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Beyond UTI: Infections in Pregnant Women

Isaacs, Lawrence MD

doi: 10.1097/01.EEM.0000357585.39438.45
Id Rounds

Dr. Isaacs is a clinical assistant professor of emergency medicine at the Temple University School of Medicine and the director of the emergency department at Virtua Hospital-Voorhees Division in Voorhees, NJ.



For most of us, not a shift goes by without seeing at least one pregnant woman. Although the issue is usually bleeding in the first trimester, we should all be familiar with the sometimes serious infections in pregnancy. Because most of us do not see patients late in pregnancy, I'll skip the infections, such as chorioamnionitis, usually found in the third trimester.

Urinary tract infections (UTI) are common during pregnancy, occurring in as many as 15 percent of pregnant women. The reasons for this are well documented; most are related to the normal physiologic changes that occur during pregnancy. Untreated UTIs confer risk to the pregnancy, including leading to pyelonephritis in 20 to 40 percent of untreated UTIs. (Obstet Gynecol Clin North Am 2001;28[3]:581.) Traditional teaching, a result of early studies on the subject, is that pyelonephritis leads to congenital abnormalities, premature rupture of the membranes, ARDS, and low birth weight, with a more recent study confirming an increased risk of lower birth weight. (Am J Obstet Gynecol 1981;141[6]:709.) The microbiology of UTI and pyelonephritis is similar in nonpregnant women, with E. coli being the most common organism found. The less common organisms include Enterobacter, Staphylococcus, and group B Streptococcus.

Treatment for a lower-tract UTI (cystitis) in pregnant women is antibiotics, deemed safe in the first trimester for three or seven days. Just as in nonpregnant women, a three-day course of certain antibiotics (amoxicillin, nitrofurantoin and TMP/SMX) is recommended, with cure rates similar to seven-day regimens. A special note concerning asymptomatic bacteriuria (ASB) in pregnancy: ASB is defined as bacteriuria (culture with >105 cfu/ml) without symptoms of cystitis. If untreated, 20 to 40 percent of pregnant woman with ASB will progress to pyelonephritis. (Urol Clin North Am 2007;34[1]:35.) Most feel that a urine culture is the gold standard, and that all urine samples from pregnant women also should be cultured. The treatment duration and choices are similar to that of a lower-tract UTI.

Although most of the literature states that any pregnant woman with pyelonephritis should be admitted, there is some evidence that certain women with pyelonephritis can be managed as outpatients. One study sets the criteria for outpatient management of pregnant patients with pyelonephritis as the ability to tolerate oral medications, no signs or symptoms of sepsis, no evidence of organ dysfunction (ARDS, hemolysis), and reliable follow-up. (Obstet Gynecol Clin North Am 2001:28[3]:581.)

Most texts and guidelines, however, still recommend admission. I personally have sent home several reliable pregnant patients with pyelonephritis with no bad outcomes (as far as I know). The microbiology of pyelonephritis mirrors lower-tract infections, and the treatment recommendations are ampicillin and gentamicin or cephalosporin (any generation). I use ceftriaxone, especially for outpatients, given its once-a-day dosing, although the obstetricians seem to like cefazolin.

Endometritis is defined as a generalized uterine infection. It is the most frequent cause of infections in the puerperal period (up to six weeks postpartum). It is much more commonly seen in post-Cesarean patients compared with vaginal delivery. Other risk factors for developing endometritis are prolonged labor, prolonged rupture of membranes, increased frequency of vaginal examinations, and use of internal fetal monitoring. (Emerg Med Clin North Am 2008;26[2]:345.)

The pathogenesis is usually a polymicrobial infection (gram-positive and gram-negative aerobes and anaerobes) ascending from the genital tract. The classic signs and symptoms of endometritis are fever, lower abdominal pain, uterine tenderness, and foul-smelling lochia. Besides the obvious CBC and urinalysis, the workup should include blood cultures due to the high rate of bacteremia and cervical cultures to screen for Chlamydia. The treatment is broad-spectrum antibiotics, with the traditional choice being clindamycin and gentamicin. Other options would be piperacillin/tazobactam with or without gentamicin and adding ampicillin to the gentamicin and clindamycin.

Varicella infections in pregnancy have the potential for high rates of maternal and fetal morbidity and mortality. Having knowledge on this topic is useful in treating patients and for pregnant staff members who may have been exposed to a patient with varicella or zoster. The mortality rate of maternal varicella is less than five percent by most studies. The American Academy of Pediatrics has defined “close exposure,” those at high risk of contracting the disease, to be household contacts, face-to-face contact for at least five minutes, and indoor contact with a case of zoster or varicella for more than an hour.

Limb abnormalities are the most commonly noted fetal complication secondary to varicella infection, with an incidence of one percent with a maternal infection before 20 weeks gestation. Depending on when the infection occurs, microcephaly, cataracts, and vocal cord paralysis are among the many reported anomalies of intrauterine varicella infection. (Clin Perinatol 2005;32[3]:671.)

Maternal complications are identical to those in nonpregnant women, with pneumonia being the most common. Early in the course of maternal pneumonia, the chest x-ray is often normal, and the lungs are clear. Only a nonproductive cough and mild dyspnea on exertion is found. Later, dyspnea at rest, a chest x-ray with diffuse and nodular consolidations, and a productive cough occur. Risk factors for a poor prognosis include smoking, lung disease, immunocompromised state, more diffuse rash on initial presentation, and onset in third trimester.

Patients should be admitted if they have chest symptoms, neurologic symptoms other than headache, immunosuppression, or hemorrhagic rash, bleeding, or significant mucous membrane involvement. (J Infect 1998;36[Suppl 1]:59.) A woman past 18 weeks gestation with varicella infection should be treated with oral acyclovir if she presents within 24 hours of rash onset. Those presenting 24 hours to 10 days after rash onset or who are less than 18 weeks gestation are at higher risk, although acyclovir has been shown to have some benefit up to 10 days from rash onset. The benefit of acyclovir is not as clear in patients earlier than 18 weeks gestation. Varicella pneumonia can be very severe, especially in later pregnancy, and should be treated with IV acyclovir (10 mg/kg TID).

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