Pyelonephritis refers to an infection of the kidney and the entire urinary tract and requires treatment with antibiotics. It is usually clinically diagnosed using urinalysis (UA) and urine cultures combined with signs and symptoms. A CT scan will also show changes of pyelonephritis. Most commonly, it is caused by the same bacteria that cause bladder infections (cystitis), but does usually require IV antibiotics as it can be a very serious infection.

Glomerulonephritis, on the other hand, refers to an entire spectrum of diseases, most of which are caused by the immune system and are characterized by inflammation of the glomerulus of the kidney. The UA will provide information indicating a glomerulonephritis, but a kidney biopsy is sometimes required to make the specific diagnosis. Some glomerulonephritides are self-limiting, while others require immune suppression therapy.