Interstitial nephritis
Key points
- Interstitial nephritis is a kidney disorder caused by inflammation of the tubules and the spaces between the tubules and the glomeruli.
- Interstitial nephritis involves inflammation of the spaces between the renal tubules and may include inflammation of the tubules.
- Signs and tests An examination may reveal edema or fluid overload, or signs of volume depletion, with abnormal sounds heard when listening with a stethoscope (auscultation) to the heart or lungs.
- Most often, interstitial nephritis is an acute but short-term disorder.
Alternative names
Tubulointerstitial nephritis; Nephritis - interstitial; Acute interstitial (allergic) nephritis
Definition
Interstitial nephritis is a kidney disorder caused by inflammation of the tubules and the spaces between the tubules and the glomeruli.
Causes, incidence, and risk factors
Interstitial nephritis involves inflammation of the spaces between the renal tubules and may include inflammation of the tubules. It may be a temporary lesion, most often associated with the effects of various medications on the kidney, or it may be chronic and progressive.
Interstitial nephritis is one of the lesions associated with analgesic nephropathy, and can also occur with allergic reaction to a drug (acute interstitial allergic nephritis) or as a side effect of medications. Medications commonly associated with interstitial nephritis include antibiotics such as penicillin, ampicillin, methicillin, sulfonamide medications, and others. Other medications include nonsteroidal anti inflammatory drugs, furosemide, and thiazide diuretics. The disorder may occur 2 or more weeks after exposure to the medication.
Interstitial nephritis causes reduction in kidney function, ranging from mild dysfunction to acute kidney failure. About one-half of the cases will exhibit decreased urine output and other signs of acute renal failure. The kidney may fail to concentrate the urine when water intake is reduced. The kidney may fail to regulate acid/base levels of the body may be reduced, with failure to excrete acid appropriately in the urine. Metabolic acidosis may occur because of the inability to excrete acid. The disorder may progress to chronic renal failure or end-stage renal disease.
The acute form of interstitial nephritis is common and may account for approximately 15% of cases of acute kidney failure. Risks include exposure to medications that may have nephrotoxic effects. The disorder may be more severe and more likely to lead to chronic or permanent kidney damage in the elderly.
Symptoms
- Increased or decreased urine output
- Fever
- Mental status changes, ranging from drowsiness to confusion to coma
- Nausea, vomiting
- Rash (sometimes)
- Swelling of the body, any area
- Weight gain (from fluid retention)
- Blood in the urine
Signs and tests
An examination may reveal edema or fluid overload, or signs of volume depletion, with abnormal sounds heard when listening with a stethoscope (auscultation) to the heart or lungs. The blood pressure commonly is high.
Written and revised by
Gerald Hurowitz, M.D.
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