Urinary Tract Infection in Women - Jeanne S. Sheffield, MD, and F. Gary Cunningham, MD
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Clinical Expert Series
Editor’s Note: Continuing medical education credit is available online at
www.greenjournal.org.
Urinary Tract Infection in Women
Jeanne S. Sheffield, MD, and F. Gary Cunningham, MD
Urinary tract bacterial infections are common in women. Moreover, they tend to recur
throughout life and in the same relatively small group of women. In most cases, bladder and
renal infections are asymptomatic and manifest by demonstrating coincidental bacteriuria. In
some instances, however, especially with frequent sexual activity, pregnancy, stone disease, or
diabetes, symptomatic cystitis or pyelonephritis develops and antimicrobial therapy is indicated.
In most cases, cystitis is easily managed with minimal morbidity. When acute pyelonephritis
develops in an otherwise healthy woman, however, consideration for ureteral obstruction is
entertained. If her clinical response to proper therapy is not optimal, then imaging studies are
indicated. Pregnancy is a common cause of obstructive uropathy, and severe renal infections are
relatively common. Because they usually arise from preexisting covert bacteriuria, experts
recommend screening and eradication of these silent infections as a routine prenatal practice.
(Obstet Gynecol 2005;106:1085–92)
U rinary tract infections are among the most com-
mon bacterial infections in women. Every year
in the United States, about 10% of women are diag-
uria. Although cystitis is usually uncomplicated, the
upper urinary tract may become involved by ascend-
ing infection. Pyelonephritis is defined as infection of
nosed with cystitis, and this is associated with direct the renal parenchyma and pelvicaliceal system, and it
costs of $1.6 billion dollars.1 During their lifetime, arises either de novo from asymptomatic renal bacte-
more than half of women will have a urinary infec- riuria or from ascending bladder infection. Renal
tion, and up to 50% of these have another infection infections are more common in the setting of obstruc-
within a year.2 In approximately 3–5% of women, tion from urinary tract malformations, urolithiasis,
there are multiple recurrences over many years.3 and pregnancy-induced changes. Recurrent and
Importantly, urinary infections complicate up to 20% chronic infections with the same organism are usually
of pregnancies and are responsible for 10% of all termed relapses or persistent infections. If infection
antepartum admissions.4 develops after a symptomatic cure, or if it is caused by
In most women, these infections are limited to the a second pathogen, it is termed a reinfection. Acute
lower urinary tract and are manifest by asymptomatic urethritis, caused predominantly by Neisseria gonor-
bacteriuria. Cystitis is the most common symptomatic rhoeae and Chlamydia trachomatis usually occurs con-
comitant with cervicitis. Management of these sexu-
infection and is characterized by dysuria, urgency,
ally transmitted diseases is detailed elsewhere.5
and frequency concomitant with pyuria and bacteri-
From the Department of Obstetrics & Gynecology, University of Texas South-
PATHOPHYSIOLOGY
western Medical Center, Dallas, Texas. Urinary infection in women results from complex
Corresponding author: Jeanne S. Sheffield, MD, Assistant Professor, Department interactions between host and microorganism. Most
of Obstetrics & Gynecology, 5323 Harry Hines Boulevard, University of Texas commonly, infection arises from perineal and periure-
Southwestern Medical Center, Dallas, TX 75390-9032; e-mail:
Jeanne.Sheffield@utsouthwestern.edu.
thral bacteria that gain entrance to the bladder. Such
© 2005 by The American College of Obstetricians and Gynecologists. Published
extension of colonization or infection most probably
by Lippincott Williams & Wilkins. is associated with physiological trauma such as sexual
ISSN: 0029-7844/05 intercourse. It may also follow urethral massage or
VOL. 106, NO. 5, PART 1, NOVEMBER 2005 OBSTETRICS & GYNECOLOGY 1085
catheterization. Ascending infection may then involve also at increased risk, presumably secondary to
the ureters, pyelocaliceal system, and renal paren- changes in the vaginal flora and possibly trauma from
chyma (Fig. 1). Rarely, renal infection may result the diaphragmatic ring. An increased risk of infection
from bacteremia or lymphatic spread. accrues with age, likely due to the hypoestrogenic
state with vaginal mucosal atrophy, impaired voiding,
Host Factors and changes in hygiene. There are other risk factors,
Women are anatomically predisposed to bacterial including medical conditions such as diabetes, obe-
colonization. The external third of the short urethra sity, and sickle cell trait; anatomical congenital abnor-
often is colonized by pathogens from normal vagina malities; urinary tract calculi; and neurological or
flora. Intercourse increases the risk of infection due to anatomical disorders that require indwelling or repet-
meatal trauma, urethral massage, and probably, itive bladder catheterization.
changes in vaginal flora. Women who use a dia- One of the most important risk factors for symp-
phragm with spermicidal agents for contraception are tomatic infection, especially acute pyelonephritis, is
pregnancy-induced physiological changes in the uri-
nary system. Dilation of the ureters and renal calyces
is evident as early as 12 weeks and is thought to be
caused by progesterone-induced relaxation of their
muscular layers. More importantly, as the uterus
enlarges, it begins to compress the ureters at the
pelvic brim, particularly on the right.6,7 Vesicoureteral
reflux may first appear or worsen during gestation in
some women, particularly multiparas. Anatomical
changes in bladder position in late pregnancy also
may render it more susceptible to infection. Finally,
bladder and urethral trauma, periurethral tears, large
vulvar lacerations, and epidural analgesia for labor
and delivery predispose to urinary retention and the
need for catheterization.
Bacterial Factors
Urinary infections in women are caused by a number
of bacterial species, the majority of which are from
normal perineal flora. Specific serogroups of “uro-
pathogenic” Escherichia coli are the most commonly
identified organisms.8 These serogroups have a num-
ber of virulence factors specific for colonization and
invasion of urinary epithelium. Some of these include
adhesins, such as P-fimbria and S-fimbria, which
enhance binding to vaginal and uroepithelial cells
(Fig. 2). These adhesins also bind to erythrocyte
membranes and inhibit serum bactericidal activity by
expression of the dra gene cluster associated with
ampicillin resistance.9 Other E coli serogroups express
an increase in K antigen production which helps
protect the microorganism from leukocyte phagocy-
tosis. Greater adherence of type I fimbriated E coli to
Fig. 1. Routes of infection in the urinary tract. Arrows depict uroepithelial cells in diabetes may be related to
the ascending nature of infection, from the bladder and impaired cytokine secretion and blunted leukocyte
urethra up the ureters to the kidneys. Modified from Amer- response.10 A complete list of identifiable virulence
ican College of Obstetricians and Gynecologists. Urogyne-
factors is beyond the scope of this review.
cology: an illustrated guide for women. Washington, DC:
ACOG; 2004. Illustration: John Yanson. Although the overwhelming majority of urinary
Sheffield. Urinary Tract Infection in Women. Obstet Gynecol infections are caused by strains of E coli, most of the
2005. remainder are caused by Enterobacter, Enterococcus,
1086 Sheffield and Cunningham Urinary Tract Infection in Women OBSTETRICS & GYNECOLOGYpregnant women is usually not recommended. More-
over, there is little evidence that treatment alters the
overall natural history of silent infection. One excep-
tion recommended by The American College of
Obstetricians and Gynecologists (ACOG) in 2003 is
the diabetic woman. During pregnancy asymptomatic
bacteriuria screening and treatment is also recom-
mended. Depending on the population, the incidence
of asymptomatic bacteriuria during pregnancy ranges
from 2% to 7%. Bacteriuria is typically present at the
time of the first prenatal visit, and after an initial negative
urine culture, less than 1% of women develop acute
cystitis.16 If asymptomatic bacteriuria is not treated, a
Fig. 2. Transmission electron microscopy showing fimbri- fourth of these women subsequently develop acute
ated Escherichia coli adhering to a transitional cell pyelonephritis. Thus, ACOG17 recommends routine
(⫻ 180,000, original magnification). Arrows show the pili. screening for bacteriuria at the first prenatal visit, with
Modified from Roberts JA. Pathophysiology of pyelonephri- eradication to prevent serious renal infections during
tis. Infect Surg 1986;Nov:633. pregnancy. There is little evidence that asymptomatic
Sheffield. Urinary Tract Infection in Women. Obstet Gynecol
2005.
bacteriuria has a significant clinical impact on other
significant adverse pregnancy outcomes.18
Treatment for asymptomatic bacteriuria is usually
Proteus mirabilis, and Klebsiella species. These latter empirical, and determination of in vitro susceptibili-
organisms also are associated with structural abnor- ties is not necessary. A number of antimicrobial
malities or renal calculi. Staphylococcus saprophyticus has regimens have proven effective. These are listed in
been isolated from 3% of nonpregnant reproductive- Table 1 with their relative costs. Although it is doubt-
age women with pyelonephritis.11 Gram-positive or- ful that 3-day exposures are harmful to the fetus, some
ganisms, including group B Streptococcus, are increas- recommend against the use of fluoroquinolone deriv-
ingly isolated in certain populations, including atives as first-line treatment because animal and hu-
pregnant women.12 Patients with indwelling catheters man toxicity data interpretation has been controversial.
are also susceptible to fungal infections. Finally anaer- For resistant infection, however, use of these drugs is
obic bacteria and mycoplasmas may play a greater certainly reasonable. We have found that nitrofurantoin
role in urinary infections than previously reported, macrocrystals, 100 mg at bedtime for 10 days, is effec-
although data are limited. tive and has a high compliance rate. Regardless of the
regimen chosen, recurrent asymptomatic bacteriuria is
LOWER URINARY TRACT INFECTIONS identified in at least 30% of women.16 At this point,
Asymptomatic Bacteriuria another regimen from Table 1 is given.
The prevalence of bacteriuria in sexually active
young women is reported to be as high as 5– 6%.13 Acute Cystitis
This prevalence is similar during pregnancy and most Acute bladder infection is often uncomplicated and
women are asymptomatic. Bacteriuria is diagnosed by accompanied by varying degrees of dysuria, fre-
using a clean-voided, midstream urine sample. For quency, and urgency. Patients may also complain of
research purposes, significant bacteriuria is defined as suprapubic pain and fullness. Although acute cystitis
isolation of a single microorganism with at least may irritate the lower uterine segment and incite
100,000 organisms/mL (colony forming units or cfu/ preterm contractions, there is no evidence that it
mL). Although some authors recommend using a causes preterm labor. Diagnosis is based on these
colony count of 10,000/mL or greater to increase the clinical findings and confirmed by urine studies.
sensitivity of the test. However, most use 100,000 Urinary dipstick testing is fast and convenient. A
cfu/mL or greater to be clinically significant and thus finding of either nitrite or leukocyte esterase is con-
require treatment.14,15 sidered a positive result, with a sensitivity of 75% and
specificity of 82%.2,19,20 Urine culture is indicated in a
Treatment symptomatic woman not responding to standard ther-
Because of its propensity for almost inevitable recur- apy who occasionally may have a resistant pathogen.
rence, treatment of asymptomatic bacteriuria in non- The distal urethra and periurethral colonized areas
VOL. 106, NO. 5, PART 1, NOVEMBER 2005 Sheffield and Cunningham Urinary Tract Infection in Women 1087Table 1. Treatment Regimens for Uncomplicated Recurrent Cystitis
Urinary Infections in Women and the Recurrent urinary infections, both symptomatic and
Relative Cost of Each Regimen* asymptomatic, are common in women, occurring in
Treatment Regimen Cost up to 35%. During pregnancy at least, a “test of cure”
Single-dose treatment urine culture is performed 1–2 weeks after completing
Ampicillin, 2 g $ therapy and a different treatment regimen used, if
Amoxicillin, 3 g $ positive. Imaging studies are rarely indicated. Women
Nitrofurantoin, 200 mg $ who have 3 or more symptomatic infections over a
Trimethoprim-sulfamethoxazole, 320/1,600 mg $
12-month period may benefit from continuous pro-
3-Day course
Amoxicillin, 500 mg 3 times daily $ phylaxis. Antibiotics, including nitrofurantoin, cipro-
Ampicillin, 250 mg 4 times daily $ floxacin, trimethoprim, or norfloxacin, have all been
Cephalexin, 250 mg 4 times daily $$$ shown to decrease the recurrence risk by 95% or more
Nitrofurantoin, 50 mg 4 times daily; 100 mg when used in a prophylactic regimen.2 Postcoital pro-
twice daily $$
phylaxis is another option available.
Trimethoprim-sulfamethoxazole, 160/800 mg
twice daily $$ Cranberry or lingonberry juice has been shown
Ciprofloxacin, 250 mg twice daily $$$ in randomized trials to decrease the risk of recurrent
Levofloxacin, 250 mg daily $$$ urinary infections. This is due to the proanthocyani-
Other dins inhibiting attachment of urinary pathogens to the
Nitrofurantoin, 100 mg at bedtime for 7–14 days $$$
epithelium.2 Doses of 200 –750 mL or equivalent
Nitrofurantoin, 100 mg 4 times daily for 7–14 days $$$$
Treatment failures concentrated tablets daily have been found effective.
Nitrofurantoin, 100 mg at bedtime for 21 days $$$$ Other proposed preventive measures, such as wiping
Suppression for bacterial persistence or recurrence techniques, postcoital voiding, douching, and timing
Nitrofurantoin, 100 mg at bedtime for remainder of of voiding, have not been shown to prevent recurrent
pregnancy N/A
infections.2
$ ⱕ $5; $$ ⬎ $5 ⱕ $15; $$$ ⬎ $15 ⱕ $30; $$$$ ⬎ $30.
* Based on generic average wholesale price (Redbook Pharmacy’s
Fundamental Reference37) per regimen when available. ACUTE PYELONEPHRITIS
Modified from Cunningham FG, Leveno KJ, Bloom SL, Hauth JC,
Gilstrap LC, Wenstrom KD. Renal and urinary tract disorders.
Nonpregnant Women
In: Cunningham FG, Leveno KJ, Bloom SL, Hauth JC, Gilstrap Acute pyelonephritis is a clinical syndrome character-
LC, Wenstrom KD, editors. Williams obstetrics, 22nd ed. New ized by flank pain, chills and fever, and variable
York (NY): McGraw-Hill; 2005. p.1095-9. Reproduced with
permission of The McGraw-Hill Companies. symptoms of dysuria, urgency, and frequency. The
diagnosis is verified by demonstrating significant bac-
teriuria. As discussed, despite its high prevalence,
may contaminate a midstream clean-voided urine asymptomatic bacteriuria in nonpregnant women
specimen but with lower colony counts. A urine rarely develops into pyelonephritis, except in diabetic
culture should be obtained by catheterization in prob- women. For nondiabetic women who develop pyelo-
lematic cases. Some cases of persistent lower-tract nephritis, urinary tract abnormalities, urolithiasis, and
symptoms may be due to epithelial infection with other obstructive causes must be considered. By far,
Chlamydia trachomatis.5 the most common risk factor for acute pyelonephritis
is pregnancy.
Treatment
In most cases, uncomplicated bacterial cystitis re- Treatment
sponds quickly to single-dose or 3-day therapy. The Unless there are overt complications, therapy for
3-day regimens shown in Table 1 are effective in at women with acute uncomplicated pyelonephritis is
least 90% of women.2 Recently, it has been recom- usually given as an outpatient. For women who have
mended that -lactams alone not be used to treat overt sepsis or those who are unable to tolerate oral
urinary infections because of increasing resistance antimicrobial agents or fluids, hospitalization and
among the common uropathogens.2 parenteral antibiotics are recommended. The woman
In pregnant women with cystitis, single-dose ther- should be given appropriate intravenous hydration,
apy is not recommended. Any of the 3-day treatment and unless previous antimicrobial sensitivity data are
regimens shown in Table 1 are effective, with the available, antibiotic therapy is empirical. Table 2 lists
same caveats for fluoroquinolone derivatives as dis- common regimens used for the treatment of uncompli-
cussed for asymptomatic bacteriuria above. cated pyelonephritis. Their relative costs are also listed.
1088 Sheffield and Cunningham Urinary Tract Infection in Women OBSTETRICS & GYNECOLOGYTable 2. Intravenous and Oral Regimens for the intravenous pyelography is used to identify an obstruct-
Treatment of Acute Uncomplicated ing stone.22 The renal parenchyma is also visualized with
Pyelonephritis and the Relative Cost per sonography, and pyelonephritis usually causes some
Day of Each Regimen* renal enlargement. Intra- or perirenal abnormalities are
Regimen Cost better assessed with contrast-enhanced computed to-
Outpatient regimens (10–14 days) mography. Parenchymal abnormalities appearing as an
Ciprofloxacin, 500 mg twice daily $ area of sharply demarcated attenuation signifies an
Ciprofloxacin-XR, 1,000 mg once daily $ intrarenal phlegmon, also termed lobar nephronia or focal
Gatifloxacin, 400 mg once daily $ or segmental pyelonephritis (Fig. 3). These areas some-
Levofloxacin, 250 mg once daily $ times suppurate and drainage may be necessary. In
Ofloxacin, 400 mg twice daily $
Amoxicillin-clavulanate, 875/125 mg twice daily $ either case, there is a prolonged hospital course. Finally,
Trimethoprim-sulfamethoxazole DS, 160/800 some women will be found to have a perinephric
mg twice daily $ phlegmon or abscess. The latter is quite serious and
Intravenous regimens drainage is frequently necessary.
Ciprofloxacin, 400 mg every 12 hours $$$
Levofloxacin, 500 mg once daily $$
Pregnancy
Cefepime, 2 g every 8 hours $$$$
Cefotetan, 2 g every 12 hours $$$ Acute pyelonephritis is the most common serious
Ticarcillin-clavulanate, 3.1 g every 6 hours $$$ medical complication of pregnancy.4 From most sur-
Trimethoprim-sulfamethoxazole, 2 mg/kg veys, 1–2% of pregnant women are admitted for this
every 6 hours $$ condition despite prenatal screening and treatment
Ceftriaxone, 1–2 g every 12–24 hours $$$$
Gentamicin, 3–5 mg/kg per day (once daily dosing for bacteriuria. Renal infections may result in signifi-
acceptable) $ cant maternal morbidity and occasional mortality. At
Ampicillin, 2 g every 6 hours – for suspected our institution, 12% of antepartum admissions to the
enterococcus $$ obstetric intensive care unit are for sepsis caused by
Aztreonam, 2 g every 8 hours $$$$ pyelonephritis.24 Acute renal infection is less common
Cefotaxime, 1–2 g every 8 hours $$$
in early pregnancy, except in diabetic women. As
$ ⱕ $20; $$ ⬎ $20 ⱕ $60; $$$ ⬎ $60 ⱕ $100; $$$$ ⬎ $100. many as 80 –90% of cases are reported to occur either
* Based on generic average wholesale price per day when available.
in the latter 2 trimesters or in the puerperium.12 This
observation is related to the increasing urinary tract
After urine is obtained for culture, one of the
regimens listed in Table 2 should be started. These
febrile women usually are quite dehydrated; there-
fore, they should receive intravenous crystalloid solu-
tions as well as a dose of parenteral antimicrobials
before discharge if outpatient management is
planned. In a recent study of 242 nonpregnant
women aged 18 – 49 years with acute pyelonephritis,
Scholes et al11 reported that only 7% required hospi-
talization. When patients are admitted, any of the
intravenous agents listed in Table 2 can be given.
When the organism susceptibility data becomes avail-
able, therapy is altered as needed. A 10-day course of
treatment is recommended.2,21
Clinical response should occur within 48 –72
hours of starting therapy. If no improvement is noted
or if the patient status worsens, aggressive investiga-
tion for complications of renal infection or urinary
obstruction should be undertaken. Renal ultrasonog-
Fig. 3. Abdominal computed-tomographic scan with contrast
raphy is the best noninvasive method to evaluate for
depicting lobar nephronia. The wedge-shaped nonenhanced
obstruction within the renal collecting system. The area within the left kidney is indicated by arrowheads.
most common cause of obstruction is stones. In many Sheffield. Urinary Tract Infection in Women. Obstet Gynecol
cases, calculi are not seen with ultrasonography, and 2005.
VOL. 106, NO. 5, PART 1, NOVEMBER 2005 Sheffield and Cunningham Urinary Tract Infection in Women 1089obstruction with stasis caused by progesterone and
uterine enlargement.
Clinical findings are similar to those for nonpreg-
nant women. In over half of cases, pyelonephritis is
unilateral and right-sided, and it is left-sided or bilat-
eral in another 25% each. The right-sided predomi-
nance may be from obstruction due to uterine dex-
trorotation, protection from obstruction provided on
the left by the descending colon, or both. Onset of
illness usually is abrupt, with fever, chills, and aching
pain in one or both lumbar regions. There frequently
is anorexia, nausea, and vomiting, which worsen
dehydration resulting from fever. Tenderness usually
can be elicited by percussion in one or both costover-
tebral angles, and urinalysis discloses bacteriuria that
is confirmed by culture. As many as 20% of these
women will have bacteremia. E coli is by far the most
common pathogen identified, but gram-positive or-
ganisms, including group B Streptococcus, account for
about 10% of cases of acute pyelonephritis at our
institution.12
About 1 in 5 pregnant women with pyelonephri- Fig. 4. Pregnant woman at 28 weeks of gestation admitted
for severe pyelonephritis, sepsis syndrome, and preterm
tis will develop evidence of multiple-system derange- labor. Within 24 hours of delivering a liveborn infant, she
ment from endotoxemia and sepsis syndrome.12,19,25–29 developed purpura fulminans and was transferred to the
These disorders result from endothelial activation that burn intensive care unit. She sloughed 90% of her skin and
is followed by capillary fluid extravasation with dimin- died from dermal septicemia.
ished perfusion. These vascular changes aggravate the Sheffield. Urinary Tract Infection in Women. Obstet Gynecol 2005.
dehydration from nausea, vomiting, and fever, and
resultant hypotension is common. Fortunately, most worst form, pulmonary injury causes severe acute
women respond to rapid fluid resuscitation with intra- respiratory distress syndrome as shown in Figure 5.
venous crystalloid solutions, and cardiac output is re- Most women with pulmonary capillary injury will
stored without the use of vasopressor drugs.
There are a number of sepsis-related derange-
ments that are commonly reported. With early and
aggressive fluid resuscitation, only about 5% of
women have seriously diminished renal function.12
Before the concept of aggressive hydration, however,
this number was 20%.25,26 Although transient, renal
dysfunction is important to recognize so that nephro-
toxic drugs can be avoided. Anemia is common, and
up to a fourth of women have a hematocrit drop to
less than 30 volumes percent. In severe cases, the
hematocrit falls as low as 20 volumes percent. Hemo-
lysis is caused by the lipopolysaccharide in endotoxin
and is associated with deranged erythrocyte morphol-
ogy and elevated serum L-lactate dehydrogenase lev-
els.27 With severe sepsis, activation of coagulation is
common with potentially serious complications (Fig. 4).
The most common serious manifestation of sepsis
Fig. 5. A semi-upright anteroposterior chest radiograph
syndrome is acute respiratory insufficiency, which demonstrating diffuse bilateral parenchymal infiltrates and
develops to varied degrees in up to 10% of pregnant pleural effusions consistent with acute respiratory distress
women.12 Endotoxin injures endothelium and alters syndrome (courtesy of Dr. Diane Twickler).
alveolar capillary membrane permeability. In its Sheffield. Urinary Tract Infection in Women. Obstet Gynecol 2005.
1090 Sheffield and Cunningham Urinary Tract Infection in Women OBSTETRICS & GYNECOLOGYrespond to increased oxygen delivered by face mask itoring with pulse oximetry should be performed. The
and a 10- to 20-mg dose of furosemide given intrave- diagnosis of pyelonephritis is confirmed promptly
nously. In severe cases, intubation and mechanical and intravenous antimicrobials are begun. Blood cul-
ventilation may be lifesaving. Some women require tures have been shown to have limited utility in
100% oxygen by nonrebreathing mask or by nasal management.33 Urinary output, blood pressure, and
continuous positive airway pressure. In some of these temperature are monitored closely. High fever can be
women, tracheal intubation and mechanical ventila- lowered with a cooling blanket or acetaminophen.
tion is necessary to maintain oxygenation.28 This is especially important in early pregnancy be-
Uterine activity stimulated by endotoxin is com- cause of possible teratogenic effects of hyperthermia.
monly seen. Millar et al30 reported that women had an Outpatient management of pyelonephritis in
average of 5.1 contractions per hour when admitted pregnancy is an option in those women able to
for pyelonephritis. This number decreased to 2.0 per
tolerate oral intake with no evidence of sepsis, serious
hour by 6 hours. Even so, preterm labor is not
underlying medical illness, respiratory insufficiency,
common. When it is identified, care must be taken
known renal or urologic disorders, or preterm la-
with tocolysis. -agonist therapy increases the likeli-
bor.34,35 Table 2 lists common outpatient regimens
hood of respiratory insufficiency from alveolar flood-
ing because of its sodium and fluid retaining proper- available.
ties.31 In the study by Towers et al,32 the incidence of A number of antimicrobial regimens that may be
pulmonary edema was 8% in women with pyelone- used are detailed in Table 2. We initially give ampi-
phritis who were given -agonists. Because of this, cillin plus gentamicin. In general, women will re-
magnesium sulfate is often used preferentially. spond to therapy within 48 hours. For nonresponders,
a search for obstruction or complicated infections is
done as outlined above for nonpregnant women.
Treatment
Once afebrile, women can be discharged to complete
Pregnant women with acute antepartum pyelonephri-
a 10-day course of therapy.
tis should initially be assessed in the hospital (see box,
Recurrent bacteriuria develops in 30 – 40% of
‘‘Management of the Hospitalized Pregnant Women
women after completion of therapy, and if untreated,
With Acute Pyelonephritis’’). During this time, hydra-
one fourth develop recurrent pyelonephritis.29 We
tion is paramount while laboratory studies and further
clinical evaluation are done. Women who cannot recommend nitrofurantoin suppression, 100 mg at
tolerate oral medications are hospitalized as are bedtime, for the remainder of pregnancy to reduce
women who appear very ill. Vigorous crystalloid the likelihood of recurrent infection.36 In our hospital,
infusion to ensure adequate urinary output is a main- 3% of women develop recurrent pyelonephritis during
stay of treatment. Because pulmonary edema is a risk the same pregnancy, and in almost every case, they
of aggressive hydration in these women, careful mon- were noncompliant with the suppression regimen.12
Management of the Hospitalized Pregnant Women With Acute Pyelonephritis
1. Hospitalization
2. Urine studies
3. Hemogram, serum creatinine, and electrolytes
4. Monitor vital signs frequently, including urinary output; consider indwelling catheter
5. Intravenous crystalloid to establish urinary output 50 mL/hr
6. Intravenous antimicrobial therapy
7. Chest radiograph if there is dyspnea or tachypnea
8. Repeat hematology and chemistry studies at 48 hours if clinically relevant
9. Change antimicrobials if necessary when sensitivity results are available
10. Discharge when afebrile for 24 hours; administer antimicrobials 10 days total therapy
11. Urine studies 1–2 weeks after therapy completed to ‘‘test for cure’’
Modified from Lucas MJ, Cunningham FG. Urinary tract infections complicating pregnancy. In: Williams obstetrics. 19th ed. (suppl 5). Norwalk (CT):
Appleton& Lange; 1994. Reproduced with permission of The McGraw-Hill Companies.
VOL. 106, NO. 5, PART 1, NOVEMBER 2005 Sheffield and Cunningham Urinary Tract Infection in Women 1091REFERENCES Williams obstetrics. 22nd ed. New York (NY): McGraw-Hill
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