Definition of Interstitial nephritis:

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.

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.