Septic Pelvic Thrombophlebitis Mimicking Acute Appendicitis: A Diagnostic Challenge and the Role of Therapeutic Anticoagulation.

Septic pelvic thrombophlebitis (SPT) is a rare postpartum complication, occurring in approximately one in 9,000 vaginal deliveries. Known risk factors include hypertensive disorders of pregnancy, multiple gestation, nulliparity, maternal age under 20, Black race, cesarean delivery, and chorioamnionitis. Due to the lack of standard diagnostic criteria, SPT can easily be missed. We present the case of a 34-year-old woman who underwent an uncomplicated vaginal birth after cesarean (VBAC). On postpartum day 4, she developed clinical signs of endometritis, with a normal white blood cell count but elevated neutrophil percentage. Her symptoms resembled acute appendicitis on imaging, although her Alvarado score was 4. Initial treatment with empiric antibiotics and prophylactic enoxaparin was ineffective. However, clinical improvement was seen after initiating therapeutic enoxaparin. Treatment response was monitored using objective markers such as C-reactive protein (CRP) trends, neutrophil percentage, fever resolution, and subjective improvement in abdominal tenderness. This case highlights endometritis as a risk factor for SPT and underscores the importance of early therapeutic anticoagulation when SPT is suspected.