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D

Answers and Explanations

• 1. The answer is D (Chapter 7, V A 1 a). The triad of a cardiac arrhythmia, the sudden onset of severe abdominal pain, and gut emptying is a classic indicator of embolic mesenteric ischemia. This combination constitutes a surgical emergency, and the patient should be treated promptly with vigorous rehydration followed by arteriography to confirm the diagnosis. Rapid embolectomy of the superior mesenteric artery could save this patient, provided that no delay occurs in her definitive surgical treatment.

Cholecystitis usually presents with right upper quadrant pain and diverticulitis with left lower quadrant pain. A perforated ulcer will have associated diffuse abdominal tenderness but also wil have signs of peritoneal irritation (guarding and rebound). A small bowel obstruction usually presents with colic or intermittent pain.

• 2. The answer is B (Chapter 7, VIII E 2 a–e). The symptomatic artery is usually repaired first because it carries the highest risk of stroke. Percutaneous transluminal angioplasty of the carotid artery is presently under investigation as an alternative to carotid endarterectomy, but it is not considered to be the standard of care at this point. Percutaneous transluminal angioplasty is sometimes used for smooth, regular lesions associated with fibromuscular dysplasia. The superficial temporal artery to middle cerebral artery bypass has not been shown to be effective for this patient's disease. Bilateral carotid endarterectomy is usually not performed because of the risk of recurrent laryngeal nerve trauma, which, if bilateral, could result in a tracheostomy.

• 3–4. The answers are 3-D (Chapter 7, VIII A), 4-D (Chapter 7, VIII A 3). Colonoscopy is not indicated if the patient's stool is heme negative. Computed tomography (CT) can help to evaluate the proximal extent of the aneurysm. Pulmonary function tests can help to assess risk and to help plan perioperative care. An arteriogram acts as a road map, showing the renal arteries in relation to the aneurysm and the extent of occlusive disease in the iliac and femoral arteries. A Persantine thallium scan helps to define perioperative cardiac risk.

Elective repair of an abdominal aortic aneurysm (AAA) can be performed with a mortality rate lower than 5%. The leading cause of death in these patients with AAA is rupture. A 6-cm AAA has a 35% rupture rate, and surgery should be recommended unless the patient has a life expectancy of less than 1 year. Rate of enlargement is not a safe predictor of risk of rupture. Patients with symptomatic or rupturing AAA have a 75% mortality rate when operated on as an emergency. An aorto-bi-iliac graft is the appropriate procedure in this patient, rather than a tube graft, to repair the associated iliac aneurysm. With no iliac occlusive disease, an aortoiliac bypass avoids groin incisions.

• 5. The answer is D (Chapter 8, I B 3). A swollen leg following a period of immobilization is a typical history leading to a deep venous thrombosis (DVT). While lymphedema or other causes can also lead to leg swelling, a pelvic CT scan would not be the next step for this patient. Physical examination is reliable only 50% of the time for DVT, so an accurate diagnostic study such as a venous duplex ultrasound is needed before starting long-term anticoagulation. If no other reason for the swelling can be found, a pelvic CT scan may be reasonable. Leg elevation is helpful to reduce swelling, but compression stockings are not recommended in the acute phase for fear of dislodging the clot. Aspirin is of no proven benefit in treating DVT.

• 6–9. The answers are 6-A [Chapter 8, I B 3 c (1)–(4)], 7-B [Chapter 8, I B 3 d (1)], 8-E [Chapter 8, I B 3 f (1)]. Physical examination is the least likely method to diagnose the cause of acute leg swelling. Currently, such a patient would undergo duplex ultrasonography or venography to confirm the presumed diagnosis of DVT. Impedance plethysmography can detect increased resistance to venous flow but does not identify the cause. ¹²⁵I Fibrinogen scanning can identify ongoing thrombosis, but the scan takes 24 hours to complete and is therefore not useful in acute situations.

Intravenous heparin therapy is the most appropriate initial treatment. Subcutaneous unfractionated heparin therapy in its current form is not acceptable treatment for DVT. Thrombolytic therapy would be contraindicated in a patient with a recent craniotomy because it would increase the risk of hemorrhage.

Aspirin therapy has no role in the treatment of DVT. Warfarin can be used once the patient is discharged but not as the initial treatment. Transition from intravenous heparin to warfarin therapy should occur on the fourth or fifth day of heparin administration.

Support hose is the mainstay of treatment for patients with chronic postphlebitic syndrome. Thrombectomies have been unsuccessful, and the efficacy of venous bypass has yet to be established. There is interest in transplanting venous valves and segments of a vein to replace short-segment thromboses, but this area is still experimental. Prosthetic grafts have no role in venous reconstruction. Chronic diuretic therapy may be useful for short-term therapy but is certainly not optimal long-term management for this problem.

• 9. The answer is D (Chapter 8, I B 3 e). The risk of DVT can be reduced by simple measures such as leg elevation, early mobilization, support hose, and sequential compression devices. Unfractionated heparin administered subcutaneously either two or three times a day or low molecular weight heparin can both reduce the risk of DVT, but either should be started prior to surgical procedures.

Study Questions for Part IV(GIS)

Directions: Each of the numbered items in this section is followed by several possible answers. Select the ONE lettered answer that is BEST in each case.

1. A 15-year-old boy is admitted with a history and physical findings consistent with appendicitis. Which finding is most likely to be positive?

A Pelvic crepitus

B Iliopsoas sign

C Murphy sign

D Flank ecchymosis

E Periumbilical ecchymosis