MRSA infections in children.

MRSA infections continue to be a serious and formidable challenge to health care providers and their prevalence is increasing exponentially. In the past, MRSA infections were observed only in hospitalized patients whereas now they are encountered in the outpatient setting. Understanding the pattern of the widespread distribution of MRSA as well as the factors associated with its spread are paramount to its recognition and eradication. The current state of MRSA transmission, control and management is reviewed.

Work of breathing associated with pressure support ventilation in two different ventilators.

The purpose of this study was to compare the work of breathing during pressure support ventilation (PSV) with positive end expiratory pressure (PEEP) utilizing the Siemens SV300 (SV300) and Dräger Evita 4 (EV4) ventilators. Our hypothesis was that patients' work of breathing (WOB(P)) would be unchanged in PSV utilizing flow triggering (FT) in both the SV300 and EV4. We compared two ventilators using six healthy, intubated, sedated, spontaneously breathing pigs weighing approximately 10 kg each. WOB(P) (j/L) and ventilator work of breathing (WOB(V)) (j/L) were measured using a portable monitor which utilizes an esophageal balloon and flow transducer. Each breath was further analyzed for duration of inspiratory effort and negative deflection of pressure needed to trigger PSV. Animals were studied with the SV300 and EV4 on a pressure support of 5 cmH(2)O and PEEP settings of 0 and 5 cmH(2)O. Data were analyzed using the Wilcoxon signed rank test with significance set at P

An evaluation of Automode, a computer-controlled ventilator mode, with the Siemens Servo 300A ventilator, using a porcine model.

BACKGROUND: Weaning of mechanical ventilation in patients optimally includes meeting their needs by making frequent ventilator adjustments. The Siemens Servo 300A mechanical ventilator is designed to allow the ventilator to be interactive with the patient's needs by making breath-by-breath adjustments in both control and support modes. We undertook the following experiment to validate that the Automode algorithm responded appropriately using a pediatric animal model when apnea occurred and if there was any impact on work of breathing. METHODS: We ventilated 6 sedated spontaneously-breathing piglets using Automode in pressure-regulated volume control/volume support (PRVC/VS) mode, pressure control/pressure support (PC/PS) mode, and volume control/volume support (VC/VS) mode. Data were collected using both a computerized respiratory monitor and data acquisition system that recorded and analyzed individual animal breaths for response time, effort of triggering, and work of breathing. Data collection began with the animals breathing spontaneously in each support mode, followed by the administration of a short-acting neuromuscular blocker (succinylcholine) to induce apnea, thus allowing the ventilator to switch between modes automatically. Data collection was continued before, during, and after apnea to observe the duration of inspiratory effort, trigger response time, and any significant pressure or flow variances of the Automode feature. In addition, patient work of breathing (WOB(P)) and ventilator work of breathing (WOB(V)) were measured before and after each phase. RESULTS: We found no instances of failure of Automode to follow the predetermined algorithms. There was a difference in both the amount of change in pressure and most negative deflection of pressure by each animal during triggering in the post-paralysis phase (p < 0.05). Response time for individual breaths was shorter from initiation of breath to most negative deflection of pressure during the post-paralysis phase (p < 0.05). Maximum flow reached was lower in the post-paralysis phase for VC/VS and PC/PS (p < 0.05). We also found WOB(P) decreased and WOB(V) increased in the post-paralysis phase for all modes tested. CONCLUSIONS: The Automode algorithm performed as expected in this animal experiment. We conclude that differences in response time and negative deflection of pressure, as an indication of animal effort, and maximum flow reached were due to continued weakness from the neuro-muscular blocker. However, the ventilator continued to trigger despite decreased effort by the animal.

Bacterial, viral and parasitic aetiology of paediatric diarrhoea in the highlands of Papua New Guinea.

Enteropathogens and clinical features associated with diarrhoea were investigated in 1526 children admitted over a 5-year period to the paediatric ward of a hospital in the highlands of Papua New Guinea. Overall, a recognized pathogen was isolated from 39 per cent of the children admitted with diarrhoea. The most commonly isolated agents were rotavirus (23 per cent), Shigella spp. (13 per cent), Campylobacter spp. (12 per cent), Cryptosporidium parvum (10 per cent) and enteropathogenic Escherichia coli (8 per cent). The clearest clinical associations were rotavirus with vomiting, and Shigella with blood and pus in the stool. A control series of children admitted with other complaints was also included, and the odds ratios for diarrhoea for the above five pathogens were 18.2, 9.6, 3.7, 2.2, and 1.6, respectively.

Comparison of work of breathing between two neonatal ventilators utilizing a neonatal pig model.

OBJECTIVE: The purpose of this study was to determine whether variations in the delivery systems of continuous positive airway pressure between two ventilators would lead to differences in patient work of breathing (WOBp). DESIGN: Comparison of two neonatal ventilators with a neonatal pig model. SETTING: Animal laboratory. SUBJECTS: Thirty healthy, intubated, sedated, spontaneously breathing neonatal piglets weighing 1.0-2.0 kg. INTERVENTIONS: Patient work of breathing (WOBp) (gm cm/kg) was measured by using measurements based on an esophageal balloon and a flow transducer. Each breath was analyzed for ventilator response times (in msecs) and negative deflection of pressure. Each animal was studied with the Siemens SV300 and Drager Babylog 8000, on continuous positive airway pressure settings of 0, 3, and 5 cm H2O. Data were analyzed by using Wilcoxon's Signed Rank Test with significance of p 1 cm H2O negative pressure before flow was available with the Babylog. CONCLUSIONS: In intubated patients, maximum energy expenditure occurs at the initiation of ventilator breaths. WOBp in neonatal pigs was significantly increased. The response time of the ventilators may explain the differences in initiation of flow times and patient work. These differences may have important implications for energy kinetics, weight gain, and duration of mechanical ventilation in preterm neonates.

Bacterial and viral etiology of severe infection in children less than three months old in the highlands of Papua New Guinea.

OBJECTIVE: Determine the bacterial and viral etiology of severe infection in young Papua New Guinean infants as part of a multicenter study in four developing countries aimed at improving case management guidelines. METHODS: Between March, 1991, and April, 1993, children aged <3 months were recruited at the outpatient department of Goroka Base Hospital, Papua New Guinea (PNG). Children with pre-defined inclusion criteria were enrolled, a history was taken and clinical examination was performed. Blood and urine were collected from children with signs suggestive of severe disease together with eye, umbilical and pernasal swabs as appropriate. Nasopharyngeal aspirates (NPAs) were collected from children with and without signs of severe disease for identification of viruses and Chlamydia trachomatis by direct fluorescent antibody staining. RESULTS: 3280 infants were triaged and 2168 enrolled, among whom 968 had signs suggestive of severe disease. Group A Streptococcus (Streptococcus pyogenes) and Staphylococcus aureus were the most important bacterial pathogens isolated from children < 1 month old with severe infections, and Streptococcus pneumoniae, S. pyogenes and Staphylococcus aureus were most important in older children. Of 292 eye swabs 19 (7%) grew Neisseria gonorrhoeae. Of 116 umbilical swabs 51 (44%) grew S. pyogenes and 45 (39%) grew Staphylococcus aureus. Respiratory syncytial virus was the most important viral cause of acute lower respiratory infection. CONCLUSIONS: S. pyogenes, S. pneumoniae and Staphylococcus aureus are important causes of severe infection in young children in the PNG highlands. It is necessary to improve access to clean water, promote hand-washing in the hospital and at home and investigate further the use of maternal immunization for the prevention of severe disease in young infants.

High rates of Chlamydia trachomatis infections in young Papua New Guinean infants.

OBJECTIVE: Determine the importance of Chlamydia trachomatis in the etiology of severe infection in young Papua New Guinean infants. METHODS: Between March, 1991, and April, 1993, children <3 months old were recruited as outpatients at Goroka Base Hospital, Papua New Guinea, as part of a multicenter study in four developing countries. Children with predefined inclusion criteria were enrolled. C. trachomatis was identified by direct fluorescent antibody staining in nasopharyngeal aspirates (NPAs) collected from children with and without signs of severe disease and eye swabs from children with and without conjunctivitis. Two to three radiologists read chest radiographs without knowledge of clinical and laboratory findings. RESULTS: Of 3280 outpatients seen 2168 enrolled, 955 NPAs were tested for C. trachomatis and 549 chest radiographs were read. Of 210 eye swabs from children with conjunctivitis 57% were positive for C. trachomatis compared with 8% from 167 children with no conjunctivitis. The prevalence of C. trachomatis in NPAs was 9% in asymptomatic children and 18 and 33% in children with nonsevere or severe pneumonia, respectively. C. trachomatis in NPAs was strongly associated with clinically severe pneumonia [odds ratio (OR), 2.91], reduced arterial oxygen saturation (OR 2.58) and radiographic evidence of pneumonia (OR 5.84) and was also associated with pneumococcal bacteremia (OR 3.48). CONCLUSIONS: In Papua New Guinea Chlamydia must be considered as a cause when treating pneumonia in infants, and effective treatment and prevention of sexually transmitted diseases are urgently needed for a number of reasons, including the need to curb high rates of chlamydial infection in women and infants.

OEIS complex (omphalocele-exstrophy-imperforate anus-spinal defects) in monozygotic twins.

The omphalocele-exstrophy-imperforate anus-spinal defects (OEIS) complex is a consistent and recognizable pattern of midline abdominal and pelvic defects. It is rare, affecting 1 in 200,000 to 400,000 pregnancies and is even rarer in twin gestations. This is an autopsy study of OEIS complex in monozygotic twins after pregnancy termination at 20 weeks of gestation. Unremarkable family history but concordance of monozygotic twins for the defects may support the theory that early malformation complexes, e.g., OEIS, and monozygotic twinning are manifestations of the same disturbance of early blastogenesis.

Legal problems related to obstetrical ultrasound.

Malpractice suits related to fetal anomalies are now the most common type of litigation involving ultrasound, surpassing ectopic pregnancy. Missing an anomaly on a sonogram performed for a standard indication, such as dating, is the most frequent type of litigation. Other causes of litigation include invented anomalies and unrecognized anomalies that are visible in retrospect on the ultrasonic images. Rarer causes of malpractice problems relate to failure to communicate the results of a sonogram in a timely fashion, failure to inform the patient of the findings about the sonogram at the time the patient is seen, and failure to perform ultrasound studies for anomalies when there is clinical indication to do so, such as elevated alpha-fetoprotein or polyhydramnios. The level of protection given by the obstetrical guidelines are discussed. Particular areas of concern relate to litigation involving missed fetal heart malformations, spina bifida, absent distal limbs, and twins.

Health impact assessments of malaria and Ross River virus infection in the Southern Highlands Province of Papua New Guinea.

Malaria at an elevation of 1050 metres is common and highly endemic in the Tagari Valley in the Southern Highlands of Papua New Guinea. Health impact assessments showed that the risks of malaria and epidemic polyarthritis at a gasfield development project in this area were high. Baseline malariometric surveys were conducted in four villages in June and August 1990 and two follow-up surveys (May and December 1991) were made in the village of Nogolitogo near the gasfield pioneer base camp. A total of 941 blood smears were examined. Average malaria prevalence rates decreased with altitude from 56% (at 1050 m) to 9% (at 1700 m) for children 1-9 years of age and from 45% (at 1050 m) to 8% (at 1550 m) for those aged 10 years or more. The spleen rate for children less than 10 years old did not vary significantly with altitude, but average enlarged spleen for all ages decreased with altitude. Mean packed cell volume increased with altitude. Plasmodium falciparum was the most common malaria parasite found and Anopheles punctulatus the predominant vector. Ross River arbovirus (RRV) antibody prevalence was 59%. These results indicate frequent or constant transmission of malaria and pathogenic arboviruses. Entomological and epidemiological data suggested that the vulnerability of the valley community, the receptivity of the environment and the health hazards from malaria and RRV were high. Nonimmune Papua New Guineans and expatriate employees face high health hazards; therefore effective preventive measures are required to mitigate epidemics and avoid the likely heightened transmission of malaria and arboviruses caused by the development project.

Criteria for the prenatal diagnosis of classic bladder exstrophy.

OBJECTIVE: To define ultrasonographic criteria for the prenatal diagnosis of classic bladder exstrophy. METHODS: Forty-three prenatal ultrasound scans were studied from 25 pregnancies in which live delivery of an infant with classic bladder exstrophy occurred. The diagnosis of bladder exstrophy could be made retrospectively in 29 prenatal studies from 17 pregnancies. The time of the fetal ultrasound varied from 14-36 weeks' gestation (mean 23). The diagnosis of bladder exstrophy was made before delivery in only three cases. RESULTS: Five factors associated with bladder exstrophy were identified: 1) The bladder was not visualized on ultrasound in 12 of 17 cases (71%); 2) a lower abdominal bulge representing the exstrophied bladder was seen in eight of 17 cases (47%); 3) a small penis with anteriorly displaced scrotum was identified in eight of 14 males (57%); 4) the umbilical insertion was low set in five of 17 cases (29%); and 5) abnormal widening of the iliac crests was seen in three of 17 cases (18%). CONCLUSION: The prenatal diagnosis of bladder exstrophy should be considered any time the bladder is not visualized or any of the aforementioned factors are noted.

Osteogenesis imperfecta and campomelic dysplasia: difficulties in prenatal diagnosis.

The classic features of osteogenesis imperfecta and campomelic dysplasia typically are so specific that these two forms of skeletal dysplasia are among the few that can be diagnosed in the second trimester of pregnancy. We report a series of seven examples of osteogenesis imperfecta and one example of campomelic dwarfism to illustrate the difficulty of differentiating these two disorders in utero. The prenatal sonographic findings in three of the osteogenesis imperfecta cases mimicked campomelic dwarfism, whereas the case of campomelic dwarfism was antenatally diagnosed as osteogenesis imperfecta.

Arbovirus disease in Papua New Guinea.

It is clear that exposure to arthropod-borne viruses is common in the populations of both Papua New Guinea and Irian Jaya. Clinical disease resulting from these infections has been reported although the paucity of case reports and combined clinical experience suggest that it is rare. Dengue epidemics due to dengue-1 and dengue-2 have occurred and it is likely that dengue-3 is also present in the region. No cases of dengue haemorrhagic fever have been described. Murray Valley encephalitis, Ross River and antigenically related viruses are widespread in Papua New Guinea and Irian Jaya, particularly in the lowland and coastal areas. Antibodies to Japanese encephalitis virus have not been found in blood samples from Papua New Guinea or Irian Jaya. As Papua New Guinea is developed, new areas of the country are opened up and ecosystems are altered. It is important that physicians based in Papua New Guinea, and those who deal with patients living or working here, are aware of the arbovirus diseases which occur and the potential and preventable problems posed by them to both the individual and the community.

Immunoglobulin G antibody responses to polyvalent pneumococcal vaccine in children in the highlands of Papua New Guinea.

The immunoglobulin G (IgG) antibody responses to a pneumococcal polysaccharide vaccine were examined for 480 children aged 3 months to 5 years and living in Tari, Southern Highlands Province, Papua New Guinea. Antipneumococcal IgG to the seven serotypes most frequently causing invasive disease (types 2, 5, 6B, 7F, 14, 19F, and 23F) was measured by an enzyme-linked immunosorbent assay in serum collected before vaccination and 1 and 6 months after vaccination. Prevaccination antibody levels fell rapidly after 3 months of age and remained low throughout the first 2 years of life. One month after vaccination, geometric mean titers of antipneumococcal IgG to serotypes 2, 7F, 23F, and 5 were at least twice those of antibodies in nonvaccinated children of the same age from the ages of 5, 6, 9, and 12 months onwards, respectively; postvaccination antibody responses to serotypes 6B, 14, and 19F rose gradually during the second year of life. Elevated antibody titers to serotypes 2 and 7F were maintained 6 months after vaccination. Thus, young Papua New Guinean children are capable of mounting a good immune response to some pneumococcal capsular polysaccharides from a young age, and the antibody responses to capsular polysaccharides are consistent with studies in developed countries. However, in Papua New Guinea, the serogroup distribution of invasive disease matches the immunogenic components of the pneumococcal polysaccharide vaccine more closely than in developed countries, a fact which helps to explain the results of controlled trials in Papua New Guinea, in which this vaccine prevented death and severe morbidity from pneumonia in young children.

The role of ultrasound in prostate cancer detection in patients with an elevated prostate specific antigen level but no prostatic nodule.

An increased level of prostate specific antigen (PSA) in the blood is a relatively sensitive indicator of prostate disease; a significant minority of men with increased PSA will have prostate carcinoma. A total of 736 men with a PSA elevation of greater than 4.2 without a rectally palpable prostate mass were evaluated with transrectal ultrasound at the Ultrasound Institute of Baltimore over a three-year period. Transrectal biopsy under ultrasound control was performed when a localized mass was seen on ultrasound or the prostate was small and the PSA level significantly elevated (93% of the series underwent biopsy). There was a positive biopsy yield for cancer of 38.5% in the cases biopsied. This high positive yield was achieved by combining high quality ultrasound with two to three samples from a visible mass and random samples from other sites.

Ultrasonic clues to the detection of chromosomal anomalies.

The ultrasonic detection of fetal anomalies may well be the most challenging aspect of diagnostic ultrasound and, because ultrasonic clues to a chromosomal anomaly may be subtle, much depends on high quality ultrasound. Although difficult, the field is exciting and rewarding. It is hoped that recognition of the various common manifestations of chromosomal anomalies described in this article will increase the number of chromosomal anomalies detected and ameliorate the consequences of these disorders.

Levels of anti-pneumococcal antibodies in young children in Papua New Guinea.

Anti-pneumococcal polysaccharide antibody (anti-PPS) levels were measured in 153 serum samples collected from children aged between 2 and 47 months living in the highlands of Papua New Guinea (PNG). Fifty-seven of the samples were collected during acute episodes of lower respiratory tract infection (ALRI). Total IgA and IgG increased steadily with age; however, no association was found between the levels of these antibodies and the health status of the child. Total IgM levels showed little relationship to the age of the child but under 12 months of age levels were somewhat higher on average in children with pneumonia. For most of eight pneumococcal serotypes tested, specific IgG levels were found to decline rapidly in the first 6-8 months, reaching a minimum at approximately 12 months of age. Serotype 3 was exceptional in having very low titres in the youngest children. A separate analysis of 24 cord sera suggested that antibodies to this serotype do not usually cross the placenta in PNG. Children with pneumonia tended to have lower levels of specific IgG than healthy controls of the same age. Specific anti-PPS IgA levels were found to increase steadily with age, but were not associated with health status.

Increased echogenicity in the fetal abdomen: use of DNA analysis to establish a diagnosis of cystic fibrosis.

The sonographic finding of increased echogenicity within the fetal abdomen presents a diagnostic dilemma, with a differential diagnosis ranging from normal variation to CF. We report the diagnostic evaluation of four cases, two of which were found to be the result of CF. On the basis of this experience, we believe that persistence of an echogenic bowel pattern, especially with bowel dilation, after 20 weeks' gestation should prompt an evaluation for CF. Using DNA analysis, approximately 75% of the cases involving CF can be detected with noninvasive studies of the parents, and confirmation by amniocentesis is performed only in those cases in which both parents are carriers of known mutations.

The carriage of Streptococcus suis type 2 by pigs in Papua New Guinea.

An indirect fluorescent antibody test was used to detect the presence of Streptococcus suis type 2 in nasal and pharyngeal swabs taken from pigs in Papua New Guinea. The rate of carriage for the two sites in domesticated indigenous village pigs was 0.5 and 2.5% respectively, compared to 39 and 43% for intensively reared pigs. These findings were supported by the results of a serological survey, using an enzyme linked immunosorbent assay, in which 87% of intensively reared pigs but only 8% of village pigs were seropositive to S. suis type 2. It is proposed that in intensive piggeries S. suis type 2 is continually cycled between pigs. In village pigs, the low population density and harsh environmental conditions prevents this cycle of infection.

The prevalence of antibodies to human T-lymphotropic virus type I in different population groups in Papua New Guinea.

Isolation and partial sequencing of human T-lymphotropic virus type I (HTLV-I) variants from inhabitants of Papua New Guinea (PNG) and the Solomon Islands has confirmed the existence of virus infection in Melanesian populations. To determine the geographical distribution of seropositivity to HTLV-I in PNG we have tested 2907 serum and plasma samples collected between 1972 to 1991 from 16 different population groups. Samples were screened using a particle agglutination assay and confirmed by p21e-enhanced Western immunoblot (WB). From a total of 94 screen positive samples run on WB, 56 (60%) were confirmed positive (positive for both env and gag products) and 38 (40%) were WB-indeterminate (gag products only). The prevalence of WB-confirmed antibodies to HTLV-I in lowland and island populations ranged from 0 to 5.4%. There were no confirmed antibody positives in the highland populations surveyed. Geographically isolated populations living on the fringes of the highlands ranged in seropositivity from 0.2 to 5.8%. Two of the subjects surveyed gave WB antibody patterns characteristic of HTLV-II rather than HTLV-I infection.