Pyelonephritis and pregnancy

Definition
Acute pyelonephritis is an infection of the kidney(s). It's one of the most serious infections that can develop during pregnancy. Affecting up to 2 percent of all pregnant women, acute pyelonephritis poses serious risks to mother and baby.

Causes/associated factors
Acute pyelonephritis is typically caused by an untreated urinary tract infection that progresses to the kidney(s). Most urinary tract infections begin in the urethra, the tube leading from the outside of the body to the bladder. From there, the infection can move to the bladder. If left untreated, the infection can move up the ureters (the tubes joining the kidneys to the bladder) and finally reach the kidney(s). Women are 14 times more likely to develop urinary tract infections than men. The risk does not increase during pregnancy. However, there is a greater risk during pregnancy that the infection will reach the kidney(s) and develop into pyelonephritis. The hormonal and structural changes that take place during pregnancy may make it easier for bacteria to travel to the kidney(s).
Pylenophretis may be related to asymptomatic bacteruria, a condition in which bacteria multiply in the urine without the typical symptoms of an infection. From 2 to 7 percent of pregnant women have asymptomatic bacteruria, and up to 25 percent of these women will develop acute pyelonephritis if the infection is left untreated.

Rarely, acute pyelonephritis is caused by bacteria that reach the kidney(s) through the bloodstream. Although many different organisms may be to blame, the most common is Escherichia coli (E. coli, a bacterium normally found in the bowel movements of healthy people).

Acute pyelonephritis is most common during the last half of pregnancy and may increase the risk of premature labor. It develops more often in the right kidney, but it may occur in the left kidney and sometimes in both kidneys at the same time.


Signs/symptoms
The symptoms of acute pyelonephritis typically develop rapidly and may include:
fever as high as 104°F or more
shaking chills
low body temperature of 96°F or less
dull middle back pain or side pain on one or both sides
appetite loss
nausea and vomiting
general feeling of discomfort
If symptoms of a bladder infection are present, they may include:

pain or burning during urination
urgent need to urinate
frequent urination

Diagnosis
If acute pyelonephritis is suspected, you'll need immediate blood and urine tests. A complete blood cell count will help verify the presence of infection, and blood and urine cultures may identify the offending organism. Additional diagnostic tests may be needed, especially if you have other medical conditions, such as diabetes or kidney disease.

Treatment
Hospitalization is typically necessary to treat acute pyelonephritis during pregnancy. Initially, antibiotics safe for use during pregnancy are given intravenously (into a vein). The choice of antibiotic depends on your medical history and the results of the urine culture. The doctor will closely monitor the functioning of your kidneys and make sure you're getting enough fluids.
When you no longer have a fever, you may be able to switch to oral (taken by mouth) antibiotics. After 24 hours without a fever, you may be able to return home. At home, you'll probably need to take the antibiotics for seven to 10 days or more. To prevent complications and incomplete healing, it's important to complete the full course of antibiotics.

One to two weeks after treatment is complete, you'll need a follow-up exam and urine culture to evaluate the effectiveness of the medication. Up to 40 percent of women with acute pyelonephritis have recurrent infections after treatment, which may require longer courses of antibiotic treatment.


Complications
Acute pyelonephritis may increase the risk of premature birth. For the mother, possible complications of acute pyelonephritis may include:
kidney damage or abscess (collection of pus)
sepsis (blood infection)
shock
obstruction of the urinary tract with kidney stones
lung damage leading to breathing difficulties
anemia (a condition marked by a decreased number of red blood cells or hemoglobin, a protein in red blood cells that contains iron)
In extreme cases, acute pyelonephritis can be fatal for the mother.


Prevention
During pregnancy, treating urinary tract infections that have no symptoms (asymptomatic bacteruria) reduces the risk of developing pyelonephritis. On your first prenatal visit, you'll be screened for the presence of bacteria in your urine. If infection is suspected, your urine will be examined in the lab for any signs of infection. At subsequent prenatal visits, your urine samples will be examined again if there's any question about a urinary tract infection. If you're at high risk for urinary tract infections (you have a history of urinary tract infections, sickle cell disease, diabetes or kidney stones), a urinalysis or lab study may be done at each prenatal visit.
At home, drink plenty of water or clear fruit juice every day. Urinate when you feel the urge, and wipe from front to back after urination or a bowel movement. Wash the area between your vagina and anus every day, as well as before and after sex. Also, be sure to urinate after sex. Avoid using feminine hygiene sprays, scented soaps or other products near your vaginal area, and wear cotton underwear and hosiery with cotton crotches.