Published: 18 Jun 2025

ICD9: 580.4      ICD10: N01.3      ICD11: GB40

Glomerulonephritis (GN) is a term that describes a group of kidney diseases that damage the glomeruli, the tiny filters in your kidneys.
These filters are crucial for cleaning your blood by removing waste products and excess fluids, which are then excreted in urine. When the glomeruli are inflamed and damaged, they can't filter properly.

Here's a breakdown of key aspects of glomerulonephritis:

What happens when glomeruli are damaged?

Proteinuria: Protein leaks into the urine because the damaged filters allow larger molecules like protein to pass through. This can lead to foamy urine.
Hematuria: Blood leaks into the urine, causing it to appear pink, red, or cola-colored.
Edema: Fluid retention, leading to swelling (edema) in the face, hands, feet, and abdomen. This happens because the kidneys aren't effectively removing excess fluid.
Hypertension: High blood pressure can develop as the kidneys struggle to regulate fluid and electrolytes.
Decreased kidney function: Over time, glomerulonephritis can lead to chronic kidney disease (CKD) and potentially kidney failure (end-stage renal disease), requiring dialysis or a kidney transplant.

Causes:

Glomerulonephritis can be caused by a variety of factors, including:

Infections: Certain bacterial (e.g., strep throat), viral (e.g., hepatitis B, hepatitis C, HIV), or parasitic infections can trigger glomerulonephritis. Post-streptococcal glomerulonephritis is a common example, developing after a strep infection.
Autoimmune diseases: The body's immune system mistakenly attacks the glomeruli. Examples include:
Lupus (systemic lupus erythematosus)
Goodpasture's syndrome
IgA nephropathy (Berger's disease)
Vasculitis (inflammation of blood vessels)
Genetic factors: Some forms of glomerulonephritis are inherited.
Other conditions:
Diabetes
High blood pressure
Focal segmental glomerulosclerosis (FSGS) - A scarring of the glomeruli, which can be primary (no known cause) or secondary (caused by other conditions).
Amyloidosis

Types:

Glomerulonephritis can be classified based on its:

Course:
Acute glomerulonephritis: Develops suddenly, often after an infection.
Chronic glomerulonephritis: Develops gradually over many years, often without noticeable symptoms until kidney damage is significant.
Cause: As listed above (infectious, autoimmune, genetic, etc.).
Histopathology: The appearance of the glomeruli under a microscope (e.g., membranous glomerulonephritis, minimal change disease, FSGS). A kidney biopsy is often necessary to determine the specific type.

Symptoms:

Symptoms can vary depending on the type and severity of glomerulonephritis. Some people may have no symptoms at all, especially in the early stages. Common symptoms include:

Foamy urine (due to protein)
Blood in the urine (hematuria)
Swelling (edema) in the face, hands, feet, and abdomen
High blood pressure (hypertension)
Fatigue
Frequent nighttime urination
Weight gain (due to fluid retention)

Diagnosis:

Diagnosis typically involves:

Medical history and physical exam: The doctor will ask about your symptoms, medical history, and any family history of kidney disease.
Urine tests: To detect protein and blood in the urine.
Blood tests: To assess kidney function (creatinine, BUN), electrolyte levels, and look for signs of infection or autoimmune disease.
Kidney biopsy: A small sample of kidney tissue is removed and examined under a microscope to determine the specific type of glomerulonephritis and the extent of damage.
Imaging tests: Ultrasound or CT scans may be used to visualize the kidneys.

Treatment:

Treatment depends on the underlying cause, the severity of the disease, and the symptoms. Goals of treatment include:

Controlling blood pressure: Medications like ACE inhibitors or ARBs are often used to lower blood pressure and protect kidney function.
Reducing inflammation: Corticosteroids or other immunosuppressant drugs may be prescribed to reduce inflammation in the glomeruli, especially in autoimmune-related glomerulonephritis.
Treating the underlying cause: If glomerulonephritis is caused by an infection, antibiotics or antiviral medications may be used.
Managing symptoms: Diuretics (water pills) can help reduce swelling. Dietary changes, such as restricting sodium and protein intake, may also be recommended.
Slowing the progression of kidney disease: This may involve controlling blood pressure, managing diabetes, and making lifestyle changes such as quitting smoking.
Dialysis or kidney transplant: If kidney failure develops, dialysis or a kidney transplant may be necessary to sustain life.

Prognosis:

The prognosis for glomerulonephritis varies widely depending on the type, severity, and response to treatment. Some forms of glomerulonephritis may resolve on their own or with treatment, while others may lead to chronic kidney disease and ultimately kidney failure. Early diagnosis and treatment are crucial to improving the outcome.

In summary, glomerulonephritis is a serious condition that affects the kidneys' ability to filter waste and fluids. It has various causes and can lead to significant health problems if left untreated. If you experience symptoms suggestive of glomerulonephritis, it's important to see a doctor for diagnosis and treatment.