A 67-year-old man with a history of hypercholesterolemia and hypertension and a 50 pack-a-year history of tobacco smoking presents for a pre-operative physical before a scheduled repair of the acromial-clavicular ligament in his left shoulder. The patient denies any history of myocardial infarction or significant chest pain or shortness of breath. His vital signs are as follows: blood pressure (BP), 165/89 mm Hg; heart rate (HR), 82 beats/minute; respiration rate (RR), 16 breaths/minute; arterial oxyhemoglobin saturation (SpO2), 98%; temperature (T), 37°C (98.6°F).
On physical examination, you note a moderately overweight male in no apparent distress. His heart rhythm is regular, and there are no murmurs. His lungs are clear to auscultation and anteroposterior (AP) diameter is not markedly increased. Examination of his extremities is significant for feet that are cool and pale, with no palpable dorsalis pedis or posterior tibial pulses. There is also an absence of body hair from his knees to his feet, in contrast to the rest of his body, which has abundant hair. The abdominal examination is unremarkable. On further questioning, the patient admits to having “Charley horses” on walking more than a few blocks that force him to stop walking, and subside after approximately a minute of rest. These have been occurring for approximately 2 years, and have gotten more frequent over the past 5 months or so. He also has been experiencing sexual impotence for approximately a year. What is the best, next course of action in management of this man's condition?
A. Advise the man to elevate his legs when resting
B. Perform a urethrogram and prescribe sildenafil
C. Perform arteriography and prescribe anticoagulants
D. Perform ultrasound of the lower extremity vessels
E. Prepare for urgent aortoiliac bypass grafting
Option D (Perform ultrasound of the lower extremity vessels) is correct. A Doppler ultrasound study of the lower extremities is the best way to evaluate intermittent ischemia to the lower extremities (followed by arteriography). The man should be advised to control his blood pressure and cholesterol, and should be strongly urged to quit smoking. He most likely is suffering from atherosclerotic iliac disease, and can need surgical, aortoiliac bypass grafting, depending on the severity of his disease.
Option A (Advise the man to elevate his legs when resting) is incorrect. Although elevating the legs can help relieve edema and discomfort associated with gravity-dependent venous stasis, it is not recommended in arterial insufficiency with intermittent ischemia to the lower extremity.
Option B (Perform a urethrogram and prescribe sildenafil) is incorrect. Although this man's impotence is a problem, it is part of a constellation of symptoms caused by arteriosclerosis that extends from the aorta and into the iliacs. Resolution of the structural cause of the ischemia is important.
Option C (Perform arteriography and prescribe anticoagulants) is incorrect. Although embolic events and thrombosis are important causes of aortoiliac ischemia, they would present as more acute events, likely to be painful, and less likely to present with lower extremity alopecia.
Option E (Prepare for urgent aortoiliac bypass grafting) is incorrect. Although bypass grafting is a possible necessary treatment for this patient, evaluation of the form and extent of vessel occlusion would be necessary first. The best initial evaluation for this is ultrasound of the lower extremities to evaluate blood flow.
High-yield Hit 1
1. Describe claudication and its physiology.
Intermittent claudication consists of reproducible lower extremity muscular pain induced by exercise and relieved by short periods of rest. It is caused by arterial obstruction to affected muscular beds, which restricts the normal exercise-induced increase in blood flow, producing transient muscle ischemia. Studies have shown that more than half of patients with intermittent claudication have never complained of this symptom to their physicians, assuming that difficulty with walking is a normal consequence of aging.
2. List the different nonoperative therapies for intermittent claudication.
Risk factor modification, exercise, and pharmacologic therapies. Smoking cessation reliably doubles walking distances, and the need for eventual amputation in patient's with lower extremity arterial occlusive disease decreases after smoking cessation. Exercise (defined as walking until onset of leg pain, resting, and then resuming walking) for 30-60 minutes, 3 days per week for 6 months has also been demonstrated in multiple randomized trials to increase walking distance by more than 100%. Currently, the only Food and Drug Administration (FDA)-approved drugs for the treatment of claudication are pentoxifylline (minimally effective) and cilostazol (appears more effective).
3. Define critical limb ischemia.
Critical limb ischemia potentially threatens the viability of the limb. Symptoms include rest pain (e.g., foot pain at rest) typically occurring at night when the patient is supine and the gravity contribution to foot arterial pressure is no longer present. This pain is relieved with foot dependency or short periods of ambulation. Poor tissue circulation does not heal minor skin breakdown caused by incidental trauma. These ischemic ulcers are frequently painful and can progress to gangrene.
4. What is the ankle brachial index (ABI)?
ABI is the highest ankle pressure (anterior tibial or posterior tibial artery) divided by the higher of the two brachial pressures. The normal ABI is slightly > 1 (1.10). An ABI of 1.0-0.5 is typical of patients with claudication. Patients with rest pain have an ABI < 0.5, and patients with tissue necrosis often have an ABI much lower.
From Abernathy's Surgical Secrets 5E by Harken & Moore
High-yield Hit 2
Vascular investigation techniques include:
Ankle/brachial pressure index.
Digital subtraction arteriography (DSA).
With Doppler ultrasound, probes can be used to detect arterial and venous blood flow. The Doppler effect is a change in frequency of a sound due to the relative movement of the source of the sound. The duplex scanner method is a pulsed Doppler combined with real-time ultrasound screening, and a computer-generated picture can be used to assess flow and anatomy in the peripheral vessels, such as the carotid artery (Figs. 22.10A and B).
Figure 22.10 A, Duplex scan of carotid arteries (single arrow, common carotid artery; double arrow, internal carotid artery). B, Duplex scan. Note clot in superficial femoral vein (arrow).
To measure the ankle/brachial pressure index, a Doppler probe can be used to locate the posterior tibial arterial signal. A proximally placed sphygmomanometer cuff is inflated to find the pressure at which the signal disappears and reappears on deflation. The mean of the pressures can be compared with the pressure in the arm (i.e., systemic pressure):
From Abernathy's Surgical Secrets 5E by Harken & Moore
High-yield Hit 3
The normal ABI is about 1. The ABI gives an indication of the severity of any reduction in arterial flow and can be used as a noninvasive monitoring tool.
The retrograde (Seldinger) transfemoral arteriogram is the standard imaging technique for defining the precise abnormalities of the peripheral vascular system. The catheter is passed into the unaffected side and passed up the iliac vessels. Contrast medium is injected to outline the vascular system and define the level and extent of any narrowing and any collateral circulation. This can be combined with angioplasty (i.e., balloon dilatation of the vessel if there is a short segment of atherosclerosis). The risks associated with these procedures are:
Initiation of intimal dissection.
Dislodgement of thrombus.
False aneurysm formation at the site of catheter insertion.
Digital subtraction arteriography is a new technique that is superseding the need for translumbar aortograms or arteriograms via the brachial route if both femoral vessels are included. The dye is injected into a peripheral vein, and the images are obtained of the artery in question. Dilutional problems may result in inferior pictures of the distal vascular tree. DSA "subtracts" the bony image and enhances the arteriographic profile.
|The above post was thanked by:|
but as u said a chronic case
|Cardiology-, Internal-Medicine-, Step-2-Questions|
|Thread Tools||Search this Thread|
|Thread||Thread Starter||Forum||Replies||Last Post|
|Claudication + Impotance + Leg atrophy||mary||USMLE Step 2 CK Classic Clues||1||07-09-2016 01:01 PM|
|Hypothyroidism Case||donofitaly||USMLE Step 1 Forum||6||11-21-2011 03:23 PM|
|What is the cause of IUGR in this case?||Hohepa||USMLE Step 2 CK Forum||8||05-28-2011 06:48 AM|
|Here is an interesting case!||chamarezka||USMLE Step 2 CK Forum||5||03-17-2011 11:13 AM|
|XY with Clitoromegaly case||good_boy_1234||USMLE Step 1 Forum||3||08-02-2010 06:56 AM|