WBR0723

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pathology
Sub Category	SubCategory::Vascular
Prompt	[[Prompt::A 38 year old female patient, previously healthy, presents to the physician's office complaining of left leg pain and swelling. Upon further questioning, she informs the physician that she recently returned to USA from a vacation in Europe. Physical examination is remarkable for tenderness on left calf with erythema and non-pitting edema. On the other hand, the right leg appears normal in comparison. Following appropriate work-up and imaging, the patient is diagnosed with May-Thurner syndrome. Which of the following anatomic anomalies best characterizes May-Thurner syndrome?]]
Answer A	AnswerA::Compression of the left iliac vein by an overriding right iliac artery
Answer A Explanation	AnswerAExp::May-Thurner syndrome (MTS) is characterized by the compression of the left iliac vein by an overriding right iliac artery.
Answer B	AnswerB::Compression of the left iliac vein by an overriding left iliac artery
Answer B Explanation	AnswerBExp::MTS is not characterized by the compression of the left iliac vein by an overriding left iliac artery.
Answer C	AnswerC::Compression of the left iliac vein by an overriding right iliac vein
Answer C Explanation	AnswerCExp::MTS is not characterized by the compression of the compression of the left iliac vein by an overriding right iliac vein
Answer D	AnswerD::Compression of the left iliac vein by an overriding left iliac vein
Answer D Explanation	AnswerDExp::MTS is not characterized by the compression of the left iliac vein by an overriding left iliac vein.
Answer E	AnswerE::Compression of the left iliac vein by the iliac crest
Answer E Explanation	AnswerEExp::MTS is not characterized by the compression of the left iliac vein by the iliac crest.
Right Answer	RightAnswer::A
Explanation	[[Explanation:: May-Thurner syndrome (MTS) is also called iliocaval compression syndrome because it is characterized by the compression of the left iliac vein by an overriding right iliac artery. Patients with MTS are typically young female patients who present with symptoms consistent with deep vein thrombosis (DVT). The DVT in MTS is obviously more common on the left side than the right side because of the anatomic etiology of the disease that compresses the left venous side with impaired venous return on that side. However, mechanical compression may not be the only cause of DVTs in patients with MTS; it seems that chronic arterial pulsations from the right common iliac artery cause trauma to the venous wall leading to "spur formation" that contributes to the formation of DVT in these patients. Educational Objective: MTS is characterized by the compression of the left iliac vein by an overriding right iliac artery. Reference: Oguzkurt L, Ozkan U, Tercan F, Koc Z. Ultrasonographic diagnosis of iliac vein compression (May-Thurner) syndrome. Diagn Interv Radiol. 2007; 13(3):152-5 Baron HC, Sharms J Wayne M. Iliac vein compression syndrome: A new method of treatment. Am Surg. 2000; 66:653-655. Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::may, WBRKeyword::thurner, WBRKeyword::syndrome, WBRKeyword::may-thurner, WBRKeyword::May-Thurner, WBRKeyword::May, WBRKeyword::Thurner, WBRKeyword::DVT, WBRKeyword::deep vein thrombosis, WBRKeyword::edema, WBRKeyword::erythema, WBRKeyword::pain, WBRKeyword::anatomical, WBRKeyword::iliac, WBRKeyword::vein, WBRKeyword::thrombosis, WBRKeyword::deep, WBRKeyword::vein
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::