Kidney Infection During Pregnancy
Pyelonephritis Signs And Treatment

Pregnancy Complications


Kidney Infection In Pregnancy


What Is Pyelonephritis?
What Causes It?
What Are The Symptoms?
How Is It Diagnosed?
How Is It Treated?
What Is The Outlook After Treatment?

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Pregnancy Complications
What Is Pyelonephritis?

The medical term for a kidney infection is pyelonephritis. Acute pyelonephritis has long been known as a common complication of pregnancy, but it is only relatively recently that it has been recognized as a potentially dangerous disease which, if it persists and becomes chronic, may progress to cause hypertension and ultimately kidney (renal) failure. A gynecologist is in the best position to prevent this, not only by giving effective treatment during pregnancy, but also by securing proper follow-up care.

What Causes It?

Diagram of the human body: Acute pyelonephritis in pregnancy is sometimes just an episode in a long-standing disease process, which began in childhood or even during early infancy. Repeated attacks of urinary tract infections may occur throughout childhood, and often there is an exacerbation with the beginning of sexual activity and during pregnancy. Infection in childhood may produce renal scarring with irregular narrowing of the renal cortex (the outer part of the kidneys). The infecting organisms, usually coliforms (common type of bacteria), probably invade the bladder from the urethra and spread into the upper urinary tract.

What Are The Symptoms?

Acute Pyelonephritis
Acute is a medical term to describe sudden. The symptoms occur suddenly.
• The woman, usually more than 16 weeks pregnant, is suddenly seized with an acute attack of abdominal pain which is felt one or both sides.
• In 50 per cent of cases the infection is confined to the right side and in 16 per cent to the left; in 34 per cent of cases both kidneys are involved. The temperature rises suddenly to levels such as 39.5°C.
• Pulse rate is rapid and often remains at about 120 per minute for several days.
• The patient may looks pale and vomits repeatedly. There is tenderness over the affected kidney.
• In severe untreated cases the volume of urine is reduced and it contains pus and debris.
• Severe chills (medically termed rigors).

Subacute Pyelonephritis
Terminology: Subacute means the disease has not come on suddenly but rather gradually.
In this form the symptoms are not so characteristic. There may be a gradual onset of feeling unwell and increasing lower back pain, vomiting, or symptoms suggesting pleurisy and pneumonia. The temperature is slightly raised and irregular; the kidney may be tender and feel enlarged. The attack in some cases is extremely mild; there may be pain but no other symptom, or the patient may have severe chills without any apparent cause.

Related Articles
Fever in pregnancy: Other causes of high temperature and chills.

How Is It Diagnosed?

A diagnosis is usually made on the presence of a raised temperature and tenderness in the kidney area. It is confirmed by examination of a midstream specimen of urine. Part of the specimen is sent to the laboratory for bacteriological examination. The rest of the specimen may be examined by the doctor immediately under the microscope for pus cells. The discovery of pus cells is enough for a preliminary diagnosis and will permit treatment to be begun while the laboratory report is awaited.

Other conditions that can cause acute abdominal pain during pregnancy include:
• Appendicitis.
• Twisting ovarian cyst
• Degeneration of uterine fibroid.
• Concealed hemorrhage from placenta abruption.

The onset of pyelonephritis may sometimes be very acute with vomiting and possibly tenderness in the tummy so that the clinical picture may closely resemble that of appendicitis. However, in acute pyelonephritis the temperature is often higher (39°C or more) than is seen in appendicitis and chills often occur, these are rare in appendicitis. Bad breath does not usually occur and the tongue is cleaner than in appendicitis. If the urine is properly examined a mistake is unlikely. In cases of torsion of an ovarian cyst or of degeneration of a uterine fibroid a tender swelling can usually be felt. In placenta abruption it is the uterus which is tender, there is often at least a little vaginal bleeding and the fetal heart may not be heard. Cases of pneumonia or pleurisy occasionally give rise to diagnostic difficulty. In all cases the chest should be properly examined. Epidemic myalgia affecting the diaphragm (Bornholm disease, a viral infection which attacks the chest) may also cause confusion, but in all these conditions the urine does not contain pus cells. Vomiting may be the predominating presenting symptom in cases of pyelonephritis - even dysuria (pain when urinating) may be not be present. In any case of vomiting in pregnancy after the first trimester the urine should be examined for pus cells.

How Is It Treated?

The patient is confined to bed for rest and pain relief. If one kidney is mainly affected she will obtain more relief if she lies on the unaffected side, with the knees flexed to relax the abdominal muscles. As soon as a specimen of urine has been obtained for bacteriological examination treatment is started with antibiotics (ampicillin), 500 mg every 6 hours. When the bacteriological report is available it may justify continuation of treatment with ampicillin; otherwise some other appropriate drug is chosen. If the correct antibacterial drug is given in adequate doses an improvement of symptoms is to be expected within 2 or 3 days, but treatment must be continued for at least 3 days after the fever and symptoms have subsided, and checked by repeated urinary cultures.

The doctor may also advise drinking extra fluids. A large intake of fluids will increase urinary flow and therefore reduce the time during which organisms can multiply in the urine, but at the same time it will dilute any antibiotic in the urine. On balance, the advantage of an increasing urinary flow outweighs the disadvantage of diluting the antibiotic. If vomiting is severe, intravenous fluids may be needed.

What Is The Outlook After Treatment?

Follow-up after delivery

It is important that recurrent or persistent pyelonephritis should be treated effectively. In any suspicious case, and indeed in any patient who has had pyelonephritis during pregnancy, the urine should be examined repeatedly for pus cells and organisms. If these are found an intravenous pyelogram should be carried out after the pregnancy. In reality kidney damage is seldom be found until the disease has been present for some years. If excretion of pus cells or bacilli continues, even intermittently, every attempt must be made to give adequate treatment with antibiotics or long-acting sulphonamides.

And For Baby...

If severe pyelonephritis with high fever is untreated miscarriage or intrauterine fetal death may occur. With less severe infection, and even in cases of asymptomatic bacteriuria, there may be birth defects or premature labor, so that the risk of mortality is increased. It is believed that effective treatment will prevent this.


If women are examined early in pregnancy about 6 per cent of them will be found to have significant bacteriuria in two or more separate fresh midstream specimens of urine. A significant level is considered as more than 105 organisms per ml in a midstream specimen. A few of the patients with bacteriuria have had evident infection in childhood, with recurrent clinical attacks, but in many the time of invasion of the upper urinary tract is unknown and the bacteriuria is completely asymptomatic. However, if asymptomatic cases are investigated by intravenous pyelography (IVP, a radiological procedure used to visualize abnormalities of the urinary system), many of the patients are found to have renal abnormalities such as chronic pyelonephritis or congenital malformations (a defect of the kidney which they were born with).

Women who are found to have bacteriuria are far more likely than others to develop acute pyelonephritis during pregnancy. If the bacteriuria responds to treatment during pregnancy the risk of acute pyelonephritis is largely prevented, but if the patients are not treated or if there is no response to treatments the incidence of pyelonephritis during pregnancy is as high as 30 per cent.

These facts show that all prenatal patients should be screened for bacteriuria, and those who have bacteriuria should be treated in an attempt to eradicate it. However, this will not eliminate all acute urinary infections in pregnant women because some attacks occur in patients who have no bacteriuria.

  Related Articles on Kidney Infections

For more conditions, see the following:

Digestive problems in pregnancy: Appendicitis to teeth!
Placenta insufficiency: Physical problems with the placenta.
Ovarian tumors in pregnancy: Signs and treatment.

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