Occult Iliac Deep Vein Thrombosis in Second Trimester Pregnancy: Clues on Bedside Ultrasound.

Isolated pelvic deep vein thromboses (DVT) are rare and difficult to diagnose, but they are more common in pregnant women and carry an increased risk of embolization. Pulmonary embolism is the most common non-obstetric cause of death in pregnancy. Compression ultrasound is the first-line imaging test for suspected lower extremity DVT, but it cannot usually aid in directly visualizing or easily diagnosing isolated pelvic DVT. Nonetheless, point-of-care ultrasound (POCUS) may provide valuable clues to help rule in pelvic DVT and expedite initiation of anticoagulant therapy. Such findings include increased venous diameter, increased resistance to compression, visible venous reflux, and blunted phasicity. This case presents an example of how these findings on POCUS led the emergency physician to make the difficult diagnosis of pelvic DVT at the bedside within seconds.