Emergency Medicine Q & A, 2009, Pg

Emergency Medicine Q & A, 2009, Pg


DisciplinaMedicina9.745 materiais29.605 seguidores
Pré-visualização50 páginas
but referred to the thigh, perineum, back, groin, or abdomen. Although a 3 cm
aneurysm is less likely to rupture, any patient with a known AAA and acute abdominal pain or a palpable abdominal
mass (whether pulsatile or not) should be presumed to have an expanding or rupturing aneurysm. Seventy percent
of patients with symptomatic AAA are normotensive at the time of presentation. A plain abdominal \ufb01lm may show
the characteristic eggshell calci\ufb01cation. Limit diagnostic delays and obtain prompt surgical consultation.
... CHAPTER 3 Cardiovascular Emergencies 51
15. A 49-year-old man complains of acute tearing chest pain radiating to his back and abdomen. His blood
pressure is 200/110 mmHg. Chest x-ray shows a widened aortic knob. His past history is signi\ufb01cant for high
blood pressure. He now complains of leg pain, and his femoral pulses are no longer palpable; his legs are
pale and he says that he cannot move his toes. At this point, you should:
a. Begin \ufb01brinolytic therapy.
b. Keep systolic blood pressure above 150 mmHg to ensure adequate distal circulation.
c. Avoid pain medicine as it will make blood pressure monitoring dif\ufb01cult.
d. Administer a 10,000 unit bolus of heparin and begin an infusion at 1000 U/h.
e. Arrange for immediate surgery or interventional radiology.
The answer is e. An aortic dissection may cause acute lower extremity ischemia from obstruction. Anticoagulation
would ensure catastrophic results. The treatment is immediate surgery. Acute extremity ischemia secondary to an
embolus or thrombosis requires heparinization. The initial treatment goal for an aortic dissection is blood pressure
reduction. Nitroprusside and propranolol are the agents of choice.
16. In evaluating a patient who has suffered syncope, the most sensitive and speci\ufb01c tests are:
a. Complete blood count and basic metabolic panel.
b. Electrocardiogram and echocardiogram.
c. Head CT and carotid Doppler ultrasound.
d. History and physical examination.
e. Cardiac monitor and postural (orthostatic) vital signs.
The answer is d. The cause of syncope can be determined by thorough history and physical examination in
50\u201385% of patients. No other laboratory examination has greater diagnostic ef\ufb01cacy. A detailed account of the
event must be obtained from the patient. This must include the circumstances surrounding the episode, precipitant
factors, activity, and position. Head CT is not part of the workup in a patient with simple syncope.
17. A 47-year-old man with no signi\ufb01cant past history complains of 4 hours of nausea and a dull chest pain
radiating to his back. He thought it was indigestion, but he is not improving with antacids or
over-the-counter medicines. He is a slender, athletic-appearing man in no distress. Heart rate is 80/min,
blood pressure 120/80 mmHg. Lung and heart examinations are normal. An EKG shows normal sinus
rhythm, a QRS axis of \u201360 degrees, a right bundle-branch block and left anterior fascicular block with minor
ST-T wave changes, and an occasional PVC. An EKG performed 2 months ago was normal. Serum creatine
phosphokinase (CPK) and troponin are normal. Of the choices below, your most appropriate choice is to:
a. Administer a \ufb01brinolytic agent.
b. Insert a transvenous pacemaker.
c. Administer an antacid with viscous lidocaine; if the pain is relieved then discharge home with follow-up by a
gastroenterologist.
d. Administer 100 mg of intravenous lidocaine followed by a 2 mg/min drip and a repeat of 50 mg bolus 20
minutes later.
e. Start a prophylactic amiodarone intravenous drip.
The answer is b. A new conduction abnormality such as the bifascicular block in this patient with associated chest
discomfort is highly suggestive of acute myocardial infarction (AMI). The risk of developing complete heart block
in this setting is as high as 30\u201340% and is an indication for prophylactic insertion of a pacemaker. You should avoid
lidocaine until the pacemaker is in place, as it can suppress ventricular escape rhythms. The utility of \ufb01brinolytic
therapy is limited to patients with acute ST elevation or a new left bundle-branch block presenting within 12 hours
after the onset of symptoms. CPK values may not rise for at least 6\u20138 hours after the onset of symptoms and a
normal value cannot be used to rule out AMI.
52 Emergency Medicine Q & A: Pearls of Wisdom ...
18. A 25-year-old man complains of swelling and pain in right arm following a tennis match yesterday. There is
generalized pitting edema of his entire right arm. His past history is unremarkable. Doppler ultrasound
con\ufb01rms thrombosis of the axillary and subclavian veins:
a. The thrombosis is probably not related to his athletic activity.
b. He requires stat echocardiography to rule out atrial thrombus.
c. Arterial \ufb02ow and pulses are normally well preserved.
d. The risk of pulmonary embolism from this site is 1\u20135%.
e. Chronic edema and pain are common long-term complaints.
The answer is e. Deep vein thrombosis of the subclavian and axillary veins is usually caused by placement of a
subclavian catheter, but effort thrombosis is also seen in young people. The risk of pulmonary embolism is as high
as 15%. The postphlebitic syndrome is common with anticoagulation, but \ufb01brinolytic agents may reduce the
symptoms.
19. The most important factor in determining the natural history and prognosis of coronary artery disease is:
a. Left ventricular function.
b. The number of prior heart attacks.
c. The severity of ventricular dysrhythmia during the \ufb01rst 24\u201348 hours post-MI.
d. Tobacco pack-years.
e. The location of atherosclerotic narrowing as determined by coronary artery angiography.
The answer is a. Left ventricular function and the extent of coronary artery obstruction are the two most important
factors determining the natural history of coronary artery disease. Although left main coronary artery disease carries
a poorer prognosis, it is the number of diseased vessels rather than the location of lesions that is more important.
Ventricular arrhythmias during the \ufb01rst 48 hours of infarction are usually from irritability and are not independently
prognostic. The number of infarctions is less signi\ufb01cant than the degree of left ventricular function impairment.
20. Of all cardiac enzymes and serum markers readily available, the one which will be present in the serum
earliest and is most sensitive during the early hours after an acute event is:
a. Mass CK-MB.
b. Troponin I.
c. Troponin T.
d. Myoglobin.
e. Lactate dehydrogenase-1.
The answer is d. Myoglobin levels are elevated in the serum within 1\u20132 hours after symptom onset, peaking 4\u20135
hours after acute myocardial infarction. Sensitivity improves from 62% on ED arrival to 100% 3 hours later,
compared with 50% and 95% respectively for CK-MB. Speci\ufb01city, however, is only 80% compared with 94% for
CK-MB.
21. By holding a magnet over a patient\u2019s pacemaker, you:
a. Turn it off.
b. Inhibit its electrical conduction.
c. Convert the pacemaker to an asynchronous or \ufb01xed-rate pacing mode.
d. Recharge the battery.
e. Convert it to a de\ufb01brillator.
... CHAPTER 3 Cardiovascular Emergencies 53
The answer is c. A magnet placed externally over the pulse generator of a pacemaker does not inhibit or turn off a
pacemaker. Rather it results in closure of a reed switch within the pacemaker circuitry, converting it to an
asynchronous or \ufb01xed-rate pacer mode so the pacemaker is no longer inhibited by the patient\u2019s intrinsic electrical
activity. This is helpful when the patient\u2019s intrinsic heart rate exceeds the pacemaker\u2019s set rate and pacemaker
function is inhibited. Magnet application then allows pacing to occur, and pacing rate and the presence of capture
can be determined.
22. Concerning congestive heart failure:
a. Nitrates decrease afterload.
b. Hydralazine decreases preload.
c. Beta-blockers are to be avoided because of negative inotropic and chronotropic effects.
d. Nitroprusside