Acute glomerulonephritis is an inflammatory disease involving the renal glomeruli of both kidneys. It is thought to involve antigen-antibody reaction which produces damage to the glomerular capillaries.
Chronic glomerulonephritis is a slowly progressive disease characterized by inflammation of the glomeruli, which results in sclerosis, scarring and, eventually, renal failure. This disorder usually develops insidiously and without symptoms, often over many years.
Acute glomerulonephritis usually follows a streptococcal infection of the respiratory tract or, less often, a skin infection such as impetigo. However, most often it is due to an allergic or immune response to infections in other parts of the body.
There are many different kinds of infections that lead to glomerulonephritis, including pneumonia, syphilis, malaria, hepatitis, and measles. If the cause is not treated immediately, or adequately or kept on antibiotics for a long enough period to eliminate the infection, then the disease continues to progress. Chronic glomerulonephritis also may be caused by structural abnormalities or systemic disorders.
If the disease is still present after one to two years, it may be considered chronic. This occurs in a very small percent of patients. Typically, the damage to the kidneys continues to progress, but so slowly that the patient is without symptoms. A normal life may be possible for 20 to 30 years, until the kidneys can no longer function. At that time, a kidney transplant or dialysis is necessary.
Pyelonephritis is an inflammation of one or both kidneys with variable manifestations. It may be acute, relapsing or chronic. The complications of this disorder are hypertension, chronic infection, renal insufficiency and renal failure. The course is extremely variable but typically the chronic disease progresses extremely slowly, with patients having adequate renal function for more than 20 years after onset.
Most cases of this condition are caused by bacterial infection. Infecting bacteria usually are normal intestinal and fecal flora that grow readily in urine. There are certain conditions that increase the likelihood of such an infection which include scars from previous infections, urinary tract infections, abnormal growth of the prostate gland, kidney stones, tumors, stagnation of urine due to backflow from the bladder, diabetes mellitus, trauma and even pregnancy.