1. Programa de Capacitación del Médico Residente de Emergencia del H2M
CUESTIONARIO (Octubre - 2009)
1. Question
What is the clinical significance of the hyperdense middle cerebral artery sign?
The hyperdense MCA sign is one of the early markers on CT scan of acute ischemic
stroke. A clot in the middle cerebral artery carries a high risk of bleeding if
anticoagulated or thrombolyzed due to the extent of tissue death (JEM, Vol. 33, pg.
417).
The normal MCA is not visible (A) while the left MCA is thrombosed and demonstrates the hyperdense MCA sign (B)
2. Question
What is the onset of action of a single bolus of IV insulin for the treatment of
hyperkalemia? When is the effect maximal?
An IV dose of 10 units of regular insulin to anephric adult patients lowers the serum
potassium by about 0.6mmol/L. The onset is within 15 minutes and the effect is maximal
at 30-60 minutes (Crit Care Med, 2008, Vol. 36, pg 3248).
3. Question
What is a Chance fracture?
A flexion injury of the spine consisting of a compression to the anterior vertebral body
and a transverse fracture through the posterior elements of the vertebra and the
posterior portion of the vertebral body (Wheeless’ Online Text of Orthopedics).
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2. Programa de Capacitación del Médico Residente de Emergencia del H2M
4. Question
What is the significance of the finding of a Chance fracture on plain films regarding
intrabdominal injury?
Evidence of Chance fractures on plain films is highly suggestive of hollow viscus injury,
with some form of bowel injury noted in 89% of those who had such fractures in one
series (JEM, 10/09, pg. 295).
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3. Programa de Capacitación del Médico Residente de Emergencia del H2M
5. Question
Why do bacterial infections of the CNS result in a low CSF glucose concentration
(CSF-to-serum ratio <0.4)?
A low CSF glucose concentration is primarily a result of impaired functioning of the
glucose transporter system across the blood-brain barrier (Mayo Clin Proc, Vol. 82,
pg. 874).
6. Question
Why did the 2007 ACC/AHA guidelines downgrad the recommendation for the use of
morphine for uncontrolled ischemic discomfort from class I to class IIa?
The use of MS was downgraded because data from a large observational registry,
although subject to uncontrolled selection biases, suggested that the adjusted likelihood
of death was higher when MS was used (Mayo Clin Proc, 10/09, pg. 917).
7. Question
ACC/AHA guidelines state that an experienced EP should review the results of 12-lead
ECG within what time frame after ED arrival of a patient with chest pain or other
symptoms suggestive of ACS?
The guidelines state that an experienced EP should review the ECG within no more
than 10 minutes after arrival (Mayo CLin Proc, 10/09, pg. 917).
8. Question
Patients with SVT commonly have significant ST segment depression in more than one
lead on 12-lead ECG. What is the significance of these changes? Are they commonly
associated with underlying coronary artery disease?
ST depression in the setting of SVT is generally benign. The magnitude of the
depression correlates with the heart rate. The majority of these patients do not have
coronary artery disease (AJEM, Vol. 120:851).
9. Question
Contrast-induced nephropathy is usually transient, with serum creatinine levels peaking
3 days after adminstration of the contrast. When does the serum creatinine typically
return to baseline?
Within 10 days after contrast administration (NEJM, Vol. 354, pg. 380).
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4. Programa de Capacitación del Médico Residente de Emergencia del H2M
10. Question
What percent of transient ischemic attack patients who present to the ED will have a
stroke within 90 days? Of these strokes, how many will occur within 2 days?
10.5% of TIA patients who present to the ED will have a stroke within 90 days. Of these
strokes, half will occur within 2 days, 64% will be disabling, and 5% of patients will die
or have a major adverse cardiac event (Annals of EM, Vol. 50, pg. 109).
Además revisen estas tablas del www.ebmedicine.net de octubre del 2008
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5. Programa de Capacitación del Médico Residente de Emergencia del H2M
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