Acute Pyelonephritis

What is acute pyelonephritis?

Acute pyelonephritis is an infection of the kidneys. This condition is often caused by bacteria traveling upwards from the bladder to the kidneys. Pyelonephritis affects women more frequently than men. Common symptoms include back or belly pain, fever, nausea and vomiting. Pyelonephritis is treated with antibiotics and pain relief. With treatment, most people recover well from this condition.


This condition is often caused by bacteria traveling upwards from the bladder to the kidneys. This condition affects women more commonly than men. It can affect people of all ages, though most often affects women between 15 and 30, as well as infants and older people. Some medical conditions that block the flow of urine through the kidneys or bladder increase the risk of urinary tract infections (for example, prostate enlargement or kidney stones). Other risk factors include a weakened immune system, pregnancy, the use of urinary catheters (medical tubes that drain urine from the bladder) and diabetes.


Typical symptoms include fever, chills, back or belly pain, nausea and vomiting. Other symptoms include a loss of appetite, passing urine frequently, blood in the urine, and an unusual smell to the urine.


Diagnosis is based on the symptoms, physical examination and by testing the urine. A dipstick test often shows pus and blood in the urine. Urine is also being tested in order to identify the specific bacteria causing the infection.


Pyelonephritis is treated with antibiotics. Simple pain-relieving medications (paracetamol, ibuprofen) are helpful in reducing pain. Drinking plenty of fluids can help flush bacteria from the kidneys and bladder. In severe cases, it might be necessary to receive intravenous antibiotics (through a drip) or have a surgical procedure to drain pus from around the kidneys.


Receiving treatment for cystitis (bladder infections) may help prevent some cases of pyelonephritis. Avoiding contraceptives that use spermicide might also be helpful. In people who suffer recurrent pyelonephritis, long-term antibiotics may help prevent new episodes.

Other names for acute pyelonephritis

  • kidney infection