Syncope

Low iron storage in children with tilt positive neurally mediated syncope

BACKGROUND

The mechanisms under neurally mediated syncope (NMS) are not fully understood. This study aimed to assess the level of storage iron in children with different hemodynamic patterns in head-up tilt test.

METHODS

Altogether 210 children (11.31±2.49 years) with syncope or pre-syncope treated between May 2008 and September 2010 were studied prospectively. Following history taking and physical examination, their levels of hemoglobin (Hb), hematocrit (Hct) and serum ferritin were measured.

RESULTS

In the 210 children, 162 (77.1%) had NMS and 48 (22.9%) had syncope due to other causes. In the 162 children with NMS, 98 children were subjected to positive tilt test. The level of serum ferritin was significantly lower in the 98 children with NMS (P<0.001). The comparison of levels of Hb, Hct and mean cell volume (MCV) displayed no significant difference between the two groups. Reduced iron storage (serum ferritin <25 ng/mL) was found to be more prevalent in children with NMS (63% vs. 20%, P<0.001). Prevalence of iron deficiency was also significantly higher in children with NMS than in children with syncope due to other causes (27% vs. 6%, P=0.003).

CONCLUSIONS

In head-up tilt test positive children with NMS, the level of serum ferritin should be evaluated. Low storage iron may be one of the underlying mechanisms of NMS.

Clinical categorization of childhood syncope

Syncope is a self-limited loss of consciousness produced by cerebral hypoperfusion/hypoxia. The objective of this study was to categorize the etiology and determine the frequency of concurrent epilepsy and whether laboratory testing is diagnostically useful. This was an institutional review board-approved retrospective chart review. Data were analyzed using descriptive statistics. There were 141 subjects (90 girls [63.8%]; mean age, 12.01 years). Of the syncope referrals, 86 of 123 (69.9%) had simple syncope, 35 of 123 (28.4%) had syncopal convulsions, and 2 of 123 (1.6%) had epilepsy alone. An electroencephalogram was performed in 64.7% (91/141) of the subjects but was diagnostic in 1 of 91 (1.4%) for epilepsy. Magnetic resonance imaging and/or computed tomography scans, electrocardiograms/Holter monitoring/stress testing, and blood tests were primarily normal or nondiagnostic, with 6 of 238 (2.5%) total tests contributing to the diagnosis. Primary neurocardiogenic syncope was identified in 78% (111/141) of all subjects (82% boys, 75% girls). Thirty-eight percent had syncopal convulsions, and 2.8% (4/141) had concurrent epilepsy. A detailed medical history was the most useful diagnostic tool.

Provocation of neurocardiogenic syncope during head-up tilt testing in children: comparison between isoproterenol and nitroglycerin

OBJECTIVE

Although nitroglycerin- and isoproterenol-augmented tilt tests are of equal value in the diagnosis of neurocardiogenic syncope in adults, no data exist in children. We compared the sensitivity and specificity of the 2 tests in a pediatric population.

PATIENTS AND METHODS

We studied 85 patients (33 boys; mean age: 11.6 +/- 2.9 years). Of them, 56 had a diagnostic history of neurocardiogenic syncope, whereas 29 served as controls. After a negative passive phase, they were randomly assigned to either intravenous isoproterenol or sublingual nitroglycerin, and tilt was continued for 20 minutes.

RESULTS

Sensitivity was 0.78 for the isoproterenol test and 0.79 for the nitroglycerin test, but specificity was significantly higher for isoproterenol test compared with nitroglycerin test. In patients with a positive test, the duration of the recovery period was significantly longer after nitroglycerin (8.4 +/- 2.7 minutes) than after isoproterenol (5.1 +/- 1.6 minutes).

CONCLUSIONS

Nitroglycerin- and isoproterenol-augmented tilt tests are associated with equal sensitivity in the diagnosis of neurocardiogenic syncope in children and adolescents. However, nitroglycerin results in more false-positive tests and produces more prolonged vasovagal symptoms. Our data do not support the routine use of nitroglycerin in the evaluation of syncope in this age group.

Síncope en el adolescente. Orientación diagnóstica y terapéutica

Syncopal episodes are frequent in adolescence. Syncope is usually a benign, self-limiting condition but it may be a warning sign of serious disease that must be diagnosed and appropriately treated. The present article provides a review of the basic principles of the differential diagnosis of syncope in the adolescent patient and treatment recommendations.

Cardiac risk factors and participation guidelines for youth sports

Accurate assessment of the cardiac system in pediatric and adolescent youth is important. The hemodynamic demands associated with exercise, training, and sport participation are usually positive and beneficial; however, when an underlying cardiac problem exists, it is imperative that such cardiac problems be identified. Safe sport-related cardiac participation guidelines should be provided for young athletes and their families and coaches. This chapter provides a physician perspective on the recognition and current cardiac management considerations for young athletes participating in both static and dynamic types of sports. The most recent guidelines for hypertension in youth are also provided.