What Is Endocapillary Proliferative Glomerulonephritis?

Endocapillary proliferative glomerulonephritis (EPGN) is a specific form of kidney inflammation commonly associated with what is widely known as acute glomerulonephritis. This condition primarily affects the glomeruli—the tiny filtering units within the kidneys—leading to impaired kidney function and a range of clinical symptoms. EPGN is characterized by the proliferation of endothelial and mesangial cells within the glomerular capillaries, which gives the disease its name.

Causes and Pathogenesis

The most frequent trigger of endocapillary proliferative glomerulonephritis is a prior infection with group A beta-hemolytic streptococci, typically occurring 1 to 3 weeks after a throat or skin infection. This post-infectious immune response leads to the deposition of immune complexes in the glomeruli, sparking inflammation and cellular proliferation. As a result, the capillary walls thicken, blood flow through the glomeruli decreases, and filtration efficiency drops.

Common Clinical Features

Patients often present with visible signs of kidney distress, including hematuria (blood in the urine), proteinuria (excess protein in the urine), hypertension, and fluid retention causing edema—especially around the face and lower limbs. In many cases, these symptoms emerge suddenly, supporting the "acute" nature of the illness. Laboratory tests usually reveal elevated anti-streptolysin O (ASO) titers, confirming recent streptococcal exposure.

Diagnosis and Histological Findings

A definitive diagnosis often requires a renal biopsy, which shows hallmark histological changes: hypercellularity within the glomeruli due to the multiplication of endothelial and inflammatory cells. This pattern is distinct from other forms of glomerulonephritis and helps guide appropriate management strategies. Immunofluorescence typically demonstrates granular deposits of immunoglobulin G (IgG) and complement C3 along the glomerular basement membrane.

Prognosis and Recovery Timeline

One of the most encouraging aspects of EPGN is its favorable prognosis. The majority of patients, especially children, experience complete recovery without long-term kidney damage. In most cases, proteinuria and microscopic hematuria resolve within 6 to 8 weeks. Blood pressure normalizes gradually as kidney function improves, and diuretics or antihypertensives may be used temporarily if needed.

Treatment Approaches

There is no targeted cure for endocapillary proliferative glomerulonephritis; instead, treatment focuses on supportive care. This includes managing hypertension with ACE inhibitors or calcium channel blockers, reducing edema through salt restriction and diuretics, and closely monitoring kidney function. Antibiotics may be prescribed if an active streptococcal infection is still present, although they do not alter the course of established nephritis.

In rare instances where symptoms persist beyond several months or show signs of progression, further evaluation for atypical or secondary forms of glomerulonephritis is warranted. However, for typical post-streptococcal EPGN, aggressive immunosuppressive therapy is generally not recommended due to the high rate of spontaneous recovery.

Prevention and Long-Term Outlook

Early recognition of streptococcal infections and prompt antibiotic treatment can reduce the risk of developing this kidney complication. While recurrence is uncommon, individuals should maintain regular follow-ups during the initial recovery phase to ensure full resolution. With proper care, most patients return to normal daily activities within a few weeks, experiencing no lasting effects on kidney health.