Friday, March 12, 2021

Deep Venous Thrombosis Case File

Posted By: Medical Group - 3/12/2021 Post Author : Medical Group Post Date : Friday, March 12, 2021 Post Time : 3/12/2021
Deep Venous Thrombosis Case File
Eugene C. Toy, MD, Lawrence M. Ross, MD, PhD, Han Zhang, MD, Cristo Papasakelariou, MD, FACOG

CASE 9
A 42-year-old diabetic woman complains of soreness of the left leg. She is moderately obese and has been recovering from surgical removal of her gallbladder (cholecystectomy) performed 2 weeks ago. On examination, she has obvious swelling in the left lower leg and some tenderness of the calf that increases when the calf is gently squeezed. There is no redness of the leg, and she is afebrile (without fever).

What is the most likely diagnosis?
 What structure is likely affected?


ANSWER TO CASE 9:

Deep Venous Thrombosis
Summary: A 42-year-old obese diabetic woman complains of soreness of the left leg. She had gallbladder surgery 2 weeks previously. Her left calf is tender but without erythema. She is afebrile.
Most likely diagnosis: Deep venous thrombosis (DVT)
Structure likely affected: Anterior and posterior tibial veins and fibular veins


CLINICAL CORRELATION
Venous thrombosis, or pathological blood clots within a vein, is a common cause of morbidity and mortality. The Virchow triad of venous stasis, hypercoagulability, and vessel wall damage comprise notable risk factors. This patient has several risk factors for DVT. She is obese, diabetic, and has been inactive because of postoperative bedrest, with the latter producing venous stasis. Although gynecological and orthopedic surgeries especially predispose individuals to DVT, any surgery increases the risk. Prevention of DVT includes using lower-limb compression devices during and after surgery. These devices intermittently squeeze the legs, thereby simulating the muscular contraction of physical activity. Anticoagulant therapy, such as small-dose heparin, is also sometimes given before surgery and for 1 or 2 days postoperatively. If DVT is confirmed with ultrasound or radiologically with venous contrast (venogram), anticoagulation therapy is important to decrease the risk of embolization of the thrombosis, which can travel directly to the lungs to produce potentially fatal pulmonary embolism.


APPROACH TO:
Vascular Supply of Lower Extremity

OBJECTIVES
1. Be able to draw the arterial blood supply to the lower limb
2. Be able to describe the deep and superficial venous drainage of the lower limb


DEFINITIONS
Afebrile: Without fever
Embolus: A mass such as part of the blood clot (thrombus), air, or fat that travels through a vessel and lodges and obstructs blood flow
Thrombosis: Process by which a blood clot forms within a blood vessel


DISCUSSION
The chief blood supply to the lower limb is from the femoral artery, the continuation of the external iliac artery inferior to the inguinal ligament, within the femoral triangle. The femoral triangle is bounded by the inguinal ligament superiorly, the sartorius muscle laterally, and the adductor longus muscle medially. It contains the femoral nerve and the femoral sheath and its contents. The femoral artery lies in the lateral compartment of the femoral sheath, with the femoral vein medial to it, and the femoral canal with its associated inguinal lymph nodes medial to the vein. The femoral nerve lies lateral to and outside the femoral sheath. Just inferior to the inguinal ligament, the superficial epigastric, superficial circumflex iliac, and two external pudendal arteries arise from the femoral artery. Within the femoral triangle, the deep femoral artery arises and descends posteriorly to the femoral vessels and the adductor longus muscle. The lateral and medial circumflex arteries usually arise from the deep femoral artery, as do muscular branches and several perforating branches, to supply the posterior thigh. As the femoral artery descends toward the apex of the femoral triangle, it enters the adductor canal and becomes the popliteal artery, and it assumes a position posterior to the femur. It descends inferiorly through the popliteal fossa, giving rise to five genicular arteries to the knee, and terminates by dividing into the anterior and posterior tibial arteries near the lower border of the popliteus muscle (Figure 9-1).

The anterior tibial artery pierces the interosseus membrane, from which it descends through the anterior compartment, supplying structures in this compartment, and terminates anterior to the ankle by becoming the dorsal artery of the foot. The dorsal artery and its lateral tarsal branch form an arch of the dorsum of the foot and provides the chief blood supply to the toes. The posterior tibial artery descends in the posterior compartment and supplies it and the lateral compartment by perforating branches in addition to its fibular branch. It passes posteriorly to the medial malleolus, enters the sole of the foot, and divides into lateral and medial plantar arteries that supply the sole of the foot.

Other arteries that supply portions of the lower limb include the obturator artery, which supplies the medial compartment of the thigh. The superior and inferior gluteal and the internal pudendal arteries provide the chief blood supply to the gluteal region.

The lower limb has superficial and deep systems of veins, both of which terminate in the femoral vein, which continues superiorly to the inguinal ligament as the external iliac vein. The deep system of veins usually consists of paired venae comitantes, which accompany the arteries for which they are named. Thus anterior and posterior tibial veins are formed from the dorsum and sole of the foot. Fibular veins arise in the posterior compartment and drain blood to the posterior tibial veins, which ascend and are joined by the anterior tibial veins to form the popliteal vein. The popliteal vein becomes the femoral vein as it traverses the adductor canal, receives the deep femoral vein in the femoral sheath, and enters the abdomen beneath the inguinal canal to become the external iliac vein. A deep vein of the thigh accompanies its artery and drains into the femoral vein. The superficial system of veins is composed of the small and great saphenous veins and is found in the superficial fascial of the limb. The small saphenous is formed posterior to the lateral

Deep Venous Thrombosis anatomy

Figure 9-1. Arterial supply to the leg. (Reproduced, with permission, from Lindner HH. Clinical Anatomy. East Norwalk, CT: Appleton & Lange, 1989:602.)

malleolus and ascends in the middle of the calf to terminate in the popliteal vein in the popliteal fossa. The great saphenous vein is formed from the dorsal venous arch of the foot anterior to the medial malleolus. It ascends along the medial aspect of the leg and the thigh. It pierces the saphenous opening in the fascia lata (deep fascia of the thigh) to empty into the femoral vein within the femoral sheath. Numerous communications exist between the two saphenous veins. Of greater clinical importance, communications between the superficial and deep systems exist as perforating branches whose valves are arranged to allow venous flow from superficial to deep, but not in the opposite direction. This important shunt allows muscular contraction to produce venous return against the effects of gravity.


COMPREHENSION QUESTIONS

9.1 While operating on the posterior compartment of the thigh, an orthopedic surgeon takes care to preserve the arterial blood supply to the muscles in that region. These are branches of which of the following arteries?
A. Deep femoral artery
B. Femoral artery
C. Superior gluteal artery
D. Inferior gluteal artery
E. Obturator artery

9.2 A patient has sustained lower-limb trauma that has damaged the posterior tibial artery. Therefore, you will be concerned about the blood supply to which of the following?
A. Posterior thigh only
B. Lateral compartment of the leg only
C. Posterior compartment of the leg only
D. Sole of the foot only
E. Posterior compartment of the leg and the sole of the foot

9.3 Which are the chief deep veins of the leg that are of concern for DVT?
A. Small saphenous vein
B. Great saphenous vein
C. Deep femoral vein
D. Anterior and posterior tibial veins
E. Obturator vein


ANSWERS

9.1 A. The blood supply to the posterior compartment of the thigh originates from
perforating branches of the deep femoral artery.
9.2 E. The posterior tibial artery provides the blood supply to the calf and the sole
of the foot.
9.3 D. The deep veins of the leg are the anterior and posterior tibial veins that
accompany the arteries of the same name.


ANATOMY PEARLS
 The relationship between lateral medial of structures within the femoral triangle is defined by the acronym NAVeL (femoral Nerve, Artery, Vein; empty space, Lymph nodes).
 The chief blood supply to the thigh and the hip arises from the deep femoral artery.
 The posterior tibial artery enters the foot through the tarsal canal, posterior to the medial malleolus.
 Venous blood flow is from superficial to deep venous systems.

References

Gilroy AM, MacPherson BR, Ross LM. Atlas of Anatomy, 2nd ed. New York NY: Thieme Medical Publishers; 2012:446−447. 

Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 7th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2014:532−535, 540, 551−556, 602−603. 

Netter FH. Atlas of Human Anatomy, 6th ed. Philadelphia, PA: Saunders; 2014: plates 470−471, 487, 499, 505.

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