Interstitial nephritis is a kidney disorder in which the spaces between the kidney tubules become swollen (inflamed). This can cause problems with the way your kidneys work.
Tubulointerstitial nephritis; Nephritis - interstitial; Acute interstitial (allergic) nephritis
The acute form of interstitial nephritis is most often caused by side effects of certain drugs.
The following can cause interstitial nephritis:
- Allergic reaction to a drug (acute interstitial allergic nephritis).
- Autoimmune disorders, such as antitubular basement membrane disease, Kawasaki disease, Sjögren syndrome, systemic lupus erythematosus, or Wegener granulomatosis.
- Long-term use of medicines such as acetaminophen (Tylenol), aspirin, and nonsteroidal anti-inflammatory drugs (NSAIDs). This is called analgesic nephropathy.
- Side effect of certain antibiotics (including penicillin, ampicillin, methicillin, sulfonamide medicines, and others).
- Side effect of other medicines such as furosemide, thiazide diuretics, omeprazole, triamterene, and allopurinol.
- Too little potassium in your blood.
- Too much calcium or uric acid in your blood.
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 may include:
- Blood in the urine
- Increased or decreased urine output
- Mental status changes (drowsiness, confusion, coma)
- Nausea, vomiting
- Swelling of the body, any area
- Weight gain (from retaining fluid)
Exams and Tests
The health care provider will perform a physical exam. This may reveal:
- Abnormal lung or heart sounds
- High blood pressure
- Fluid in the lungs (pulmonary edema)
Common tests include:
- Arterial blood gases
- Blood chemistry
- BUN and blood creatinine levels
- Complete blood count
- Kidney biopsy
- Kidney ultrasound
Treatment depends on the cause of the problem. Avoiding medicines that lead to this condition may quickly relieve symptoms.
Limiting salt and fluid in the diet can improve swelling and high blood pressure. Limiting protein in the diet can help control the buildup of waste products in the blood (azotemia) that can lead to symptoms of acute kidney failure.
If dialysis is necessary, it usually is required for only a short time.
Corticosteroids or stronger anti-inflammatory medicines such as cyclophosphamide can sometimes be helpful.
Most often, interstitial nephritis is a short-term disorder. In rare cases, it can cause permanent damage, including chronic kidney failure.
Acute interstitial nephritis may be more severe and more likely to lead to long-term or permanent kidney damage in older people.
When to Contact a Medical Professional
Call your provider if you have symptoms of interstitial nephritis.
If you have interstitial nephritis, call your provider if you get new symptoms, especially if you are less alert or have a decrease in urine output.
Often, the disorder can't be prevented. Avoiding or reducing your use of medicines that can cause this condition can help reduce your risk.
Arend LJ. Tubulointerstitial diseases. In: Lager DJ, Abrahams NA, eds. Practical Renal Pathology. Philadelphia, PA: Elsevier Saunders; 2013:chap 7.
Nangaku M. Chronic interstitial nephritis. In: Johnson RJ, Feehally J, Floege J, eds. Comprehensive Clinical Nephrology. 5th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 64.