MedicineNet defines nephritis as inflammation of the kidney, causing impaired kidney function. The types of nephritis are interstitial nephritis, pyelonephritis and glomerulonephritis, according to Healthline. Common symptoms include pelvic, kidney or abdominal pain; cloudy or bloody urine; painful urination; high blood pressure; and swelling of the face, legs and feet.
Interstitial nephritis is an acute condition in which inflammation of the spaces between kidney tubules causes swelling, explains Healthline. This may be caused by low potassium, an allergic reaction to medication or prolonged use of medication. Pyelonephritis is usually caused by E.coli bacteria, but may also be related to cytoscopic urinary examinations, kidney stones, or bladder, kidney or ureter surgery. It is also acute, and tends to begin in the bladder before travelling upward to the kidneys.
Glomerulonephritis, or GN, occurs in the small capillaries that filter blood inside the kidneys, notes Healthline. It an be either acute or chronic. Acute GN is usually triggered by an infection or an immune system reaction. Chronic GN can be genetic or exposure-related, or due to immune disease.
While some types of nephritis may go away on their own, others may not and should be treated quickly to avoid permanent kidney damage or failure, cautions Healthline.