Health Encyclopedia

Interstitial nephritis

Definition

Interstitial nephritis is a kidney disorder in which the spaces between the kidney tubules become swollen (inflammed). The inflammation can affect the kidneys' ability to filter waste.

Alternative Names

Tubulointerstitial nephritis; Nephritis - interstitial; Acute interstitial (allergic) nephritis

Causes, incidence, and risk factors

Interstitial nephritis may be temporary (acute) or it may be chronic and get worse over time.

The following can cause interstitial nephritis:

Allergic reaction to a drug (acute interstitial allergic nephritis)
Analgesic nephropathy
Side effect of certain antibiotics (penicillin, ampicillin, methicillin, sulfonamide medications, and others)
Side effect of medications such as nonsteroidal anti-inflammatory drugs (NSAIDs), furosemide, and thiazide diuretics

The acute form of interstitial nephritis is common. It is most often caused by side effects of certain drugs. This disorder may be more severe and more likely to lead to chronic or permanent kidney damage in elderly people.

Symptoms

Interstitial nephritis can cause mild to severe kidney problems, including acute kidney failure. In about half of cases, people will have decreased urine output and other signs of acute kidney failure.

Symptoms of this condition include:

Blood in the urine
Fever
Increased or decreased urine output
Mental status changes (drowsiness, confusion, coma)
Nausea, vomiting
Rash (sometimes)
Swelling of the body, any area
Weight gain (from retaining fluid)

Signs and tests

An exam may show edema or too much fluid. The health care provider might hear abnormal sounds when listening to the heart or lungs with a stethoscope (auscultation). Blood pressure commonly is high.

Common tests include:

Arterial blood gases and blood chemistry
BUN and creatinine levels
Complete blood count
Kidney biopsy
Red blood cell count - urine
Urinalysis
Urine pH
Urine specific gravity and osmolality
White blood cell count

Treatment

Treatment focuses on the cause of the problem. Avoiding medications that lead to this condition may relieve the symptoms quickly.

Limiting salt (sodium) and fluid in the diet can control swelling and high blood pressure . Also limiting protein can help control the buildup of waste products in the blood (azotemia) that can lead to acute kidney failure.

If dialysis is necessary, it usually is required for only a short time.

Corticosteroids or anti-inflammatory medications can help in some cases.

Expectations (prognosis)

Most often, interstitial nephritis is a short-term disorder. In rare cases, it can cause permanent damage, including chronic kidney failure.

Complications

Metabolic acidosis can occur because the kidneys aren't able to remove enough acid. The disorder can lead to acute or chronic kidney failure or end-stage kidney disease.

Calling your health care provider

Call your health care provider if you have symptoms of interstitial nephritis.

If you have interstitial nephritis, call your health care provider if you get new symptoms, especially if you are less alert or have a decrease in urine output.

Prevention

In many cases, the disorder can't be prevented. Avoiding or reducing your use of medications that can cause this condition can help reduce your risk.

Review Date:8/14/2007
Reviewed By:Charles Silberberg, DO, Private Practice specializing in Nephrology, Affiliated with NY Medical College, Division of Nephrology, Valhalla, NY. Review provided by VeriMed Healthcare Network.

ADAM Quality A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.