What Causes Glomerulonephritis in Children? Understanding the Triggers and Types

Glomerulonephritis in children is a complex kidney condition that affects the glomeruli—the tiny filtering units within the kidneys responsible for removing waste and excess fluids from the blood. When these structures become inflamed, it can lead to a range of health complications, including swelling, high blood pressure, and even kidney failure if left untreated. While the term "nephritis" is commonly used, the medical community refers to this condition more precisely as glomerulonephritis. Understanding its causes, classifications, and contributing factors is essential for early diagnosis and effective treatment.

Classifying Pediatric Glomerulonephritis

Glomerulonephritis in children can be categorized based on both duration and origin. From a time perspective, it is typically divided into three types:

Acute glomerulonephritis: Develops suddenly, often following an infection, and may resolve within weeks.
Subacute or persistent glomerulonephritis: Symptoms last longer than three months but do not meet the full criteria for chronic disease.
Chronic glomerulonephritis: A long-term condition that progresses slowly and may lead to permanent kidney damage.

These distinctions help doctors determine the appropriate treatment plan and predict the likely outcome for each child.

Primary Causes: Infections and Immune Responses

One of the most common triggers of acute glomerulonephritis in children is a recent infection—particularly streptococcal infections such as strep throat or skin infections like impetigo. This specific form is known as post-streptococcal glomerulonephritis (PSGN). After the body fights off the infection, the immune system may mistakenly attack the kidney's glomeruli, causing inflammation and impaired function.

In other cases, primary kidney diseases are responsible. These include:

IgA Nephropathy (Berger's Disease)

A condition where immunoglobulin A (IgA) builds up in the glomeruli, leading to recurrent episodes of blood in the urine. It's one of the most common forms of primary glomerulonephritis worldwide.

Membranoproliferative Glomerulonephritis (MPGN)

This involves thickening of the glomerular basement membrane and increased cellularity, often linked to abnormal immune complex deposition.

Minimal Change Disease and Focal Segmental Glomerulosclerosis (FSGS)

Though sometimes classified separately, these conditions also fall under the broader spectrum of glomerular disorders and may present with significant proteinuria and nephrotic syndrome in children.

The exact cause of many primary glomerular diseases remains unclear, but researchers believe they result from a combination of immune dysregulation, genetic predisposition, and environmental influences.

Secondary Glomerulonephritis: Linked to Systemic Diseases

Besides primary kidney-specific disorders, glomerulonephritis can also develop as a complication of systemic illnesses—conditions that affect multiple organs throughout the body. These are referred to as secondary glomerulonephritides and include some well-documented associations:

Lupus Nephritis

A serious manifestation of systemic lupus erythematosus (SLE), where the immune system attacks various tissues, including the kidneys. Children with SLE are at high risk for developing progressive kidney damage.

Hepatitis B-Associated Glomerulonephritis

Particularly prevalent in certain regions, this type occurs when hepatitis B virus particles form immune complexes that deposit in the glomeruli, triggering inflammation.

Henoch-Schönlein Purpura (HSP) Nephritis

HSP is a form of vasculitis that primarily affects small blood vessels and often follows an upper respiratory infection. Skin rash, joint pain, abdominal discomfort, and kidney involvement—including hematuria and proteinuria—are hallmark features.

ANCA-Associated Vasculitis

Although less common in children, anti-neutrophil cytoplasmic antibody (ANCA)-related conditions like granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) can lead to rapidly progressive glomerulonephritis requiring urgent intervention.

Genetic and Hereditary Forms of Kidney Inflammation

Some forms of glomerulonephritis are directly tied to inherited genetic mutations. These hereditary types tend to run in families and can appear early in childhood. The most notable example is Alport syndrome, caused by mutations in genes responsible for type IV collagen—a key structural protein in the glomerular basement membrane.

Children with Alport syndrome often present with hematuria, progressive hearing loss, and ocular abnormalities. Early genetic testing and family screening are crucial for managing this condition and preventing end-stage renal disease.

Environmental and Contributing Risk Factors

While infections and genetics play major roles, other elements may increase susceptibility. These include:

Poor hygiene or crowded living conditions that facilitate infection spread
Exposure to certain toxins or medications
Underlying immune deficiencies or autoimmune tendencies
Geographic location—some forms are more common in Asia or developing countries

Recognizing these risk factors allows healthcare providers to monitor at-risk children more closely and intervene earlier when symptoms arise.

Conclusion: Early Detection Saves Kidneys

Glomerulonephritis in children stems from a wide array of causes—from post-infectious reactions and autoimmune disorders to genetic defects. Because symptoms like dark urine, facial swelling, fatigue, and high blood pressure can be subtle, parents and pediatricians must remain vigilant. Timely urinalysis, blood tests, imaging, and sometimes kidney biopsy are essential tools for accurate diagnosis.

With proper medical care, many children recover fully, while others require long-term management to preserve kidney function. Raising awareness about the origins and warning signs of pediatric glomerulonephritis is a critical step toward better outcomes and improved quality of life.