A 24-year-old nulliparous woman presents to the emergency department with sudden-onset, severe left lower abdominal pain and vomiting for 3 hours. Transvaginal ultrasound with color Doppler shows an enlarged left ovary (8 cm) with peripherally displaced follicles and heterogeneous edematous stroma. The structure marked **B** in the diagram—the twisted vascular pedicle—is visualized as concentric hypoechoic rings. Which of the following best explains the pathophysiologic consequence of this finding if left untreated?
A. Lymphatic obstruction alone, causing ovarian edema without vascular compromise
B. Venous engorgement with preserved arterial flow, resulting in chronic ovarian ischemia
C. Compromise of venous and lymphatic drainage first, followed by arterial inflow obstruction, leading to hemorrhagic infarction and ovarian necrosis
D. Direct arterial insufficiency with immediate loss of all blood supply to the ovary and surrounding tissues
Explanation
Why "Compromise of venous and lymphatic drainage first, followed by arterial inflow obstruction, leading to hemorrhagic infarction and ovarian necrosis" is right
The twisted vascular pedicle (marked B) in ovarian torsion mechanically obstructs the infundibulopelvic and utero-ovarian ligaments. Because venous and lymphatic vessels are thinner-walled and lower-pressure than arteries, they are compressed first, causing venous congestion and edema. Continued torsion then progressively compromises arterial inflow, culminating in hemorrhagic infarction and ovarian necrosis if detorsion is not performed promptly. This sequence is the pathophysiologic hallmark of ovarian torsion and explains why early surgical intervention is critical (ACOG Committee Opinion; Williams Gynecology 4e).
Why each distractor is wrong
"Direct arterial insufficiency with immediate loss of all blood supply...": Arterial compromise occurs after venous obstruction due to the pressure gradient; arteries are not the first vessels affected. Immediate total arterial loss is not the mechanism.
"Lymphatic obstruction alone, causing ovarian edema without vascular compromise": Lymphatic obstruction contributes to edema but does not occur in isolation; venous obstruction is the primary initial event and is far more clinically significant.
"Venous engorgement with preserved arterial flow, resulting in chronic ovarian ischemia": While venous engorgement does occur first, the process is acute and progressive, not chronic. Arterial flow is eventually compromised, not preserved indefinitely.
High-YieldNEET PG
In ovarian torsion, venous/lymphatic obstruction precedes arterial compromise—this is why the ovary may retain some Doppler flow early in torsion, yet the diagnosis remains clinical/surgical and delays >24–48 hours significantly reduce salvage.
ACOG Committee Opinion; Williams Gynecology 4e
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