What are the differences in diagnosis and treatment between puerperal sepsis, endometritis, and septic pelvic thrombophlebitis?

Comparison of Puerperal Sepsis, Endometritis, and Septic Pelvic Thrombophlebitis

Puerperal sepsis, endometritis, and septic pelvic thrombophlebitis represent a spectrum of postpartum infections with distinct diagnostic features and treatment approaches, with endometritis being the most common, puerperal sepsis the most severe, and septic pelvic thrombophlebitis the most diagnostically challenging condition.

Puerperal Sepsis

Definition and Pathophysiology

• Systemic infection occurring during the puerperium (up to 10 days postpartum)
• Can progress to septic shock and multiorgan failure
• Caused by bacterial invasion of the genital tract with spread to adjacent structures, lymphatics, and bloodstream 1
• Common pathogens include group A streptococci, mixed aerobic/anaerobic flora

Risk Factors

• Home birth in unhygienic conditions
• Low socioeconomic status
• Poor nutrition
• Primiparity
• Anemia
• Prolonged rupture of membranes
• Prolonged labor
• Multiple vaginal examinations
• Cesarean section
• Retained placental fragments
• Postpartum hemorrhage 1

Clinical Presentation

• Fever >100.4°F (38.0°C) on more than two occasions >6 hours apart after the first 24 hours postpartum 2
• Chills, tachycardia
• Abdominal pain and uterine tenderness
• Foul-smelling lochia
• May rapidly progress to septic shock

Diagnosis

• Clinical diagnosis based on symptoms
• Blood cultures
• Complete blood count showing leukocytosis
• Imaging (ultrasound, CT) to identify source of infection

Treatment

• Immediate broad-spectrum antibiotics (clindamycin plus gentamicin plus ampicillin) 3
• Fluid resuscitation
• Source control (removal of retained products if present)
• Supportive care

Endometritis

Definition and Pathophysiology

• Infection of the endometrial lining of the uterus
• Usually polymicrobial (mixed aerobic and anaerobic bacteria)
• Most common postpartum infection, especially after cesarean delivery
• Can be reduced by antibiotic prophylaxis during cesarean section 4

Risk Factors

• Cesarean delivery (especially unplanned)
• Prolonged labor
• Prolonged rupture of membranes
• Multiple vaginal examinations
• Manual removal of placenta
• Retained placental fragments 3

Clinical Presentation

• Fever >100.4°F (38.0°C)
• Uterine tenderness
• Foul-smelling lochia
• Subinvolution of the uterus
• Usually presents 2-5 days postpartum 2, 3

Diagnosis

• Clinical diagnosis based on symptoms
• Blood cultures and endometrial cultures if available
• Complete blood count
• Testing for Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and HIV should be considered 3

Treatment

• Clindamycin plus gentamicin is the first-line treatment for postpartum endometritis, with significantly fewer treatment failures compared to other regimens 3
• Continue antibiotics until patient is afebrile for 24-48 hours
• If no response within 48-72 hours, consider imaging to rule out retained products of conception or abscess

Septic Pelvic Thrombophlebitis

Definition and Pathophysiology

• Thrombosis of pelvic veins (ovarian or uterine) with superimposed infection
• Usually a complication of endometritis
• Thrombi can extend into the inferior vena cava 5
• Incidence: approximately 1:3000 deliveries (1:800 after cesarean section) 6

Risk Factors

• Cesarean delivery
• Endometritis
• Pelvic surgery
• Hypercoagulable states

Clinical Presentation

• Persistent fever despite appropriate antibiotic therapy for endometritis
• Minimal or absent abdominal pain (classic presentation)
• May have flank pain if ovarian veins are involved
• Absence of purulent lochia 7, 6

Diagnosis

• Clinical suspicion in patients with persistent fever despite appropriate antibiotic therapy
• Contrast-enhanced CT or MRI showing filling defects in pelvic veins 2, 6
• Negative cultures from other potential sources of infection

Treatment

• Continued broad-spectrum antibiotics
• Controversy exists regarding anticoagulation:
  • Some evidence suggests antibiotics alone may be sufficient 6
  • Other reports advocate for heparin in addition to antibiotics 7, 5
• The most recent evidence from a randomized trial showed no significant difference in outcomes between women treated with antibiotics alone versus antibiotics plus heparin 6

Key Diagnostic Differences

1. Timing and Fever Pattern:

   • Endometritis: Usually presents 2-5 days postpartum with continuous fever
   • Septic pelvic thrombophlebitis: Presents as persistent fever despite appropriate antibiotic therapy for endometritis
   • Puerperal sepsis: Can occur anytime during the puerperium, often with high spiking fevers

2. Pain Characteristics:

   • Endometritis: Significant uterine tenderness
   • Septic pelvic thrombophlebitis: Often minimal abdominal pain ("enigmatic fever")
   • Puerperal sepsis: Severe abdominal pain, may have signs of peritonitis

3. Diagnostic Imaging:

   • Endometritis: Ultrasound may show thickened endometrium
   • Septic pelvic thrombophlebitis: Requires contrast-enhanced CT or MRI to visualize thrombosed vessels
   • Puerperal sepsis: May require multiple imaging modalities to identify source

Key Treatment Differences

1. Antibiotic Selection:

   • Endometritis: Clindamycin plus gentamicin 3
   • Septic pelvic thrombophlebitis: Continued broad-spectrum antibiotics (clindamycin, gentamicin, ampicillin)
   • Puerperal sepsis: Broader coverage may be needed based on severity

2. Anticoagulation:

   • Only considered in septic pelvic thrombophlebitis, though evidence is mixed 6

3. Duration of Treatment:

   • Endometritis: Until afebrile for 24-48 hours
   • Septic pelvic thrombophlebitis: 7-14 days
   • Puerperal sepsis: Depends on severity, often 14+ days

Clinical Pearls and Pitfalls

• Persistent fever despite appropriate antibiotic therapy for endometritis should raise suspicion for septic pelvic thrombophlebitis
• Septic pelvic thrombophlebitis can extend beyond the pelvis, even up to the diaphragm 5
• Empiric addition of heparin for persistent postpartum fever is not supported by the strongest evidence 6
• Prophylactic antibiotics for cesarean delivery significantly reduce the risk of endometritis 4
• Group A streptococcal puerperal sepsis can progress rapidly to toxic shock syndrome and requires immediate aggressive treatment 8