Your kidneys are your body’s filters. These two bean-shaped organs are a sophisticated waste removal system. They process 120 to 150 quarts of blood per day and remove up to 2 quarts of waste products and excess water, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
Acute nephritis occurs when your kidneys suddenly become inflamed. Acute nephritis has several causes, and it can ultimately lead to kidney failure if it’s left untreated. This condition used to be known as Bright's disease.
There are several types of acute nephritis:
In interstitial nephritis, the spaces between the kidney tubules become inflamed. This inflammation causes the kidneys to swell.
Pyelonephritis is an inflammation of the kidney, usually due to a bacterial infection. In the majority of cases, the infection starts within the bladder and then migrates up the ureters and into the kidneys. Ureters are two tubes that transport urine from each kidney to the bladder.
This type of acute nephritis produces inflammation in the glomeruli. There are millions of capillaries within each kidney. Glomeruli are the tiny clusters of capillaries that transport blood and behave as filtering units. Damaged and inflamed glomeruli may not filter the blood properly. Learn more about glomerulonephritis.
Each type of acute nephritis has its own causes.
This type often results from an allergic reaction to a medication or antibiotic. An allergic reaction is the body’s immediate response to a foreign substance. Your doctor may have prescribed the medicine to help you, but the body views it as a harmful substance. This makes the body attack itself, resulting in inflammation.
Taking medications for long periods of time may damage the tissues of the kidneys and lead to interstitial nephritis.
The majority of pyelonephritis cases results from E.coli bacterial infections. This type of bacterium is primarily found in the large intestine and is excreted in your stool. The bacteria can travel up from the urethra to the bladder and kidneys, resulting in pyelonephritis.
Although bacterial infection is the leading cause of pyelonephritis, other possible causes include:
- urinary examinations that use a cystoscope, an instrument that looks inside the bladder
- surgery of the bladder, kidneys, or ureters
- the formation of kidney stones, rocklike formations consisting of minerals and other waste material
The main cause of this type of kidney infection is unknown. However, some conditions may encourage an infection, including:
- problems in the immune system
- a history of cancer
- an abscess that breaks and travels to your kidneys through your blood
Certain people are at greater risk for acute nephritis. The risk factors for acute nephritis include:
Your symptoms will vary depending on the type of acute nephritis you have. The most common symptoms of all three types of acute nephritis are:
- pain in the pelvis
- pain or a burning sensation while urinating
- a frequent need to urinate
- cloudy urine
- blood or pus in the urine
- pain in the kidney area or abdomen
- swelling of the body, commonly in the face, legs, and feet
- high blood pressure
A doctor will perform a physical exam and take a medical history to determine if you could be at an increased risk for acute nephritis.
Lab tests can also confirm or rule out the presence of an infection. These tests include a urinalysis, which tests for the presence of blood, bacteria, and white blood cells (WBCs). A significant presence of these can indicate an infection.
A doctor may also order blood tests. Two important indicators are blood urea nitrogen (BUN) and creatinine. These are waste products that circulate in the blood, and the kidneys are responsible for filtering them. If there’s an increase in these numbers, this can indicate the kidneys aren’t working as well.
A renal biopsy is one of the best ways to diagnose acute nephritis. Because this involves testing an actual tissue sample from the kidney, this test isn’t performed on everyone. This test is performed if a person isn’t responding well to treatments, or if a doctor must definitively diagnose the condition.
Treatment for glomerulonephritis and interstitial nephritis may require treating the underlying conditions causing the problems. For example, if a medication you’re taking is causing kidney problems, your doctor may prescribe an alternate medication.
A doctor will typically prescribe antibiotics to treat the kidney infection. If your infection is very serious, you may require intravenous (IV) antibiotics within the hospital inpatient setting. IV antibiotics tend to work faster than antibiotics in pill form. Infections such as pyelonephritis can cause severe pain. Your doctor may prescribe medication to relieve pain as you recover.
If your kidneys are very inflamed, your doctor may prescribe corticosteroids.
When your kidneys aren’t working as well, it can impact the balance of electrolytes in your body. Electrolytes, such as potassium, sodium, and magnesium, are responsible for creating chemical reactions in the body. If your electrolyte levels are too high, your doctor may prescribe IV fluids to encourage your kidneys to release the extra electrolytes. If your electrolytes are low, you may need to take supplements. These could include potassium or phosphorus pills. However, you shouldn’t take any supplements without your doctor’s approval and recommendation.
If your kidney function is significantly impaired due to your infection, you may require dialysis. This is a process in which a special machine acts like an artificial kidney. Dialysis may be a temporary necessity. However, if your kidneys have experienced too much damage, you may need dialysis permanently.
When you have acute nephritis, your body needs time and energy to heal. Your doctor will likely recommend bed rest during your recovery. Your doctor may also advise you to increase your fluid intake. This helps to prevent dehydration and keep the kidneys filtering to release waste products.
If your condition affects your kidney function, your doctor may recommend a special diet low in certain electrolytes, such as potassium. Many fruits and vegetables are high in potassium. Your doctor may instruct you regarding which foods are low in potassium.
You can also soak some vegetables in water and drain the water before cooking them. This process, known as leaching, can remove extra potassium.
Your doctor may also recommend cutting back on high-sodium foods. When you have too much sodium in your blood, your kidneys hold onto water. This can increase your blood pressure.
There are steps you can take to reduce sodium in your diet.
Eat less sodium
- Use fresh meats and vegetables instead of prepackaged ones. Prepackaged foods tend to be high in sodium.
- Choose foods labeled “low sodium” or “no sodium” whenever possible.
- When eating out, ask your restaurant server to request that the chef limit salt added to your dishes.
- Season your food with spices and herbs instead of sodium-blended seasonings or salt.
All three types of acute nephritis will improve with immediate treatment. However, if your condition goes untreated, you may develop kidney failure. Kidney failure occurs when one or both kidneys stop working for a short time or permanently. If that happens, you may need dialysis permanently. For this reason, it’s vital to seek immediate treatment for any suspected kidney issues.