Nephritis is inflammation of the kidney. The word comes from the Greek nephro- meaning "of the kidney" and -itis meaning "inflammation". Nephritis is often caused by infections, toxins, and auto-immune diseases.
Subtypes
glomerulonephritis is inflammation of the glomeruli. (Often when the term "nephritis" is used without qualification, this is the condition meant.)
Nephritis is the most common cause of glomerular injury. It is a disturbance of the glomerular structure with inflammatory cell proliferation. This can lead to: reduced glomerular blood flow leading to reduced urine output (oliguria) & retention of waste products (uremia). As a result, there can also be leakage of red blood cells from damaged glomerulus (hematuria). Low renal blood flow activates the renin-angiotensin-aldosterone system (RAAS), which therefore causes fluid retention and mild hypertension.