What is interstitial nephritis?
Interstitial nephritis is a disease that causes inflammation (swelling) around parts of your kidneys' filters called the tubules. This inflammation lowers your kidneys' ability to clean your blood and make urine (pee). There are two kinds of interstitial nephritis:
- Acute interstitial nephritis, which lasts a short time. This is the most common type of interstitial nephritis.
- Chronic interstitial nephritis, which lasts longer: weeks, months or years.
Without treatment, interstitial nephritis can cause kidney damage or kidney failure.
What are the symptoms of interstitial nephritis?
The most common symptom of interstitial nephritis is urinating less than normal. Other symptoms can include:
- Blood in your urine
- A rash
- Feeling tired or confused
- Feeling sick to your stomach and throwing up
- Swelling in your hands, feet or other parts of your body
- Weight gain
- High blood pressure
What causes interstitial nephritis?
Acute interstitial nephritis is usually caused by an allergic reaction or other type of reaction to a medicine or drug that you take. The symptoms of acute interstitial nephritis can happen quickly.
There are more than 100 different medicines that might cause acute interstitial nephritis. The types of medicine that are most likely to cause acute interstitial nephritis include:
- Antibiotics, such as penicillin
- Over-the-counter pain medicines called nonsteroidal anti-inflammatory drugs (NSAIDs)
- Medicines used to treat excess stomach acid called proton pump inhibitors (PPIs)
Chronic interstitial nephritis is usually caused by another health problem you have. Problems that can cause interstitial nephritis include:
- Autoimmune diseases (diseases that cause your body's immune system to attack its own tissues) such as lupus
- Low levels of potassium in your blood
- Levels of calcium in your blood that are too high
- Sarcoidosis (a disease that causes inflammation, most commonly in the lungs and lymph nodes)
- Some infections
How do doctors treat interstitial nephritis?
Treating acute interstitial nephritis
Doctors treat acute interstitial nephritis by having you stop or change the medicine that is causing it. Often, this restores kidney function quickly and your symptoms go away. However, acute interstitial nephritis can cause permanent kidney damage if it is not found early enough.
If you have severe loss of kidney function due to acute interstitial nephritis, you may need to go on dialysis for a short time until your kidney function improves.
Treating chronic interstitial nephritis
In chronic interstitial nephritis, doctors treat the health problem that is causing it. They may also prescribe medicines that help control your blood pressure and lower inflammation.
Doctors may recommend changes in what you eat to lower the amount of sodium (salt) and protein you take in.
How can doctors tell if I have interstitial nephritis?
If your doctor thinks your kidneys may not be working as they should due to interstitial nephritis, they will ask about any medicines you take, including how often you take them and how long you have been on them. Tell your doctor about all the medicines you take even if you do not take them every day, including over-the-counter medicines and supplements.
They will also do a physical exam, including:
- Listening to your heart and lungs with a stethoscope
- Taking your blood pressure
- Weighing you
Other tests and checks doctors may use to tell if you have interstitial nephritis include:
- Blood tests
- Urine tests
- A kidney biopsy (a procedure where doctors take a small piece of tissue from your kidneys to look at it under a microscope).
During a biopsy, doctors may see granulomas (areas of inflammation in your blood vessels). This is a rare form of acute interstitial nephritis called granulomatous interstitial nephritis. Seeing granulomas can help doctors figure out what is causing the disease.
How can I prevent interstitial nephritis?
Talk to your doctor about any medicines you take and your chance (risk) of getting interstitial nephritis.