Intrauterine Infection and Beyond

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Intrauterine Infection and Beyond

• Edwin M. Thorpe, Jr., MD
• Division of Gynecologic Specialties
• Department of Obstetrics and Gynecology
• University of Tennessee Health Science Center

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Chorioamnionitis

• Amnionitis, intra-amniotic infection
• 1-5 percent of term pregnancies
• Clinical or subclinical infection up to 25
• Hematogenous dissemination rare
• Ascending infection most common
• - Bacteroides
• - Prevotella species
• - E. coli
• - Anaerobic streptococci
• - Group B streptococci

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Clinical Risk Factors for Choroiamnionitis

• Young age
• Low socioeconomic status
• Nulliparity
• Extended duration of labor and ruptured membranes
• Multiple vaginal examinations
• Preexisting lower genital tract infections

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Diagnosis of Chorioamnionitis

• Based on clinical findings
• Maternal fever
• Maternal and fetal tachycardia
• Absence of localizing signs
• Uterine tenderness
• Purulent amniotic fluid

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Differential Diagnosis of Chorioamnionitis

• Upper respiratory infection
• Bronchitis
• Pneumonia
• Pyelonephritis
• Viral syndrome
• Appendicitis

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Diagnostic Tests for Chorioamnionitis
Test Abnormal Finding Comment
Maternal WBC count gt15,000 cells/mm³
Labor/steroids may predominantly
leukocytes increase WBC count Amniotic
fluid glucose lt10 to 15 mm/dl Excellent
correlation with positive amniotic fluid
culture and clinical
infection Amniotic fluid IL-6 gt7.9
ng/ml Excellent correlation with positive
amniotic fluid culture and
clinical infection Amniotic fluid LE gt1
reaction Good correlation with positive
amniotic fluid culture and
clinical infection
Adapted from PA Duff in Obstetrics Normal and
Abnormal, Churchill Livingstone, 2002
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Diagnostic Tests for Chorioamnionitis
Test Abnormal Finding
Comment
Amniotic fluid Any organism in OIF Very
sensitive to inoculum Grams stain
May identify virulent organisms e.g. Group
B streptococcus Amniotic fluid culture Growth
of aerobic or Results usually not available
anaerobic microorganism for clinical
management Blood cultures Growth of aerobic
or Positive 5-10 of patients.
anaerobic microorganism Usually not of value
clinically
Adapted from PA Duff in Obstetrics Normal and
Abnormal, Churchill Livingstone, 2002
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Complications of Chorioamnionitis

• Bacteremia 3 to 12 percent of infected women
• Wound infection up to 10 of cesarean
  deliveries
• Pelvic abscess 1
• 5-10 of neonates pneumonia and bacteremia
• Perinatal mortality 1-4 term, up to 15
  preterm
• Prompt intrapartum treatment!

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Treatment of Chorioamnionitis

• Most extensively tested IV antibiotic regimen
• Ampicillin 2 g or Penicillin 5 million units q 6
  hours
• plus
• Gentamicin 1.5 mg/kg every 8 hours
• Allergic to ß-lactam antibiotics? Ampicillin or
  Penicillin substitutes
• Vancomycin 500 mg q 6hr or 1 g q 12hr
• Erythromycin 1 g q 6hr
• Clindamycin 900 mg q 8hr

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Single Agents of Value in the Treatment of
Chorioamnionitis
Drug Dosage and Relative Cost to
Dose Interval the Pharmacy
Extended spectrum penicillins
Ampicillin-sulbactam 3.0 g
q6h Low Mezlocillin 3-4 g
q6h Intermediate Piperacillin 3-4 g
q6h Intermediate Piperacillin-tazobactam
3.375 g q6h Intermediate Ticarcillin-clavulani
c acid 3.1 g q6h Low
Adapted from PA Duff in Obstetrics Normal and
Abnormal, Churchill Livingstone, 2002
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Single Agents of Value in the Treatment of
Chorioamnionitis
Drug Dosage and Relative Cost
to Dose Interval the
Pharmacy
Extended spectrum cephalosporins
Cefotaxime 2 g q8-12h
Intermediate Cefotetan 2 g q12h
Intermediate Cefoxitin 2
g q 6h High Ceftizoxime
2 g q12h Intermediate
Carbapenem
Imipenem-cilastatin 500 mg q6h
High Meropenem 1 g q12h High
Adapted from PA Duff in Obstetrics Normal and
Abnormal, Churchill Livingstone, 2002
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Treatment of Chorioamnionitis

• Risk of dysfunctional labor with chorioamnionitis
• 75 require augmentation
• 30-40 require cesarean delivery
• Careful fetal monitoring required
• If patient with chorioamionitis requires cesarean
  delivery
• Add anti-anaerobic antibiotic to regimen
• Clindamycin 900 mg every 8hr
• Metronidazole 500 mg every 6hr
• Without anaerobic coverage, treatment failure in
  20 to 30 percent of patients

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Treatment of Chorioamnionitis

• Continue IV antibiotics until
• Afebrile and asymptomatic for 24 hr
• Discharge home without oral antibiotics
• Except
• Documented staphylococcal bacteremia longer IV
  therapy and extended oral antibiotics
• Rapid defervescence after vaginal delivery
  short-course of oral antibiotics as outpatient
• Amoxicillin-clavulanate 875/125 mg po BID for 3
  days

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Treatment of Chorioamnionitis

• Single additional dose postpartum therapy for
  women with chorioamnionitis
• - RK Edwards, PA Duff - Univ of Florida
• Randomized trial
• - Study group received next scheduled dose of
  drugs postpartum
• - Controls received antibiotics until afebrile
  for 24 hours
• - Cesarean delivery add clindamycin
• N292
• - 151 study patients, 141 controls
• - No difference in treatment failure rate
• Conclusion Following prompt intrapartum
  treatment, one additional dose is sufficient
  postpartum therapy

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and beyond
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Postpartum (Puerperal) Endometritis

• 1 following vaginal delivery
• 5 to 15 after scheduled cesarean
• Extended labor and prolonged ruptured membranes
• 30 to 35 without antibiotic prophylaxis
• 15 to 20 with prophylaxis
• Nearly doubled infection rates in highly indigent
  populations

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Postpartum (Puerperal) Endometritis

• Polymicrobial, ascending infection
• (Normal) vaginal microorganisms
• Most common pathogenic bacteria
• Group B streptococci
• Anaerobic streptococci (Peptostreptococci)
• Aerobic gram-negative bacilli (E.coli, Klebsiella
  pneumoniae, Proteus species
• Anaerobic gram-negative bacilli (Bacteroides,
  Prevotella)
• Chlamydia late-onset infection

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Prophylactic Antibiotics for Prevention of
Postcesarean Endometritis

• Most appropriate agent limited spectrum
  cephalsporin
• Cefazolin 1-2 g immediately after cord clamped
• Second dose 8 hours after first dose
• High-risk patients
• Operating time greater than 1 hour
• Extended spectrum penicillins and cephalosporins
  effective, but no advantage
• Use of extended spectrum drugs may limit
  usefulness for treatment
• For ß-lactam hypersensitivity
• Clindamycin 900 mg plus gentamicin 1.5 mg/kg as a
  single dose

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Postpartum (Puerperal) Endometritis

• Fever - 38C (100.4F) or higher within first 36
  hours
• Malaise, tachycardia, lower abdominal pain,
  uterine tenderness, discolored, malodorous lochia
  
• Differential diagnosis
• - Endometritis - Viral syndrome
• - Atelectasis - Pyelonephritis
• - Pneumonia - Appendicitis

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Combination Antibiotic Regimens for the
Treatment of Postpartum Endometritis
Relative Cost to the Antibiotics
Intravenous Dose the Pharmacy
Regimen 1
Clindamycin 900 mg q8h
Intermediate Gentamicin 1.5 mg/kg q8h
Low or 5-7 mg/kg ideal
body weight q 24h
Adapted from PA Duff in Obstetrics Normal and
Abnormal, Churchill Livingstone, 2002
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Combination Antibiotic Regimens for the
Treatment of Postpartum Endometritis
Relative Cost to the Antibiotics
Intravenous Dose the Pharmacy
Regimen 2
Clindamycin 900 mg q8h
Intermediate Aztreonam 1-2 g q8h
High
Regimen 3
Metronidazole 500 mg q 12h
Low Penicillin or 5 million units
q 6h Low Ampicillin 2 g q 6h
Low Gentamicin 1.5 mg/kg q 8h
Low 5-7 mg/kg ideal Low
weight q 24 h
Adapted from PA Duff in Obstetrics Normal and
Abnormal, Churchill Livingstone, 2002
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Treatment of Resistant Microorganisms in Patients
with Postpartum Endometritis
Initial Principal Weakness Modification
of Antibiotic(s) in Coverage
Therapy
Extended spectrum Some aerobic and
Change treatment to cephalosporins
anaerobic gram-negative clindamycin or MTZ
plus bacilli, Enterococci penicillin
or AmpGent Extended spectrum Some aerobic
and As above penicillins
anaerobic gram-negative
bacilli Clindamycin plus Enterococci, some
Add Amp or PCN gentamicin or
anaerobic gram-negative Consider
substitution of aztreonam bacilli
MTZ for clindamycin
Adapted from PA Duff in Obstetrics Normal and
Abnormal, Churchill Livingstone, 2002
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Principal Risk Factors for Postcesarean Wound
Infection

• Poor surgical technique
• Low socioeconomic status
• Extended duration of labor and ruptured membranes
• Preexisting infection such as chorioamnionitis
• Obesity
• Type 1 (insulin-dependent) diabetes
• Immunodeficiency disorder
• Corticosteroid therapy
• Immunosuppressive therapy

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Postcesarean Wound Infection

• 3-5 of patients with endometritis
• Principal causative organisms
• - Staphylococcus aureus
• - Aerobic streptococci
• - Aerobic and anaerobic bacilli
• Strong consideration patients with poor
  response to treatment of endometritis

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Diagnosis of Postcesarean Wound Infection

• Erythema, induration, tenderness
• Probed with sterile cotton-tipped applicator or
  fine-needle
• Extensive cellulitis without pus
• Gram stain and culture Rule-out MRSA

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Diagnosis of Postcesarean Wound Infection

• Open wound, drain completely
• Antibiotic therapy targeted toward staphylococci
• Nafcillin 2 g IV q 6hr
• Vancomycin 1 g IV q 6hr
• Careful inspection of fascia for disruption
• Irrigation with warm saline, clean dressing 2-3
  times/day
• Antibiotics continued until all signs of
  cellulitis resolved, wound base clean

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Differential Diagnosis of Persistent Postpartum
Fever
Condition Diagnostic Test(s) Treatment
Resistant Endometrial culture Modify
antibiotic therapy microorganism Blood
culture Wound infection Physical examination
Incision and drainage, Needle
aspiration antibiotics
Ultrasound Pelvic abscess Physical examination
Drainage Ultrasound, CT, MRI
Antibiotics Septic pelvic
vein Ultrasound, CT, MRI Heparin
anticoagulation thrombophlebitis Antibiotics
Adapted from PA Duff in Obstetrics Normal and
Abnormal, Churchill Livingstone, 2002
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Differential Diagnosis of Persistent Postpartum
Fever
Condition Diagnostic Test(s) Treatment
Recrudescence of Serology
Corticosteroids connective tissue
disease Drug fever Inspection of
temperature Discontinue WBC
eosinophilia antibiotics
Mastitis Physical examination
Modify antibiotics to cover
staphylococca l microorganisms
Adapted from PA Duff in Obstetrics Normal and
Abnormal, Churchill Livingstone, 2002
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Intrauterine Infection and Beyond Summary

• Recognition of risk factors for intraamniotic
  infection
• Prompt diagnosis and treatment of
  chorioamnionitis
• Recognition of potential sequelae of intrapartum
  infection
• Prompt and appropriate treatment of postpartum
  complications

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off into the sunset!