Chronic cough in children is closely related to gastroesophageal reflux (GER). However, this association has not been adequately studied due to a lack of diagnostic tools. Combined esophageal multichannel intraluminal impedance and pH (MII-pH) monitoring is considered the most accurate method for evaluating the association between symptoms and reflux, but data on its use in children with chronic cough are still lacking. We aimed to assess the association between chronic cough and GER in children through MII-pH monitoring. Children with chronic cough (> 4 weeks) who were suspected gastroesophageal reflux disease(GERD) were selected to undergo 24 h MII-pH monitoring at our hospital. Patients were divided into groups according to their age, body position, reflux index (RI) or total reflux events, and the differences between the groups were analyzed. Then the significance and value of 24 h pH and impedance monitoring in chronic cough and the relationship between chronic cough and reflux were discussed. Overall, 426 patients were included. The median age was 12 months (interquartile range: 6–39.5 months), 129 (30.3%) patients had RI > 7% detected by pH-metry, and 290 (68.1%) patients had positive diagnosis based on the impedance data. GER predominantly occurred in the upright position and mostly involved weakly acidic reflux and mixed gas–liquid reflux. There were 14.1% of children in non-acid GER group were SAP positive showing no difference in acid GER group 13.2% (P = 0.88), whereas patients with SAP > 95% in MII positive group (47[16.2%]) is higher than in MII negative group (P < 0.05). Twenty four hour MII-pH monitoring is safe, well tolerated in children, but also has a higher detection rate of gastroesophageal reflux. It can find identify weakly acidic reflux, weakly alkaline reflux and reflux events with different physical properties, which can explain the relationship between GER and chronic cough more comprehensively. It provides new approach for exploring the etiology, diagnosis and treatment of children with chronic cough.

Kawasaki disease (KD) has replaced rheumatic fever as the main cause of acquired heart disease in Japanese, American, and Chinese children. Polymorphisms in angiotensin-converting enzyme may be associated with susceptibility to KD, but the association of angiotensin-converting enzyme 2 (ACE2) with vascular endothelial injury in KD and the possibility for prognosis of vascular injury in KD by evaluating changes in serum ACE2 have not yet been assessed. Thus, this study aimed to investigate ACE2 levels in patients with KD to further explore the relationship between ACE2 and vascular injury in KD. Blood samples were collected from 49 children with KD before intravenous immunoglobulin treatment and 28 healthy children in the same period as the control group. Clinical data were collected from the patients and serum ACE2 levels of all participants were measured using an enzyme-linked immunosorbent assay. Serum ACE2 levels were significantly higher in the KD group than in the control group, and were negatively correlated with platelet levels in patients with KD. Serum ACE2 levels are related to the pathogenesis of KD and may be used as a potential serum marker for KD diagnosis.

Background: Kawasaki disease (KD) has replaced rheumatic fever as the main cause of acquired heart disease in Japanese, American, and Chinese children. Polymorphisms in angiotensin-converting enzyme (ACE) may be associated with susceptibility to KD, but the association of ACE2 with vascular endothelial injury in KD and the possibility for prognosis of vascular injury in KD by evaluating changes serum ACE2 has not yet been assessed. Thus, this study aimed to investigate angiotensin-converting enzyme 2 (ACE2) levels in patients with KD to further investigate the relationship between ACE2 and vascular injury in KD.Methods: Blood samples were collected from 49 children with KD before intravenous immunoglobulin treatment and 28 healthy children as a control group. Clinical data were collected from the patients and serum ACE2 levels of all participants were measured using enzyme-linked immunosorbent assay.Results: Serum ACE2 levels were significantly higher in the KD group than in the control group. Serum ACE2 levels were negatively correlated with platelet count (Plt) levels in patients with KD.Conclusions: Serum ACE2 levels may be related to the severity of coronary artery damage in children with KD.