A kidney infection, or pyelonephritis, refers to a urinary tract infection that reaches the kidneys. It causes kidney inflammation and leads to symptoms such as renal colic, foul-smelling urine, fever and pain when urinating.

Kidney infections can be caused by bacteria, such as Escherichia coli (or E. Coli), as well as Candida species fungi or viruses. With chronic kidney infections, in addition to an infection by a microorganism, the presence of lesions along the urinary organs or kidney stones can also cause promote an infection.

A kidney infection should be diagnosed and treated as soon as it is discovered to prevent serious damage to the kidneys or septicemia. This is a condition in which the microorganism reaches the bloodstream and spreads to different areas of the body, causing a systemic, life-threatening infection.

Main symptoms

The main symptoms of a kidney infection are:

Renal colic or cramps;
Severe lower back pain
Difficulty urinating
Urge to urinate frequently and in small quantities
Pain or burning when urinating
Foul-smelling urine
Fever
Chills
Nausea and vomiting

The symptoms of a kidney infection usually appear suddenly and intensely, a disappear within a few days of starting treatment. Infections that are left untreated can cause permanent damage, which can interfere with kidney function and lead to kidney failure.

Confirming a diagnosis

To diagnose a kidney infection, it is important to consult a nephrologist or urologist, who will start by evaluating the presenting symptoms.

The doctor may perform a physical examination, which involves as palpation and percussion of the lower back. He or she may also order a urine test to check for the presence of blood or white blood cells in the urine.

Possible causes

Escherichia coli bacteria are the most common cause of a kidney infections. These bacteria are commonly found in the intestines, and can be transferred from the anal region to the genitals from incorrect wiping, inadequate hygiene or after sex. This bacteria enters the urinary tract through the urethra, which is the canal that transports urine out of the body. The bacteria can then multiply, reach the bladder and go up to the kidneys.

Other bacteria from infections in other parts of the body can also spread through the bloodstream and reach the kidneys, causing a kidney infection. This can occur in people with infections in artificial joints, or in prosthesis or heart valves.

Kidney infections can also be caused by Candida albicans fungus, which are a normal component of normal vaginal bacterial flora. When this flora overgrows, this fungus can multiply, enter the urethra, and travel up to the kidneys.

Additionally, some factors can increase the risk for developing a kidney infection, such as kidney problems, kidney stones, diabetes or a weakened immune system.

Kidney infections in pregnancy

A kidney infection during pregnancy is quite common and is usually the result of a prolonged bladder infection that was either left untreated or treated inadequately.

During pregnancy, increased hormone levels, like progesterone, relax the muscles in the urinary tract and vessels, facilitating the entry of bacteria into the bladder. These bacteria can multiply and cause inflammation. Infections that are not diagnosed or treated effectively will lead to further growth and spread up the urinary tract, until they reach the kidneys and cause further inflammation.

Treatment for kidney infections during pregnancy can be done with antibiotics that are safe for use during pregnancy.

Treatment options

Treatment for kidney infections will depend on the underlying cause of the infection, and whether the infection is acute or chronic. Bacterial infections can be treated with antibiotics, taken for 10 to 14 days. The doctor can also prescribe analgesics or anti-inflammatories to relieve pain.

The best way to treat chronic kidney infections is to eliminate the underlying cause. Some medications for kidney infections, like antibiotics, can also be used to treat chronic kidney infection if there are symptoms of a bacterial infection.

When treating a kidney infection, drinking plenty of water is important to ensure a full cure.