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Resuscitation Quick Actions • First 2 Minutes

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Diagnostic Endometritis Triad

Fever >= 38.0°C (> 24h postpartum) + Foul-smelling purulent lochia + Marked uterine fundal tenderness on bimanual exam

Cesarean is #1 Risk

Cesarean section carries a 20–30x higher risk of endometritis than vaginal delivery (prolonged rupture of membranes and labor)

Gold Standard Antibiotics

Clindamycin 900 mg IV q8h + Gentamicin 5 mg/kg IV once daily (90–95% cure rate); continue until afebrile x 24–48 hours

Add Ampicillin If Sepsis

Add Ampicillin 2g IV q6h (or Ampicillin-Sulbactam) to cover Enterococcus faecalis and GBS in severe sepsis or Cesarean delivery

Retained Products (RPOC)

Transvaginal ultrasound: thickened echogenic intracavitary mass with internal vascular color Doppler flow = SURGICAL D&C REQUIRED

Septic Pelvic Thrombophlebitis

Persistent spiking fevers despite 72h of IV antibiotics: CT shows thrombosed ovarian vein; therapeutic Heparin trial

Bottom-Line Clinical Pearl

Postpartum endometritis is the most common cause of postpartum fever, with Cesarean delivery increasing risk by up to 30-fold compared to vaginal delivery. It is an ascending polymicrobial infection of the decidua and myometrium by vaginal and enteric flora (anaerobes, GBS, Enterococcus, gram-negative bacilli). The diagnostic triad is: FEVER >= 38.0°C (100.4°F) occurring > 24 hours postpartum, FOUL-SMELLING/PURULENT LOCHIA, and MARKED UTERINE SUBINVOLUTION AND FUNDAL TENDERNESS. The gold-standard evidence-based antibiotic regimen is IV Clindamycin (900 mg IV q8h) + IV Gentamicin (5 mg/kg IV once daily); add IV Ampicillin (2g q6h) if Enterococcus or GBS is suspected, or for patients with sepsis. If fevers persist despite 48–72 hours of appropriate broad-spectrum IV antibiotics, suspect SEPTIC PELVIC THROMBOPHLEBITIS (ovarian vein thrombosis): confirm with contrast CT/MRI and initiate therapeutic anticoagulation (Unfractionated Heparin); rapid defervescence within 48 hours confirms the diagnosis.

1. Microbiology & Risk Factors

Postpartum endometritis is a polymicrobial ascending infection of the decidua and underlying myometrium. Organisms originate from the lower genital tract and gastrointestinal flora: anaerobes (Bacteroides fragilis, Peptostreptococcus, Prevotella), gram-positive aerobes (Group B Streptococcus, Enterococcus faecalis), and gram-negative coliforms (Escherichia coli, Klebsiella).

Cesarean Delivery is by far the single greatest risk factor, increasing incidence from 1–3% after normal spontaneous vaginal delivery to 15% to 30% following unscheduled emergency Cesarean sections. Secondary risk factors include: prolonged rupture of membranes ($> 18\text{ hours}$), prolonged second stage of labor, multiple digital vaginal examinations, internal fetal monitoring, and retained placental fragments.

2. Gold-Standard Intravenous Antimicrobial Therapy

Antimicrobial AgentDosing Regimen & RouteCoverage & Clinical Rationale
Clindamycin900 mg IV every 8 hoursPotent coverage against penicillin-resistant anaerobic organisms (Bacteroides) and gram-positive cocci.
Gentamicin5 mg/kg IV once daily (extended-interval dosing) OR 1.5 mg/kg IV q8hBroad-spectrum coverage against aerobic gram-negative bacilli (E. coli, Klebsiella). Single daily dosing provides equivalent efficacy with reduced nephrotoxicity.
Ampicillin (Add for Sepsis/Cesarean)2.0 grams IV every 6 hoursProvides mandatory bactericidal coverage against Enterococcus faecalis and Group B Streptococcus. Indicated if patient has severe sepsis, bacteremia, or fails to defervesce on clindamycin/gentamicin alone.
Duration EndpointContinue IV antibiotics until the patient has been afebrile (< 38.0°C) and asymptomatic for 24 to 48 hoursOral outpatient antibiotic courses following successful IV resolution have been proven unnecessary in multiple randomized trials.

3. Refractory Fever: Septic Pelvic Thrombophlebitis (SPT)

If a postpartum patient continues to experience high spiking fevers, chills, and tachycardia despite 48 to 72 hours of appropriate broad-spectrum IV antibiotics, the differential diagnosis narrows to two entities: (1) Retained Products of Conception (RPOC)/pelvic abscess, or (2) Septic Pelvic Thrombophlebitis (SPT).

SPT occurs when bacterial endometritis spreads into the pelvic venous plexuses and ovarian veins (right ovarian vein is involved in $> 80\%$ of cases due to longer anatomical course and dextrorotation of the puerperal uterus). Contrast-enhanced CT or MRI of the pelvis demonstrates an enlarged, non-enhancing, thrombosed ovarian vein with surrounding inflammatory stranding. In addition to continuing broad-spectrum antibiotics, initiate therapeutic anticoagulation with Unfractionated Heparin (80 units/kg bolus + 18 units/kg/hr). Rapid defervescence within 48 to 72 hours of starting heparin is classic ('the heparin challenge').

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