Infections Related to Pregnancy

Emerg Med Clin N Am 26 (2008) 345–366

Infections Related to Pregnancy Diane L. Gorgas, MD Department of Emergency Medicine, The Ohio State University Medical Center, 164 Means Hall, 1654 Upham Drive, Columbus, OH 43210, USA

Urinary tract infection is a common complication of pregnancy, occurring in as many as 15% of pregnant women. More concerning is the predisposition of the patient to sustain pyelonephritis. Twenty percent to forty percent of pregnant women with asymptomatic bacteriuria will experience pyelonephritis [1]. Conversion of bacteriuria to pyelonephritis will most likely occur in multiparous women during the second trimester of pregnancy [2], and women with a history of antenatal urinary tract infections are particularly at risk [3]. This risk has led to a debate over the screening and treating of asymptomatic bacteriuria in pregnant patients [4–6]. Factors that predispose to bacteriuria and its complications include normal physiologic changes in the pregnant woman’s anatomy, including impaired emptying of the urinary bladder, relative stasis of urine within the ureters, an increased vesiculoureteral reflux, and an increased pH of urine [7].

Diagnosis The purpose of diagnosing a urinary tract infection in pregnancy is multifactorial concerning fetal health. In addition to the maternal dangers of acute pyelonephritis, there are independent risks to the fetus, including congenital abnormalities, premature rupture of membranes, and low birth weight infants [8]. Socioeconomic status, personal hygiene, education level, pregnancy duration, contraceptive use, and the use of underclothing have no significant bearing on the risk for urinary tract infection [9]. The only independent risk is a history of previous urinary tract infection. Etiologic agents for urinary tract infection in the pregnant patient mirror those in nonpregnant cohorts. The most common isolated bacteria are Escherichia coli; other organisms less commonly seen are Enterobacter, Staphylococcus, or group B streptococcus [10,11]. Despite obvious logistical E-mail address: [email protected] 0733-8627/08/$ - see front matter Ó 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.emc.2008.01.007 emed.theclinics.com

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limitations in collecting a clean catch midstream or in obtaining a sample in a gravid woman, similar colony counts have been proposed to define ‘‘bacteriuria.’’ Two consecutive positive cultures with colony counts greater than 105 colony forming units defines significant bacteriuria [6,9]. Treatment The antibiotic choice in pregnancy should consider the likely pathogens in conjunction with fetal and maternal safety based on gestational age. Recommended antibiotics in pregnancy should be US Food and Drug Administration category B. These drugs include cephalosporins and penicillins. Other common agents used to treat urinary pathogens may have untoward effects in pregnancy. Antibiotics that can have deleterious effects near term are the sulfonamides, which can increase the risk of neonatal kernicterus, and nitrofurantoin, which can cause hemolysis in an infant with glucose6-phosphate dehydrogenase deficiency [2,5]. First trimester antibiotic untoward effects occur from the use of tetracyclines, which can cause bone and teeth dysplasia; from trimethoprim, which inhibits folate metabolism and may predispose the fetus to neural tube defects; from aminoglycosides, which can cause eighth cranial nerve palsies; and from fluoroquinolones, which have been associated with cartilaginous abnormalities [12]. The duration of treatment has received significant attention in the literature. Although general agreement is found regarding the duration of treatment for pyelonephritis (minimum of 7–10 days), several conflicting studies can be found regarding the duration of treatment for uncomplicated lower urinary tract infections [13]. The current literature has espoused the efficacy and safety of single dose oral treatment of cystitis in pregnant patients [14,15]. Limitations of this therapeutic practice in the emergency department are thought to be related to unreliable follow-up. Although it may be prudent to obtain urine cultures for all pregnant women, the literature does not spell out this recommendation as routine practice [16]. Certainly all pregnant women with a urinary tract infection that is resistant to therapy, recurrent, or associated with pyelonephritis should have a culture performed routinely. In the United States, no studies have been published specifically looking at the development of antibiotic resistance in pregnant patients, but pathogens tend to mirror those in nonpregnant populations [17]. Chorioamnionitis Chorioamnionitis is an infection of the chorioamniotic membranes and amniotic cavity that occurs most commonly in the third trimester. It is not an uncommon infection associated with pregnancy, occurring in 1% to 10% of all pregnancies [18]. The incidence of the condition increases significantly with preterm labor.

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The etiology in most cases is an ascending vaginal infection through the cervical os [19], most commonly seen in cases of premature rupture of membranes and prolonged labor [20]. The condition can be acquired hematogenously or transabdominally from amniocentesis. It has also been reported in association with other obstetric procedures including cerclage placement. Diagnosis The diagnosis of chorioamnionitis is a clinical one characterized by fever, uterine tenderness, foul smelling amniotic fluid on rupture of membranes, and maternal and fetal tachycardia. Of these symptoms, fever is found most commonly and is present in 85% to 100% of cases [21]. Laboratory adjuncts in diagnosing the infection include a maternal white blood cell count which is usually elevated with a left shift. The most sensitive and specific laboratory finding is the presence of leukoattractants in the amniotic fluid. These proteins act as markers for subsequent leukocyte migration and activation [22]. Because leukoattractant assays are not readily available in the emergency setting, other amniotic fluid tests that may point toward the diagnosis are the microscopic presence of bacteria and leukocytes. Some studies have proposed the presence of amniotic fluid leukocyte esterase, low glucose, and elevated C-reactive protein as suggestive findings [23]. Fluid culture can be helpful in tailoring therapy and is recommended. It has been unclear in studies whether chorioamnionitis represents a polymicrobial infection, or whether the majority of cases are caused by single etiologic agents. The most commonly identified organism is Ureaplasma urealyticum [24], but Mycoplasma hominis, Gardnerella vaginalis, Bacteroides bivius, Escherichia coli, group B streptococci, anaerobic streptococci, and aerobic gram-negative rods have also been implicated. Bacterial vaginitis has been associated with the condition as well, but most sources believe this is a correlation and not a causative relationship. Although prevention of chorioamnionitis is not absolute, there are predictable risk factors for the development of the condition. Major risk factors for disease include an increased number of vaginal examinations, the duration of ruptured membranes and of total labor, and the use of internal fetal monitors. Minor risk factors for the condition include coitus during pregnancy, bacterial colonization, particularly vaginal group B streptococci colonization, premature rupture of membranes or premature labor, or any invasive procedures, but particularly endovaginal procedures [25]. It is unclear at what duration premature rupture of membranes becomes a significant risk factor, but there has been no proven difference in the rate of chorioamnionitis development between 12 hours and 72 hours [26]. The presence of chorioamnionitis during labor and in the puerperal period can have significant manifestations in maternal and fetal care. Chorioamnionitis significantly increases the risk of maternal and fetal bacteremia, with estimates being 10% in both populations [27]. From

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a delivery perspective, the presence of chorioamnionitis can cause slow cervical dilatation, prolonged labor, and decreased responsiveness to oxytocin. From a fetal perspective, increased mortality is associated with early gestational age, low birth weight, or an infection with Escherichia coli or group B streptococci. Fetal mortality also increases exponentially with the delay in maternal antibiotic treatment. The early philosophy in the treatment of chorioamnionitis was to withhold maternal antibiotic treatment until after the infant was delivered and the cord clamped to allow for unadulterated cultures to be obtained from the infant. This practice has largely been abandoned in favor of early and aggressive maternal treatment. In cases of mild chorioamnionitis, there is a 2.6-fold increase in fetal mortality; in moderate to severe cases, a 4.1-fold increase is noted [21]. Long-term fetal morbidity is associated with lower developmental scores and a higher rate of neurologic abnormalities. Treatment Once the condition is suspected, treatment should be initiated with intravenous antibiotics, although no standard of therapy regarding antibiotic choice has been established. Treatment suggestions in the literature include cefoxitin, piperacillin, or combination therapy with ampicillin plus an aminoglycoside. It has been suggested that clindamycin should be added if Bacteroides sp are suspected, or if the patient will be delivered by cesarean section, although this is controversial [28]. Intravenous antibiotic treatment, once initiated, should be continued for at least 48 hours after the patient becomes afebrile. Continued oral therapy should be completed for an additional 7 to 10 days. The question of when and how to deliver an infant in a chorioamniotic environment is unsettled. Conflicting opinions regarding emergent versus urgent delivery and cesarean section versus vaginal delivery have been debated in the literature, but, largely, the specifics of the case determine the course of action [25].

Endometritis Endometritis, or a generalized uterine infection also called endomyometritis or endoparametritis, is the most frequent cause of infection in the puerperal period. The risk of endometritis rises exponentially in post–cesarean section patients, particularly in nonelective high-risk patients, in whom the risk can reach 85% to 95% [29]. It is a more uncommon diagnosis post vaginal delivery, complicating 1% to 3% of uncomplicated vaginal deliveries [30]. Complicating features of endometritis such as pelvic thrombophlebitis and pelvic abscess are also proportionately more likely to occur post cesarean (4%–9%) than with vaginal deliveries (!2%) [31]. Bacteremia is also more common in the post–cesarean section patient (20%) when compared with vaginal delivery cases of endometritis (4%) [32]. Other risk factors

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for the development of endometritis include prolonged labor, prolonged rupture of membranes, increased frequency of vaginal examinations, and the use of internal fetal monitoring. Diagnosis The pathogenesis of endometritis appears to be a mixed polymicrobial ascending infection from the lower genital tract. Anaerobic organisms are found in 80% of uterine isolates and aerobic organisms in 70% of late (3–6 days) postpartum infections [33]. Common isolates include gram-positive anaerobes such as group B streptococci, Enterococcus, and Gardnerella sp; gram-negative aerobes such as Escherichia coli and Enterobacter; and other anaerobes such as Bacteroides and Peptostreptococcus. Post–cesarean section infections are thought to be derived in a similar ascending fashion, but the increased risk is believed to be due to increased uterine manipulation, the presence of devitalized tissue at the suture sites, and the possibility of bacterial contamination through the incision. The classic triad found in endometritis is fever, lower abdominal pain and uterine tenderness, and foul smelling lochia [29]. Other sources of infection must be ruled out to confirm the diagnosis of endometritis. The work-up of patients with suspected endometritis should include a complete blood count, urinalysis, and blood cultures because of the high rate of concomitant bacteremia. Cervical cultures, although not particularly useful in the initial management of these cases, may help direct therapy for treatment failures and help identify Chlamydia as an etiologic agent; therefore, they are recommended. Treatment Treatment of postpartum endometritis includes broad-spectrum intravenous antibiotic therapy, the gold standard of which has been clindamycin and gentamicin [34]. After initiation of treatment, a response should be seen within 48 hours, and therapy should be continued for an additional 48 hours after defervescence. No proven utility of continued oral antibiotic therapy after discharge has been noted. Treatment failures at 48 hours should prompt consideration of Enterococcus as an etiologic agent, particularly if antibiotics (usually a cephalosporin) were administered peripartum in cases of cesarean section delivery [35]. The addition of ampicillin to the treatment regimen is usually associated with a positive therapeutic response. Persistent treatment failures should lead to continued diagnostic work-up for complications of endometritis, including septic thrombophlebitis, ovarian vein thrombosis, or pelvic abscess. Group B streptrococcal infection Group B streptococci have been a leading cause of maternal and neonatal mortality. The first set of national consensus guidelines was published in

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1996. Since then, there has been a 70% reduction in early neonatal infection but no significant impact on the rates of late group B streptococcal neonatal infection [32]. Diagnosis Multiple studies have reported rates of group B streptococcal maternal colonization of 10% to 30%, with repeated screenings during gestation resulting in higher positive culture rates [36,37]. Both rectal and vaginal colonization rates have been studied. Although vaginal colonization is more common, rectal growth of group B streptococci occurs frequently enough for many studies to recommend swabs of both areas to determine the presence of the bacterium. These infections can be separated into four different categories: chronic (36%), transient (20%), intermittent (15%), and acute (29%) [36]. Streptococcal carriage has been noted to be significantly less in patients aged 20 years old or older and in multiparous patients (four pregnancies or greater) [36]. Risk factors for colonization include African American race [38]. It is unclear whether Latino American descent places patients at increased or decreased risk, because study findings are conflicting. Maternal colonization leads to invasive disease in 1 to 2 cases per 1000 total births [39]. Ultimately, the risk of fetal loss or group B streptococcal disease in the infant occurs in 28% of maternal cases [38]. Neonatal group B sepsis occurred in 1.6 to 2.6 of 1000 live births (dependent on when group B streptococci was cultured, that is, 23 versus 26 weeks) [40]. An independent risk factor for development of disease in the neonate is the amount of maternal colonization, with heavy colonization being more likely to cause neonatal infection. Neonatal infection is only one complication of maternal colonization; preterm delivery and low birth weight infants are more frequently seen in heavily colonized mothers [41]. Current recommendations regarding the screening of term, otherwise healthy pregnant (35–37 weeks’ gestation) patients include obtaining vaginal and rectal swabs between 35 and 37 weeks or at the time of labor. Treatment Treatment should be initiated in all women with positive cultures during the 35- to 37-week screening, and in any woman who has had an infant infected with group B streptococci in the neonatal period or with a positive group B streptococcal urine culture (regardless of the colony count). Other groups that should be treated empirically include all patients with labor at less than 37 weeks’ gestation unless a negative screen has been obtained within the last 5 weeks. Additional scenarios in which treatment is recommended include fever during labor and premature rupture of membranes for greater than 18 hours [41]. Group B streptococci–associated chorioamnionitis is reported in most (88%) cases in which neonatal infection occurred despite intrapartum maternal antibiotic therapy [42].

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Intrapartum chemoprophylaxis of group B streptococci colonization has resulted in a significant reduction of neonatal infection [43]. Because of the now routine outpatient treatment of patients with positive cultures, antibiotic resistance is becoming more common. Traditional treatment called for penicillin or, as alternatives in a penicillin-allergic patient, oral clindamycin or erythromycin [44]. This treatment regimen has traditionally been very effective at preventing group B streptococcal neonatal colonization. Recent studies have shown a virtual eradication of positive group B streptococcal neonatal skin cultures if antibiotics are given 6 hours before delivery [45], with slightly lower rates if they are given intrapartum [46]. In vitro resistance to clindamycin and erythromycin is increasing, with recent (1990) numbers approaching resistance rates of 5% and 18%, respectively [47]. Empiric treatment of the neonate should take place in high-risk cases. These cases include infants of mothers with group B streptococci bacterium, mothers with previous deliveries complicated with early onset group B streptococcal disease, and all mothers with chorioamnionitis. This empiric treatment in the neonate should continue until the infant’s screening cultures are negative [42]. An alternative approach is immunoprophylaxis of the mother against group B streptococci with a type III polysaccharide vaccine. This treatment can impart vertical immunity to the newborn and may eventually obviate the need for antibiotic treatment entirely [48,49].

Septic abortion Although it is an infrequently seen complication since the advent of legalized pregnancy termination, septic abortion still can occur. Although this has largely become obsolete in developed nations, the World Health Organization estimates that one in eight pregnancy-related deaths world-wide is directly attributable to unsafe abortion practices [50]. The mechanism of septic abortion is most commonly associated with substandard nonsterile techniques and inadvertent retained products of conception after incomplete uterine evacuation. This mechanism translates into 68,000 deaths per year, almost exclusively in developing countries [51]. The clinical presentation of a septic abortion is similar to endometritis and is characterized by fever, abdominal pain, and uterine tenderness. The presentation of disease can vary from minor fever and discomfort to fulminant septic shock with pulmonary edema, adult respiratory distress syndrome, disseminated intravascular coagulation, pulmonary embolism, and subsequent cardiovascular collapse and death [52]. Etiologic agents in cases of septic abortion are nearly uniformly polymicrobial and are caused by ascending infections through an open cervical os. Common isolates are Escherichia coli, Bacteroides sp, anaerobic gram-negative rods, group B beta-hemolytic streptococci, and staphylococcus. Sexually transmitted disease may also be implicated, including gonorrhea and

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infection with Chlamydia and Trichomonas [21]. Pre-procedural screening for sexually transmitted diseases before pregnancy termination may help prevent infection in selected cases. Diagnosis Although largely a clinical diagnosis, laboratory adjuncts for the diagnosis should include arterial blood gases, lactate levels, a Gram stain of the cervix with cultures of the endocervix, blood, and urine, and screening for disseminated intravascular coagulation (coagulation profile with fibrin, fibrinogen, and fibrin split products). Plain radiographic examination of the abdomen may reveal free air or retained post-procedural foreign bodies and may be helpful. Similarly, pelvic ultrasound may suggest surgical complications, including retained products of conception or retained surgical foreign bodies [53]. Treatment Treatment of septic abortion should focus on removal of any inciting agents (products of conception or foreign bodies) and is usually accomplished through dilatation and curettage of the uterine cavity. This procedure removes the source of the endotoxin. Although theoretically curative in these cases, it is rarely held as an isolated therapeutic approach. Antibiotic therapy is almost always instituted and should be started concomitantly with uterine evacuation. Parenteral administration of triple antibiotic therapy is the standard of care. Suggested regimens include (1) gram-positive anaerobic and aerobic coverage with penicillin, ampicillin, or a cephalosporin; (2) gram-negative aerobic coverage with an aminoglycoside; and (3) gramnegative anaerobic coverage with clindamycin or metronidazole [21]. Tetanus toxoid should also be considered.

HIV in pregnancy Entire texts have been and still will be written regarding HIV infection in pregnancy. This section attempts to review salient information regarding testing, maternal management, and, most importantly, limiting vertical transmission of the disease. The rate of HIV infection in the United States has appeared to reach a plateau or steady state, with roughly 40,000 new cases developing yearly [54]. Recent Centers for Disease Control guidelines have given special emphasis to the role of the emergency physician in surveillance and treatment with regards to HIV, because the emergency department represents the only source of medical care for many patients and may serve a primary care role for many at-risk populations. In underdeveloped countries, notably throughout the continent of Africa, rates of HIV infection are steadily increasing yearly. Efforts are now being made to protect

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newborns from the development of disease, but the first barrier in this crusade has been knowledge of the maternal HIV status. There are many obstacles in determining this status, not the least of which is the consideration of the impact of a positive test on these women and their families. Women who test positive may receive a disproportionately more difficult time from society, partners, and their families than do their male counterparts [55]. This realization has led to an opinion that women should be tested before pregnancy so informed reproductive choices can be made; however, prenatal testing imposes an unfair burden on women in cultures, either globally or locally, when support structures do not exist to aid in post diagnosis. Other strategies proposed to ease the burden of prenatal testing include provider initiated testing and counseling with a right to refuse (opt out), group pretest counseling, rapid HIV testing, and community and male involvement for support [56]. The consequences of undiagnosed HIV in pregnancy are sobering. High rates of infant mortality, usually secondary to overwhelming infection, are common (25%), and the majority of infants have long-term neurologic sequelae (65%) [57]. When HIV infection occurs intrauterine as opposed to during delivery, the fetus can develop growth failure, microcephaly, and craniofacial abnormalities [58]. Prevention of vertical transmission has fallen into two different and complementary strategies. One focuses on the timing and route of delivery and the second on a pharmacologic approach to peripartum care. Regarding the route and timing of delivery, two studies published in 1999 demonstrated that cesarean section before the initiation of labor and rupture of membranes (also known as elective cesarean section) reduced the risk of vertical transmission by up to 50% to 70% [59,60]. One study showed a 1.8% incidence of HIV transmission (3 of 170) versus 10.5% (21 of 200) with vaginal deliveries [60]. Based on these results, current recommendations from the American College of Obstetricians and Gynecologists and the US Public Health Service suggest counseling of women with viral loads greater than 1000 copies/mL for elective cesarean section [61,62]. Since 1999, these recommendations have led to a dramatic increase in the numbers of cesarean sections among HIV-positive mothers. Unfortunately, this increase has resulted in an ethical conundrum, because a recent study has just shown that elective cesarean section to prevent vertical transmission in HIV-infected mothers leads to increased maternal morbidity and mortality. HIVinfected mothers undergoing elective cesarean section are more likely to develop endometritis (11.6% versus 5.8% in noninfected controls), maternal sepsis (1.1% versus 0.2%), and pneumonia (1.3% versus 0.3%), and are more likely to require postpartum transfusions (4.0% versus 2.0%). The risk of maternal mortality also increases from 0.1% in noninfected controls to 0.8% in the HIV-infected population [63]. Given these risks, it is unclear what recommendations should be made if the viral load is low (ie, !1000), or if the patient is currently taking antiretroviral agents [62].

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Pharmacologic therapy is synergistic in decreasing HIV transmission along with the delivery strategies outlined previously. Antiretroviral agents should be tailored based on the maternal viral load but should, at a minimum, include zidovudine from 28 weeks; gestation; zidovudine, lamivudine, and a single dose of nevirapine during delivery; and zidovudine and lamivudine for 7 days after delivery to reduce the development of nevirapine resistance [64]. The use of zidovudine alone decreased the risk of vertical transmission 43%, and the addition of nevirapine improved that reduction to 68% [65]. Newborn infants should receive a single dose of nevirapine and 1 to 4 weeks of zidovudine. Infants undergoing this chemoprophylaxis not only have a decreased risk of contracting HIV infection but also a decreased risk of neonatal mortality (80% reduction) [65]. Currently published US standards recommend a three-part zidovudine prophylaxis regimen (prenatal, intranatal, and neonatal) even for mothers with a viral load less than 1000 copies/mL [62]. This strategy has ultimately led to a risk of vertical transmission of less than 1% [66]. An alternative strategy of just using single dose nevirapine has been studied as well which, in and of itself, can lead to a decrease in maternal transmission to 10% to 15% [67]. Safety profiles for any drug given during pregnancy are a concern. Protease inhibitors have been associated with an increased risk of maternal glucose intolerance, preeclampsia, and preterm birth [68]. Any pregnancy exposed to antiretroviral agents should be registered with the Antiretroviral Pregnancy Registry to better understand the risk of birth defects. Neonatal treatment with antiretrovirals seems to be well tolerated, but a concern over persistent mitochondrial dysfunction resulting in increased cancer development rates has been raised [69]. Although peripartum prophylaxis has been the mainstay of therapy, there are significant concerns regarding vertical transmission for breastfeeding infants as well. Although somewhat less studied, vertical transmission through breastfeeding accounts for 50% of all neonatal and infant HIV cases worldwide and carries a transmission risk of 15% when continued beyond the first year [69]. Studies are underway to examine methods to decrease this risk, including early intensive breastfeeding only plans with rapid weaning at 3 to 6 months, treatments of expressed milk to inactivate the virus, and antiretroviral therapy for the mother and infant during breastfeeding periods [70].

Pneumonia in pregnancy (non-varicella type) Before the 1960s, pneumonia was a common scourge to obstetricians, affecting 6 to 8 women per 1000 deliveries. These figures reached a nadir in the 1970s and 1980s, decreasing to a rate of 0.4 to 0.8 women per 1000 deliveries, but have recently increased in incidence, thought to be a product of higher numbers of infertility pregnancies and the emergence of chronically

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ill women becoming pregnant at higher rates when compared with the general population [71]. Nevertheless, there does not appear to be an appreciable increased risk of developing pneumonia in pregnancy. Risk factors for the development of pneumonia do not appear to be influenced by maternal age or parity. The incidence is lowest in the first trimester and increases steadily throughout pregnancy, most likely owing to mechanical limitations of the growing uterus on pulmonary function [72]. Maternal comorbidities, including anemia and asthma, have been postulated as risk factors [73] and in combination impart a fivefold risk for developing pneumonia [74]. Independent iatrogenic risk factors for the development of pneumonia are the use of antepartum corticosteroids to enhance fetal lung maturity and tocolytics to induce labor. Diagnosis The diagnosis of pneumonia in pregnancy is commonly more difficult than in nonpregnant matched cohorts, and the disease is frequently misdiagnosed on initial presentation. The most common misdiagnoses noted are pyelonephritis, appendicitis, and preterm labor [71]. The diagnosis can be confounded by attributing symptoms of the disease state to normal physiologic changes in pregnancy. These symptoms include dyspnea, chest discomfort, and fatigue. Some distinguishing features that help define pathology are the presence of cough and dyspnea at rest [71]. Pregnancy-specific diagnoses that can be mistaken for pneumonia and that present with similar symptoms and a positive chest radiograph include noncardiogenic pulmonary edema in preeclampsia and eclampsia or secondary to tocolytic agents or aspiration pneumonia. Rarely, choriocarcinoma with pulmonary metastases can occur and be mistaken for pneumonia. Common pathogens of pneumonia in pregnant patients tend to parallel that in nonpregnant age-matched cohorts. Streptococcus pneumoniae is the most common organism identified, followed by Haemophilus influenzae [75,76]. Legionella has been reported as well. Pathogens associated with aspiration pneumonia in pregnancy are believed to mirror pathogens in nonpregnant patients, but no confirmatory studies have been done. Anaerobes such as the gram-positive cocci, Peptostreptococcus, and Peptococcus sp and the gram-negative bacilli Fusobacterium and Bacteroides sp predominate in two thirds of cases. The pregnant patient in the third trimester is at increased risk of aspiration due to several features, including relaxation of the gastroesophageal sphincter, delayed gastric emptying, and increased intra-abdominal pressure. Patients undergoing cesarean section, especially under general anesthetic, have even higher risks of aspiration [77]. Other pathogenic organisms are theoretically more likely to be seen in pregnancy because of changes in cellular immunity, but no surveillance studies have demonstrated definitively higher incidence rates [77]. These organisms include fungi leading to infections, including coccidioidomycosis. When it

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occurs, coccidioidomycosis tends to be associated with a higher rate of dissemination and systemic illness when contracted in the third trimester. Treatment Treatment options, although not specifically studied for efficacy in pregnant patients, must be considered from a fetal safety point of view. Penicillins, macrolides (including newer ones), and cephalosporins have good safety records in pregnancy and should be efficacious. Quinolones, tetracyclines, chloramphenicol, and sulpha compounds should generally be avoided unless dictated use is mandated by culture and sensitivity [71].

Varicella infections in pregnancy Although chickenpox is a relatively uncommon disease in adults, with only 7% of cases occurring within the child-bearing age period of 14 to 45 years, it receives a significant amount of attention because of the morbidity and mortality associated with it [78]. Overall, the incidence of the disease is between 0.5 to 3 cases per 1000 pregnancies, although as many as 10% of pregnant women are susceptible to infection based on a lack of antibody titers [79]. Historically, the mortality rate associated with maternal varicella infection has been high, up to 41% documented before 1965 [78,79]. More recent studies and advances in antimicrobial therapy in conjunction with improved ICU support of the ventilatory compromised patient have led to much improved mortality, with most studies citing mortality rates of less than 5%. Nonetheless, maternal and fetal morbidity is still a concern, and if prevention can be offered in exposed cases, primary effort at disease control should occur. The American Academy of Pediatrics has defined ‘‘close exposure’’ cases, those at increased risk for the development of disease, to be (1) household contacts, (2) face-to-face contact for at least 5 minutes, and (3) contact indoors with a case of chickenpox or herpes zoster for more than 1 hour [78]. These definitions do not account for the fact that 20% of infected mothers state that they have had no known chickenpox exposures. Nonetheless, current recommendations advise post-exposure treatment of pregnant women with varicella-zoster immune globulin (VZIG) within 72 hours of exposure, although some benefit is inferred if treatment is initiated within 10 days of exposure [80]. The administration of VZIG has been proven beneficial to maternal morbidity and mortality, and some evidence has shown that it may have some protective properties against fetal varicella syndrome [78]. Diagnosis The timing of a varicella infection in pregnancy can help predict consequences. Infection within the first 20 weeks of pregnancy has a 1% risk of

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embryopathy, most notably manifesting as limb abnormalities diagnosed in subsequent ultrasound fetal interrogation [78]. Virus is not uncommonly found in amniotic fluid and cord blood post infection, but levels do not correlate with any definable disease state within the fetus; therefore, amniocentesis and cordocentesis are not recommended. Varicella pneumonitis during pregnancy manifests in two clinical stages, early and late. The early phase is characterized by the onset of respiratory symptoms 1 to 6 days after the onset of a rash, a dry cough associated with exertional dyspnea, and mild hypoxemia. Patients within the early phase typically have normal lung sounds, no cyanosis, and frequently have a normal chest radiograph. Pneumonia without a rash has not been reported. In the late phase, respiratory symptoms progress, with dyspnea at rest noted and resting cyanosis. The cough can become productive and blood streaked. Physical findings show basilar crepitance and moderate-to-severe hypoxia [78]. The chest radiograph in late phases is not characterized by consolidation but by diffuse, sometimes nodular, infiltrates [81]. Risk factors have been identified for the acquisition of varicella pneumonia and the severity of the clinical presentation. These factors include non– pregnancy-related features such as maternal smoking, pre-existing chronic obstructive pulmonary disease, a mother who is immunocompromised (including steroid use), and certain characteristics of the rash, such as the initial extent of the eruption and a hemorrhagic rash [78]. Exposure in late pregnancy also infers a higher risk for varicella pneumonitis and predicts a more virulent course of illness [82]. It is unclear whether this risk is attributable to immunosuppressive or other biochemical changes inherent in pregnancy or because of mechanical changes in pulmonary function brought on by decreased diaphragmatic excursion as the uterus enlarges. Overall, there is debate as to whether the severity of illness in pregnancy is as serious as once believed [83]. Mortality rates in nonpregnant versus pregnant patients in whom pneumonitis develops have been reportedly similar (15%–40% versus 2%–35%), although tremendous variability can be found from case series to case series [78]. General rates of developing pneumonitis are between 5% and 14%. Although some data support the supposition that varicella pneumonia is a more serious illness in pregnancy, this cannot be uniformly supported. Once a diagnosis of varicella pneumonia has been made, assessing the severity of the illness is paramount. Criteria for hospitalization have been set forth as follows: (1) chest symptoms, (2) neurologic symptoms other than headache, (3) hemorrhagic rash or bleeding or a dense rash with mucous membrane involvement, and (4) significant immunosuppression [78]. Factors that should be considered in predicting maternal and fetal morbidity are pregnancy approaching term, a history of obstetric complications, a smoking history or chronic obstructive pulmonary disease, or poor social supports.

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Treatment Treatment considerations for varicella in pregnancy should begin when a patient presents with a rash whose duration is 24 hours or less. If the patient is in her second half of pregnancy, the consensus opinion is that she should receive a course of oral acyclovir [80]. This recommendation largely stems from the increased pulmonary morbidity found in late pregnancy. No consensus opinion has been published regarding acyclovir administration in patients who present 24 hours to 10 days after rash onset, although acyclovir may be beneficial up to 10 days post symptom onset. Also, no consensus has been reached on early pregnancy exposure or disease development. Although no studies have been specifically designed to test for the safety of acyclovir in early pregnancy, the drug appears to have low teratogenicity and untoward fetal effects [84]. Treatment issues for varicella pneumonia that are unique in pregnancy focus on fetal health and growth. The severe hypoxia that can develop in cases of advanced maternal pneumonitis can be difficult to treat and the deleterious effects of hypoxia magnified in a developing fetus. Case reports of extracorporeal membrane oxygenation suggest this may be helpful in prolonged maternal hypoxia despite maximal ventilator support [85]. Maternal nutrition should be observed closely as well, because fetal intrauterine growth is closely linked to maternal nutrition. Acyclovir administration for varicella pneumonitis treatment should begin with intravenous dosing for rapid establishment of plasma peak concentrations. Appropriate dosing is 10 mg/kg three times a day with the intravenous route maintained for at least 5 days [82,86]. Oral acyclovir is poorly, incompletely, and slowly absorbed, making it less than ideal as a primary therapy. Concurrent bacterial sepsis can occur, as well as secondary consolidated bacterial pneumonia. The most common causative bacterial organisms are Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae [87]. No concrete recommendations have been published regarding the routine use of antibacterial agents in varicella pneumonia, but with the high risk of secondary infection and slow response to antiviral therapy, early institution of antibiotic therapy is reasonable. Fetal infection can occur via three routes: (1) transplacental viremia, (2) ascending infection via vaginal or external genitalia lesions during birth, or (3) respiratory droplets or direct contact with lesions after birth. The most virulent of these exposures occurs when an infant is born to a mother who develops the rash up to 4 days pre- or 2 days postpartum. These infants have a 20% risk of developing varicella infection and a subsequent 20% to 30% mortality rate; therefore, they should all be treated [88]. Maternal chickenpox 5 to 21 days pre-delivery generally results in benign neonatal chickenpox [89]. The difference between these two clinical scenarios is that the likelihood of transplacental antibodies imparting some immunity to the fetus rises exponentially within the 4- to 7-day window. Although this

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suggests the idea of passive immunity in newborns, and although it is known that 90% of cord blood is varicella zoster virus antibody positive, there have been cluster cases of primary varicella infection in newborns less than 8 weeks of age [78]. Maternal shingles at birth imparts no increased risk to the fetus because it is not associated with viremia. Mastitis Mastitis is a spectrum of illnesses ranging from mild breast redness and warmth in a lactating mother to an extremely painful condition associated with systemic toxicity, high fevers, and complications including abscess [90]. It is a common post partum, with incidences between 1% and 30% depending on the reporting source [91–93]. Together with urinary tract infection, mastitis accounts for over 80% of postpartum infections [94]. It generally occurs within the first 3 months post partum, with a peak occurrence in the second and third postpartum week, and has a 4% to 8% recurrence rate within the 3-month period [93]. A debate in the literature exists as to whether this condition represents a variant of normal lactation physiology or a true disease state [95]. For the purposes of this article, it will be treated as a pathologic condition. Predictable risk factors for the infection include a history of mastitis in the past, the presence of cracked, sore nipples, ineffective breastfeeding techniques leading to incomplete breast emptying and persistent breast engorgement, and the use of a manual breast pump [95]. A past medical history of any immunocompromising disease process, including diabetes or steroid use, as well as previous alterations in breast anatomy, such as a previous lumpectomy with radiotherapy or the presence of breast implants, increases the risk. Maternal risks that may be altered that increase the risk include employment outside the home, wearing tight-fitting bras or clothing, and the presence of stress or fatigue [95]. Features that are somewhat protective for mastitis are maternal smoking during pregnancy, supplementation with water in the first month, the use of a pacifier on a daily basis within the first month, and a feeding frequency less than 10 times per day. The duration of breastfeeding is not associated with risk [93]. Diagnosis Mastitis is a clinical diagnosis and can present with a wide spectrum of symptoms. Minor cases may be characterized by slight warmth, redness, and tenderness within the breast and some pain with nursing. Systemic symptoms in more severe cases can be malaise, myalgia, fever, and chills [93]. Other localized breast findings consistent with mastitis are decreased milk output, a localized hard-wedge shaped area of the breast, a breast mass near the nipple, and possibly enlarged axillary nodes or sinus tract formation in granulomatous mastitis [96].

360

Table 1 Summary of infectious complications associated with pregnancy Timing

Causative organisms

Treatment

Urinary tract infection

All trimesters, more likely second and third

Cephalosporins, penicillins

Chorioamnionitis

Third trimester

Endometritis

24 Hours to 2 weeks post delivery

Septic abortion

8 Hours to 1 week post procedure

Escherichia coli; other organisms less commonly seen are Enterobacter, Staphylococcus, or group B streptococcus Ureaplasma urealyticum, Mycoplasma hominis, Gardnerella vaginalis, Bacteroides bivius, Escherichia coli, group B streptococcus, anaerobic streptococci, and aerobic gram-negative rods Gram-positive anaerobes: group B streptococcus, Enterococcus, and Gardnerella sp; gram-negative aerobes: Escherichia coli, Enterobacter, Bacteroides, and Peptostreptococcus Escherichia coli, Bacteroides sp, anaerobic gram-negative rods, group B beta-hemolytic streptococci, and Staphylococcus Consider gonorrhea and chlamydia

Cefoxitin, piperacillin, or combination therapy with ampicillin plus an aminoglycoside

Clindamycin and gentamicin  ampicillin

Check for retained products of conception/foreign bodies; use triple antibiotic therapy (ampicillin or cephalosporin, aminoglycoside, clindamycin or metronidazole

GORGAS

Diagnosis

Peripartum through lactation, fetal risk of vertical transmission

HIV

Pneumonia (non-varicella type)

Any (third trimester risk from respiratory mechanics)

Pneumonia (varicella type) Mastitis

Any (risk of vertical transmission, peripartum greatest) Within 3 months post partum

Streptococcus pneumoniae, Haemophilus influenzae, Legionella Varicella Staphylococcus aureus, coagulase-negative staphylococci, group A and B-hemolytic streptococci, Escherichia coli, and Bacteroides sp

? Elective cesarean section; zidovudine from 28 weeks’; gestation; lamivudine at delivery and for 10 days post partum; single dose nevirapine at delivery Penicillins, macrolides, cephalosporins

Acyclovir at 20 weeks or greater Warm compresses, frequent nursing; dicloxacillin, cloxacillin treatment failure: cephalosporin, Augmentin; penicillin allergic: erythromycin or clindamycin

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HIV

361

362

GORGAS

When infection is responsible for the clinical syndrome and not primary engorgement and inflammation, the etiologic agents most commonly seen are Staphylococcus aureus, coagulase-negative staphylococci, group A and B-hemolytic streptococci, Escherichia coli, and Bacteroides sp. There has recently been an increasing incidence of methicillin-resistant Staphylococcus aureus mastitis, and rare instances with Salmonella sp, mycobacteria, Candida, and Cryptococcus have also been reported [97]. Other conditions that can present in a similar fashion to mastitis are plugged lactiferous ducts, inflammatory breast cancer, or other cancers. Care should be taken to rule out a breast abscess, which can occur as a complication of mastitis [98]. In cases of a localized area of swelling, ultrasound or needle aspiration should be considered to rule out this complication. Recurrent mastitis should alert the clinician to the presence of a possible underlying breast abnormality, keeping in mind that 3% of all new cases of breast cancer are diagnosed within the lactation period [95]. Diagnostic studies need not be undertaken in cases of simple mastitis. For patients who appear toxic, white blood cell counts and blood cultures may be warranted, and milk cultures for antibiotic sensitivity can be obtained. Treatment Treatment of mastitis should be multipronged, with a focus on restoring lactation flow and treating infection. Warm compresses, increased maternal fluid intake, continued frequent nursing, and special attention to complete breast emptying all help speed recovery [98]. These conservative therapies can be augmented with anti-inflammatory medications and analgesics. Oxytocin nasal spray can be used to facilitate the letdown reflex. Initial antimicrobial therapeutic choices of dicloxacillin or cloxacillin are common, with broadening of therapy to cephalexin or amoxicillin/clavulanate (Augmentin) for treatment failures. Erythromycin or clindamycin is a reasonable choice in penicillin allergic mothers (Table 1) [99].

Summary Although excellent prenatal care is generally available in the United States, all emergency providers should have some basic knowledge of the subject of maternal infection and the risks that it imparts to the mother and newborn. Moreover, with the advent of shorter postpartum hospital stays, not to mention the popularity of in-home births, emergency physicians are becoming the frontline for diagnosing and treating postpartum infections. This article has discussed the common (mastitis and urinary tract infections) as well as less common (varicella pneumonia and maternal HIV infection) but more controversial clinical scenarios that may be encountered in any emergency department.

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References [1] Kremery S, Hromec J, Demesova D. Treatment of lower urinary tract infection in pregnancy. Int J Antimicrob Agents 2001;17(4):279–82. [2] Sharma P, Thapa L. Acute pyelonephritis in pregnancy: a retrospective study. Aust N Z J Obstet Gynaecol 2007;47(4):313–5. [3] Pastore LM, Savitz DA, Thorp JM Jr, et al. Predictors of symptomatic urinary tract infection after 20 weeksapos; gestation. J Perinatol 1999;19(7):488–93. [4] Colau JC. Urinary tract infections in pregnancy. Rev Prat 2003;53(16):1797–800. [5] Connolly A, Thorp JM Jr. Urinary tract infections in pregnancy. Urol Clin North Am 1999; 26(4):779–87. [6] Kinningham RB. Asymptomatic bacteriuria in pregnancy. Am Fam Physician 1993;47: 1232–8. [7] Weissenbacher ER, Reisenberger K. Uncomplicated urinary tract infections in pregnant and non-pregnant women. Curr Opin Obstet Gynecol 1993;5(4):513–6. [8] Karat C, Madhivanan P, Krupp K, et al. The clinical and microbiological correlates of premature rupture of membranes. Indian J Med Microbiol 2006;24(4):283–5. [9] Sheikh MA, Khan MS, Khatoon A, et al. Incidence of urinary tract infection during pregnancy. East Mediterr Health J 2000;6(2–3):265–71. [10] Le J, Briggs GG, McKeown A, et al. Urinary tract infections during pregnancy. Ann Pharmacother 2004;38(10):1692–701. [11] MacLean AB. Urinary tract infection in pregnancy. Int J Antimicrob Agents 2001;17(4):273–6. [12] Einarson A, Shuhaiber S, Koren G. Effects of antibacterials on the unborn child: what is known and how should this influence prescribing. Paediatr Drugs 2001;3(11):803–16. [13] ACOG educational bulletin: antimicrobial therapy for obstetric patients. Number 245, March 1998. American College of Obstetricians and Gynecologists. Int J Gynaecol Obstet 1998;61:299–308. [14] Grio R, Porpiglia M, Vetro E, et al. Asymptomatic bacteriuria in pregnancy: maternal and fetal complications. Panminerva Med 1994;36(4):198–200. [15] Gerstner GJ, Mu¨ller G, Nahler G. Amoxicillin in the treatment of asymptomatic bacteriuria in pregnancy: a single dose of 3 g amoxicillin versus a 4-day course of 3 doses 750 mg amoxicillin. Gynecol Obstet Invest 1989;27(2):84–7. [16] Andriole VT, Patterson TF. Epidemiology, natural history, and management of urinary tract infections in pregnancy. Med Clin North Am 1991;75(2):359–73. [17] Mohammad M, Mahdy ZA, Omar J, et al. Laboratory aspects of asymptomatic bacteriuria in pregnancy. Southeast Asian J Trop Med Public Health 2002;33(3):575–80. [18] Casey BM, Cox SM. Chorioamnionitis and endometritis. Infect Dis Clin North Am 1997; 11(1):203–22. [19] Martius J. Ascending infection in pregnancy as a cause of premature labor. Z Geburtshilfe Perinatol 1989;193(1):1–7. [20] Newton ER. Premature labor, preterm premature rupture of membranes, and chorioamnionitis. Clin Perinatol 2005;32(3):571–600. [21] Martens KA. Sexually transmitted and genital tract infections during pregnancy. Emerg Med Clin North Am 1994;12(1):91–113. [22] Pankuch GA, Cherouny PH, Botti JJ, et al. Amniotic fluid leukotaxis assay as an early indicator of chorioamnionitis. Am J Obstet Gynecol 1989;161(3):802–7. [23] Teichmann AT, Arendt P, Speer CP. Premature rupture of the membranes and amniotic infections: the significance of laboratory tests. Eur J Obstet Gynecol Reprod Biol 1990; 34(3):217–22. [24] Gonc¸alves LF, Chaiworapongsa T, Romero R. Intrauterine infection and prematurity. Ment Retard Dev Disabil Res Rev 2002;8(1):3–13. [25] Gilstrap LC III. Acute chorioamnionitis. In: Gilstrap LC III, editor. Obstetric and perinatal infections, vol. 16. St. Louis (MO): Mosby-Year Book; 1991. p. 5.

364

GORGAS

[26] Shalev E, Peleg D, Eliyahu S, et al. Comparison of 12- and 72-hour expectant management of premature rupture of membranes in term pregnancies. Obstet Gynecol 1995;85(5 Pt 1):766–8. [27] Lee W, Clark SL, Cotton DB, et al. Septic shock during pregnancy. Am J Obstet Gynecol 1988;159(2):410–6. [28] McGregor JA. Chlamydial infection in women. Obstet Gynecol Clin North Am 1989;16(3): 565–92. [29] Cox SM, Gilstrap LC III. Postpartum endometritis. Obstet Gynecol Clin North Am 1989; 16(2):363–71. [30] Druelinger L. Postpartum emergencies. Emerg Med Clin North Am 1994;12(1):219–37. [31] Yonekura ML. Treatment of postcesarean endomyometritis. Clin Obstet Gynecol 1988; 31(2):488–500. [32] Gibbs RS. Clinical risk factors for puerperal infection. Obstet Gynecol 1980;55(Suppl 5): 178S–84S. [33] Gibbs RS. Infection after cesarean section. Clin Obstet Gynecol 1985;28(4):697–710. [34] Faro S, Phillips LE, Baker JL, et al. Comparative efficacy and safety of mezlocillin, cefoxitin, and clindamycin plus gentamicin in postpartum endometritis. Obstet Gynecol 1987;69(5):760–6. [35] Hillier S, Watts DH, Lee MF, et al. Etiology and treatment of post cesarean section endometritis after cephalosporin prophylaxis. J Reprod Med 1990;35(Suppl 3):322–8. [36] Anthony BF, Okada DM, Hobel CJ. Epidemiology of the group B streptococcus: maternal and nosocomial sources for infant acquisitions. J Pediatr 1979;95(3):431–6. [37] McKenna DS, Iams JD. Group B streptococcal infections. Semin Perinatol 1998;22(4):267–76. [38] Zaleznik DF, Rench MA, Hillier S, et al. Invasive disease due to group B streptococcus in pregnant women and neonates from diverse population groups. Clin Infect Dis 2000; 30(2):276–81. [39] Glantz JC, Kedley KE. Concepts and controversies in the management of group B streptococcus during pregnancy. Birth 1998;25(1):45–53. [40] Regan JA, Klebanoff MA, Nugent RP, et al. Colonization with group B streptococci in pregnancy and adverse outcome: VIP Study Group. Am J Obstet Gynecol 1996;174(4): 1354–60. [41] Money DM, Dobson S, Canadian Paediatric Society Infectious Diseases Committee. The prevention of early-onset neonatal group B streptococcal disease. J Obstet Gynaecol Can 2004;26(9):826–40. [42] Benitz WE, Gould JB, Druzin ML. Risk factors for early-onset group B streptococcal sepsis: estimation of odds ratios by critical literature review. Pediatrics 1999;103(6):1–14. [43] Baker CJ. Group B streptococcal infections. Clin Perinatol 1997;24(1):59–70. [44] Edwards RK, Clark P, Duff P. Intrapartum antibiotic prophylaxis 2: positive predictive value of antenatal group B streptococci cultures and antibiotic susceptibility of clinical isolates. Obstet Gynecol 2002;100(3):540–4. [45] Lim DV, Morales WJ, Walsh AF, et al. Reduction of morbidity and mortality rates for neonatal group B streptococcal disease through early diagnosis and chemoprophylaxis. J Clin Microbiol 1986;23(3):489–92. [46] Smaill F. Intrapartum antibiotics for group B streptococcal colonisation. Cochrane Database Syst Rev 2000;(2):CD000115. [47] Morales WJ, Dickey SS, Bornick P, et al. Change in antibiotic resistance of group B streptococcus: impact on intrapartum management. Am J Obstet Gynecol 1999;181(2):310–4. [48] Schuchat A. Epidemiology of group B streptococcal disease in the United States: shifting paradigms. Clin Microbiol Rev 1998;11(3):497–513. [49] Noya FJ, Baker CJ. Prevention of group B streptococcal infection. Infect Dis Clin North Am 1992;6(1):41–55. [50] Singh S. Hospital admissions resulting from unsafe abortion: estimates from 13 developing countries. Lancet 2006;368(9550):1887–92. [51] Grimes DA, Benson J, Singh S, et al. Unsafe abortion: the preventable pandemic. Lancet 2006;368(9550):1908–19.

INFECTIONS RELATED TO PREGNANCY

365

[52] Schwartz RH. Septic shock. In: Charles D, editor. Obstetric and perinatal infections. St. Louis (MO): Mosby-Yearbook; 1993. p. 118. [53] Stubblefield PG, Grimes DA. Septic abortion. N Engl J Med 1994;331(5):310–4. [54] Rothman RE. Current Centers for Disease Control and Prevention guidelines for HIV counseling, testing, and referral: critical role of and a call to action for emergency physicians. Ann Emerg Med 2004;44(1):31–42. [55] de Bruyn M, Paxton S. HIV testing of pregnant women–what is needed to protect positive womenapos;s needs and rights? Sex Health 2005;2(3):143–51. [56] Bolu OO, Allread V, Creek T, et al. Approaches for scaling up human immunodeficiency virus testing and counseling in prevention of mother-to-child human immunodeficiency virus transmission settings in resource-limited countries. Am J Obstet Gynecol 2007;197(Suppl 3):S83–9. [57] Struik SS, Tudor-Williams G, Taylor GD, et al. Infant HIV infection despite ‘universal’ antenatal testing. Arch Dis Child 2007;93(1):59–61. [58] Ellis GL, Melton J, Fikins K. Viral infections during pregnancy: a guide for the emergency physician. Ann Emerg Med 1990;19(7):802–11. [59] The mode of delivery and the risk of vertical transmission of human immunodeficiency virus type 1–a meta-analysis of 15 prospective cohort studies. The International Perinatal HIV Group. N Engl J Med 1999;340(13):977–87. [60] Elective caesarean section versus vaginal delivery in prevention of vertical HIV-1 transmission: a randomised clinical trial. The European Mode of Delivery Collaboration. Lancet 1999;353(9158):1035–9. [61] Jamieson DJ, Clark J, Kourtis AP, et al. Recommendations for human immunodeficiency virus screening, prophylaxis, and treatment for pregnant women in the United States. Am J Obstet Gynecol 2007;197(Suppl 3):S26–32. [62] Jamieson DJ, Read JS, Kourtis AP, et al. Cesarean delivery for HIV-infected women: recommendations and controversies. Am J Obstet Gynecol 2007;197(Suppl 3):S96–100. [63] Louis J, Landon MB, Gersnoviez RJ, et al, Maternal-Fetal Medicine Units Network, National Institute of Child Health and Human Development. Perioperative morbidity and mortality among human immunodeficiency virus infected women undergoing cesarean delivery. Obstet Gynecol 2007;110(2 Pt 1):385–90. [64] Dao H, Mofenson LM, Ekpini R, et al. International recommendations on antiretroviral drugs for treatment of HIV-infected women and prevention of mother-to-child HIV transmission in resource-limited settings: 2006 update. Am J Obstet Gynecol 2007;197(Suppl 3):S42–55. [65] Suksomboon N, Poolsup N, Ket-Aim S. Systematic review of the efficacy of antiretroviral therapies for reducing the risk of mother-to-child transmission of HIV infection. J Clin Pharm Ther 2007;32(3):293–311. [66] Gilling-Smith C, Nicopoullos JD, Semprini AE, et al. HIV and reproductive care: a review of current practice. BJOG 2006;113(8):869–78, Epub 2006 Jun 2. [67] McIntyre JA. Controversies in the use of nevirapine for prevention of mother-to-child transmission of HIV. Expert Opin Pharmacother 2006;7(6):677–85. [68] Watts DH. Treating HIV during pregnancy: an update on safety issues. Drug Saf 2006;29(6): 467–90. [69] Kourtis AP, Jamieson DJ, de Vincenzi I, et al. Prevention of human immunodeficiency virus1 transmission to the infant through breastfeeding: new developments. Am J Obstet Gynecol 2007;197(Suppl 3):S113–22. [70] Fowler MG, Lampe MA, Jamieson DJ, et al. Reducing the risk of mother-to-child human immunodeficiency virus transmission: past successes, current progress and challenges, and future directions. Am J Obstet Gynecol 2007;197(Suppl 3):S3–9. [71] Lim WS, Macfarlane JT, Colthorpe CL. Pneumonia and pregnancy. Thorax 2001;56:398–405. [72] Goodrum LA. Pneumonia in pregnancy. Semin Perinatol 1997;21(4):276–83. [73] Madinger NE, Greenspoon JS, Ellrodt AG. Pneumonia during pregnancy: has modern technology improved maternal and fetal outcome? Am J Obstet Gynecol 1989;161(3):657–62.

366

GORGAS

[74] Munn MB, Groome LJ, Atterbury JL, et al. Pneumonia as a complication of pregnancy. J Matern Fetal Med 1999;8(4):151–4. [75] Benedetti TJ, Valle R, Ledger WJ. Antepartum pneumonia in pregnancy. Am J Obstet Gynecol 1982;144(4):413–7. [76] Berkowitz K, LaSala A. Risk factors associated with the increasing prevalence of pneumonia during pregnancy. Am J Obstet Gynecol 1990;163(3):981–5. [77] Rodrigues J, Niederman MS. Pneumonia complicating pregnancy. Clin Chest Med 1992; 13(4):679–91. [78] Nathwani D, Maclean A, Conway S, et al. Varicella infections in pregnancy and the newborn: a review prepared for the UK Advisory Group on Chickenpox on behalf of the British Society for the Study of Infection. J Infect 1998;36(Suppl 1):59–71. [79] Eder SE, Apuzzio JJ, Weiss G. Varicella pneumonia during pregnancy: treatment of two cases with acyclovir. Am J Perinatol 1988;5(1):16–8. [80] Haake DA, Zakowski PC, Haake DL, et al. Early treatment with acyclovir for varicella pneumonia in otherwise healthy adults: retrospective controlled study and review. Rev Infect Dis 1990;12(5):788–98. [81] Weinstein L, Meade RH. Respiratory manifestations of chickenpox: special consideration of the features of primary varicella pneumonia. AMA Arch Intern Med 1956;98(1):91–9. [82] Smego RA Jr, Asperilla MO. Use of acyclovir for varicella pneumonia during pregnancy. Obstet Gynecol 1991;78(6):1112–6. [83] Clements DA, Katz SL. Varicella in a susceptible pregnant woman. Curr Clin Top Infect Dis 1993;13:123–30. [84] Spangler JG, Kirk JK, Knudson MP. Uses and safety of acyclovir in pregnancy. J Fam Pract 1994;38(2):186–91. [85] Clark GP, Dobson PM, Thickett A, et al. Chickenpox pneumonia, its complications and management: a report of three cases, including the use of extracorporeal membrane oxygenation. Anaesthesia 1991;46(5):376–80. [86] Barbosa-Cesnik C, Schwartz K, Foxman B. Lactation mastitis. JAMA 2003;289(13):1609–12. [87] Ellenbogen C, Graybill JR, Silva J Jr, et al. Bacterial pneumonia complicating adenoviral pneumonia: a comparison of respiratory tract bacterial culture sources and effectiveness of chemoprophylaxis against bacterial pneumonia. Am J Med 1974;56(2):169–78. [88] Weller TH. Varicella and herpes zoster: changing concepts of the natural history, control, and importance of a not-so-benign virus. N Engl J Med 1983;309(23):1434–40. [89] Hermann KL. Congenital and perinatal varicella. Clin Obstet Gynecol 1982;25:605–9. [90] Marchant DJ. Inflammation of the breast. Obstet Gynecol Clin North Am 2002;29(1):89–102. [91] Foxman B, D’Arcy H, Gillespie B, et al. Lactation mastitis: occurrence and medical management among 946 breastfeeding women in the United States. Am J Epidemiol 2002;155(2): 103–14. [92] Vogel A, Hutchison BL, Mitchell EA. Mastitis in the first year postpartum. Birth 1999;26(4): 218–25. [93] Vogel A , Hutchinson BL, Mitchell EA. Factorsa associated with the duration of breastfeeding. Acta Paediatr 1999;88(12):1320–6. [94] Yokoe DS, Christiansen CL, Johnson R, et al. Epidemiology of and surveillance for postpartum infections. Emerg Infect Dis 2001;7(5):837–41. [95] Fetherston C. Mastitis in lactating women: physiology or pathology? Breastfeed Rev 2001; 9(1):5–12. [96] Asoglu O, Ozmen V, Karanlik H, et al. Feasibility of surgical management in patients with granulomatous mastitis. Breast J 2005;11(2):108–14. [97] Osterman KL, Rahm VA. Lactation mastitis: bacterial cultivation of breast milk, symptoms, treatment, and outcome. J Hum Lact 2000;16(4):297–302. [98] Pouchot J, Foucher E, Lino M, et al. Granulomatous mastitis: an uncommon cause of breast abscess. Arch Intern Med 2001;161(4):611–2. [99] Deshpande W. Mastitis. Community Pract 2007;80(5):44–5.