KM is a 16 year old G1 at 40 weeks who reports having had leakage of fluid approximately 7 days ago. Rupture of membranes is confirmed by exam and labor is induced via pitocin infusion. Her labor progresses gradually over 36 hours, during which time she undergoes multiple examinations and placement of several intrauterine pressure catheters and fetal scalp electrodes due to equipment malfunction. Her cervix dilates to 7 cm but despite adequate contractions does not continue to dilate and arrest of dilatation is diagnosed.

The decision is made to perform a Caesarean delivery The decision is made to perform a Caesarean delivery. Immediately before taking the patient to the operating room, the nurse notes that the fetal heart rate has increased from a baseline of 140 bpm to 180 bpm. The patient undergoes an uncomplicated C-section with delivery of a healthy-appearing male infant. The patient appears well until the evening of POD#1 when she reports flu-like symptoms and some abdominal tenderness. Her temperature is found to be 39.2C. On examination, her uterine fundus is markedly tender to palpation, and sero-sanguinous drainage and erythema are noted along her incision.

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

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

Prophylactic Antibiotics for Prevention of Postcesarean Endometritis Most appropriate agent – limited spectrum cephalsporin Cefazolin 1-2 g 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

Postpartum (Puerperal) Endometritis Fever - 38°C (100.4°F) 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

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

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

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 Amp+Gent 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