Objective      To investigate the causes

clinical features and differential diagnosis of children transient loss of consciousness (TLOC).       Methods      A total of 106 children with TLOC were collected from the outpatient or inpatient department of our hospital from January 2013 to March 2014. And their etiology and clinical features were analyzed.       Results      In the cohort

89 cases (84.0%) were syncope and the other 17 (16.0%) were non-syncope. Among the syncope cases

42 (39.6%) were orthostatic intolerance (OI)

16 (15.1%) cardiac syncope (CS)

and 1 (0.9%) situational syncope

while the other 30 cases (28.3%) had no explanation. For these non-syncope children

5 (4.7%) had neurogenic diseases

10 (9.4%) had psychogenic pseudo-syncope

and 2 (1.9%) had metabolic disorders. In the 42 OI patients

39 (92.9%) had inducement and pre-syncope

25 (59.5%) had loss of consciousness within 1 min

and 11 (26.2%) had family history. CS often occurred with sudden onset. Exertion related syncope spells were found in 9 cases (56.3%

9/16). All CS (100%

16/16) patients had abnormal electrocardiograms

and 3 of them died in hospital. In 10 children of psychogenic pseudo-syncope

definite inducement was found in 8 patients (80.0%)

and 7(70.0%)   had loss of consciousness beyond 10 min.       Conclusion      OI is the most common cause for TLOC in children

with manifested clinical signs and symptoms. OI should be differentiated with CS firstly

while psychogenic pseudo-syncope and epilepsy should also be differentiated.