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Acute glomerulonephritis
Acute nephritis pathological characteristics
The changes in acute nephritis are characterized by diffuse intracapillary proliferative glomerulonephritis, and the main structures in the kidney are the glomeruli, renal tubules, and renal interstitium. Therefore, pathological examination can be divided into light microscopy, immunofluorescence, and electron microscopy examinations. Under light microscopy, the pathological changes in acute nephritis mainly include proliferation of mesangial and endothelial cells in the glomeruli. In the acute phase, there is significant infiltration of neutrophils and mononuclear cells. Masson's trichrome staining can reveal subepithelial immune complex deposits, and there is also edema and infiltration of inflammatory cells in the interstitium; Immunofluorescence examination shows diffuse coarse granular deposits of immune complexes along the capillary walls and in the mesangial areas, mainly composed of IgG and C3; Under electron microscopy examination, there are hump-like electron-dense deposits beneath the epithelial cells.
Early symptoms of acute nephritis
The occurrence of acute nephritis is related to streptococcal infections and is commonly seen in children. Typically, 1-3 weeks before the onset of acute nephritis, patients often have a history of infections in the throat, upper respiratory tract, or skin. Once acute nephritis occurs, the initial symptoms include hematuria, which can manifest as either gross or microscopic hematuria. There is also the appearance of edema, especially noticeable swelling of the eyelids and facial area upon waking up in the morning, and even a decrease in urine output. Additionally, patients with acute nephritis often experience increased foam in the urine, indicating the presence of proteinuria, as well as general weakness, back pain, nausea, and vomiting. After the onset of acute nephritis, some patients may experience elevated blood pressure and even transient renal failure.
post-acute nephritis sequelae
Acute nephritis is a self-limiting disease, and most patients can fully recover, so the vast majority of patients generally start to show improvement in routine urine tests three to four weeks after onset, with normal kidney function and resolution of edema, resulting in few, if any, sequelae. Of course, a small number of patients may experience prolonged unhealed conditions that can progress to chronic nephritis. These patients may then develop complications, including hypertension and renal anemia, which are long-term potential issues. However, the vast majority of patients with acute nephritis do not experience complications or sequelae.
What are the symptoms of acute nephritis?
Acute nephritis is commonly seen in children, and in cases of acute nephritis in children, it is often preceded by an upper respiratory tract infection or skin infection one to three weeks prior to the onset. Once acute nephritis occurs, the most prominent clinical symptom in patients is gross hematuria, though some individuals only show microscopic hematuria, accompanied by an increase in urinary proteins. Additionally, patients with acute nephritis may experience swelling of the eyelids and lower limbs, especially noticeable swelling of the eyelids and facial area upon waking in the morning. Some patients may also experience elevated blood pressure, leading to symptoms such as dizziness and headache. A few may suffer from nausea, vomiting, loss of appetite, reduced urine output, or even symptoms of acute renal failure.
What causes acute nephritis?
The full name of acute nephritis is post-infectious glomerulonephritis, so as the name suggests, acute nephritis is related to infections. The most common cause is acute streptococcal infection. There are also infections caused by Staphylococcus aureus, Staphylococcus epidermidis, and Gram-negative bacteria. The main pathogenic mechanism is due to a series of immune responses caused by streptococcal infections, leading to an immune complex-mediated glomerulonephritis. The most common sites of infection are the respiratory tract and skin, with a latent period of one to three weeks.
How should acute nephritis be treated?
Patients with acute nephritis generally have a good prognosis after reasonable and standardized treatment, and rarely develop into chronic nephritis. The main means of treating acute nephritis is symptomatic supportive care, requiring patients to rest in bed during the acute phase. At the same time, spicy food should be avoided and salt intake should be appropriately controlled. If the patient has an infection, sensitive antibiotics should be actively selected for treatment. Additionally, diuretics can be appropriately used for patients with edema, and if the patient also has hypertension, antihypertensive drugs may be used to keep blood pressure within an appropriate range. Of course, some severe cases of acute nephritis may lead to heart failure or renal failure, in which case dialysis should be actively pursued. (Specific medication use should be carried out under the guidance of a doctor.)
Symptoms of acute nephritis.
The symptoms of acute nephritis are mainly manifested as acute nephritic syndrome, that is, hematuria, proteinuria, edema, hypertension, and transient acute kidney injury. Hematuria is a symptom present in almost all cases of acute nephritis, but it is mostly microscopic hematuria, meaning during examination, the routine urine analysis shows positive occult blood, or red blood cells are found in the urinary sediment. About 40% of the patients may exhibit gross hematuria, where the urine color appears like wash-water or may be bright red, deep tea-colored, and so on. The second symptom is proteinuria, which is also often indicated by a positive urine protein test during routine checks. The third symptom is edema, an early symptom of acute nephritis. Mildly, it presents as swelling of the eyelids in the morning and can spread to the whole body if severe. The fourth symptom is hypertension, with about 80% of patients showing a moderate increase in blood pressure. In severe cases, patients might experience oliguria, with urine output less than 400ml/d, accompanied by transient mild increases in blood creatinine and urea nitrogen, indicating acute kidney injury. This condition is mostly self-limiting, and many patients can recover within a few weeks.
How long should one with acute nephritis stay in bed for rest?
After the onset of acute nephritis, patients should rest in bed for 2-3 weeks until gross hematuria disappears, blood pressure returns to normal, and edema subsides. If the patient's condition is severe, with complications such as high blood pressure, noticeable edema, and significant hematuria, then bed rest should be extended to 4-6 weeks. Bed rest can increase renal blood flow and improve kidney function, which is beneficial for enhancing treatment effectiveness. Gradually, indoor activity can be increased. If the condition does not worsen after 1-2 weeks, the patient may begin outdoor activities. Patients with mild residual proteinuria and microscopic hematuria should be followed up and closely observed without the need for indefinite bed rest. If urine changes worsen again after activity, further bed rest is necessary. For students who develop acute nephritis, it is advisable to take a break from school to ensure enough rest time for recovery.
Can acute nephritis be cured completely?
The main cause of acute nephritis is related to streptococcal infections. Many patients with acute nephritis often have a history of infections in the throat, upper respiratory tract, or skin before the onset of the disease. Therefore, once acute nephritis occurs, patients often exhibit hematuria, which can be either gross hematuria or microscopic hematuria. Severe cases of acute nephritis may also show swelling of the eyelids and face, as well as the presence of mild to moderate urinary protein. In addition, some severe cases of acute nephritis also show elevated blood pressure, decreased renal function, and overall poor outcomes from acute nephritis. Currently, there are no specific treatments available; the main approach is bed rest and symptomatic treatment. For example, diuretics can be used if there is edema, and antihypertensive drugs can be used if there is a need to lower blood pressure. If an infection still exists, antibiotics are used for treatment. With proper and standardized treatment, the vast majority of acute nephritis cases can be completely cured without recurrence.
How is acute nephritis diagnosed?
The diagnosis of acute nephritis is actually not difficult, focusing on the following key points: 1. A history of upper respiratory or skin infections prior to the onset of the disease. 2. Typical manifestations of acute nephritis syndrome, including hematuria, proteinuria, reduced urine output, edema, and elevated blood pressure. Among these, hematuria is the most important basis for diagnosing acute nephritis, which can be gross hematuria or microscopic hematuria, and proteinuria can be mild or severe. 3. During the acute phase, there can be an increase in anti-O and a decrease in serum complement C3 concentration. 4. It commonly affects adolescents and children. 5. Most cases improve or even recover after four to eight weeks of treatment.