What is pyelonephritis? Pyelonephritis is a kidney infection. It is usually bacterial in origin and stems from an infection in another part of the urinary tract, such as the bladder. Pyelonephritis can occur in anyone, although it is more likely to occur in women. Symptoms of pyelonephritis include pain or burning during urination, an urgent need to urinate, fever, nausea with or without vomiting, hematuria (blood in the urine), and pain, particularly in the sides and groin. Left untreated, pyelonephritis can lead to further kidney infections, scarring, chronic kidney disease, or permanent damage. Serious infections can spread to other parts of the body, including the blood (sepsis). Pyelonephritis is easily diagnosed with a physical examination and urine tests. In cases of bacterial infection, pyelonephritis can be treated with antibiotics. For mild pain with pyelonephritis, home remedies, including heating pads, may be helpful. Fluid therapy and pain medications may also be administered as needed. Any permanent damage caused by pyelonephritis may require surgery. Preventing urinary tract infections may be the best way to prevent pyelonephritis. Good personal hygiene is critical in preventing urinary tract infections. Seek immediate medical care (call 911) for serious symptoms of pyelonephritis, such as a high fever (higher than 101 degrees Fahrenheit), fainting or change in level of consciousness, severe or uncontrolled pain, or persistent vomiting. Seek prompt medical care for painful or persistent symptoms of pyelonephritis, such as painful or frequent urination.