Glomerulonephritis (GN) refers to a group of kidney diseases characterized by inflammation of the glomeruli—the tiny filtering units within the kidneys. These glomeruli are responsible for filtering blood and removing waste products and excess fluid from the body. When they become inflamed and damaged, the kidneys lose their ability to filter effectively, leading to a buildup of waste in the blood and potential leakage of protein and blood into the urine.

What is Glomerulonephritis?

Glomerulonephritis is not a single disease but rather a term for several conditions that cause inflammation and damage to the glomeruli. This damage can range from mild to severe, and if left untreated, it can lead to chronic kidney disease (CKD), end-stage renal disease (ESRD), and a need for dialysis or kidney transplant.

How Glomerulonephritis Affects Kidneys:

When glomeruli are inflamed, their delicate filtering membranes become damaged. This allows substances that should stay in the blood (like proteins and red blood cells) to leak into the urine. At the same time, the kidneys' ability to remove waste products and excess fluid is compromised, leading to symptoms like swelling and high blood pressure.

Causes of Glomerulonephritis

Glomerulonephritis can be classified as primary (originating in the kidneys) or secondary (caused by other systemic diseases). The causes are varied and often involve the immune system:

• Infections:
  • Post-infectious Glomerulonephritis: Often follows a bacterial infection, such as strep throat (post-streptococcal GN).
  • Other infections like hepatitis B and C, HIV, and endocarditis.
• Autoimmune Diseases: The body's immune system mistakenly attacks its own tissues, including the kidneys.
  • Lupus Nephritis: Kidney inflammation caused by Systemic Lupus Erythematosus (SLE).
  • Goodpasture's Syndrome.
  • Vasculitis (e.g., ANCA-associated vasculitis).
• Genetic Factors: Some forms, like Alport Syndrome, are inherited.
• Other Kidney Diseases: Some kidney conditions can lead to GN.
• Idiopathic: In some cases, the cause remains unknown.

Types of Glomerulonephritis

Glomerulonephritis can be acute (sudden onset) or chronic (developing slowly over time). Specific types include:

• IgA Nephropathy (Berger's Disease): The most common form of primary GN, characterized by deposits of IgA antibody in the glomeruli. It often presents with episodes of blood in the urine, especially after infections.
• Rapidly Progressive Glomerulonephritis (RPGN): A severe, aggressive form that causes rapid loss of kidney function over weeks or months. It requires urgent diagnosis and aggressive treatment.
• Membranous Nephropathy: Characterized by thickening of the glomerular basement membrane, often leading to nephrotic syndrome (heavy protein in urine, swelling).
• Focal Segmental Glomerulosclerosis (FSGS): Involves scarring of some glomeruli in segments. It can be primary, secondary to other conditions (e.g., obesity, certain drugs), or genetic. A common cause of nephrotic syndrome.
• Minimal Change Disease: A common cause of nephrotic syndrome in children, but can also affect adults. It's called "minimal change" because the glomeruli appear normal under a light microscope.
• MPGN (Membranoproliferative Glomerulonephritis): Involves changes in the structure of the glomeruli, often associated with autoimmune diseases or chronic infections.

Symptoms of Glomerulonephritis

Symptoms vary depending on the type and severity of GN. In acute cases, they can appear suddenly, while chronic GN may develop subtly over years. Common symptoms include:

• Hematuria: Blood in the urine (may appear reddish-brown or cola-colored).
• Proteinuria: Excess protein in the urine, leading to foamy or frothy urine.
• Edema: Swelling in the face (especially around the eyes), hands, feet, and abdomen, due to fluid retention.
• Hypertension: High blood pressure.
• Reduced Urine Output: (Oliguria) in severe cases.
• Fatigue, weakness, loss of appetite, nausea, and vomiting (due to waste buildup).
• Shortness of breath (due to fluid overload).

Diagnosis of Glomerulonephritis

Accurate diagnosis is crucial for effective treatment. It typically involves:

• Urine Tests: To detect blood, protein, and other abnormalities (e.g., urine microscopy for red blood cell casts).
• Blood Tests: To assess kidney function (creatinine, eGFR), electrolyte levels, and check for signs of inflammation or autoimmune markers (e.g., ANCA, ANA, complement levels).
• Kidney Biopsy: This is often the definitive diagnostic tool. A small piece of kidney tissue is removed and examined under a microscope to determine the specific type of GN, its severity, and the extent of damage. This guides treatment decisions.
• Imaging Tests: Ultrasound may be used to assess kidney size and structure.

Treatment and Management

Treatment for glomerulonephritis depends heavily on the specific type, cause, and severity. The goals are to reduce inflammation, suppress the immune response, control symptoms, and prevent further kidney damage.

• Immunosuppressive Medications:
  • Corticosteroids: (e.g., prednisone) Often used to reduce inflammation and suppress the immune system.
  • Other Immunosuppressants: (e.g., cyclophosphamide, mycophenolate mofetil, rituximab, cyclosporine, tacrolimus) Used to control specific types of GN or in cases unresponsive to steroids.
• Blood Pressure Control: Medications like ACE inhibitors or ARBs are crucial to lower blood pressure and reduce protein in the urine, protecting kidney function.
• Dietary Management: Restrictions on sodium, potassium, phosphorus, and protein may be necessary as kidney function declines. A renal dietitian can provide guidance.
• Diuretics: To manage fluid retention and swelling.
• Cholesterol-Lowering Medications: If high cholesterol is present, particularly in nephrotic syndrome.
• Dialysis or Kidney Transplant: If GN progresses to end-stage renal disease, kidney replacement therapy becomes necessary.