Nephritis is an inflammation of the kidneys, which can affect their ability to filter waste from the blood. This condition can be caused by infections, autoimmune diseases, or exposure to certain drugs and toxins. Symptoms may include swelling, high blood pressure, and changes in urine output. There are different types of nephritis, including glomerulonephritis and interstitial nephritis. Diagnosis typically involves blood tests, urine tests, and imaging studies. Treatment depends on the underlying cause and may include medications, lifestyle changes, or, in severe cases, dialysis or kidney transplant.