bubble_chart Overview

Rapidly progressive glomerulonephritis (RPGN) is a rapidly progressing and deteriorating form of glomerulonephritis. After onset, it progresses rapidly within weeks or months, with progressively worsening renal function, eventually leading to uremia. There is usually a decrease in urine output. The pathological hallmark is the presence of crescents in more than 50% of the glomeruli. This disease can be primary or secondary to certain systemic diseases such as systemic lupus erythematosus or purpuric nephritis. In recent years, it has been classified into the following types based on immunological manifestations:

1. Anti-glomerular basement membrane (GBM) antibody-mediated rapidly progressive nephritis. Its characteristic feature is linear immune deposits along the GBM on immunofluorescence, with anti-GBM antibodies present in the blood. Clinically, it may also be accompanied by pulmonary hemorrhage (referred to as Goodpasture syndrome in such cases).
2. Immune complex-mediated rapidly progressive nephritis, characterized by granular immune deposits on immunofluorescence. Examples include cases secondary to acute streptococcal infection, systemic lupus erythematosus, allergic purpuric nephritis, IgA nephropathy, membranoproliferative glomerulonephritis, etc.
3. Cases without immune complex deposition. It has recently been recognized that a significant proportion of these cases are vasculitis with positive anti-neutrophil cytoplasmic antibodies (ANCA). Additionally, there may be cases mediated by cellular immunity or of unknown cause.

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bubble_chart Auxiliary Examination

1. Urinalysis: Presence of red blood cells, red blood cell casts, moderate proteinuria, occasionally reaching nephrotic-range proteinuria.
2. Renal function tests: Progressive increase in blood urea nitrogen and creatinine, gradually leading to water, electrolyte, and acid-base imbalances characteristic of acute renal failure. Some children test positive for anti-GBM antibodies, immune complexes, or ANCA, which are related to the disease cause and pathogenesis.
3. Imaging studies: Bilateral kidney enlargement with diffuse parenchymal changes.

The diagnosis of rapidly progressive glomerulonephritis is usually based on the above clinical manifestations. If diagnosis is difficult and a renal biopsy is performed, the typical light microscopy finding is crescentic glomerulonephritis. Immunofluorescence findings vary depending on the pathogenesis, showing linear immune deposits along the basement membrane, granular deposits, or negative results.

﹝Symptoms and signs﹞

The onset resembles acute nephritis, often preceded by a respiratory or streptococcal infection. Common findings include edema, grade II hypertension, gross or microscopic hematuria. Severe general symptoms such as fever, body aches, anorexia, nausea, and abdominal pain are typically present. Most children develop oliguria (urine output <250ml/m²/day) or even progress to anuria (<50ml/day). The condition persistently worsens, leading to acute renal failure and uremic symptoms within weeks or months, accompanied by corresponding water, electrolyte, and acid-base imbalances, such as hypertension, worsening edema, pulmonary edema, cardiac insufficiency, and acidosis. Most children also exhibit symptoms and signs of anemia.

bubble_chart Treatment Measures

1. Corticosteroid Pulse Therapy Methylprednisolone 15-30mg/kg (total dose not exceeding 1g) dissolved in 100-200ml of glucose solution for intravenous drip. Administered once daily or every other day, with 3 doses constituting one course. During pulse therapy, side effects such as facial flushing and tachycardia may occur, along with complications like hypertension, gastrointestinal ulcers, and concurrent infections. Depending on the condition, 1-3 courses may be used, followed by oral prednisone therapy. Treatment often requires medication for over six months.
2. Cyclophosphamide Cyclophosphamide is often added to corticosteroid pulse therapy. Previously, oral administration was common, but intravenous pulse therapy has also been used in recent years. Some institutions administer 0.75g/m² once monthly for 3-6 months, then switch to once every 3 months. This may improve long-term prognosis.
3. Plasmapheresis This method can remove antibodies, antigens, immune complexes, and inflammatory mediators from the blood. It is particularly suitable for cases caused by anti-GBM antibodies or circulating immune complexes. However, it requires specialized equipment and a large amount of plasma.
4. Manage water-electrolyte imbalances and azotemia according to the principles of acute renal failure. Actively control hypertension.
5. Dialysis Therapy Indicated for conditions not controlled by conservative treatment, such as fluid overload (pulmonary edema, hypertension), elevated blood urea nitrogen (>80mg/dl, 29.5mmol/L), serum potassium >6.5mmol/L, and severe acidosis (CO₂CP < 12mmol/L)應行透析治療。
6. Advanced Stage Patients who do not recover and progress to end-stage renal failure may consider kidney transplantation. However, this should only be performed after anti-GBM antibodies in the blood have cleared, otherwise the transplanted kidney may develop recurrence.

bubble_chart Differentiation

1. Acute post-streptococcal glomerulonephritis: The onset is similar, but acute post-streptococcal glomerulonephritis has a shorter duration of oliguria, milder renal dysfunction, often with a tendency for spontaneous remission, decreased C3 levels in the blood, and pathologically mainly manifests as endocapillary proliferative glomerulonephritis.
2. Hemolytic uremic syndrome: In addition to rapidly progressing renal dysfunction, there are manifestations of hemolysis, rapidly developing anemia, elevated reticulocytes, abnormal morphology of peripheral red blood cells (such as fragmented red blood cells and helmet-shaped red blood cells), thrombocytopenia, and other changes.
3. Attention should be paid to whether there are primary diseases causing this condition, such as systemic lupus erythematosus, vasculitis, Henoch-Schönlein purpura, acute streptococcal infection, etc.
4. Differentiation from acute renal failure caused by other diseases, such as drug poisoning, acute tubular necrosis, etc.