Why are some South African children with Down syndrome not being offered cardiac surgery?

About 1 in 1,000 children has Down syndrome. Extra chromosomal material results in a myriad of potential problems for the affected individual. About 40% of Down syndrome children will have cardiac abnormalities, ranging from the simple arterial duct to the complex atrioventricular septal defect. Virtually all these defects are amenable to surgical correction and extended survival is possible. In South Africa many of these children do not undergo cardiac surgery.

Factors influencing successful closure with indomethacin of the patent ductus arteriosus in premature infants.

The incidence of persistent patency of the ductus arteriosus (PDA) is inversely related to birth weight. A PDA contributes to pathological conditions in the neonate and timely closure in these low-L birth-L weight infants could potentially prevent these complications. Prostaglandin inhibition with indomethacin is one treatment strategy currently available. This retrospective descriptive study evaluated the parameters that influenced the effectiveness of indomethacin in closure of the PDA in 101 consecutive premature infants and the adverse effects of indomethacin in these infants. Independent variables found to increase the risk of unsuccessful closure with indomethacin significantly were caesarean section, lower haematocrit at delivery and severity of hyaline membrane disease. Non-L closure also resulted in prolonged ventilation. No significant adverse effects were recorded in the infants who received indomethacin but neonatal jaundice was more common in those infants who responded to indomethacin.

Atrioventricular septal defect with 'absent' pulmonary valve in the setting of Down's syndrome: a rare association.

We report a rare case of a 2-year-old boy with Down's syndrome, atrioventricular septal defect and so-called 'absent pulmonary valve syndrome'. Diagnostic imaging also revealed the presence of an anomalous high origin of the right coronary artery from the ascending aorta. Surgical repair was successful.

Pathophysiological aspects after cavopulmonary anastomosis.

The ventricle of a functionally univentricular heart is known to be dilated, hypertrophic and hypocontractile before and after completion of a Fontan type of circuit. Ventricular dysfunction can be due to the congenital malformation itself, previous surgical conditions, or the very abnormal working conditions of the ventricle at the various stages of palliation. Because of the very different types of ventricle, it remains difficult to assess size, shape, hypertrophy, stress, strain, contraction and relaxation. The ventricle after birth tries to adapt to different and very abnormal circulations, evolving from overloaded and overstretched while shunted, to underloaded and overgrown after a Fontan type of circulation.

An explanation of the unusual electrocardiographic findings in a patient with pulmonary agenesis and dextrocardia.

Interpretation of the electrocardiagram (ECG) is extremely helpful in distinguishing between the different forms of dextrocardia. The patient in this report had agenesis of the right lung and dextroposition; the ECG mimicked mirror-image dextrocardia, with elements of dextroversion also present.

Complete atrioventricular septal defect.

Complete atrioventricular septal defect (CAVSD) is known to be associated with Down syndrome (DS) and to be a major cause of infantile death in these patients. Recently several leading articles reported that complete surgical repair before 6 months of age is a relatively low-risk procedure leading to a dramatic improvement in outcome. Most surgical reviews, however, fail to describe their selection criteria and to include patients who die early in infancy or who are unfit for surgery for some or other reason. A retrospective descriptive study was done of all children with CAVSD treated over a period of 15 years from 1980 to 1994 at our institution. The aims were to describe the profile of children with CAVSD in our population, and to evaluate screening procedures and treatment received versus outcome. Thirty-three patients were included in the study, 25 with DS and 8 without. The basic skills of careful auscultation, interpretation of chest radiograph and electrocardiograms (ECGs) are all 100% sensitive in alerting the physician to this condition. Careful screening, especially of DS babies, is essential to ensure early optimal intervention. Echocardiography is the least invasive, most informative investigation to establish a definite diagnosis. The Rastelli anatomical classification is highly indicative of outcome. Children in the Rastelli C group showed a universally dismal prognosis. Digitalis and furosemide are still the mainstay of medical treatment. No additional benefit was observed with the limited introduction of angiotensin-converting enzyme (ACE) inhibitors. Complete repairs were undertaken earlier and more frequently in recent years, but limited resources had led to the majority of patients not receiving surgery at all. There was insufficient urgency to aim for early complete repair, and more than 20% of children died before even being considered for surgery. This study is the first in South Africa to describe our own patient population and to evaluate local practice. Adequate screening of babies (especially those with DS), with early referral for complete repair in the first 6 months of life, remains the goal of optimal management.

Second-degree atrioventricular heart block after doxapram administration.

Doxapram, a respiratory stimulant, is used to treat idiopathic apnea of prematurity. The side effects reported are minimal. We present three cases of second-degree atrioventricular block caused by QT interval prolongation associated with doxapram administration. All three infants returned to normal sinus rhythm after doxapram administration was stopped.

Myosin-reactive autoantibodies in rheumatic carditis and normal fetus.

EBV-transformed B cells from a 20-week human fetal spleen and from blood of patients with poststreptococcal rheumatic carditis were studied. Most antibodies from nine fetal and six patient myosin-reactive B cell clones were multireactive (reacting with cardiac myosin, Streptococcus pyogenes, and rat cardiac myocytes) which supports a role for molecular mimicry in stimulation of these autoantibodies. Sequence analysis revealed that fetal and patient anti-myosin repertoires were composed of unrelated clones with diverse V gene usages. Fetal and patient antibodies had reduced VH CDR3 length on average and reduced light chain N region addition with a low rate of somatic mutation in the variable region genes, characteristics generally associated with fetal B cells but also with some adult B cells. Five of six myosin-reactive patient clones used VH3, whereas only two of nine fetal clones used VH3, suggesting skewing from the average 50-60% VH3 gene usage found in randomly selected adult and fetal antibodies.

Cardiac tamponade following umbilical vein catheterisation in a neonate.

Umbilical vein catheterisation (UVC) should not routinely be used in the neonatal intensive care unit, and when it is used special precautions should be taken and guidelines followed. We present an unusual complication which occurred following use of an umbilical vein catheter in a term neonate. This case highlights another potentially lethal complication of UVC, and emphasises the risks associated with the procedure. In order for the benefits of UVC to outweigh the risks, certain guidelines are reviewed. The importance of confirming the position of the catheter tip with both anteroposterior and lateral radiographs is emphasised.

Sydenham's chorea--analysis of 27 patients and a review of the literature.

The first documented epidemic of Sydenham's chorea was in 1418. In 1686 Thomas Sydenham was the first to describe the condition, but it was Richard Bright who in 1831 first made the association between chorea and rheumatic fever. Chorea is one of the major diagnostic criteria for rheumatic fever. Chorea is often considered a benign self-limiting condition. Little is known about the pathophysiological process. A link between the group A beta-haemolytic streptococcus through an antibody-mediated immune response targeting the basal ganglia has been described. Special investigations have been done to ascertain the pathophysiology, but none is of diagnostic value. The aims of this study were to analyse the clinical findings, the role of special investigations in the management and course of Sydenham's chorea and to review the literature. Data on 27 patients were analysed. Special investigations in these patients can be divided into those necessary to assist in diagnosing acute rheumatic fever and those to exclude other causes that mimic chorea. None of these tests was helpful in diagnosing chorea due to other causes; neither did they influence the management of these patients. In conclusion, Sydenham's chorea remains a clinical diagnosis and extensive and expensive special investigations are seldom warranted.

Isolation of the left subclavian artery in tetralogy of Fallot and bronchial anomalies.

In the normal left-sided aorta, the vertebral arteries arise from the respective subclavian arteries. Isolation of the left subclavian artery takes place when the distal subclavian artery arises as an extension of a patent ductus arteriosus. This report describes a patient with tetralogy of Fallot and a right-sided aortic arch with isolation of the left subclavian artery. In addition, the patient also has congenital tracheal and bronchial stenosis, with a horseshoe lung.

Congenitally absent pulmonary veins--diagnostic pitfalls. Two case reports.

Two patients with partial absence of the right and left pulmonary veins respectively are described. Congenitally absent pulmonary veins are a rare phenomenon and the diagnosis is often missed or delayed. When children present with haemoptysis and/or recurrent respiratory infections with no obvious underlying cause, absence of the pulmonary veins must be part of the differential diagnosis. Special investigations to be done in these patients are chest roentgenograph to compare the lung volumes, radio-isotope scan, echocardiography and cardiac catheterisation. Magnetic resonance imaging may be helpful in defining the cause and site of obstruction of the pulmonary veins. Depending on the cause, surgery might be considered.

Dynamics of respiratory gas exchange during exercise after correction of congenital heart disease.

In pediatric exercise testing, conventional measures of aerobic exercise function such as maximal O2 uptake or the ventilatory anaerobic threshold (VAT) use only one value for the assessment of exercise capacity. We studied a more comprehensive approach to evaluate aerobic exercise function by analyzing the steepness of the slope of CO2 production (VCO2) vs. VO2 above the VAT (S3). This was calculated in 32 patients operated on for congenital heart disease [16 for transposition of the great arteries (TGA) and 16 for tetralogy of Fallot (TF)] and was compared with 16 age-matched controls (nl). The results show that the reproducibility of this new assessment method was excellent (coefficient of variation for S3: 8.6%). S3 was significantly steeper (P<0.05) in the patients (1.31 +/- 0.22 for TGA and 1.28 +/- 0.16 for TF) compared with the nl (1.10 +/- 0.22). Also, the difference between S3 and the slope of VCO2 vs. VO2 below the VAT was significantly higher in the patients (0.37 +/- 0.22 for TGA and 0.31 +/- 0.10 for TF) than in controls (0.22 +/- 0.06). The steeper slopes were associated with lower than normal values for VAT and O2 during exercise. It is concluded that the analysis of the steepness of the slope of CO2 is a sensitive, reproducible, and objective approach to evaluate the integrative cardiopulmonary response to exercise. It complements the assessment of a subnormal VAT by reflecting the extent of anaerobic metabolism.

Risk of pulmonary tuberculosis in children with congenital heart disease.

Children with low-flow congenital heart lesions are reported to have an increased incidence of pulmonary tuberculosis. The aim of this study was to investigate if children with congenital heart disease have an increased incidence of pulmonary tuberculosis and to determine if patients with certain heart conditions are more susceptible to pulmonary tuberculosis than others. This retrospective study over a 6-year period showed that pulmonary tuberculosis was 2.5-fold more common in children with congenital heart disease than in normal children from the same community. Children with congenital pulmonary stenosis had a prevalence equal to those with acyanotic (ventricular and atrial septal defects) and cyanotic (transposition of the great arteries) high-flow heart lesions, whereas there were no cases of tuberculosis in children with low-flow cyanotic heart lesions such as tetralogy of Fallot. Cardiac surgery had to be postponed as a result of pulmonary tuberculosis in 7.2% of all patients in whom it was required. Over the 6-year period of the study, cardiac surgery had to be delayed in 60% of cases with pulmonary tuberculosis and congenital heart lesions so antituberculosis therapy could be completed. Physicians treating children with congenital heart lesions should maintain a high index of suspicion for the development of pulmonary tuberculosis, especially in those with acyanotic and cyanotic high-flow lesions and pulmonary stenosis.

Repair of aortico-left ventricular tunnel associated with subpulmonary obstruction.

Aortico-left ventricular tunnel is a rare congenital cardiac defect. Because the tunnel traverses the upper portion of the interventricular septum, the potential exists for an aneurysmal tunnel to obstruct the outflow of the right ventricle. We report our clinical experience with such a patient, and emphasize the importance of a two-patch technique to avoid its occurrence.

Cerebral oedema with coning in diabetic keto-acidosis. Report of 2 survivors.

Two children presented with a first episode of diabetic ketoacidosis. Initially both patients made a good clinical and biochemical recovery, but suddenly developed neurological signs consistent with a diagnosis of tentorial herniation. Cranial computed tomography showed signs of cerebral oedema in both cases with evidence of uncal and tentorial herniation in 1 patient, which resolved after the appropriate treatment. The excellent neurological outcome emphasises the need for early recognition and treatment of sudden onset brain oedema in diabetic keto-acidosis.