Medical & Clinical Reviews

Description

The etiological spectrum, pathogenesis, diagnosis and treatment of syncope in children and adolescents are different from those in adults and recurrent syncopal episodes can affect children’s physical and mental health as well as their quality of life. The “Chinese Pediatric Cardiology Society (CPCS) guidelines for the diagnosis and treatment of syncope in children and adolescents” has promoted the standardized clinical diagnosis and treatment of syncope in the pediatric population. Since then, significant advances have been made in this field, including the etiological spectrum of syncope, diagnostic procedures, postural tests, clinical diagnosis and individualized treatment, especially in terms of neurally mediated syncope. For an update, the “Guidelines for the diagnosis and treatment of neurally mediated syncope in children and adolescents” have been revised based on the latest research evidence. Here, we briefly introduce the new progresses. Prevalence and etiology spectrum of syncope. The prevalence of syncope in the pediatric population is about 17.37% which is higher in females than males. The primary etiology spectrum of pediatric syncope includes Neurally Mediated Syncope (NMS), Cardiogenic Syncope (CS) and unexplained syncope. NMS is the most common type of syncope, accounting for nearly 67%-85.67%, while CS accounts for 1.5%-6.95%. Unexplained syncope refers to the possibility of other causes of syncope after excluding the currently known causes of syncope.

Pediatric diagnosis

Vasovagal Syncope (VVS) is the primary symptom of NMS, but it can also occasionally involve other related disorders, such as orthostatic dysregulation or Orthostatic Intolerance (OI), which are characterized by syncope or presyncope brought on by aberrant neuroreflex regulation or autonomic system dysfunction. VVS, Postural Orthostatic Tachycardia Syndrome (POTS) and Orthostatic Hypotension (OH) were among the hemodynamic types of reactions seen during the Head-Up Tilt Test (HUTT) for children with suspected NMS, according to the findings of a multicenter study on pediatric syncope conducted in China. When it comes to OH in pediatric patients, initial OH (iOH) is more prevalent and typically has milder symptoms than classic OH (cOH), which is comparatively rare in children. Sitting Tachycardia Syndrome (STS) and Sitting Hypertension (SHT) in children were brought up by the ideas of Orthostatic Hypertension (OHT). Additionally, breath-holding episodes might be a particular way that NMS presents in babies. Comorbidities frequently coexist with pediatric NMS and between 30 and 40 percent of pediatric VVS and POTS can coexist with conditions like joint hypermobility syndrome, migraines, allergic disorders, mental disorders, sleep disorders, chronic fatigue syndrome, gastrointestinal disorders and hyperventilation syndrome. Clinical management of NMS with comorbidities becomes more complicated. Additionally, certain hemodynamic categories may overlap. Approximately 32% to 45% of children with POTS experience syncopal attacks, according to clinical practice. Researchers hypothesized that POTS's aberrant neuronal reflex or the co-occurrence of POTS and VVS could be the cause of syncopal attacks in POTS. The patient with OHT is in a similar circumstance. Nevertheless, the processes underlying the syncopal occurrence in OHT or POTS patients remain unclear. Future research is necessary to determine the true etiology of syncope in POTS or OHT patients. Neurally mediated syncope diagnosis. Though some patients may first experience presyncope symptoms, syncopal episodes are the primary clinical presentation of NMS. Although NMS can be observed across a wider age range, from early infancy to adolescent, the peak age of onset is around school age. Consequently, age guidelines have been eliminated from the diagnostic criteria. When the features of a syncope episode point to NMS, postural tests can be performed to help determine the etiological diagnosis of NMS in patients with recurrent syncope whose diagnosis cannot be made with a thorough medical history, careful physical examination, supine and upright Blood Pressure (BP) measurement and primary electrocardiogram examination.

Postural testing

Postural tests are used to support the etiologic diagnosis of NMS and to cause syncope or presyncope by altering position (e.g., from supine to upright, slanted, or seated posture). Test of active standing: It has great diagnostic value for POTS, OH, or OHT and is simple to execute. Tilt test with the head up: When other causes of the symptoms are ruled out, HUTT can also be used to evaluate pediatric patients who primarily have presyncope symptoms. This will help determine the patient's autonomic function status and hemodynamic changes during tilting, which will aid in the diagnosis. Approximately 30% of patients exhibiting the aforementioned symptoms had positive HUTT results, indicating that the prevalence of these illnesses is somewhat correlated with autonomic dysfunction. Children's HUTT protocol is different from adults'. The hemodynamic parameters are contraindicated because the autonomic nervous system is always growing and changing during childhood and its functioning status is prone to imbalance. During sitting, the patient's heart rate, blood pressure variations and SI symptoms are dynamically monitored and documented. When the results of the active standing or active sitting tests for children exhibiting symptoms of SI or OI are negative, HUTT might be used to further determine the etiological diagnosis. It is important to carefully explain the findings of these postural tests in light of the patients' clinical presentations.