Bacteruria in Pregnancy: Difference between revisions
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== Pathophysiology == | == Pathophysiology == | ||
* '''Urologic Anatomic and Physiologic Changes during Pregnancy (4)''' | * '''<span style="color:#ff0000">Urologic Anatomic and Physiologic Changes during Pregnancy (4)''' | ||
*# '''Increase in renal size''' (≈1cm); thought to be result of increased renal vascular and interstitial volume | *# '''<span style="color:#ff0000">Increase in renal size</span>''' (≈1cm); thought to be result of increased renal vascular and interstitial volume | ||
*# '''Hydronephrosis from:''' | *# '''<span style="color:#ff0000">Hydronephrosis from:</span>''' | ||
*## '''Obstructive effect of the enlarging uterus (likely main factor)''' | *## '''<span style="color:#ff0000">Obstructive effect of the enlarging uterus (likely main factor)</span>''' | ||
*## '''Progesterone mediated relaxation''' of smooth muscle of collecting system and bladder resulting in decreased collecting system and ureteral peristalsis, ureteral dilatation, increased bladder capacity | *## '''<span style="color:#ff0000">Progesterone mediated relaxation</span>''' 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''' | *# '''<span style="color:#ff0000">Bladder changes</span>'''; 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 | *# '''<span style="color:#ff0000">Improved renal function; glomerular filtration increases by 30-50%,</span>''' 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:''' | * '''<span style="color:#ff0000">Changes to the urinary tract in pregnancy that increase risk of UTI:''' | ||
*# '''Decreased bladder tone because of edema and hyperemia''' | *# '''<span style="color:#ff0000">Decreased bladder tone because of edema and hyperemia</span>''' | ||
*# '''Increased urine volume in the upper collecting system as the physiologic dilation of pregnancy evolves,''' can increase the propensity to develop pyelonephritis | *# '''<span style="color:#ff0000">Increased urine volume in the upper collecting system as the physiologic dilation of pregnancy evolves,''' can increase the propensity to develop pyelonephritis</span> | ||
* '''Complications associated with bacteruria during pregnancy''' | * '''Complications associated with bacteruria during pregnancy''' | ||
*# '''Pyelonephritis''' | *# '''Pyelonephritis''' | ||
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** Spontaneous resolution of asymptomatic bacteriuria in pregnant females is unlikely unless treated, unlike non-pregnant females who often clear their asymptomatic bacteriuria | ** 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''' | *** '''Risk of UTI progression to pyelonephritis''' | ||
**** '''Non-pregnant females: 1%§''' | **** '''Non-pregnant females: 1%[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1314413/ §]''' | ||
**** '''Pregnant females: 20-40%''' | **** '''Pregnant females: 20-40%''' | ||
***** '''Factors contributing to increased risk of progression from asymptomatic bacteruria to acute clinical pyelonephritis in pregnancy''' '''(2):''' | ***** '''Factors contributing to increased risk of progression from asymptomatic bacteruria to acute clinical pyelonephritis in pregnancy''' '''(2):''' |
Latest revision as of 10:29, 16 March 2024
Pathophysiology[edit | edit source]
- 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[edit | edit source]
- Similar to non-pregnant females
Asymptomatic bacteriuria[edit | edit source]
- 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[edit | edit source]
- 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[edit | edit source]
- 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[edit | edit source]
Answers[edit | edit source]
References[edit | edit source]
- Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, vol 2, chap 12