary artery bands (PAB) and 2 had surgical septectomies. SPS was most often done for children with Tetralogy of Fallot (TOF, 26 cases) or complex univentricular hearts with right ventricular outflow tract obstruction (27 cases). PAB was done chiefly for ventricular septa! defects, alone (VSD, 8 cases) or with coarctation of the aorta (9 cases). Children were referred from a wide area with 63 cases being referred from other major centres and foreign countries. Overall, 36 children died (30 % mortality): 5 died at surgery, 6 within 48 hours of surgery, a further 5 within 31 days; and 20 died after 31 days. SPS and PAB had the same early mortality rates ( 13 % ) • SPS had higher late and overall mortality rates (20 and 33 %) than PAB (10 and 23 %). Age at operation was found to be the most significant determinant of the overall mortality rate: children less than six months had a mortality of 42 % and those over 6 months, 13 % • The children were grouped into those with lesions which were probably correctable and those that were unlikely to be so, based on diagnosis and age at surgery: those with correctable lesions had a lower overall mortality (22 %) than those with uncorrectable lesions (43 %). Where the surgery was performed as an emergency, there was a higher overall and early mortality (55 and 35 respectively), compared to those operations which were performed electively ( 25 and 9 % ) • The presence of other medical conditions, for example congenital abnormalities and infections, was also a determinant of death (44 % mortality if other medical condition present, 26 % if absent). sex, population group, home address and type of surgery performed did not significantly affect mortality when examined by multivariate analysis. Using routine methods of follow up, it was initially thought that 17 % of all patients (22 % of survivors) were lost to follow up. An important determinant of this was the referral centre. 31 % of cases from other major centres and 20 % of foreign cases were lost, as compared to 8 % of cases from smaller towns near Cape Town and 2 % of children from Cape Town. Population group (35 % Blacks, 14 % Coloureds and 7 % Whites were lost), and palliative operation (23 % SPS, and 5 % PAB lost) were also significant determinants. It was possible to trace 12 of the 20 children who were thought to be lost to follow. 8 had died, 3 were still awaiting correction and 1 was traced and received corrective surgery. The records of the children who underwent cardiac surgery in 1987 were also analysed. There was no difference in the demographic characteristics of either group, and the early mortality was the same. This study shows that the outcome after palliative cardiac surgery is poor, with a high mortality rate and children often being lost to follow up. The decision to palliate rather than to correct a congenital heart defect must be made after balancing these risks with those of early correction for the particular surgical team. Should palliative surgery be undertaken, careful follow up is essential to ensure that complications of palliation do not set in and that corrective surgery is done at the optimal time.

Bibliography: pages 47-49. / This dissertation is based largely on an original study performed by myself and Dr EB Hoffman on 34 neonates with bone and joint sepsis. Our experience of 19 septic hips is the largest in the literature. The study was performed at the Red Cross Children's Hospital in 1987 and 1988. The paper has been accepted for publication in the Journal of Bone and Joint Surgery (September 1990). The literature has been reviewed in depth and compared with our findings. In order to avoid repetition, I have not included a separate literature review in my dissertation. I have however incorporated the literature review in the introduction and especially in the discussion.

No description available.

This dissertation discusses distal humeral epiphyseal injuries in children, i.e. lateral condylar fractures, medial condylar fractures, fracture-separation of the distal humeral epiphysis and T-condylar fractures. Medial and lateral epicondylar fractures, being apophyseal, are excluded. The research was done at the Red Cross Children's Hospital Trauma Unit. It was based on two clinical retrospective studies and one case report: a: 60 lateral condylar fractures presenting from 1984 to 1987 -were reviewed. b: 12 fracture-separations of the distal humeral epiphysis presenting from 1984 to 1989 were reviewed. c: One case report of a medial condylar fracture with associated elbow dislocation The distal humeral epiphysis is the second most commonly injured epiphysis in the body, after that of the distal radius (Peterson 1972). Supracondylar fractures are the most common fractures around the elbow in children, making up 65% of the total (Canale 1987). Lateral condyle fractures have an incidence of 17.4%, compared to 3.2% for medial condylar fractures and 0.8% for T-condylar fractures (Canale 1987). At the Red Cross Children's Hospital, 60 displaced supracondylar fractures, 20 lateral condylar fractures and 2 to 3 fracture-separations of the distal humeral epiphysis are seen every year. Medial condylar fractures are rare.

Indiana University-Purdue University Indianapolis (IUPUI)

Osteoporosis is a disease that may be pre-determined from the condition of bone health during youth. In South Africa, the situation is quite unique in that the population of black people has a reduced fracture rate compared to white people. As lifestyle and dietary patterns change with urbanisation and there is a shift towards westernised diets and sedentary behaviour in youth, fractures in elderly South African blacks may become more prevalent. With these rapid lifestyle changes, it will become increasingly important to prioritise osteoporosis and its related conditions as a major public health concern in South Africa. Very few of the factors influencing osteoporosis have been well studied in children of different ethnic groups. Physical activity in childhood, especially in the prepubertal years, confers residual benefits to the adult skeleton. In this thesis, the associations between ethnicity, history of participation in physical activity and skeletal health were explored in a sample of pre-/early pubertal children from South Africa who participated in four different studies. Furthermore, a novel aspect of the thesis was the use of peripheral quantitative computed tomography (pQCT) to investigate the mechanistic role that physical activity plays on bone health in this unique population. First the use of an existing physical activity questionnaire for the assessment of bone loading had to be validated in a sample of black and white boys and girls (n=38). A bone loading algorithm was used to calculate a peak bone strain score (PBSS) from the physical activity questionnaire. Therefore a bone specific physical activity questionnaire (B3Q) was used in subsequent studies. The PBSS was shown to be reliable and reproducible with significant (p<0.001) intraclass correlation coefficients. There were significant correlations between PBSS and moderate (r=0.38; p=0.02), vigorous (r=0.36; p=0.03) and combined moderate to vigorous intensity activity counts (r=0.38; p=0.02) as measured by accelerometry. The ability of the PBSS algorithm to classify children into high or low weight bearing groups was in moderate agreement with accelerometer derived combined moderate and vigorous activity counts (κ=0.42; p=0.008). PBSS was significantly correlated to body size adjusted bone mineral content at all sites scanned by DXA (r=0.43-0.57; p<0.05). Positive correlations were observed between PBSS and area, density and strength at the radius and tibia (r=0.40-0.64; p<0.05). At the radial metaphysis, significant correlations between moderate activity (r=0.46; p=0.005) and combined moderate and vigorous activity counts (r=0.42; p=0.01) were seen for bone strength. No associations were seen between accelerometer measured physical activity and bone outcomes at the tibial diaphysis. Multiple regression analysis showed that the PBSS was a better predictor of bone mass and structure than was accelerometry. The next study sought to determine whether children who were classified as being high bone loaders for the past two years would present with greater bone mass and strength regardless of their ethnicity. Sixty six children [black boys, 10.4(1.4) yrs, n=15; black girls, 10.1(1.2) yrs, n=27; white boys, 10.1(1.1) yrs, n=7; white girls, 9.6(1.3) yrs, n=17] reported on all their physical activities over the past two years in the interviewer administered bone specific physical activity questionnaire (B3Q). Children were classified as being either high or low bone loaders based on the cohort’s median peak bone strain score estimated from the B3Q. In the low bone loading group, black children had greater femoral neck bone mineral content (BMC) (2.9 (0.08)g) than white children (2.4 (0.11)g; p=0.05). There were no ethnic differences in the high bone loaders for femoral neck BMC. At the cortical sites, the black low bone loaders had a greater radius area (97.3 (1.3) vs 88.8 (2.6) mm2 ; p=0.05) and a greater tibia total area (475.5 (8.7) vs. 397.3 (14.0) mm2 ; p=0.001) and strength (1633.7 (60.1) vs. 1271.8 (98.6) mm3 ; p=0.04) compared to the white low bone loaders. These measures were not different between the black low and high bone loaders or between the black and white high bone loaders. Ethnic differences in bone area and strength apparent between children classified as having a lower bone loading physical activity history appear to have been attenuated when children partaking in high bone loading physical activities were compared. Greater levels of mechanical loading seemed to have no apparent benefits in black children. Cross-sectional studies in black and white pre-pubertal children have observed significant ethnic differences in structural bone outcomes as measured by pQCT but there are a limited number of intervention studies that have been conducted in black children. The cortical bone of black and white children may respond differently to mechanical forces, yet no physical activity interventions and their effects on bone structure in black children have been done. The aim of the third study was to determine whether a weight-bearing physical activity intervention improves measures of bone mass, structure and strength in pre-pubertal black children. Children (9.7 ± 1.1 years) were randomised into an exercise (EX; n=12) and control (CON; n=11) group. The EX children performed a 20-week weightbearing exercise program performed twice a week for 45 minutes per session, while CON children continued their regular activities. Changes in tibial trabecular volumetric bone density, area and strength were greater in the EX than the CON group (all p<0.01). At the cortical site of the tibia, the change in bone density was greater in the EX group than the CON group (all p<0.05). The greater change in tibial periosteal circumference in the EX groups also resulted in a greater change in cortical thickness of the tibia compared to the CON group (p<0.05). The final study assessed whether rates of bone accrual differed over one year between high and low bone loaders and also between black and white South African children. Forty seven children (18 boys, 29 girls) were followed up after one year. High bone loaders tended to have greater baseline BMC at all sites measured by DXA but the difference was only significant at the femoral neck (p=0.03). At the follow up visit, femoral neck BMC remained significantly higher in the high compared to the low bone loaders (p=0.003). Bone strength index (BSI) at the follow up visit was significantly greater in the high bone loaders compared to the low bone loaders (p=0.05). Although there was a trend for the high bone loaders to have greater indices of density and area at the 65% tibia compared to the low bone loaders, this was not significantly different at baseline or at follow up. High bone loaders had greater relative changes in whole body BMC (p=0.002), tibial cortical area (p=0.03), cortical density (p=0.04) and cortical thickness (p=0.03) compared to low bone loaders. There were no significant differences in DXA bone outcomes between black and white children at baseline and follow up. At baseline, total density at the 4% radius was greater in black than in white children (p<0.001) but total density at the follow up visit was not significantly different between black and white children (p=0.06). Trabecular density was greater in the black than in the white children at baseline (p=0.01) as well as at follow up (p=0.04). BSI at baseline was greater in the black than in the white children (p=0.05) but this significance disappeared at follow up. Similar to the 4% radius, cortical density at baseline was significantly greater in the black compared to the white children at the 65% radius (p=0.01) and at the 65% tibia (p=0.04). In conclusion, the PBSS algorithm from the B 3Q can be used to reliably and accurately collect data on previous participation in weight bearing exercise and is able to classify children as being either high or low bone loaders. It appears that in order for White children to reach the same bone mass/health levels as Black children, they may need to participate in higher levels of weight-bearing physical activity. Ethnic differences in bone area and strength apparent between children classified as having a lower bone loading physical activity history appear to have been attenuated when children partaking in high bone loading physical activities were compared. The associations may indicate that a strong environmental influence (i.e. high participation in physical activity) may offer similar or even superior benefits to bone over genetic (ethnic) influences. The use of pQCT appears to be sufficiently sensitive in detecting bone structural changes in response to mechanical loading interventions. As such, pQCT measures were able to determine the efficacy of a weight bearing physical activity intervention on trabecular and cortical sites in black children, and, similar to what has previously been observed in white and Asian children, our knowledge on the attainment of bone in response to an exercise intervention in black children is deepened. Moreover, the bone accrual that occurs in a population of black and white children from a low-middle income country may also differ between ethnicities and may reflect an environmental influence that modifies existing paradigms on physical activity and bone health in children. The promotion of weightbearing physical activity should occur in all youth, to oppose the possible lifestyle induced risks for developing osteoporosis in adulthood.

Cytomegalovirus (CMV) is the most common congenitally acquired infection. It is of major concern due to the long-term neurodevelopmental morbidity in both symptomatic and asymptomatic newborns. While CMV infection is less commonly diagnosed in infancy to adulthood, mostly due to its asymptomatic presentation, it is still an important differential to consider. A missed diagnosis could lead to visual impairments and neurological complications. Infants can acquire CMV by encountering bodily secretions from those who have an active infection. Symptoms of infection include fever, fatigue, pharyngitis, and hepatitis. Laboratory abnormalities include thrombocytopenia, elevated transaminases, and abnormal lymphocyte count. We investigated a clinical case of a previously healthy 5-month-old whose only symptoms were petechial rash and thrombocytopenia. They presented to the ED with a worsening petechial rash for 11 days. The patient’s mother had prenatal care and an uncomplicated pregnancy. In the ED IgM for CMV was positive and platelet count on admission was 35K. The patient was discharged without intervention because platelet count remained above 20K. Outpatient hematology workup ruled out other potential causes of thrombocytopenia. There is no family history of bleeding disorders. The patient was prescribed valganciclovir for 2 months and urine CMV PCR was ordered for the patient and the patient’s mother. The patient’s urine CMV was positive, but the mother’s urine CMV was negative. The patient’s petechiae and thrombocytopenia improved while on valganciclovir treatment. In this case, since the patient’s mother was negative for CMV, it is unlikely that the infection was maternally acquired. Our case illustrates that CMV infection in infancy can be acquired through horizontal transmission and its only presentation can be thrombocytopenia. Since the CMV infection was diagnosed early the patient did not have any neurological symptoms, such as sensorineural hearing loss or delayed developmental milestones.

Older infants are good referential learners. That is, at around 14-months of age, they begin to learn the verbal labels of objects and events around them. However, referential learning can be made more challenging by increasing the lexical similarity between labels. The primary goal of this study was to examine whether an adult speaker's ostensive cues and eye gaze-object contingency could augment referential learning in 14-month-old infants under difficult conditions (i.e., minimal pair labels). In Experiment 1, infants were familiarized and tested on two word-object associations with minimal pairs (e.g., "bin" and "din"), presented on an eye-tracker. Importantly, each session began when infants made eye contact with a female speaker on the screen, and she continually looked at and verbally referenced each object in an infant-directed style. On test trials when the familiar object+label was switched, infants significantly increased their visual scanning of the speaker's mouth compared to control trials. In Experiment 2, the same procedure was followed with a new group of 14-month-olds, except that the speaker now looked in the opposite direction from the objects on the screen, but continued to label them with minimal pairs in an infant-directed style. In contrast to the results of Experiment 1, infants in this latter experiment did not differentially attend to any area of her face during the switch trials. This pattern of results shows that the ostensive nature of a social partner augments infants' referential learning under cognitive challenge, but it is the contingent nature of the speaker's regard to what is being labeled that is a necessary factor in promoting learning. / Ph. D.