Glomerulonephritis

Overview

Glomerulonephritis refers to inflammation of the glomeruli, the microscopic filtering units within the kidneys. Each kidney contains approximately one million glomeruli that filter waste products from the blood while retaining essential proteins and blood cells. When these delicate structures become inflamed, the kidneys lose their ability to filter properly, allowing blood and protein to leak into the urine while waste products accumulate in the bloodstream.

The condition represents one of the leading causes of end-stage kidney disease worldwide. Glomerulonephritis can develop suddenly (acute) following an infection, or progress slowly over many years (chronic) with few initial symptoms. Some forms affect only the kidneys (primary glomerulonephritis), while others occur as part of systemic diseases such as lupus or diabetes (secondary glomerulonephritis). IgA nephropathy stands as the most common form globally, particularly among Asian and Caucasian populations.

Symptoms

Many forms of glomerulonephritis remain silent in early stages, detected only through routine blood or urine testing. High blood pressure may be the sole indication of kidney damage, earning this condition its reputation as a “silent” threat to kidney health.

When symptoms do appear, hematuria ranks among the most characteristic findings. Visible blood in the urine produces a red, pink, or cola-colored appearance, though often the blood remains microscopic and detectable only on laboratory testing. Patients frequently notice foamy urine, which indicates significant protein loss into the urine (proteinuria).

Swelling develops as the kidneys struggle to regulate fluid balance. Edema typically appears first in the ankles, feet, and legs, often becoming more pronounced by day’s end. Facial puffiness, particularly around the eyes, commonly occurs in the morning. Some patients experience decreased urine output as kidney function declines.

Systemic symptoms include fatigue, nausea, and loss of appetite. Patients with glomerulonephritis caused by underlying autoimmune conditions may also experience joint pain, muscle aches, or skin rashes related to their primary disease.

Causes

IgA Nephropathy (Berger’s Disease) represents the most common form of glomerulonephritis worldwide. In this condition, immunoglobulin A antibodies deposit within the glomeruli, triggering inflammation. Patients often present with visible blood in the urine during respiratory infections. The disease course varies considerably—some individuals remain stable for decades while others progress toward kidney failure. Peak onset occurs during the twenties and thirties.

Post-Streptococcal Glomerulonephritis develops one to three weeks following a streptococcal throat or skin infection, occurring most frequently in children. The classic presentation includes dark urine, swelling, and elevated blood pressure. Most patients recover completely without long-term kidney damage.

Lupus Nephritis affects approximately half of all patients with systemic lupus erythematosus. Severity ranges from mild to life-threatening, requiring immunosuppressive treatment to prevent permanent kidney injury.

Rapidly Progressive Glomerulonephritis constitutes a medical emergency, with kidney function deteriorating over weeks rather than months or years. Causes include ANCA-associated vasculitis, anti-GBM disease (Goodpasture syndrome), and severe forms of lupus nephritis. Without prompt treatment, irreversible kidney failure develops rapidly.

Other causes include membranous nephropathy, focal segmental glomerulosclerosis (FSGS), minimal change disease (most common in children), and infections such as hepatitis B or C.

Diagnosis

Initial evaluation begins with urinalysis, which reveals blood cells, protein, and characteristic structures called casts that indicate glomerular damage. Blood tests measure creatinine and estimated glomerular filtration rate (eGFR) to assess kidney function, along with inflammatory markers and complete blood count.

Quantifying protein loss through a 24-hour urine collection or protein-to-creatinine ratio helps classify disease severity. Immunological testing searches for specific causes: antinuclear antibodies (ANA) for lupus, ANCA for vasculitis, anti-GBM antibodies for Goodpasture syndrome, and complement levels to assess immune system activation. Streptococcal antibody tests confirm recent bacterial infection when post-streptococcal glomerulonephritis is suspected. Hepatitis B and C serology screens for viral causes.

Kidney ultrasound evaluates organ size and structure while excluding obstruction conditions such as hydronephrosis.

Kidney Biopsy often proves essential for definitive diagnosis. A small tissue sample obtained under ultrasound guidance undergoes examination with standard microscopy, immunofluorescence, and electron microscopy. Biopsy findings determine the specific type of glomerulonephritis, guide treatment decisions, and predict long-term outcomes.

Treatment

Blood Pressure Control remains fundamental to managing all forms of glomerulonephritis. Maintaining pressure below 130/80 mmHg slows disease progression and reduces cardiovascular risk. ACE inhibitors (such as ramipril or lisinopril) and angiotensin receptor blockers (ARBs, such as losartan) serve as first-line agents. These medications not only lower blood pressure but also reduce protein leakage and protect kidney function, making them valuable even in patients without hypertension.

Dietary Modifications support medical treatment. Salt restriction helps control blood pressure and reduce swelling. Patients with impaired kidney function may need to limit potassium and phosphorus intake. A registered dietitian can provide individualized guidance on protein intake and other nutritional considerations.

Post-Streptococcal Glomerulonephritis typically requires only supportive care with blood pressure control and fluid restriction. Most children and adults recover completely within weeks without specific treatment.

IgA Nephropathy management depends on severity. Mild disease responds to ACE inhibitors or ARBs alone, while moderate to severe cases may require immunosuppressive therapy including corticosteroids.

Lupus Nephritis demands aggressive immunosuppression. Initial treatment typically combines high-dose corticosteroids with either mycophenolate or cyclophosphamide, followed by long-term maintenance therapy to prevent relapse.

ANCA Vasculitis and Anti-GBM Disease require urgent intervention with cyclophosphamide or rituximab combined with corticosteroids. Severe cases may benefit from plasma exchange to remove harmful antibodies from circulation.

When glomerulonephritis progresses to kidney failure despite treatment, renal replacement therapy becomes necessary. Options include hemodialysis, peritoneal dialysis, and kidney transplantation, though some forms of glomerulonephritis can recur in transplanted kidneys.

When to See a Doctor

Seek urgent medical evaluation for dark or bloody urine, rapid onset of swelling (particularly in the face and legs), significantly decreased urine output, severe headache accompanied by high blood pressure, or shortness of breath. These symptoms may indicate rapidly progressive disease requiring immediate treatment.

Schedule an appointment with your GP if you notice persistently foamy urine, discover blood on a routine urine test, develop new or worsening high blood pressure, or receive abnormal kidney function results on blood testing. Symptoms developing one to three weeks after a streptococcal throat or skin infection warrant prompt evaluation.

Patients diagnosed with glomerulonephritis require ongoing monitoring with regular kidney function tests, blood pressure checks, and urine protein measurements. Avoid nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen, which can worsen kidney function. Always consult your doctor or pharmacist before starting new medications, including herbal supplements.

Long-term management benefits from specialist nephrology care. Lifestyle modifications that support kidney health include maintaining a healthy weight, exercising regularly, avoiding smoking, and limiting alcohol consumption. If urinary tract infections develop, prompt treatment helps prevent additional kidney stress.