Neurocardiogenic syncope in children : current concepts in diagnosis and management

Lack of Utility in Performing Blood Glucose Measurement and Electrocardiogram in the Outpatient Evaluation of Benign Pediatric Syncope

We aimed to determine the frequency of blood glucose and electrocardiogram (EKG) abnormalities in previously healthy children who present to an emergency department (ED) with a diagnosis of benign syncope. Chart review of consecutive children aged 5 to 18 years presenting to the pediatric ED from 2004 to 2014 with a discharge diagnosis of benign syncope was done. Of 969 patients, hypoglycemia (serum glucose <60 mg/dL) was present in only 3 cases (0.3%). Of 754 patients with EKG performed, only 4 cases (0.6%) was an abnormality requiring further cardiac evaluation identified; cardiac echocardiogram was performed in 3 of these 4 patients, which revealed no cardiac pathology. Financial analysis for performing blood glucose measurement and EKG on these patients amounted to total health care cost of $222 526. We concluded that previously healthy children with syncope rarely have hypoglycemia or underlying cardiac abnormality. The routine performance of tests can incur significant health care expenditure.

Syncope in Pediatric Practice

Syncope is defined as a sudden, self-limited loss of consciousness and postural tone followed by spontaneous and complete recovery without any neurological sequelae. It is one of the most common paroxysmal disorders in children and adolescents. The three major causes of syncope in children are neural, cardiovascular and other non-cardiovascular causes. The common unifying mechanism is transient global hypoperfusion of the brain. The diagnosis is primarily clinical and objective laboratory investigations add little to the diagnosis in children especially in neurocardiogenic subtype. Specific management depends on the underlying cause of syncope in children. For cardiac causes, management includes early referral to the pediatric cardiology specialist. When paroxysmal non-epileptic events are suspected, child psychology or psychiatry consultation should be sought to identify the stressors and counseling. For neurocardiogenic syncope, the main objective of treatment is to prevent recurrent events to improve the quality of life, psychological stress and school absenteeism by behavior and lifestyle modifications followed by drugs in refractory cases. The prognosis is excellent for neurocardiogenic syncope and is variable based on the underlying pathology in cardiogenic cases. As syncope is not a disease in itself but a symptom of an underlying disorder; hence, all children with syncope require assessment to exclude an underlying life-threatening cardiac or non-cardiac disorder.

Pediatric syncope: is detailed medical history the key point for differential diagnosis?

Syncope is a transient loss of consciousness as a result of global cerebral hypoperfusion. It is generally benign but may be a sign of pathology. The purpose of this study was to analyze the frequency of syncope due to cardiac, neurocardiogenic, neurologic, situational, psychiatric, and other causes and make a differential diagnosis of syncope types according to detailed medical history and further investigations. We examined prospectively 268 children presented to pediatric polyclinics as well as cardiology and neurology departments (age range, 1-18 years) with a primary complaint of syncope for the study. Cardiac syncope was diagnosed in 12 patients, neurocardiogenic syncope in 232, neurologic syncope in 9, psychiatric syncope in 9, situational in 4, and benign paroxysmal positional vertigo in 2. The neurologic syncope group consists of patients diagnosed with epilepsy after evaluation. Eight patients in the cardiac syncope group were found to have diseases such as long QT syndrome, and the remaining patients had hypertrophic cardiomyopathy, atrioventricular nodal reentry tachycardia, ventricular tachycardia, and a second-degree heart block that can cause sudden death. In conclusion, syncope is a common problem in childhood that requires hospitalization. Because it may be the first finding of an underlying malignant cardiac or neurologic disease, clinicians must be very careful during medical evaluation. An electrocardiogram and a medical history including the details of the event, chronic diseases, and familial diseases are among the most important steps for the right diagnosis and prognosis. Instead of a routine procedure, further diagnostic workup should be directed according to medical history for high yield. Convulsive movements may be defined in all types of syncope related with cerebral hypoxia, and this may lead to a misdiagnosis of seizure by the clinician.

Clinical approach to syncope in children

Pediatric syncope is one of the most common neurological problems in the pediatric population in both the office setting and in the emergency department. The abrupt brief loss of consciousness is usually dramatic and alarming to patients, family, onlookers, and providers. The differential diagnosis of syncope is wide but most cases are benign. A comprehensive but focused history and a thorough clinical examination are usually the cornerstones in the diagnosis of high-risk patients. It should be noted that the evaluation of syncope in children is costly and testing provides a low diagnostic yield. This chapter reviews the various types of syncope and provides a succinct clinical approach to the diagnosis, investigation, and management of syncope in children.

Physiologic neurocirculatory patterns in the head-up tilt test in children with orthostatic intolerance

BACKGROUND

Orthostatic intolerance (OI) is a common clinical manifestation in clinical pediatrics. The head-up tilt (HUT) table test is considered the standard of orthostatic assessment, but the physiologic neurocirculatory profile during HUT has not been fully realized in children with OI. The present study, therefore, was designed to investigate the physiologic patterns that occur during HUT in children with OI.

METHODS

Ninety children (56 girls; mean age, 11.6 +/- 2.3 years) with OI underwent HUT under quiet circumstances. Blood pressure and heart rate were monitored simultaneously.

RESULTS

Forty-nine children with OI (54.4%) had vasovagal response with HUT testing; 33 (36.7%), vasodepressor response; six (6.7%), cardioinhibitory response; and 10 (11.1%), mixed response. Twenty-eight children (31.1%) had postural orthostatic tachycardia; one (1.1%), orthostatic hypotension (OH); and 12 (13.3%), normal physiologic response. Patterns of cerebral syncope response and chronotropic incompetence were not observed.

CONCLUSIONS

Classical vasovagal response was the major physiologic pattern seen in children with OI during HUT testing, and postural orthostatic tachycardia response ranked second.

Aetiologic and clinical characteristics of syncope in Chinese children

AIM

This study aimed to improve diagnostic efficacy of syncope in children by analyzing the aetiology and clinical characteristics of syncope in Chinese children.

METHODS

We retrospectively analyzed the causes of syncope and diagnostic workup in 154 consecutive children seen in the Department of Pediatrics, Peking University First Hospital, China, because of a syncope-related event.

RESULTS

In all patients with transient loss of consciousness (TLOC), there were 136 (88.31%) patients attributing to syncope, and 18 (11.69%) belonging to nonsyncopal cases. Neurally mediated syncope (NMS) was the most common cause of syncope (99 cases; 64.3%), with cardiac causes ranking second (10 cases; 6.5%). Other nonsyncopal causes included psychiatric problems and neurological and metabolic disorders. In 25 cases (16.2%), the cause was uncertain. Cases of NMS often had clear inducement of syncope and prodromes. Children with cardiac syncope often had a history of cardiac disease, were often younger than those with NMS, and showed exercise-related syncope, syncope spells in any body position or at an early age, or sudden death in family members but no prodromes. Neurological disorder was suspected in cases of TLOC with seizures, TLOC spells in any position, postictal phase of disorientation or abnormal neurological signs. A metabolic cause is suspected with a history of metabolic disease, prolonged anger, or violent vomiting and diarrhoea. Children with psychiatric disorders were adolescent girls, with prolonged TLOC spells, who had more frequent TLOC. Although many tests were used in diagnosis, most were not goal directed. Now, electrocardiography is recommended in almost all children with syncope. Neurological testing, including electroencephalography and computed tomography were rarely helpful unless with evidence of neurological signs and symptoms. Head-up tilt test (HUTT) was most useful in children with recurrent syncope in whom heart disease was not suspected.

CONCLUSION

NMS was the most common cause of syncope. We recommended HUTT as the important basis of the TLOC workup.

The efficacy of midodrine hydrochloride in the treatment of children with vasovagal syncope

OBJECTIVE

To determine whether midodrine hydrochloride therapy can prevent vasovagal syncope (VVS) in pediatric patients.

STUDY DESIGN

Children with recurrent syncope (n = 26) were randomly assigned into 2 groups. Group I comprised children given midodrine hydrochloride as first-line therapy in addition to conventional therapy, and group II comprised patients receiving conventional therapy only. Repeat head-up tilt (HUT) testing and follow-up of least 6 months were conducted to evaluate the therapeutic effectiveness and side effects of midodrine in treating VVS in children.

RESULTS

The HUT-based effective rate was significantly higher in group I than in group II (75% vs 20%; P < .05). During the follow-up period, the recurrence of syncope was significantly lower in group I than in group II (P < .05).

CONCLUSIONS

Midodrine hydrochlorate is effective in treating VVS in children, especially in preventing recurrent episodes. Few side effects were observed in the present study.

Fludrocortisone in the management of an infant with a single ventricle and an overly tightened pulmonary artery band

We describe a 2-month-old female infant with a univentricular heart and overly tightened pulmonary artery band (PAB) resulting in hypercyanotic episodes. Despite adequate doses of morphine and a beta-blocker, she continued to have multiple hypercyanotic events per day. Treatment with fludrocortisone resulted in resolution of these episodes and allowed performance of a Glenn shunt at 3 half months of age. We conclude that fludrocortisone may be beneficial in the management of an overly tightened PAB until the patient is suitable for surgical intervention.

Understanding and Managing Neurally Mediated Syncope in the Adolescent

Syncope and near-syncopal symptoms are common events in the adolescent population. Syncope is defined as the transient loss of postural tone and consciousness with spontaneous recovery. Although most syncopal events are benign, they can generate extreme anxiety in the adolescent and his or her family. The reoccurrence of these events can have a negative impact on an adolescent’s participation in daily activities. Understanding the process of assessment, diagnosis, and management of these teens can enable the school nurse to augment initial assessment and to support the prescribed treatment plan. This knowledge then can be used to help allay the adolescent’s anxiety and to support efforts at self-management. This article explores current literature in regards to etiology, diagnosis, and medical treatment, and advocates a self-management protocol for neurally mediated syncope in the adolescent population with support of that plan by the school nurse.

Syncope in pediatric patients presenting to an emergency department

OBJECTIVE

To assess the epidemiology of syncope coming to medical attention among unselected children referred to an emergency department in Western Europe.

STUDY DESIGN

We analyzed the cause of syncope and diagnostic workup of 226 consecutive pediatric patients seen in our emergency department because of a syncopal event.

RESULTS

Neurocardiogenic syncope and neurologic disorders were the most common diagnoses (80% and 9%, respectively). Other causes included psychologic, cardiac, respiratory, toxicologic, and metabolic problems. The neurocardiogenic and disease-related syncopes were easily identified or suspected by history and physical examination. Electrocardiography was not performed in 132 cases (58%). Most patients with suspected neurocardiogenic syncope had an electroencephalogram, and 29% were admitted to the hospital. Cardiac disorders represented 5 cases (2%); 2 had been previously misdiagnosed.

CONCLUSIONS

Syncope in children can result from a wide variety of causes. Consequently, an evaluation that fails to approach this problem in a goal-directed fashion proves to be very expensive, time-consuming, and frustrating to all concerned. Thorough history and physical examination are usually all that are necessary to guide practitioners in choosing the diagnostic tests that apply to a given patient.

Diagnosis and Management of Vasovagal Syncope and Dysautonomia

Vasovagal syncope is a condition better known as neurocardiogenic or neurally mediated syncope. Dysautonomic syncope is the irregular neuroautonomic response during the body's attempt to maintain homeostasis. Both types of syncope are associated with orthostatic hypotension and are nonlethal. The underlying pathophysiology manifests the vast symptoms suffered by the individual. Research continues to develop new markers to improve diagnostic testing and therapies for treatment. Advanced practice nurses now have a new tool with Head-Up Tilt Training Programs to offer the patients who suffer from frequent and refractory neurocardiogenic and dysautonomic syncope.