Septic Pelvic Thrombophlebitis (SPT)

Definition

Septic pelvic thrombophlebitis (SPT) is a rare postpartum or post-pelvic infection complication characterized by:

• Infected thrombus formation within pelvic veins
• Persistent bacteremia/inflammation
• Ongoing fever despite adequate antimicrobial therapy

The condition represents a combination of:

1. Venous thrombosis
2. Pelvic infection
3. Septic embolic/inflammatory state

Most common setting

Postpartum endometritis following cesarean section.

Types

Anatomy Relevant to SPT

Ovarian Veins

Right ovarian vein

• Drains directly into IVC
• Longer
• More incompetent valves
• More commonly affected (80–90%)

Left ovarian vein

• Drains into left renal vein

Why Right Side is More Common

Causes

1. Dextrorotation of gravid uterus compresses right ovarian vein
2. Retrograde flow more common
3. Longer vein
4. Valve incompetence
5. Direct drainage into IVC

Etiology

Polymicrobial infection is typical

Risk Factors

Pathogenesis

SPT follows Virchow’s triad:

1. Venous stasis

Occurs postpartum due to:

• Dilated pelvic veins
• Uterine compression
• Reduced venous return

2. Endothelial injury

Caused by:

• Delivery trauma
• Surgery
• Infection

3. Hypercoagulability

Pregnancy is physiologically hypercoagulable:

• Increased clotting factors
• Reduced fibrinolysis

Sequence of Disease Development

Stepwise Pathophysiology

1. Pelvic infection develops
2. Endothelial injury occurs
3. Thrombus forms in pelvic veins
4. Bacteria colonize thrombus
5. Septic thrombus propagates
6. Persistent fever despite antibiotics
7. Septic embolization may occur

Clinical Features

A postpartum woman:

• Usually after cesarean section
• Has endometritis
• Receives adequate antibiotics
• Fever initially improves or persists
• Continues to spike fevers despite therapy
• Cultures may be negative

→ Think SPT.

Timing

Usually:2–10 days postpartum

Can occur:Up to several weeks postpartum

Symptoms

Fever

• Persistent spiking fever
• Often >39°C
• Minimal response to antibiotics

Abdominal/Pelvic Pain

Especially in ovarian vein thrombosis:

• Lower abdominal pain,Flank pain,RLQ pain

Other Symptoms

• Malaise
• Chills
• Nausea
• Tachycardia

Signs

General

• Fever,Tachycardia

Abdominal Findings

May show:

• RLQ tenderness
• Adnexal tenderness
• Palpable rope-like mass (rare)

Pelvic Findings

May reveal:

• Uterine tenderness
• Endometritis

Ovarian Vein Thrombosis (OVT)

Typical Presentation

Triad:

1. Fever
2. Pelvic pain
3. Right-sided abdominal mass

Can mimic:

• Appendicitis
• Pyelonephritis
• Ovarian torsion
• Tubo-ovarian abscess

Deep Septic Pelvic Thrombophlebitis (DSPT)

Persistent fever with:

• Minimal abdominal findings
• Often negative imaging

Diagnosis often clinical.

Complications

1. Septic Pulmonary Emboli

2. Pulmonary Embolism

3. Extension of Thrombosis IVC,Renal veins

4. Sepsis

Diagnosis

SPT is often a: Diagnosis of exclusion

Especially when postpartum fever persists despite antibiotics.

Diagnostic Criteria (Clinical)

Typical Diagnostic Pattern

1. Persistent postpartum fever
2. Failure to respond to antibiotics within 48–72 hr
3. No alternative source identified
4. Imaging evidence of thrombosis OR dramatic response to anticoagulation

Laboratory Findings

CBC

• Leukocytosis

CRP/ESR

• Elevated

Blood Cultures

Positive in minority.

May show:

• Polymicrobial bacteremia

Imaging

CT Scan (Most Commonly Used)

Triad:

1. Enlarged vein
2. Central hypodensity (thrombus)
3. Enhancing wall

Ultrasound

Limitations

• Bowel gas
• Deep pelvic veins difficult to visualize

Can show:

• Noncompressible tubular structure
• Absent Doppler flow

Imaging Sensitivity

Differential Diagnosis

Management

Empiric Regimens

If Enterococcus Suspected

Add: Ampicillin OR Vancomycin

Duration

Usually:Continue until afebrile 48–72 hr

Common total duration:7–14 days

Anticoagulation

Historical Controversy

Older studies debated benefit.

Current modern practice generally favors anticoagulation, especially:

• Ovarian vein thrombosis
• Radiologically confirmed thrombosis
• Persistent fever

Mechanism

Anticoagulation:

• Prevents propagation
• Improves thrombus resolution
• May rapidly defervesce fever

Preferred Agents

Duration of Anticoagulation

Role of DOACs

Evidence postpartum is increasing but limited.

Usually avoided:

• During breastfeeding in some settings
• In unstable septic patients

LMWH remains standard.

Surgical Management

Rarely required today.

Indications

• Abscess
• Failure of medical therapy
• Ongoing embolization
• Extensive necrosis

Procedures

• Ovarian vein ligation
• Thrombectomy
• Hysterectomy (rare)

Guideline/Reference

Recommendations align broadly with:

• American College of Obstetricians and Gynecologists principles for postpartum infection management
• Society for Maternal-Fetal Medicine approaches to ovarian vein thrombosis
• Major reviews from:
• StatPearls
• Williams Obstetrics
• Harrison’s Principles of Internal Medicine
• Recent obstetric thrombosis literature