interstitial nephritis, inflammation of the interstitial tissue of the kidney, including the tubules. The condition may be acute or chronic. Acute interstitial nephritis is an immunological adverse reaction to certain drugs, often sulfonamide or methicillin (allergic interstitial nephritis). Acute renal failure, fever, rash, and proteinuria are characteristic of this condition. Most people regain normal kidney function when the offending drug is discontinued. Chronic interstitial nephritis is a syndrome of interstitial inflammation and structural changes, sometimes associated with such conditions as ureteral obstruction, pyelonephritis, exposure of the kidney to a toxin, rejection of a transplant, and certain systemic diseases. Gradually renal failure, nausea, vomiting, weight loss, fatigue, and anemia develop. Acidosis and hyperkalemia may follow. The nurse watches carefully for signs of electrolyte imbalance, dehydration, and hypovolemia, especially if there is frequent vomiting. Fluids and electrolytes may be replaced intravenously. Treatment includes correction of the underlying cause. If the cause is an obstruction of the urinary tract, rapid recovery may follow removal of the obstruction. In other cases, hemodialysis and kidney transplantation may be necessary.
