Biomedical subjects
Publications and source records attributed to H H Bain.
Accurate localization of infection after pediatric cardiac operation is essential for correct decisions regarding treatment. We report a case of infection and endocarditis of a Blalock-Taussig shunt. Localization by computed tomography led to successful surgical intervention.
Cytogenetic analysis was carried out in a prospective series of 36 children with DiGeorge syndrome. High-resolution banding (> 850 bands/haploid set) was achieved in 30 cases. Monosomy 22q11.21-->q11.23 was found in 9 of these 30 cases. In each of these cases monosomy 22q11.21-->q11.23 resulted from an interstitial deletion and not from a translocation. No other chromosome abnormalities were seen.
DiGeorge syndrome was diagnosed in an infant who had an interrupted aortic arch, hypoparathyroidism, and low T lymphocyte numbers. Two siblings had heart defects that are not commonly described in DiGeorge syndrome (a membranous ventricular septal defect and coarctation of the aorta respectively). These siblings did not have evidence of thymic dysfunction or hypoparathyroidism. Chromosome analysis showed that the mother, whose cardiovascular examination was normal, and her three offspring with heart defects had a 22q11 interstitial deletion, which was confirmed by molecular analysis. This family suggests that 22q11 deletions can cause apparently isolated heart defects and that the range of these defects may be wider than previously recognised. Once the genes that are deleted in this family are characterised they will be useful candidate genes in the investigation of isolated cardiac malformations.
Three children who presented with heart failure in infancy caused by severe hypertension as a result of unilateral renal arterial disease are described. One presented at 3 days of age with persistent fetal circulation and heart failure. He had abnormal great vessels that indicated that the hypertension was of long standing and therefore fetal; this has not been described previously. The other two children failed to thrive because of unrecognised hypertension and subsequently presented with heart failure. All three underwent unilateral nephrectomy which cured their hypertension, and all were thriving at the time of writing. The benefits of nephrectomy outweighed the operative risks and loss of renal function. Blood pressure should be measured in children who are failing to thrive as part of routine clinical practice.
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Severe transplacental lithium toxicity in a neonate is described. There were gross functional lesions of the cardiovascular, renal, and neuromuscular systems with no structural abnormalities. At 1 year of age cardiovascular and renal function is normal, but there is developmental delay.
To investigate the role of the renin-angiotensin-aldosterone system as a cause of hypertension, 20 hypertensive patients with coarctation of the aorta were studied during normal and low sodium intake and after diuresis with flurosemide. Eight patients with essential hypertension and 13 control subjects were similarly studied. Plasma renin activity values in patients with coarctation were similar to those in patients with essential hypertension and in control patients during normal and low sodium diets. However, after the administration of furosemide, plasma renin activity values were significantly higher in the patients with coarctation than in the other two groups (P less than 0.005 and less than 0.01, respectively). The values for urinary aldosterone, plasma volume and extracell fluid volume (bromide space) were increased in patients with coarctation during both normal and low sodium intake. These renin and aldosterone responses and body fluid spaces in patients with coarctation suggest that their hypertension resembles a one-kidney Goldblatt model. The data help to better define the role of the renin-angiotensin-aldosterone system in the hypertension of coarctation and thus may help guide the clinician in therapeutic interventions.
A necroscopy study of 34 patients with interruption of the aortic arch was carried out to characterize more fully the ventricular septal defect and the anatomic basis of subaortic obstruction. In 21 patients (61.8 percent) the site of interruption was between the left common carotid artery and the left subclavian artery; in 13 (38.2 percent) it was distal to the left subclavian artery; no case of interruption just distal to the innominate artery was found. A ventricular septal defect was present in all but two patients, both with large aortopulmonary fenestrations. All patients had visceroatrial situs solitus and D-ventricular loop. The great arteries were normally related in 33 patients and D-transposition was found in one patient. Twenty-one patients had a ventricular septal defect involving the conal septum. Conoventricular malalignment resulted in a typical subpulmonary ventricular defect. The malignant was characteristically in a leftward direction allowing for potential muscular narrowing of the left ventricular outflow tract. In some patients, the conal ventricular septal defect was characterized by a deficiency of a the conal septum without malalignment. In 4 of 21 patients with a ventricular septal defect involving the conal septum, the defect was immediately adjacent to the pulmonary.value. Typical infracristal membranous ventricular defects five patients), cushion defects (3 patients) and muscular defects (3 patients), were also found. The potential for subaortic narrowing was present in some of these patients as well. No relation between position of ventricular septal defect and type of arch interruption could be discerned. The presence or absence of subaortic obstruction was not predictive of a specific type of interruption. Similarly, although deformity of the aortic valve was not uncommon in this series, it was not associated with any specific type of interruption.
The angiocardiographic findings were reviewed in 21 patients with congenital mitral valve disease in whom the exact anotomic diagnosis was known independently. Patients with discordant (1)transposition and simple atrioventricular canal defects were excluded. No precise diagnosis was made in five patients (24%), all of whom had a cleft anterior leaflet or congenital short chordae. In the remainder, the specific diagnosis could have been made by injection of constrast medium downstream to the mitral valve alone in 15 (71%). Upstream injection was performed in 13 of these but would have made the precise diagnosis in only three (23%). In one patient both upstream and downstream injections were necessary. Anomalies giving characteristic angiocardiographic appearances were parachute valve, atresia, annular hypoplasia, dysplasia, anomalous arcade and anomalies associated with subaortic stenosis. Thus injection downstream to the valve is preferable to upstream injection, because it gives information about its patency, competence, tensor apparatus, and annular dimensions.
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