Pyelonephritis---the medical term used to describe an infection within the kidneys---occurs when pathogenic bacteria invade the kidneys. This infection is most frequently caused by an untreated bladder infection (urinary tract infection) in which the bacteria from the bladder flow up into the kidneys. Contact your doctor immediately if you develop any of the symptoms of a kidney infection, as complications resulting from this infection can be life-threatening.
Increased Urination
In healthy humans, the kidneys remove waste from the body, which is excreted in the form of urine. If you have bacteria within your kidneys, your body will attempt to flush this infection out of your body through your urine. This can cause you to experience increased urinary urgency or frequency if you have a kidney infection. You can develop the sensation that you need to urinate immediately after emptying your bladder, explain health professionals at the Better Health Channel, an Australian health information website.
Pain while Urinating
Increased urination due to a kidney infection is often accompanied by painful sensations experienced while urinating. You might notice a burning sensation in your genital region when you urinate, which can be unpleasant, explains the National Kidney and Urologic Diseases Information Clearinghouse.
Back Pain
The kidneys are located on either side of your back immediately beneath your ribcage. A bacterial infection of the kidneys can cause these organs to become irritated or inflamed. If this occurs, you can experience dull, achy pain within your lower back. Depending upon the severity of this infection, painful symptoms may spread around the sides of your body and into your abdominal or pubic region. You can notice that back pain symptoms are sharper and more severe if your doctor pushes into your back muscles near the site of your kidneys.
Flu-like Symptoms
An infection of the kidneys can lead to the development of flu-like symptoms. You can experience a fever, which may be accompanied by nausea or vomiting. Your body's immune system increases your body temperature (fever) to prevent bacteria from multiplying and spreading throughout your body. Additional symptoms of a kidney infection can include chills and body aches.
Blood in the Urine
Bacteria within the kidneys can cause you to excrete small amounts of blood within your urine (hematuria). Such symptoms can cause your urine to appear pink or orange in color. When you have an infection, the immune system sends specific immune cells (white blood cells) to the site of infection to help kill off the pathogenic invader. If you have a kidney infection, you can excrete these white blood cells within your urine, causing it to appear cloudy. A severe kidney infection can also lead to the excretion of pus (yellowish discharge) within your urine.
