Your kidneys are your body’s filters. These two bean-shaped
organs are a sophisticated waste removal system. Your kidneys process 200
quarts of blood per day and remove 2 quarts of waste products and excess water.
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
Types of Acute Nephritis
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.
What Causes Acute Nephritis?
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.
Low potassium in your blood is another cause of interstitial
nephritis. Potassium is a mineral that helps regulate many functions in the
body, including heartbeat and metabolism.
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 Escherichia coli (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, which are rock-like
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
Who Is at Risk for Acute Nephritis?
Certain people are at greater risk for acute nephritis. The
risk factors for acute nephritis include:
- a family history of kidney disease and infection
- having an immune system disease, such as lupus
- taking too many antibiotics or pain medications
- recent surgery of the urinary tract
What Are the Symptoms of Acute Nephritis?
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
Diagnosing Acute Nephritis
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. 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 the kidneys are responsible for filtering. If there’s an
increase in these numbers, this can indicate the kidneys aren’t working as
An imaging scan, such as a CT scan or renal ultrasound, can show
a blockage or inflammation of the kidneys or urinary tract.
According to the American Academy of Family
Physicians (AAFP), 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. If a person isn’t responding
well to treatments or a doctor must definitively diagnose the condition, a
kidney biopsy is performed.
Treating Acute Nephritis
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 like 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
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
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 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.
The following are steps you can take to reduce sodium in your
- 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”
- 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.
What Is the Long-Term Outlook?
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