Introduction: Atresia of the inferior vena cava (IVCA), also known as IVC agenesis or aplasia is a rare vascular anomaly with an estimated prevalence of 1% in the general population [1]. While deep vein thrombosis (DVT) in young patients is most often associated with risk factors like congenital and acquired thrombophilia, pregnancy, OCPs, neoplasms, autoimmune diseases, or prolonged immobilization and trauma, IVCA is found in approximately 5% of cases of unprovoked lower extremity DVT in young adults ( < 30 years old).
Description: A 19-year-old female patient with a history of premenstrual syndrome and taking oral contraceptive pills (OCPs) presented to the emergency department with swelling and tenderness in her right leg. She had a recent pilonidal cyst removal surgery and increased OCP dose in the past. She occasionally used marijuana. Physical examination showed an enlarged right leg with induration, and a positive Homan's sign. Ultrasound revealed extensive blood clots in multiple veins of the right leg. Further imaging confirmed the absence of the inferior vena cava (IVC) below the renal veins. The patient underwent various procedures to remove the clots, including thrombolysis and thrombectomy. Around 80% of the clot burden was removed. She was stabilized and started on anticoagulation therapy with Lovenox, followed by Eliquis. Lifelong anticoagulation was recommended.
Discussion: Young adults with IVC atresia are usually asymptomatic unless they have other risk factors like oral contraceptives, pregnancy, smoking, or hypercoagulability. The relative risk of thrombotic events increases with combined oral contraception but remains low for healthy adolescents. Inherited thrombophilia is a common risk factor for lower extremity thrombosis in patients under 50.
This case of a patient with IVC atresia, recent surgery immobilization, oral contraceptive use, and regular marijuana use for premenstrual syndrome. Marijuana use has been associated with an increased risk of thromboembolic complications and clot formation. The synergistic effects of IVC atresia, surgery immobilization, oral contraceptives, and marijuana use predispose the patient to DVT. It emphasizes the importance of considering individual and combined risk factors in assessing a patient's susceptibility to DVT.
