Infantile Rotavirus Enteritis

　　1. Causes of disease:Rotavirus is the main pathogen of pediatric diarrhea in autumn and winter. The virus is composed of an inner and outer shell and a double-stranded RNA core containing 11 segments. According to the antigenicity of the main protein of the inner shell (VP6, i.e., virus 6 protein), the virus can be divided into serotypes A, B, C, D, E, etc., by enzyme-linked immunosorbent assay (ELISA) and complement fixation tests. The rotavirus causing pediatric diarrhea in autumn and winter is serotype A, and rotavirus diarrhea in adults is serotype B; rotavirus of other serotypes is associated with animal infections. Rotavirus can be divided into several serotypes according to the antigenicity of the outer shell proteins VP4 and VP7. Through neutralization tests, it can be further divided into several serotypes, among which serotypes 1 to 4 cause pediatric diarrhea; animal rotavirus is limited to serotypes 3 to 7.

　　2. Pathogenesis:Rotavirus mainly invades the mucosal epithelial cells of the duodenum and the proximal jejunum, causing the apical epithelium of the villi to fall off, shortening the villi. The shedded epithelium is replaced by newly produced epithelium from the crypts. These new epithelial cells are not mature and lack disaccharidase. Therefore, the mechanism of diarrhea is related to the destruction of villi affecting absorption, lack of disaccharidase, and damage to epithelial cells, with an increase in secretion into the intestinal lumen. Recent research has found that there are rotavirus receptors on the membrane of intestinal epithelial cells. The viral coat protein VP4 is the adsorption protein of the infected cell, entering the epithelial cell by binding to the receptor of the target cell. After the virus invades the intestines, it mainly replicates in the columnar epithelial cells at the apical villi of the duodenum and jejunum, causing cell变性, necrosis, swelling, irregularity, and shortening of microvilli. The involved intestinal mucosal epithelial cells are shed, and lymphocytic infiltration is visible in the lamina propria. Therefore, the ability of the small intestinal mucosa to absorb water and electrolytes is impaired, leading to diarrhea. On the other hand, secondary insufficient secretion of disaccharidase causes incomplete digestion of carbohydrates in food, resulting in retention in the intestinal lumen and decomposition by bacteria into small molecules of short-chain organic acids, increasing the osmotic pressure of the intestinal fluid and aggravating vomiting and diarrhea.

　　It often occurs with dehydration, acidosis, and electrolyte disorder, and some may cause convulsions due to high fever:

　　1. Sodium salt:(NaCl, NaHCO3) is the main inorganic salt that determines the osmotic pressure of extracellular fluid, therefore, the serum sodium concentration is the main factor that determines the osmotic pressure of plasma. Due to the different proportions of water and sodium deficiency, there are different changes in plasma sodium concentration and osmotic pressure. During dehydration, the clinical classification of dehydration is often based on the level of serum sodium concentration, which is divided into three types: isotonic dehydration, hypotonic dehydration, and hypertonic dehydration.

　　2. Acidosis:Endocrine diseases, the accumulation of acidic substances in the body and tissues, the essence of which is the increase of hydrogen ion concentration in the blood and the decrease of pH value.

　　3. Common symptoms of electrolyte disturbance:Fatigue, muscle cramps, weakness, restlessness, nausea, dizziness, confusion, fainting, irritability, vomiting, dry mouth. Decreased urination is one of the most common symptoms of electrolyte disturbance. Patients may not have the awareness of urination for 7-8 hours or more. In addition, the following symptoms can be observed in severe electrolyte imbalance: coma, slow heart rate, seizures, palpitations, low blood pressure, lack of coordination in limbs.

　　It is prevalent in autumn and winter, mostly seen in infants and young children aged 6 months to 2 years, with an incubation period of 36-72 hours. Typical cases often have mild upper respiratory tract infection symptoms, fever, which can reach 39-40°C, vomiting for 1-2 days at the beginning of the disease, which can appear before diarrhea. Diarrhea is watery stool, like egg flower soup, without pus and blood, about 3-10 times a day. Due to vomiting and diarrhea, dehydration, acidosis, and electrolyte disturbance can occur, and the concentration of electrolytes in the child's feces is significantly lower than that in bacterial enteritis, such as cholera, pathogenic Escherichia coli, etc.; and most are acute dehydration, so it often causes isotonic or slightly hypertonic dehydration. The natural course of the disease is 3-8 days, averaging about 5 days.

　　Rotavirus vaccine is under development and has not yet reached the stage of widespread promotion:

　　8. Maintain good personal, food, and environmental hygiene.

　　7. Wash hands before handling food or eating, and after using the toilet.

　　6. When cleaning vomit, feces, and diapers, gloves must be worn, and hands must be thoroughly washed again.

　　5. Clean and disinfect contaminated items and surfaces.

　　4. If children show symptoms of vomiting or diarrhea, they should seek medical attention as soon as possible and rest, avoiding school.

　　1. The microscopic examination of feces shows 0-3 white blood cells per high power field (HP), bacterial culture shows no pathogenic bacteria. The initial diagnosis of etiology was made through electron microscopy and immunoelectron microscopy, directly observing rotavirus particles in duodenal drainage fluid and feces. However, it is not suitable for routine clinical application. Currently, immunological or nucleic acid methods are mostly used to detect antigens in feces, and results can generally be obtained within 4 hours. In China, enzyme-linked immunosorbent assay (ELISA) and extraction of viral RNA from feces are widely used for nucleic acid gel electrophoresis (PAGE). Rotavirus PAGE shows 11 RNA fragments, integrated into 4 groups, each containing 4-2-3-2 fragments as its characteristic. They can also be divided into long and short types according to the distance between the last two fragments. At present, dot hybridization, oligonucleotide, and polymerase chain reaction (PCR) methods have been developed to detect the VP7 protein molecule of the outer capsid of group A rotavirus for the diagnosis of rotavirus infection and its serotyping.

　　2. This method is highly specific and sensitive, but can only be performed in some scientific research units. In recent years, the culture of rotavirus has also been successful on the Mal04 cell line treated with trypsin, generally no special auxiliary examination is required, and chest X-ray and electrocardiogram examinations are necessary when necessary to clarify whether there are any lung lesions. When there are electrolyte disorders such as hypokalemia, the electrocardiogram shows a decrease in the S-T segment, a low flat T wave, biphasic, and finally inverted, with the appearance of u waves and gradually increasing, often exceeding the T wave of the same lead, or the T wave and u wave are connected in a hump-like shape.

　　Firstly, should

　　1. Diet should be light.

　　2. Pay attention to the proportion of sugar, fat, and protein in food, and pay attention to the content of vitamins and other essential nutrients for the body.

　　Secondly, avoid

　　1. Avoid irregular eating and drinking.

　　2. Avoid unclean food and drink: especially in summer, wash raw fruits and vegetables, and do not eat spoiled food. Foods stored in the refrigerator must be thoroughly cooked and boiled before eating. If spoilage is found, it should be discarded resolutely and not consumed.

　　3. Avoid cold, hot, and hard foods: such as, cold and hot food and beverages.

　　4. Avoid spicy foods such as chili, mustard, pepper, strong tea, coffee, cocoa, and other food or beverage.

　　There is no specific treatment for this disease, mainly using correction of water and electrolyte disorders and symptomatic treatment. Mild cases can take oral rehydration salts, and severe cases can use intravenous rehydration to correct. Traditional Chinese medicine such as horseshoe grass has been reported to be effective, and interferon has also been used, which is believed to shorten the course of the disease. However, more repeated experiments are needed to confirm this. Specific antiviral antibodies from human milk and other sources can reduce the amount of virus excretion and the severity of the disease.