“Acute glomerulonephritis is a kind of glomerulonephritis after acute infection, mostly common after streptococcal infection, with more incidence in pediatric adolescents and occasionally in the elderly, with men higher than women. In this issue, let’s learn what is acute glomerulonephritis. In modern medicine, based on epidemiological, immunological and clinical studies, it is proved that this disease is an immune complex glomerulonephritis caused by β-hemolytic streptococcal group A infection. The disease often occurs after streptococcal infections such as tonsillitis, pharyngitis, scarlet fever, dengue, and pyoderma gangrenosum. Clinical manifestations of acute nephritis Acute nephritis is most often seen in children and is more common in males than females. The incubation period is equivalent to the time required to induce immune complexes after the initial immunization with the causative antigen, and is shorter in respiratory tract infections than in skin infections. The disease has an acute onset and varies in severity, from the subclinical type (only urinary routine and serum C3 abnormalities) in mild cases to the acute nephritis syndrome in typical cases, and acute renal failure in severe cases. However, this disease generally has a good prognosis, often within a few months of clinical self-healing, but some patients can also be chronic kidney disease. The typical manifestations of acute nephritis 1, urinary routine: almost all patients have glomerulogenic hematuria, about 30% of patients can be seen carnivorous hematuria, can be accompanied by mild or moderate proteinuria, a few patients (< 20% of patients) can be presented with nephrotic syndrome range of large amounts of proteinuria. In addition to erythrocytes, the urine sediment also shows an increase in leukocytes and epithelial cells in the early stage, which may be accompanied by erythrocyte tubular pattern. 2, edema: more than 80% of patients have edema, often the initial manifestation of the disease, mostly morning eyelid edema or with mild concave edema of the lower limbs, a few severe cases can spread to the whole body. Hypertension: about 80% of patients have transient mild to moderate hypertension, often related to water and sodium retention, and blood pressure can gradually return to normal after diuresis, but a few patients can develop severe hypertension and even hypertensive encephalopathy. 4, renal insufficiency: early onset of the disease can be due to decreased glomerular filtration rate, water and sodium retention and reduced urine volume, a few patients even less urine (less than 400ml / d). Renal function may be transiently impaired, manifested by a mild increase in blood creatinine. Most of the time, urine output increases after 1-2 weeks, and renal function can return to normal in a few days after diuresis. Only a few patients may show acute renal failure. 5, congestive heart failure: often occurs in the acute nephritis syndrome period, severe water and sodium retention and hypertension are important precipitating factors. Patients may have symptoms of jugular venous anger, gallop rhythm and pulmonary edema, which often require emergency treatment. The incidence is higher in elderly patients (up to 40%) and rare in pediatric patients (less than 5%). 6. Immunological abnormalities: Serum C3 and total complement decrease at the beginning of the disease and gradually return to normal within 8 weeks, which is significant for the diagnosis of the disease. The patient's blood anti-streptococcal hemolysin "O" antibody (anti-O antibody) titer increased, suggesting a recent streptococcal infection. In addition, some patients have positive circulating immune complexes and serum cold globulin at the beginning of the disease.