CASE Pregnant woman with dysuria and suprapubic pain
A 25-year-old primigravid woman at 18 weeks of gestation requests evaluation because of the acute onset of frequent urination, dysuria, urination hesitancy, and suprapubic pain on the morning following intercourse. She has not experienced similar symptoms in the past. On physical examination, her temperature is 38 °C, pulse is 96 beats per minute, respirations are 18 per minute, and blood pressure is 100/76 mm Hg. She has no urethral discharge but is tender to palpation in the suprapubic area.
- What is the most likely diagnosis?
- What tests would be of greatest value in confirming the diagnosis?
- What is the most appropriate treatment for this patient?
Meet our perpetrator
Urinary tract infections (UTIs) are among the most common infections that occur during pregnancy. They may take one of 4 forms: acute urethritis, asymptomatic bacteriuria, acute cystitis, and acute pyelonephritis.1 The first 3 conditions usually are straightforward to diagnose and treat, and they usually do not cause major problems for the mother or fetus. The latter, however, can cause serious complications that pose risk to the mother and fetus.
This article will review the microbiology, clinical manifestations, diagnosis, and treatment of these 4 disorders in pregnancy. Particular emphasis will be placed on measures to avoid adverse effects on the mother and fetus from antimicrobial agents.
Acute urethritis
Acute urethritis can be caused by low concentrations of coliform organisms in the lower urinary tract, but it usually is secondary to infection by Neisseria gonorrhea or Chlamydia trachomatis. In most prenatal populations, the prevalence of one or the other of these 2 infections is approximately 5%.1
The most common clinical manifestations of acute urethritis are a purulent urethral discharge, increased frequency of urination, dysuria, and urination hesitancy. The diagnosis most easily is confirmed by obtaining a specimen of urethral discharge or urine and evaluating the sample by a nucleic acid amplification test for both gonorrhea and chlamydia.
Antibiotic therapy is preferred. The current recommended treatment for gonococcal urethritis is a single intramuscular injection of ceftriaxone 500 mg. If the patient prefers oral therapy, she can receive cefixime 800 mg in a single dose. For patients with an allergy to beta-lactam antibiotics, the alternative regimen is gentamicin 240 mg in a single intramuscular injection, combined with oral azithromycin in a single 2,000-mg dose. For treatment of chlamydia in pregnancy, the recommended therapy is azithromycin 1,000 mg in a single oral dose.2 A test of cure should be performed within 4 weeks of treatment.
Asymptomatic bacteriuria
Asymptomatic bacteriuria (ASB) is the most common UTI in women. Approximately 5% to 8% of all sexually active women have ASB. The condition is not unique to pregnancy; it is associated primarily with the assumption of coital activity. In point of fact, the ASB typically precedes pregnancy by several years.1
The principal pathogens responsible for ASB are shown in the FIGURE. Over 80% of first-time infections are secondary to Escherichia coli. As more recurrent episodes occur, the other Gram-negative bacilli (ie, Klebsiella pneumoniae, Proteus species) become more prevalent. The 3 major Gram-positive cocci that cause UTIs are enterococci, Staphylococcus saprophyticus, and group B streptococci.1,3,4
In nonpregnant women, ASB usually remains completely asymptomatic, and ascending infections only rarely occur. In pregnancy, however, urinary stasis is present due to the effects of progesterone on ureteral peristalsis and because of pressure on the ureters (particularly the right) by the expanding gravid uterus. As a result, ascending infection may occur in approximately 20% of patients if the lower tract infection is not identified and treated adequately.1
Clean-catch specimens and treatment
The standard criterion for the diagnosis of ASB is a urine culture that shows greater than 100,000 colonies/mL of a recognized uropathogen.1 The urine usually is obtained as a midstream, clean-catch specimen, and the test should be performed at the time of the first prenatal appointment. Once identified, ASB should be treated promptly with one of the antibiotics listed in the TABLE. Nitrofurantoin monohydrate macrocrystals (nitrofurantoin) and trimethoprim-sulfamethoxazole should be avoided in the first trimester unless no other drug is active against the identified microorganism.
Both have been linked to teratogenic fetal effects.5-8 The defects associated with the former drug include eye abnormalities, heart defects, and facial clefts. The abnormalities associated with the latter include neural tube defects, heart defects, choanal atresia, and diaphragmatic hernia. In the first trimester, amoxicillin and cephalexin are reasonable choices for treatment. As a general rule, a 3-day course of antibiotics will be effective for eradicating the initial episode of ASB. For recurrent infections, a 7- to 10-day course is indicated.1,3,4
Acute cystitis
The microbiology of acute cystitis essentially is identical to that of asymptomatic bacteriuria. The usual clinical manifestations include increased frequency of urination, dysuria, and urination hesitancy in association with suprapubic discomfort and a lowgrade fever.
The diagnosis can be quickly confirmed by testing the urine pH and assessing for leukocyte esterase and nitrites. If both the leukocyte esterase and nitrite test are positive, the probability of a positive urine culture is high; however, the nitrite test can be falsely negative if the urine has been incubating in the bladder for only a short period of time or if a Gram-positive organism is responsible for the infection. The urine pH is particularly helpful if it is elevated in the range of 8. This finding strongly is associated with a Proteus infection.1,9-11
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