Glomerulonephritis – a kidney disease

At a Glance:

What is glomerulonephritis?

Inflammation of the glomeruli (network of blood vessel) of the kidney results in a condition known as glomerulonephritis. A healthy glomerulus allows waste products and extra water to pass in urine while keeping blood cells and protein in the bloodstream. However in glomerulonephritis, proteins and sometimes red blood cells leak out which is not just the loss but also a cause of fluid accumulation and swelling (edema) in the body.

The nephron is the smallest filtering unit of the kidney. Each nephron comprises of a renal corpuscle and renal tubule. The renal corpuscle, in turn, is formed by the glomerulus and the Bowman’s capsule. The glomerulus is that part of the nephron which removes the waste and excess fluid from the blood. Thus, it has a primary role in filtration. For assessing the functional capacity of kidneys, Glomerular Filtration Rate (GFR) is determined. 

Glomerulonephritis may be acute or chronic and may be caused due to a variety of reasons including underlying diseases such as diabetes. If the condition remains untreated and inflammation lasts for a longer period, risk of kidney damage severely increases.

What are the symptoms of glomerulonephritis?

In many cases, glomerulonephritis may remain asymptomatic, and the condition is diagnosed accidentally when blood and urine tests are done for other diseases. Some of the symptoms experienced by the persons with glomerulonephritis include:

Frothy urine due to proteinuria: Glomerulonephritis alters the filtering function, which leads to an increased level of protein in the urine. A high level of protein in the urine causes frothiness.

Haematuria: In glomerulonephritis, blood may also leak into the urine. In severe cases, the presence of blood may be determined by naked eyes while in mild glomerulonephritis, tests are conducted to determine the presence of blood in the urine.

Edema: Proteins are responsible for keeping the fluid in the blood vessels due to osmotic pressure. In case of low levels of proteins, the fluid leaks from the blood vessels and gets accumulated in tissues, leading to edema.

High blood pressure or hypertension: Kidneys are also responsible for maintaining blood pressure through the secretion of hormones, known as the Renin-Angiotensin system, that regulate the blood pressure. Consequentially, alteration in kidney function due to glomerulonephritis may cause hypertension.

Lack of energy: Anaemia type symptoms may also occur due to loss of blood. These symptoms include lack of energy and lethargy.

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What are the causes of glomerulonephritis?

Most cases of glomerulonephritis are because of problems in the immune system. In some cases, the reason remains unknown. The immune system may be hyperactive because of these triggers and may attack glomeruli. Following are some of the prominent causes of glomerulonephritis:

Immune diseases: Autoimmune diseases are one of the primary causes of glomerulonephritis. Lupus, a chronic disease, may affect the kidney along with other organs such as the heart, lungs, and joints. Glomerulonephritis may also be caused due to Goodpasture’s disease and IgA nephropathy. IgA nephropathy may lead to slow-progressing glomerulonephritis characterized by recurrences of haematuria.

Infections: Body’s response to infection may trigger the immune system to become hyperactive. This may lead to glomerulonephritis. In cases of streptococcal throat infections, the body produces excess antibodies. These excessive antibodies get accumulated in the glomeruli leading to inflammation. Other infections that may cause glomerulonephritis include viral infections like hepatitis B, hepatitis C, HIV, and certain fungal infections.

Vasculitis: It is characterized by swelling or inflammation of blood vessels. Conditions like polyarteritis and granulomatosis with polyangiitis may cause glomerulonephritis.

Medications: Glomerulonephritis may also be caused due to the adverse effects of certain medications such as NSAIDs (Nonsteroidal anti-inflammatory drugs).

Genetic: In a few cases, glomerulonephritis may run in families. In such cases, the condition is most often seen with people having hearing and vision loss.

Idiopathic glomerulonephritis: In some cases, the exact cause of glomerulonephritis remains unknown.

What are the types of glomerulonephritis?

There are various ways of classifying glomerulonephritis.

It may be classified based on the development of glomerulonephritis:

• Chronic glomerulonephritis: Chronic form of glomerulonephritis develops over several years. If the symptoms are not identified in an early stage, this may lead to complete kidney failure.
• Acute glomerulonephritis: Acute glomerulonephritis is characterized by the sudden appearance of symptoms. This may be due to infection or due to some other reason. At times, no treatment is required, and the condition becomes normal with time. In some cases, medical intervention is necessary.

Classification may also be done based on the cause of glomerulonephritis:

• Primary glomerulonephritis: Primary glomerulonephritis occurs on its own and is not developed due to other existing diseases in the body.
• Secondary glomerulonephritis: Reason for secondary glomerulonephritis is an underlying disease. These diseases may include infection, lupus, or diabetes.

Glomerulonephritis can be classified based on immune reactions:

• IgA glomerulonephritis: Such type of glomerulonephritis may be due to the accumulation of IgA antibody in the glomeruli, which causes damage.
• IgM glomerulonephritis: Accumulation of IgM antibody damages the glomeruli.

Glomerulonephritis can be classified based on the location and extent of damage within the glomerulus:

• Membranous glomerulonephritis: In this type of glomerulonephritis, only the membrane of the glomerulus is affected while other portions remain normal.
• Focal and segmental glomerulosclerosis: The condition is characterized by sclerosis and scarring of glomeruli. In focal type, some of the glomeruli are affected while in segmental type, only a portion of glomerulus gets affected.

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What are the risk factors for glomerulonephritis?

Although it is believed that glomerulonephritis is mainly caused due to the immune system, the detailed mechanism of development is still not very clear.

Some of the factors that increase the risk of glomerulonephritis:

• Infections: Development of infections increases the risk of glomerulonephritis. This is because the immune system may become hyperactive and attack the glomeruli. Infection may be bacterial, viral, or fungal.
• Genetic factors: Genetic factors sometimes increases the risk of glomerulonephritis. 
• Medications: Prolonged intake of medications such as NSAIDs like aspirin increases risk of glomerulonephritis.
• Underlying diseases: Glomerulonephritis caused due to underlying disease is known as secondary glomerulonephritis. The diseases involved may be related to the immune system or general diseases. Diseases that increase risk of glomerulonephritis include Henoch-Schönlein purpura, Goodpasture’s syndrome, vasculitis, diabetes, sickle cell, lupus nephritis, and membranoproliferative glomerulonephritis.
• Exposure to toxic chemicals: Risk of glomerulonephritis is also increased when the person is exposed to toxic chemicals such as hydrocarbon solvents.

How is glomerulonephritis diagnosed by doctors?

The symptoms of glomerulonephritis do not appear in most of the persons, and the disease is diagnosed when the urine and blood tests are done either during a routine check-up or for evaluating some other disease. Following are some of the tests used for diagnosing glomerulonephritis:

Blood tests: Various blood tests are conducted to evaluate the physiological functioning of kidneys. Serum creatinine level is examined to determine the filtering capacity of glomeruli. Blood tests are also helpful in determining the level of urea, electrolytes, albumin, and other proteins. Presence of anemia may also be diagnosed through blood tests.

Urine tests: Urine tests are done to determine the presence of protein and blood in the urine. Other substances whose high-level presence may be a cause of concern are urea and creatinine.

Imaging technique: Various imaging tests are used to detect the presence of any tissue destruction in kidneys. These imaging techniques may include X-ray, CT scan, or ultrasound.

Kidney Biopsy: Kidney biopsy is an essential diagnostic test to confirm the presence of glomerulonephritis. A small tissue of the kidney is taken and tested under the microscope. It may also help in evaluating the cause of glomerulonephritis.

Diagnosis for the cause: Various tests are conducted to determine the underlying cause of glomerulonephritis. This includes chest X-ray for the presence of infection or blood tests for lupus.

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What is glomerulonephritis urinalysis test?

Urinalysis is the comprehensive testing of urine for diagnosis of various diseases and for routine evaluation of kidney health. As glomerulonephritis causes impaired functioning of kidneys, detailed urinalysis is conducted to diagnose the condition.  Urine is analyzed for the presence of protein and blood. Other substances that can be evaluated include cellular casts of RBC and WBC, oval fat bodies, acanthocytes, granular casts, dysmorphic RBCs, and differentiated RBC and WBC. Various chemical assays are also the part of glomerulonephritis urinalysis test. These assays include the assay of urine sodium, urine electrolytes, and fractional excretion of sodium.

What is glomerulonephritis pathophysiology?

Various pathophysiological mechanisms have been elucidated for glomerulonephritis. Following are some of the common pathophysiological mechanisms:

Cell-mediated immune response: Cell-mediated immune response is one of the primary causes of glomerulonephritis. Due to the presence of trigger such as bacterial, fungal or viral infection, the immune system becomes hyperactive and may cause damage to glomeruli.

Accumulation of antibodies: IgA and IgM get deposited into the glomeruli and cause damage.

Circulating immune complex: Circulating immune complex (3D complex of antigen-antibody) present in people with autoimmune disease such as lupus are related to glomerulonephritis.

Scarring due to soluble factors: Various soluble factors such as cytokines, reactive oxygen species, chemokines, and proteases also play a major role in the progression of the disease.

Drugs and toxic substances: Exposure to various drugs and toxic substances such as captopril, mercury, formaldehyde, and hydrocarbons also cause glomerulonephritis.

Other non-immune conditions: Conditions which lead to a reduction in kidney function, loss of nephron and reduction in GFR are also responsible for glomerulonephritis. These conditions may include hemodynamic changes that cause renal damage or kidney hypertrophy.

What are the treatment options for glomerulonephritis?

Aim of treating glomerulonephritis is to prevent the progression of the disease. The treatment is initiated depending upon the cause. Treatment strategy also depends upon whether the condition is acute or chronic and the severity of the disease. Certain changes in the diet and fluid intake is advised by the nephrologist. 

1. If the condition is caused due to infection, treatment should be focused on the management of infection especially in nephrotic syndrome and chronic kidney disease. Vaccinations such as influenza and pneumonia shots are recommended. 
2. Plasma exchange is suggested for glomerulonephritis called ANCA vasculitis. 
3. Treatment for underlying causes such as diabetes, high blood pressure, or autoimmune disease.
4. Immunosuppressants for glomerulonephritis caused due to immune responses.
5. In severe cases of glomerulonephritis with kidney failure, dialysis and kidney transplant may be the only option.

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What are the glomerulonephritis complications?

Untreated glomerulonephritis may cause serious and life-threatening complications and result in kidney failure. Some of the complications of glomerulonephritis are:

Acute Kidney failure: Glomerulonephritis may lead to acute kidney failure due to an accumulation of waste, and the patient may require emergency dialysis.

Hypertension: Kidney damage may lead to abnormal blood pressure. Increased blood pressure may lead to heart attack and stroke.

Chronic Kidney Disease: Glomerulonephritis may lead to chronic kidney disease, which may progress to end-stage renal disease.

Is glomerulonephritis preventable?

Although complete prevention of glomerulonephritis is not possible, the risk can be reduced through the following steps:

• Control hypertension and diabetes through strict adherence to prescription and lifestyle management.
• Take adequate treatment for streptococcal infections.
• Follow safe-sex guidelines to stay away from HIV infections.
• A routine check-up may help in the diagnosis of glomerulonephritis at an early stage.

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Conclusion:

The glomerulus is the part of nephron responsible for filtration. Inflammation in glomeruli is known as glomerulonephritis. Symptoms include protein and blood in urine, edema, electrolyte imbalance, lethargy, and frothy urine. Causes of glomerulonephritis include infection, autoimmune disease, and exposure to certain medications and toxins. Diagnosis is done through urine tests, blood tests, imaging techniques, and kidney biopsy. Treatment is aimed at managing the underlying cause and preventing the progression of the disease. 

References:

• Mayo clinic, Glomerulonephritis. Available at: https://www.mayoclinic.org/diseases conditions/glomerulonephritis/symptoms-causes/syc-20355705. Accessed on June 24, 2019
• Medical News Today, What is Glomerulonephritis? Available at: https://www.medicalnewstoday.com/articles/167252.php. Accessed on June 24, 2019
• NHS, Overview Glomerulonephritis. Available at: https://www.nhs.uk/conditions/glomerulonephritis/ Accessed on June 24, 2019
• Patient, Glomerulonephritis. Available at: https://patient.info/kidney-urinary-tract/glomerulonephritis-leaflet. Accessed on June 24, 2019