Kidney infection, also known as pyelonephritis, can damage kidneys if left untreated. Kidney infections are generally caused by bacteria entering through the urinary tract and traveling up to the kidneys, according to the Mayo Clinic. Kidney infections are more common in women because they have a shorter urethra than men, with less distance for bacteria to travel to the kidneys. Kidney infection symptoms often come on suddenly, according to the Merck Manual.
Back Pain
Kidney infections cause pain on either side of the back, just above the waist. This corresponds to the location of the kidneys. Pain can be felt if the area is tapped, even lightly, and the kidney may be enlarged. Muscles in the area may be very tight, increasing pain, according to the Merck Manual.
Chills and Fever
Fever, accompanied by chills and shivering, are common in pyelonephritis, according to the Merck Manual. Fever often reaches 102 degrees or higher over a 2-day period, according to Linda Vorvick, M.D. of the University of Washington School of Medicine.
Cystitis
According to the Merck Manual, approximately one-third of people with kidney infections also have symptoms of cystitis, with pain on urination and urinary frequency. Blood and white blood cells indicating infection or bacteria may be found in the urine, according to Vorvick. Spasms of the ureters, the tubes that carry urine from the bladder, can also occur, resulting in severe pain known as renal colic, says the Merck Manual.
Other Symptoms
Abdominal pain may be present, along with nausea and vomiting, according to Vorvick. Feelings of being ill with extreme fatigue may also be present. In the elderly, mental confusion might be the only symptom of kidney infection. A life-threatening infection of the blood known as septicemia can develop if kidney infections are not treated promptly and adequately with antibiotics.
