Kidney Infection (Pyelonephritis)


What happens under normal conditions?

The kidneys function is to remove waste products from your body as urine. Urine travels from the kidneys to the bladder where it is excreted via the urethra. The kidneys in their healthy state are sterile, that is, they are not infected with bacteria. However, bacteria can infect the kidneys, usually by entering the urethra and ascending into the bladder (causing cystitis or urinary tract infection) and from the bladder continuing their ascent into the kidneys.

Cystitis (bladder infection) is very common in females, occurring in 1-3% of adult women per year. Extension of a bladder infection to the kidneys to cause pyelonephritis is less common (about 1 in every 30 cases of urinary tract infection) but more severe. Pyelonephritis risk is increased during pregnancy, with obstruction of the urinary system (from a kidney stone for example), with abnormalities of the urinary system (seen in young girls but also in adults due to diverticula and other abnormalities), with diabetes, and with a weakened immune system.

What are the signs of a kidney infection?

The symptoms of pyelonephritis are pain and tenderness in the flank (the part of the back between the ribs and the hip) with fever, and usually with frequent, urgent and/or painful urination. Nausea and vomiting are common. Much less common are lightheadedness, confusion or loss of consciousness due to sepsis and shock (this can occur if bacteria enter the bloodstream from the kidney).

Because it can be life threatening, it is important for you to seek immediate medical care should you have symptoms that suggest pyelonephritis. Many other problems in the pelvis and abdomen can cause symptoms that mimic pyelonephritis, such as kidney stones or appendicitis.

What are treatment options for pyelonephritis?

Pyelonephritis is treated with antibiotics. In many cases orally administered antibiotics will suffice, but with severe infection, or when someone is not able to tolerate pills because of vomiting, intravenous antibiotics may be required. In order to eradicate the infection and prevent relapse, a prolonged treatment course is required, usually a total of 2 weeks or more of antibiotics. Surgery may be needed if an obstruction in the urinary track is discovered.