Definition

Two of the most common kidney disorders due to infections are glomerulonephritis and bacterial pyelo-nephritis (pyelos means pelvis of the kidney + nephro + itis)

Glomerulonephritis

Acute glomerulonephritis is an inflammatory disease involving the renal glomeruli of both kidneys. It is thought to involve antigen-antibody reaction that 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

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.

Causes and Risk Factors

Strep infection is the most common cause of glomerulonephritis. Pyelonephritis can be caused by any of the organisms that cause lower urinary tract infection (e.g., E. coli, klebsiella)

Symptoms

Symptoms and signs of acute glomerulonephritis are often vague and ill-defined. On the other hand, symptoms associated with pyelonephritis are often acute with fever, chills, back ache, and nausea.

Diagnosis

Glomerulonephritis is diagnosed through tests of kidney function and an assessment as to whether protein is being passed in the urine.

Pyelonephritis is diagnosed by means of assessment of the clinical history (fever, chills, back pain) and clinical exam (tenderness over the involved kidney). Definitive evidence is obtained by means of culturing the offending organism from the urine.

Treatment

For glomerulonephritis, treatment consists of antibiotics for any bacterial infection and rest. The treatment may continue for one to two weeks after tests of blood, blood pressure, and the urine indicates that the kidneys are back to normal. Sodium and protein may be restricted.

For pyelonephritis, the most important measures are to eliminate the bacteria with antibiotics given orally or intravenously and to correct any obstruction. When obstruction cannot be eliminated and recurrent infections are common, then long-term antibiotic therapy may be required.

Questions to Ask Your Doctor

• What tests need to be done to diagnose and to determine the cause?
• What type of infection is it?
• What is the cause of the kidney problem?
• How serious is it? What is the prognosis?
• What treatment do you recommend?
• Will any medications be prescribed? What are the side effects?