Understanding Acute Glomerulonephritis: A Modern Family Doctor's Perspective

Overview

Acute Glomerulonephritis (AGN), commonly known as acute肾炎 (Nephritis), is a group of diseases characterized by acute nephritic syndrome. This condition often arises from infections caused by Streptococcus pyogenes, specifically the nephritogenic strains, such as serotypes A12 and A49. AGN is commonly triggered by prior infections like streptococcal pharyngitis, scarlet fever, and skin infections. Other bacterial, viral, and parasitic infections can also lead to AGN. It is more prevalent in children and adolescents, with a higher incidence in males.

Diagnosis

Symptoms and Signs

• Onset: AGN typically presents with an acute onset, often following a 1-3 week (average 10 days) incubation period after a preceding streptococcal infection, such as upper respiratory or skin infections.
• Mild Cases: May exhibit only abnormalities in urine routine tests and serum complement C3 levels.
• Typical Cases: Present with symptoms of acute nephritic syndrome, including hematuria, proteinuria, edema, and hypertension.
• Severe Cases: Can lead to acute renal failure.

Laboratory Findings

• Urine Analysis: Hematuria is common, with 30-40% of patients experiencing gross hematuria. Proteinuria is also common, with most patients showing proteinuria levels of 0.5-3.5 grams per day.
• Blood Tests: Complement C3 and total complement levels may decrease, returning to normal within 8 weeks.
• Immunological Tests: Elevated serum anti-streptolysin O titers suggest prior streptococcal infection.
• Renal Pathology: Light microscopy, electron microscopy, and immunofluorescence may be used for kidney biopsy.

Diagnosis

The diagnosis is based on the presence of prior streptococcal (or other bacterial) infection, symptoms of hematuria, proteinuria, edema, hypertension, and a decrease in serum complement C3, which typically returns to normal within 8 weeks. Renal biopsy may be necessary for atypical cases or if symptoms persist for 1-2 months.

Treatment

General Measures

• Rest: Bed rest is essential until hematuria, edema, and hypertension resolve.
• Diet: Low-sodium diet (less than 3 grams per day) and protein restriction if renal function is impaired.

Antibiotic Therapy

• Streptococcal Infection: Penicillin injection for 10-14 days or macrolide antibiotics for penicillin allergy.
• Tonsillectomy: Considered for recurrent tonsillitis after resolution of the condition.

Symptomatic Treatment

• Edema: Diuretics may be used for edema.
• Hypertension: Antihypertensive medications may be added if blood pressure remains uncontrolled despite rest, low-sodium diet, and diuretics.

Dialysis

• Acute Renal Failure: Dialysis may be necessary in cases of acute renal failure with dialysis indications.

Chinese Herbal Medicine

• Wind-Type AGN: Use herbs like Mahuang, Shengjiang, Baizhu, and Shigao to expel wind and promote diuresis.
• Heat-Type AGN: Use herbs like Lianhua, Yejuhua, Pugongying, Zishayingding, and Zibaiye to clear heat and promote diuresis.

Prevention

• Environmental Hygiene: Keep living spaces and bedding dry.
• Physical Exercise: Strengthen the body and enhance resistance.
• Comprehensive Treatment: Treat underlying conditions promptly and thoroughly.

Conclusion

Acute Glomerulonephritis is a condition that requires prompt diagnosis and appropriate treatment. Understanding the symptoms, diagnosis, and treatment options is crucial for effective management. Regular health check-ups and maintaining a healthy lifestyle can help prevent complications and improve outcomes.