A 24-year-old woman, gravida 1 para 0, at 11 weeks gestation comes to the office for a routine prenatal visit. The patient is doing well and has no vaginal bleeding or cramping. Earlier in the pregnancy, she had mild nausea that she managed by eating multiple small meals throughout the day. The patient has a history of cystitis that occurred prior to pregnancy, but currently has no dysuria or hematuria. She has no chronic medical conditions or previous surgeries. She takes a daily prenatal vitamin. The patient has no known drug allergies and does not use tobacco, alcohol, or illicit drugs. She runs on a treadmill for 45 minutes, 4 times a week. Temperature is 36.7 C (98 F), blood pressure is 124/74 mm Hg, and pulse is 78/min. Fetal heart rate is 140/min by Doppler ultrasound. Physical examination is otherwise unremarkable. Laboratory results from her initial prenatal visit are reviewed; a routine clean catch urine culture grew 100,000 colony-forming units/mL of Escherichia coli. Which of the following is the best next step in management of this patient?

Question

A 24-year-old woman, gravida 1 para 0, at 11 weeks gestation comes to the office for a routine prenatal visit.  The patient is doing well and has no vaginal bleeding or cramping.  Earlier in the pregnancy, she had mild nausea that she managed by eating multiple small meals throughout the day.  The patient has a history of cystitis that occurred prior to pregnancy, but currently has no dysuria or hematuria.  She has no chronic medical conditions or previous surgeries.  She takes a daily prenatal vitamin.  The patient has no known drug allergies and does not use tobacco, alcohol, or illicit drugs.  She runs on a treadmill for 45 minutes, 4 times a week.  Temperature is 36.7 C (98 F), blood pressure is 124/74 mm Hg, and pulse is 78/min.  Fetal heart rate is 140/min by Doppler ultrasound.  Physical examination is otherwise unremarkable.  Laboratory results from her initial prenatal visit are reviewed; a routine clean catch urine culture grew >100,000 colony-forming units/mL of Escherichia coli.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c08e_3bf4_8f63_5f5143366a7e_MD0005_00 Asymptomatic bacteriuria is the presence of >100,000 colony-forming units/mL in a clean catch urine specimen from a patient without symptoms of cystitis (eg, dysuria, hematuria, frequency, urgency). Nonpregnant patients with asymptomatic bacteriuria do not require treatment as it does not reduce the risk of symptomatic infection or its complications (eg, pyelonephritis) in this patient population. In contrast, pregnant patients with asymptomatic bacteriuria are at increased risk for acute pyelonephritis due to the effects of progesterone on the upper urinary tract (eg, smooth muscle dilation, ureteral enlargement, vesicoureteral valve dysfunction). In addition, untreated asymptomatic bacteriuria is associated with fetal complications, including preterm birth, low birth weight, and perinatal mortality. Therefore, pregnant women are screened at the initial prenatal visit via clean catch urine culture and treated as needed with antibiotics to decrease the risk of both maternal and fetal complications (Choice D). Although treatment is guided by culture susceptibility, first-line antibiotics during pregnancy include cephalexin for 3-7 days, amoxicillin-clavulanate for 3-7 days, or fosfomycin as a single dose. Because treatment failure is common, a repeat urine culture is performed a week after completion of the antibiotic regimen to test for cure. (Choice B) Patients with acute pyelonephritis during pregnancy receive a treatment course of antibiotics. Once treatment is completed, they receive daily antibiotic suppression until 6 weeks postpartum to prevent recurrence. During the first trimester, nitrofurantoin is a second-line antibiotic due to potential associations with congenital defects. It is contraindicated at term due to an increased risk of hemolytic anemia in the newborn. (Choice C) Trimethoprim-sulfamethoxazole is a first-line treatment for acute cystitis in nonpregnant women. However, its use in the first trimester has been associated with neural tube defects due to the folate antagonist properties of trimethoprim. Use in the late third trimester is associated with neonatal kernicterus. (Choice E) This patient's bacteriuria is unlikely to clear without antibiotic treatment; therefore, a confirmatory urine culture is not indicated. In addition, delaying treatment to await the results of a second culture places the patient at increased risk of progression to symptomatic cystitis and/or pyelonephritis. Educational objective: Treatment of asymptomatic bacteriuria during pregnancy decreases the risk of maternal (eg, pyelonephritis) and fetal complications (eg, preterm birth, low birth weight, perinatal mortality). First-line antibiotics during pregnancy include cephalexin, amoxicillin-clavulanate, or fosfomycin. References: Duration of treatment for asymptomatic bacteriuria during pregnancy. (http://www.ncbi.nlm.nih.gov/pubmed/22161364) Screening and treating asymptomatic bacteriuria in pregnancy (http://www.ncbi.nlm.nih.gov/pubmed/20139763)

A 24-Year-Old Woman, Gravida 1 Para 0, at 11 Weeks