Bacteruria in Pregnancy: Difference between revisions
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* '''Pregnant females with bacteruria should be prescribed a full 3-7 day course of therapy''' | * '''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.''' | ** '''Pregnant females with acute pyelonephritis should be hospitalized and treated initially with parenteral antimicrobial agents.''' | ||
* '''Agents considered safe (4):''' | * '''<span style="color:#ff0000">Agents considered safe (4):''' | ||
** '''<span style="color:#ff0000">Penicillins''' | ** '''<span style="color:#ff0000">Penicillins''' | ||
*** Ampicillin 500mg qid | *** Ampicillin 500mg qid | ||
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*** Cefaclor 500mg qid | *** Cefaclor 500mg qid | ||
** '''<span style="color:#ff0000">Fosfomycin'''[https://www.aafp.org/afp/2000/0201/p713.html §] | ** '''<span style="color:#ff0000">Fosfomycin'''[https://www.aafp.org/afp/2000/0201/p713.html §] | ||
**'''Nitrofurantoin''' (if penicillin allergy) 100mg qid | **'''<span style="color:#ff0000">Nitrofurantoin''' (if penicillin allergy) 100mg qid | ||
*** '''Should be discontinued at 35 weeks (see above)''' | *** '''<span style="color:#ff0000">Should be discontinued at 35 weeks (see above)''' | ||
* '''<span style="color:#ff0000">Agents that should be avoided:''' | * '''<span style="color:#ff0000">Agents that should be avoided:''' | ||
*# '''<span style="color:#ff0000">Fluoroquinolones: risk of damage to immature cartilage''' | *# '''<span style="color:#ff0000">Fluoroquinolones: risk of damage to immature cartilage''' |
Revision as of 10:27, 16 March 2024
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
- The degree of renal function impairment is the major determinant for pregnancy outcome
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%.
- Factors contributing to increased risk of progression from asymptomatic bacteruria to acute clinical pyelonephritis in pregnancy (2):
- Risk of UTI progression to pyelonephritis
- Spontaneous resolution of asymptomatic bacteriuria in pregnant females is unlikely unless treated, unlike non-pregnant females who often clear their asymptomatic bacteriuria
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
- Fosfomycin§
- Nitrofurantoin (if penicillin allergy) 100mg qid
- Should be discontinued at 35 weeks (see above)
- Penicillins
- 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 the culture is positive, the cause of bacteriuria must be determined to be lack of resolution, bacterial persistence, or reinfection.
- 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
Answers
References
- Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, vol 2, chap 12