2016年 · 第54卷第07期

Diarrhea is a common disease in children in China, caused by multiple causes. The main cause of diarrhea in children under 5 years old is the infection of various pathogens, mainly viruses, followed by bacteria, parasites and fungi are relatively rare, and the clinical manifestations are diverse. Although the treatment principles are similar, the treatment plans are different. In order to standardize the diagnosis and treatment of childhood diarrheal diseases, the World Health Organization (WHO) and various countries and regions have developed guidelines or expert consensus for childhood diarrheal diseases. In 1991, WHO developed the first edition of guidelines for childhood acute diarrheal diseases, and in 2005, WHO and the United Nations Children's Fund (UNICEF) developed the second edition^[1]In 1993 and 2009, Chinese experts formulated the expert consensus on acute diarrhoeal disease in Chinese children based on the WHO guidelines and the national conditions of China^[2,3]。 These consensus have played an important role in the standardized diagnosis and treatment of acute diarrheal disease in children in China. According to the principles of evidence-based medicine, the Gastroenterology Group of Pediatrics Branch of Chinese Medical Association and the Editorial Committee of Chinese Journal of Pediatrics formulated "Clinical Practice Guidelines for Acute Infectious Diarrhea in Children in China"^[4]In order to standardize the diagnosis and treatment of infectious diarrhea in children in China, several issues such as liquid therapy, nutrition therapy, anti-infection therapy, traditional Chinese medicine therapy and vaccine are now discussed.

Infectious diarrheal disease is an infectious disease with high incidence and widespread epidemic in the world, which poses serious harm to human health, especially children. In China, according to the household survey data of some provinces, the incidence of diarrheal disease in the whole population is 0.17~0.70 times/person-year, and that in children under 5 years old is 2.50~3.38 times/person-year^[1]。 Acute infectious diarrhea in children is usually caused by gastrointestinal viral and bacterial infections, and is often accompanied or not clinically by vomiting, nausea, fever, abdominal pain and other symptoms. The causes of acute infectious diarrhea in children are mostly viral infections, with rotavirus and norovirus the most common. Bacterial pathogens include Escherichia coli, Campylobacter, Salmonella and Shigella. According to the investigation results of pediatric diarrhea diseases in China, there are two peak seasons every year, one peak is from June to August, and the main pathogens are diarrheogenic Escherichia coli and Shigella dysenteriae, and the other peak is from October to December, and the main pathogen is rotavirus. Regardless of the cause of acute infectious diarrhea, the main treatment methods are rehydration therapy [oral rehydration salts (ORS), intravenous rehydration] to prevent and treat water-electrolyte disorders and acid-base imbalances, dietary therapy, and drug therapy. In order to standardize the diagnosis and treatment of diarrheal diseases, in 2009, the Gastroenterology Group, the Infectiology Group of the Pediatric Branch of Chinese Medical Association and the Editorial Board of Chinese Journal of Pediatrics formulated the "Expert Consensus on Diagnosis and Treatment Principles of Children's Diarrheal Diseases" according to the recommended guidelines for diarrheal management jointly published by the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) in 2005^[2], emphasizes the identification of dehydration signs in the management of diarrheal diseases, oral rehydration, continued feeding, advocates breastfeeding, and recommends the use of hypotonic ORS and zinc supplementation therapy. The implementation and implementation of the "Expert Consensus" has played a positive role in standardizing the treatment of diarrheal diseases, early application of ORS to prevent and correct dehydration, reducing intravenous fluid rehydration and reducing antibiotic abuse, and some results have been achieved. However, the efficacy, safety and economic indicators of the above-mentioned treatment methods and many drugs are of concern to the majority of pediatric medical workers. In order to better help clinicians properly manage children with acute infectious diarrhea, the Gastroenterology Group of Pediatrics Branch of Chinese Medical Association and the Editorial Committee of Chinese Journal of Pediatrics once again organized an expert working group composed of pediatric digestive diseases, infectious diseases and epidemiology experts. Based on the original "expert consensus", with reference to the "Clinical Management Guidelines for Diarrhea Diseases" issued by WHO and UNICEF and the guidelines related to diarrhea diseases in the United States and the United Kingdom, the clinical research data at home and abroad as of June 2013 were analyzed according to the principles of evidence-based medicine, and the "Clinical Practice Guidelines for Acute Infectious Diarrhea Diseases in Chinese Children" were formulated for pediatricians' reference in clinical practice.

A 6-month-old daughter came to Xi' an Children's Hospital in August 2015 because she found that her eyelids were drooping and her limbs were weak.

The kidney has many physiological functions, the most important of which is the glomerular filtration function. glomerular filtration rate (GFR) refers to the amount of plasma filtered through the glomeruli per unit time. It is directly related to the number of functional glomeruli and is the best index to evaluate renal filtration function. Accurate assessment of GFR is important for clinicians to promptly detect renal function decline, select drug dosage, and stage and manage chronic kidney disease. However, in clinical practice, it is not easy to accurately evaluate GFR. For example, commonly used serum creatinine and cystatin C are only GFR markers, and the approximate range of GFR can only be roughly estimated, while endogenous creatinine clearance rate will overestimate GFR. So, what are the ways to get an accurate GFR? What are the advantages and disadvantages of commonly used GFR serum markers – serum creatinine and cystatin C? How to interpret its concentration change? How do you get the estimated GFR (eGFR)? How to apply? They are briefly described below.

Inflammatory bowel disease (IBD) is a class of chronic diseases involving the ileum, rectum, colon and even the whole digestive tract, mainly including Crohn's disease, ulcerative colitis (UC) and undefined colitis. Up to 25% of IBD patients begin to develop the disease in childhood or adolescence, and the incidence rate is increasing year by year worldwide^[1]。 IBD in children not only manifests as recurrent abdominal pain, diarrhea and extraintestinal symptoms, but also causes growth retardation and delay in puberty^[2]。 Although its etiology and pathogenesis are not completely clear, it is generally believed that IBD is a non-specific inflammatory disease caused by autoimmune dysfunction of hosts carrying genetic susceptibility genes induced by environmental factors and the participation of intestinal flora. The research progress of the etiology and pathogenesis of IBD in children is reviewed.

Inflammatory bowel disease (IBD) is a group of chronic non-specific inflammatory diseases of the intestine, commonly Crohn's disease and ulcerative colitis (UC), and some of them are undefined inflammatory bowel disease (IBDU). About 25% of IBD patients develop before the age of 20^[1]。 In European and American countries, the incidence of childhood IBD is 1 in 10 000^[1,2]In China, it is also showing an upward trend year by year. Children with IBD often have a prolonged course of disease, which is characterized by chronic diarrhea, mucus, pus and bloody stool, absorption dysfunction, and growth retardation^[3]。 With the deepening of research on the etiology and pathogenesis of IBD, it is generally believed that it is difficult to explain all the phenomena by a single mechanism, and genetic, environmental, infection and immune factors together affect the pathogenesis of IBD^[4]。 It is generally believed that the pathogenesis of IBD is that environmental and infectious factors act as initiating factors on genetically susceptible people, causing abnormal intestinal immune response, thus leading to persistent intestinal inflammation and tissue destruction^[5]。 In terms of infectious factors, a variety of microorganisms may be related to the course of IBD. The role of various pathogenic microorganisms discovered in recent years in the pathogenesis of IBD and their relationship with IBD are summarized as follows.

Respiratory insufficiency is a major threat to the life of premature infants, especially for extremely low gestational age newborns (ELGANs) with a gestational age of less than 28 weeks and/or extremely low birth weight infants (ELBWIs) with a birth weight of less than 1 000 g. At present, the mortality and disability rates of ELGANs and ELBWIs are as high as 30% ~50%, which are basically related to respiratory insufficiency^[1]。 This is because the lungs of ELGANs and ELBWIs are in a critical period of transition from duct formation to vesicle and alveolar formation. The original gas exchange units are scarce in number and simple in structure, and the ability of gas exchange and self-synthesizing pulmonary surfactants is seriously insufficient. The incidence of respiratory distress syndrome is as high as 67.8%, so the dependence on exogenous pulmonary surfactants is extremely high; At the same time, because of its fragile and immature structure, it is quite sensitive to barotrauma, free radicals and inflammatory damage caused by mechanical ventilation, and is prone to alveolar structure destruction and pulmonary interstitial fibrosis, resulting in chronic lung diseases such as bronchopulmonary dysplasia, which seriously affects the quality of life of ELGANs and ELBWIs^[2,3,4,5]。 In recent years, although the survival rate of premature infants has increased significantly with the development of prenatal hormones, surfactants and mechanical ventilation techniques, the incidence of bronchopulmonary dysplasia has not decreased significantly. How to provide opportunities for immature lungs to continue to develop and reduce lung development stagnation caused by various injury factors after birth has become the focus of research. The development of artificial placenta support (APS) is based on this purpose. Because of its potential in ELGANs and ELBWIs respiratory support, it has developed rapidly in recent years. The current progress and challenges of APS research are reviewed.

Hemolytic uremic syndrome (HUS) is a thrombotic microvascular disease characterized by the triad of non-immune intravascular hemolytic anemia, thrombocytopenia and acute renal insufficiency. It is one of the common causes of acute renal failure in children^[1,2,3]。 According to the presence or absence of prodromal symptoms of diarrhea, HUS was classified into typical HUS and atypical HUS (aHUS). HUS that are not caused by Shiga toxin-producing bacteria and Streptococcus pneumoniae infections are referred to as aHUS depending on the specific cause^[2]。 The prognosis of aHUS is poor, with 50% of patients progressing to end-stage renal disease (ESRD) in the acute phase, with a mortality rate of 25%^[2]。 About 50% of aHUS patients are related to complement bypass pathway dysregulation, that is, complement bypass pathway dysregulation aHUS^{[4,5,6,7,8,9,10]}。 The pathogenesis, diagnosis and therapeutic progress of complement bypass pathway dysregulation aHUS are briefly reviewed.

In many clinical studies, we all hope to establish "causality", but the establishment of causality depends largely on the study design itself, not the statistical association. In order to avoid excessive inference of statistical association as "causality", clinical researchers need to know the criteria of causality inference. A complete causality inference needs to clearly include the timing, strength, repeatability, causality argument strength, dose-response relationship, biological rationality, consistency and specificity of the association before making a clear inference.