Editing Bacteruria in Pregnancy

== Pathophysiology ==

* '''Urologic Anatomic and Physiologic Changes during Pregnancy (4)'''
*# '''Increase in renal size''' (≈1cm); thought to be result of increased renal vascular and interstitial volume
*# '''Hydronephrosis from:'''
*## '''Obstructive effect of the enlarging uterus (likely main factor)'''
*## '''Progesterone mediated relaxation''' of smooth muscle of collecting system and bladder resulting in decreased collecting system and ureteral peristalsis, ureteral dilatation, increased bladder capacity
*# '''Bladder changes'''; enlarging uterus displaces bladder, progesterone stimulates relaxation resulting in '''increased capacity'''; estrogen may cause '''bladder hypertrophy'''
*# '''Improved renal function; glomerular filtration increases by 30-50%,''' and urinary protein excretion increases; '''values considered normal in non-pregnant females may represent renal insufficiency during pregnancy'''. Similarly, urinary protein in pregnancy is not considered abnormal until > 300 mg of protein in 24 hours is excreted
* '''Changes to the urinary tract in pregnancy that increase risk of UTI:'''
*# '''Decreased bladder tone because of edema and hyperemia'''
*# '''Increased urine volume in the upper collecting system as the physiologic dilation of pregnancy evolves,''' can increase the propensity to develop pyelonephritis
* '''Complications associated with bacteruria during pregnancy'''
*# '''Pyelonephritis'''
*# '''Prematurity and prenatal mortality'''
*# '''Maternal anemia (conflicting evidence)'''
* Recurrent UTIs are not a contraindication to pregnancy
* Pregnancy in women with renal insufficiency
** The degree of renal function impairment is the major determinant for pregnancy outcome
*** Fetal survivors of pregnant women with mild or moderate renal disease is only slightly diminished.
*** However, the perinatal mortality is approximately 4x higher with severe disease

== Pathogens ==

* '''Similar to non-pregnant females'''

== Asymptomatic bacteriuria ==

* '''One of the most common infections encountered during pregnancy.'''
** Prevalence of bacteriuria in pregnant females varies from 4-7%
* '''Prevalence of asymptomatic bacteriuria in pregnancy is similar to that of the general population'''
* '''More likely to progress to pyelonephritis'''
** Spontaneous resolution of asymptomatic bacteriuria in pregnant females is unlikely unless treated, unlike non-pregnant females who often clear their asymptomatic bacteriuria
*** '''Risk of UTI progression to pyelonephritis'''
**** '''Non-pregnant females: 1%§'''
**** '''Pregnant females: 20-40%'''
***** '''Factors contributing to increased risk of progression from asymptomatic bacteruria to acute clinical pyelonephritis in pregnancy''' '''(2):'''
*****# '''Anatomic and physiologic changes induced by the gravid state''' (see above)
*****# '''Urine from pregnant females exhibits a more suitable pH for growth of E. coli''' in all stages of gestation.
***** '''Treatment for asymptomatic bacteruria reduces the risk of pyelonephritis to 0-5%.'''

== Diagnosis and Evaluation ==

* '''Labs: initial screening culture''' (significant false-negative rates with urinalysis or reagent strip testing) '''should be performed in all pregnant women during the first trimester'''
** '''If the culture shows no growth, repeat cultures are generally unnecessary because patients who have no growth in their urine early in their pregnancy are unlikely to develop bacteriuria later'''

== Management ==

* '''Pregnant females with bacteruria should be prescribed a full 3-7 day course of therapy'''
** '''Pregnant females with acute pyelonephritis should be hospitalized and treated initially with parenteral antimicrobial agents.'''
* '''Agents considered safe (4):'''
** '''Penicillins'''
*** Ampicillin 500mg qid
*** Amoxicillin 250mg tid
*** Penicillin V 500mg qid
** '''Cephalosporins'''
*** Cephalexin 500mg qid
*** Cefaclor 500mg qid
** '''Nitrofurantoin''' (if penicillin allergy) 100mg qid
*** '''Should be discontinued at 35 weeks (see above)'''
** '''Fosfomycin''' (§)
* '''Agents that should be avoided:'''
*# '''Fluoroquinolones: risk of damage to immature cartilage'''
*# '''Trimethroprim: risk of megaloblastic anemia because of anti-folic acid action'''
*# '''TMP/SMX: early, risk of teratogenicity; late, risk of kernicterus'''
*# '''Nitrofurantoin: avoid during 3rd trimester due to risk of hemolytic anemia'''
*# '''Chloramphenicol: risk of “gray baby” syndrome'''
*# '''Erythromycin: risk of maternal cholestatic jaundice'''
*# '''Tetracyclines: risk acute liver decompensation in the mother and inhibition of new bone growth in the fetus'''
* '''Follow-up cultures should be obtained to document absence of infection'''.
** If the culture is positive, the cause of bacteriuria must be determined to be lack of resolution, bacterial persistence, or reinfection.
*** If the infection is unresolved, proper selection and administration of another drug probably will solve the problem.
*** If the problem is bacterial persistence or rapid reinfection, antimicrobial suppression of infection or prophylaxis throughout the remainder of the pregnancy should be considered.
* '''If a pregnant female has a single episode of pyelonephritis or two episodes of cystitis, daily suppression with either nitrofurantoin or cephalexin should be considered until delivery.'''

== Questions ==

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== Answers ==

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== References ==

* Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, vol 2, chap 12