The most common urinary tract infections (UTIs) affect the bladder and the urethra, through which urine is expelled out of the body. When the kidneys become infected, the condition is known as pyelonephritis, and symptoms and prognosis can be more serious. Kidney infection sometimes results when a UTI is not completely cured with antibiotics, but it may have a different cause. Anyone experiencing these common symptoms should contact a health-care practitioner.
Increased Urge to Urinate
As with a lower UTI, individuals who have a kidney infection or upper UTI often experience an increase in the need to urinate. They may need to do so more frequently, and the need may feel more urgent. Often, despite the urgency, very little fluid actually comes out.
Burning During Urination
A burning sensation or feeling of pain often occurs during urination when the kidneys are infected, similar to the sensation one has when one has a bladder infection. A patient may also experience general pain in the groin area at times other than during elimination.
Back or Side Pain
Pain in the back or sides, sometimes referred to as "flank pain," can also signal the presence of infection in the kidneys. The kidneys are located in the middle of the back below the ribcage, but it can be difficult to localize the sensation, and a physician's examination is needed to determine the source of the back pain and assess whether the kidneys are involved.
Fever and Chills
Other symptoms of kidney infection may include fever, chills or both. According to MedlinePlus, a project of the National Institutes of Health (NIH), such symptoms typically last at least two days, and the fever may exceed 102 degrees Fahrenheit.
Nausea or Vomiting
Individuals with a kidney infection may become nauseous or actually vomit, and these symptoms can develop quite rapidly. The Mayo Clinic advises individuals experiencing nausea or vomiting along with bloody urine and lower UTI symptoms to seek immediate medical attention.
Bloody or Cloudy Urine
According to the MedlinePlus, urine can be bloody or cloudy, can have a strong unpleasant smell, and may be of unusual color. A physician may test a urine sample for the presence of bacteria, pus or blood.
