Renal infection is one of the most frequent serious medical complications of pregnancy. Data from the 2006 Nationwide Inpatient Sample showed that nearly 29,000 pregnancy-associated hospitalizations were for acute pyelonephritis Qolley, 2012). In one hospital-system database of nearly 550,000 births, its incidence was 0.5 percent (Wing, 2014). Importantly, pyelonephritis is a leading cause of septic shock during pregnancy (Snyder, 2013). In one Parkland Hospital Obstetrical Intensive Care Unit review, 12 percent of antepartum admissions were for sepsis syndrome caused by renal infections (Zeeman, 2003). Urosepsis may be related to an increased incidence of cerebral palsy in preterm infants Qacobsson, 2002). Fortunately, afected mothers sufer no serious long-term sequelae (Raz, 2003).
Renal infection develops more frequently in the second trimester, and nulliparity and young age are risks (Hill, 2005).
Pyelonephritis is unilateral and right-sided in more than half of cases, and it is bilateral in a fourth. Fever and shaking chills usually develop rather abruptly, and patients have aching pain in one or both lumbar regions. Anorexia, nausea, and vomiting may worsen dehydration. Tenderness usually can be elicited by percussion in one or both costovertebral angles. he differential diagnosis includes, among others, labor, chorioamnionitis, adnexal torsion, appendicitis, placental abruption, or infarcted leiomyoma. Evidence of the sepsis syndrome is common (Chap. 47, p. 921).
If this infection is suspected, a urine sample obtained by catheterization may be preferred to avoid obscuring contamination from the lower genital tract. he urinary sediment contains many leukocytes, frequently in clumps, and numerous bacteria. Bacteremia is demonstrated in 15 to 20 percent of these women. E coli is isolated from urine or blood in 70 to 80 percent of infections, Klebsiela pneumoniae in 3 to 5 percent, Enterobacter or Proteus species in 3 to 5 percent, and gram-positive organisms, including group B Streptococcus and Staphylococcus aureus, in up to 10 percent of cases (Hill, 2005; Wing, 2000).
Plasma creatinine is monitored because early studies reported that 20 percent of pregnant women developed acute kidney injury . More recent findings, however, show this to be only 5 percent if aggressive fluid resuscitation is provided (Hill, 2005). Follow-up studies have demonstrated that this endotoxin-induced damage is reversible long term. s shown in Figure 53-2, varying degrees of respiratory distress syndrome from endotoxin-induced alveolar injury are manifest in up to 2 percent of women (Cunningham, 1987; Snyder, 2013; Wing, 2014).
Uterine activity from endotoxin is common and is related to fever severity (Graham, 1993). In one study, women with pyelonephritis averaged five contractions per hour at admission, and this decreased to two per hour within 6 hours of intravenous luid and antimicrobial administration (Millar, 2003). Notably, 3-agonist therapy for tocolysis increases the likelihood of respiratory insuiciency from permeability edema (Lamont, 2000). The incidence of pulmonary edema in women with pyelonephritis who were given 3-agonists was reported to be 8 percent-a fourfold increase over that expected (Towers, 1991) .