Tubulointerstitial Nephritis

Tubulointerstitial nephritis (TOO-byuh-lo-in-ter-STISH-uhl nuh-FRAYH-tis) is a type of kidney disease. It causes inflammation and damage to your kidneys. It affects the small tubes (tubules) and surrounding tissues (interstitial tissue) in your kidneys. But it doesn’t affect the tiny blood vessels (glomeruli) that remove waste and extra fluid from your blood. Waste and extra fluid eventually leave your body in your urine (pee). So, tubulointerstitial nephritis may not be as severe as other kidney diseases that affect your glomeruli if you get a quick diagnosis and treatment.

Tubulointerstitial nephritis (TIN) is a big name. But breaking it down can help you understand how it affects your body:

• tubulo-. This refers to the tiny tubes in your kidneys.
• -interstitial. This word refers to the surrounding interstitial tissues in your kidneys.
• nephr-. This comes from the Greek word “nephros,” which means kidney or something that relates to your kidney.
• -itis. This means inflammation.

Without treatment, TIN often causes chronic kidney disease (CKD) and kidney failure.

Types of tubulointerstitial nephritis

There are two different types of tubulointerstitial nephritis. They develop at different times:

• Acute tubulointerstitial nephritis: This type develops suddenly, usually as an allergic reaction to certain types of medications.
• Chronic tubulointerstitial nephritis: This type takes longer to develop.

What are the signs of tubulointerstitial nephritis?

The signs and symptoms of tubulointerstitial nephritis depend on the type you have. Some people might not have any symptoms, or the symptoms may take a long time to appear. For others, symptoms develop quickly.

Acute TIN symptoms may include:

• Peeing a lot more or a lot less than expected
• Waking up more than once to pee (nocturia)
• Pain while peeing (dysuria)
• Fever
• Lower back pain
• Flank pain

Chronic TIN symptoms typically include kidney failure symptoms, including:

• Feeling really tired (fatigue)
• Itchiness
• Nausea and vomiting
• Loss of appetite
• Trouble breathing
• Peeing more than usual

Tubulointerstitial nephritis causes

Acute TIN causes include:

• Allergic reaction to certain medications: These may include nonsteroidal anti-inflammatory drugs (NSAIDs), penicillin, proton pump inhibitors (PPIs), sulfa drugs (medications that help treat infections), antineoplastic agents (medications that help treat cancer), diuretics and vaccines. Medications are the most common cause of TIN.
• Conditions that affect your immune system: These may include lupus and Sjögren’s syndrome.
• Bacterial infections: Examples include coli, Proteus mirabilis and Staphylococcus. These bacteria cause urinary tract infections (UTIs) that start in the urinary bladder and move up into the kidneys.
• Viral infections: Examples include COVID-19, hepatitis B, HIV and cytomegalovirus.
• Fungal infections: Histoplasmosis can cause acute TIN.
• Parasitic infections: Examples include Toxoplasma and Leishmania.

A kidney transplant rejection can also cause TIN.

Some chronic TIN causes include:

• Certain medications, including analgesics and lithium
• Heavy metal exposure, including lead and mercury
• Conditions that affect your metabolism, including hypercalcemia and hyperoxaluria
• Genetic disorders

What is the most common drug to cause acute tubulointerstitial nephritis?

Some of the most common drugs that cause acute TIN include:

• Antibiotics
• NSAIDs
• Proton pump inhibitors

Risk factors

Anyone can get tubulointerstitial nephritis. But you’re more likely to get TIN if you have a:

• Hypersensitive reaction to a medication
• Condition that affects your immune system
• Bad bacterial, viral, fungal or parasitic infection
• Job that exposes you to heavy metals
• Genetic condition that affects your kidneys
• Long history of taking NSAIDs

Complications of tubulointerstitial nephritis

Tubulointerstitial nephritis may continue to get worse. This can eventually lead to kidney failure (end-stage renal disease). Kidney failure treatment includes dialysis or a kidney transplant.

How doctors diagnose tubulointerstitial nephritis

Healthcare providers can use kidney function tests to look for signs of kidney damage. These are blood tests and urine tests (urinalysis) that determine how well your kidneys function.

In many cases, the presence of kidney damage symptoms is enough for healthcare providers to determine that something is affecting your kidneys and you need treatment. But the only way to know for sure that tubulointerstitial nephritis is causing kidney damage is to get a kidney biopsy. During a kidney biopsy, a provider removes a small sample of your kidney tissue and examines it under a microscope.

What is the best treatment for tubulointerstitial nephritis?

Tubulointerstitial nephritis treatment includes avoiding or treating the cause. A healthcare provider may prescribe corticosteroids to help manage inflammation if your symptoms don’t improve within a week.

Providers may also recommend ways to preserve your kidney function. They may advise you to:

• See specialists, including a nephrologist
• Manage your blood pressure
• Manage your blood glucose (sugar) if you have diabetes
• Follow kidney-friendly eating patterns
• Quit smoking
• Maintain a weight that’s healthy for you

Is tubulointerstitial nephritis reversible?

If you have tubulointerstitial nephritis, you can restore kidney function if you get a prompt diagnosis and treatment. Without treatment, TIN may cause permanent kidney damage.

When should I see my healthcare provider?

Getting a tubulointerstitial nephritis diagnosis as soon as possible helps prevent permanent kidney damage that can lead to kidney failure. Contact a healthcare provider if you:

• Have any changes to your peeing habits
• Feel more tired than usual
• Don’t feel like eating
• Have pain in your lower back or sides
• Have trouble breathing

Make sure to schedule regular appointments with a kidney specialist if you receive a TIN diagnosis. They can monitor your kidney health.

Can tubulointerstitial nephritis be prevented?

Scheduling annual appointments with a healthcare provider throughout your life is a good way to help monitor your kidney health and prevent tubulointerstitial nephritis, especially if you’re at a greater risk of getting TIN.

You can also take care of your kidneys by:

• Eating healthy foods every day
• Maintaining a healthy weight for you
• Being active for at least 30 minutes for at least five days a week
• Avoiding smoking, vaping and using tobacco products in general
• Taking medications only as directed

What can I expect if I have tubulointerstitial nephritis?

Your outlook depends on many things, including:

• What’s causing tubulointerstitial nephritis
• How quickly you get treatment
• How well your kidneys worked before you got TIN

Many people have improved kidney function once they stop taking the medication that causes TIN or a healthcare provider treats the underlying cause. Though even with treatment, chronic TIN can eventually cause kidney failure.

Is tubulointerstitial nephritis the same as pyelonephritis?

No. Pyelonephritis is another name for a kidney infection. But pyelonephritis can cause tubulointerstitial nephritis.