Question 1

A 24-year-old woman is admitted to the hospital after a motor vehicle accident resulted in a right humerus fracture, multiple rib fractures, and a contusion over her right leg.  The patient receives multiple packed red blood cell transfusions.  Chest and abdominal evaluation show a right-sided hemothorax.  A chest tube is inserted.  Pain is controlled with intravenous morphine.  The next morning, she has a crawling and burning sensation and worsening pain in her right leg despite repeated doses of morphine.  Temperature is 37.2 C (99 F), blood pressure is 140/82 mm Hg, heart rate is 96/min, and respirations are 18/min.  The right leg is swollen and tense.  Pulses are palpable in both lower extremities. Which of the following is the most important determinant in this patient's prognosis?
A)Absence of arterial pulse
B)Elevated creatine kinase level
C)Presence of skin lesions
D)Sensory deficits in the affected extremity
E)Timing of surgical intervention

Accepted Answer

Explanation: Signs and symptoms of compartment syndrome (CS) are unreliable, and a high index of suspicion is needed to make the diagnosis. Disease severity cannot be assessed based on clinical features alone. Time to intervention is the most important factor predicting complete functional recovery of the limb. All constrictive coverings (casts, dressings) should be removed and supplemental oxygen given. Supportive measures to maintain perfusion pressure include keeping the limb at torso level and treating hypotension if present. Fasciotomy is the definitive treatment of choice. Absence of arterial pulses (Choice A) is not a consistent finding and does not indicate a poor prognosis. Similarly, patients may have sensory deficits (Choice D) or even motor weakness but may recover completely if compartment pressure is relieved early in the disease course. Complete paralysis is a late finding, usually occurs in patients with a nonviable limb, and is generally not reversible with treatment. (Choice B) Rhabdomyolysis is a common complication of CS. However, creatine kinase level is not a prognostic indicator; such patients may have complete functional limb recovery if surgical intervention is well timed. Muscle death occurs if fasciotomy is not performed, and then limb amputation may be needed. (Choice C) The extremity may appear pale and have prolonged capillary refill with arterial occlusion from CS. Skin breakdown is a late and rare finding, usually occurring from tissue infiltration of intravenous fluids. Most patients will recover completely with early intervention. Educational objective: Clinical assessment is an unreliable indicator of disease severity in compartment syndrome. A high index of suspicion and timely fasciotomy are the most important factors predicting complete functional recovery. References: Early fasciotomy in patients with extremity vascular injury is associated with decreased risk of adverse limb outcomes: a review of the National Trauma Data Bank. (http://www.ncbi.nlm.nih.gov/pubmed/21719009)

Question 2

A 24-year-old woman is admitted to the hospital after a motor vehicle accident resulted in a right humerus fracture, multiple rib fractures, and a contusion over her right leg.  The patient receives multiple packed red blood cell transfusions.  Chest and abdominal evaluation show a right-sided hemothorax.  A chest tube is inserted.  Pain is controlled with intravenous morphine.  The next morning, she has a crawling and burning sensation and worsening pain in her right leg despite repeated doses of morphine.  Temperature is 37.2 C (99 F), blood pressure is 140/82 mm Hg, heart rate is 96/min, and respirations are 18/min.  The right leg is swollen and tense.  Pulses are palpable in both lower extremities. 
Which of the following complications is most commonly associated with the condition affecting this patient's right leg?
A)Acute renal failure
B)Iliac artery occlusion
C)Microangiopathic hemolytic anemia
D)Paraparesis
E)Pulmonary embolism

Accepted Answer

Explanation: 11ec2b69_c113_986f_8f63_d7fed36bfea2_MD0005_00 Increased edema in an enclosed compartment leads to compression of neurovascular bundles. Arterial and venous occlusion in the extremity results in anoxic muscle necrosis (rhabdomyolysis). The released myoglobin is filtered and degraded in the kidney. Heme pigment from myoglobin degradation: Is directly toxic to proximal tubular cells Combines with Tamm-Horsfall protein to form tubular casts Induces vasoconstriction, reducing medullary blood flow These mechanisms lead to acute renal failure (ARF), particularly in volume-depleted states (eg, hemorrhage), which worsens vasoconstriction and cast formation. (Choice B) Compartment syndrome (CS) of the leg in this patient can cause occlusion of the anterior and posterior tibial arteries and the fibular artery but not the iliac artery due to location. Arterial shearing resulting in intimal tear is a complication of blunt trauma, and the arterial lumen can be partially or completely occluded by the intimal flap; this complication is very rare. (Choice C) Microangiopathic hemolytic anemia in both trauma and CS may be caused by disseminated intravascular coagulation. However, ARF is a more common complication of CS. (Choice D) Compression of nerves in CS causes sensory and motor loss below the compression site in the affected limb. Paraparesis would be expected with spinal cord injury. (Choice E) Extremity immobilization does increase this patient's risk for deep venous thrombosis and pulmonary embolism. However, ARF is more commonly associated with CS. Educational objective: Patients with compartment syndrome may develop rhabdomyolysis and release of myoglobin. Heme pigment from myoglobin is nephrotoxic; patients may develop acute renal failure, especially if they are volume depleted. References: Acute lower-leg compartment syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/23937740)

Question 3

An 80-year-old man is admitted to the cardiac care unit after a complicated percutaneous coronary intervention procedure.  He has chest discomfort and shortness of breath.  The patient's blood pressure is 82/50 mm Hg and pulse is 114/min and regular.  Hemodynamic readings from the pulmonary artery catheter are shown below.  Which of the following is the most likely cause of this patient's hypotension?
A)Early stages of septic shock
B)Impaired myocardial contractility
C)Pericardial tamponade
D)Pulmonary embolism
E)Retroperitoneal bleeding

Accepted Answer

Explanation: 11ec2b69_c112_d51d_8f63_4df83e0f6748_MD0005_00 This patient's clinical presentation (chest discomfort, tachycardia, hypotension) and hemodynamic findings are consistent with cardiogenic shock after a complicated percutaneous coronary procedure. This is most likely due to an abrupt coronary occlusion leading to impaired contractility of the involved myocardium. Hemodynamic parameters from pulmonary artery catheterization in cardiogenic shock show low cardiac index (CI) due to impaired cardiac contractility, elevated pulmonary capillary wedge pressure (PCWP) due to volume overload, with a compensatory elevation in systemic vascular resistance (SVR). (Choice A) Patients with early sepsis or neurogenic shock (distributive shock) have a compensatory increase in cardiac output/index. PCWP and SVR are typically decreased, which is useful in differentiating septic shock from other causes of shock. (Choice C) In cardiac tamponade, rapid accumulation of fluid in the limited pericardial space leads to increased right atrial and ventricular pressures, but there is also a characteristic equalization of right atrial, right ventricular end diastolic, and PCWPs (not seen in this patient whose PCWP is higher than his right ventricular end diastolic pressure). (Choice D) Patients with pulmonary embolus have elevated right atrial, right ventricular, and pulmonary artery pressures. They may have hyperdynamic left ventricular function with increased CI. PCWP and SVR are generally not affected. (Choice E) Patients with retroperitoneal bleeding and/or intravascular volume depletion will have low right atrial and PCWP. CI is slightly reduced and SVR is increased. Educational objective: Patients with significant left ventricular dysfunction and cardiogenic shock have reduced cardiac index and elevated pulmonary capillary wedge pressures. Systemic vascular resistance is typically increased to maintain adequate tissue perfusion pressure. References: The ability to achieve complete revascularization is associated with improved in-hospital survival in cardiogenic shock due to myocardial infarction: Manitoba cardiogenic SHOCK Registry investigators. (http://www.ncbi.nlm.nih.gov/pubmed/21547996)

Question 4

A newborn boy is delivered by cesarean delivery at 39 weeks gestation to a 26-year-old woman, gravida 1 para 1, with gestational diabetes mellitus.  First-trimester laboratory testing was normal, and second-trimester ultrasound showed no anomalies.  At 28 weeks gestation, oral glucose tolerance testing indicated hyperglycemia, for which the patient initiated dietary modification and exercise.  At 34 weeks gestation, maternal fasting blood sugars were consistently >100 mg/dL.  She was started on subcutaneous insulin therapy but was frequently hyperglycemic.  Other than prenatal vitamins, the patient's mother did not take any medications and did not use tobacco, alcohol, or illicit drugs.  The infant's birthweight is 3.99 kg (8.8 lb).  Temperature is 36.8 C (98.2 F), blood pressure is 70/40 mm Hg, pulse is 150/min, and respirations are 62/min.  Pulse oximetry on room air is 92% in the right upper extremity and 93% in the left lower extremity.  Examination shows a nondysmorphic infant with mild tachypnea, nasal flaring, and retractions.  Auscultation reveals a heart murmur, but breath sounds are clear.  Chest radiograph reveals mild pulmonary congestion. 
An echocardiogram in this neonate would most likely show which of the following findings?
A)Atrialized right ventricle
B)Hypertrophic interventricular septum
C)Hypoplastic left ventricle
D)Narrowing of the aorta
E)Obstruction of the pulmonary valve

Accepted Answer

Explanation: 11ec2b69_c117_6905_8f63_b385e77750eb_MD0005_00 This newborn with respiratory distress (tachypnea, nasal flaring, retractions) and a heart murmur likely has transient hypertrophic cardiomyopathy, a cardiac anomaly found in infants of mothers with gestational diabetes. This disease occurs in the late second to early third trimesters due to fetal hyperinsulinemia in response to maternal and fetal hyperglycemia. Insulin triggers glycogen synthesis, and excess glycogen and fat are deposited within the myocardium, particularly the interventricular septum. Increased oxidative stress of the interventricular septum may contribute to this selective thickening. A hypertrophic interventricular septum is usually asymptomatic; however, if left ventricular outflow is obstructed, manifestations of congestive heart failure may occur. In infants, these can include respiratory distress, tachycardia, and hypoxia (as seen in this patient), as well as failure to thrive. Despite the presence of pulmonary edema, crackles may not be auscultated. Pulmonary congestion and cardiomegaly may be evident on chest radiograph, and echocardiography confirms the diagnosis. Although transient tachypnea of the newborn is a common cause of tachypnea and respiratory distress, this patient's murmur makes cardiogenic pulmonary edema due to transient hypertrophic cardiomyopathy the most likely etiology. Poorly controlled gestational diabetes mellitus carries numerous additional risks for the infant, including macrosomia, hypocalcemia, hypoglycemia, hyperviscosity due to polycythemia, and respiratory difficulties. Most of these adverse effects can be avoided with strict glycemic control throughout pregnancy (ideal fasting blood glucose ≤95 mg/dL). (Choice A) Ebstein anomaly is characterized by atrialization of the right ventricle due to a malformed tricuspid valve. Severely affected newborns present with tricuspid regurgitation and cyanosis. Although some infants have mild symptoms, this diagnosis is unlikely in this patient who had a normal second-trimester ultrasound. (Choice C) Hypoplastic left ventricle (ie, hypoplastic left heart syndrome) is an embryologic malformation that occurs early in the first trimester in infants of mothers with pregestational diabetes. It presents with cyanosis, and the structural abnormality is often recognized on second-trimester ultrasound. (Choice D) Coarctation, or narrowing of the aorta, is typically associated with Turner syndrome rather than prenatal maternal hyperglycemia. Neonates with severe coarctation have weak femoral pulses and decreased postductal oxygen saturation. Aortic arch indentation ("3 sign") is seen on radiography. (Choice E) Congenital pulmonary valve stenosis, characterized by an obstruction of the pulmonary valve, is typically associated with Noonan syndrome. Right ventricular outflow tract obstruction may result in cyanosis if right-to-left shunting occurs. Educational objective: Infants born to mothers with diabetes and poor glycemic control during pregnancy are at increased risk for transient hypertrophic cardiomyopathy with a thickened interventricular septum due to excess glycogen deposition in the fetal myocardium. Tachypnea and respiratory distress may be early signs of congestive heart failure. References: Neonates of diabetic mothers: the starting point for developing novel therapeutic approaches to ischemic heart and brain? (http://www.ncbi.nlm.nih.gov/pubmed/27959282) Myocardial hypertrophy and dysfunction in maternal diabetes. (http://www.ncbi.nlm.nih.gov/pubmed/22445568)

Question 5

A 28-year-old man comes to the emergency department with palpitations. For the past 6 months, he has had palpitations that were intermittent and short-lived but seem persistent today. Past medical history is unremarkable. His BMI is 24 kg/m². Cardiac auscultation reveals a II/VI mid-systolic murmur at the left upper sternal border. Electrocardiogram (ECG) shows atrial fibrillation with rapid ventricular response. Echocardiogram shows normal left ventricular size and function and right atrial and ventricular dilation. Which of the following is the most likely diagnosis? A)Atrial septal defect, secundum type B)Dilated cardiomyopathy C)Hypertrophic cardiomyopathy D)Membranous ventricular septal defect E)Patent ductus arteriosus

Accepted Answer

Explanation: This patient's clinical presentation - mid-systolic murmur at the left upper sternal border with right atrial and ventricular dilation - is most suggestive of atrial septal defect (ASD) with a left-to-right shunt. ASDs are the second most common congenital heart defect in adults (bicuspid aortic valve is the most common). Many patients remain asymptomatic until adulthood. Those with significant shunt flow may have decreased exercise tolerance (ie, dyspnea and fatigue) and other complications such as pulmonary hypertension, right heart failure, stroke due to paradoxical embolization, and atrial arrhythmias (atrial fibrillation or flutter). Cardiac auscultation in patients with ASD (with large left-to-right shunt and normal pulmonary artery pressure) typically reveals a characteristic wide and fixed splitting of the second heart sound. Patients may also have a mid-systolic ejection murmur over the left upper sternal border resulting from increased flow across the pulmonic valve, and a mid-diastolic rumble resulting from increased flow across the tricuspid valve. Transthoracic echocardiogram can show the abrupt discontinuity of the interatrial septum, with right atrial and ventricular dilation (from volume overload due to left-to-right shunt). (Choice B) Patients with dilated cardiomyopathy can develop atrial or ventricular arrhythmias; however, echocardiogram will typically show a dilated left ventricular (LV) cavity with reduced LV function. (Choice C) Cardiac auscultation in patients with hypertrophic cardiomyopathy (HCM) and LV outflow tract obstruction reveals a harsh crescendo-decrescendo systolic murmur heard best at the apex and lower left sternal border. The murmur increases in intensity with Valsalva and also when rising from a sitting or squatting position. Echocardiogram shows LV hypertrophy (often asymmetric and involving the septum), and increased LV outflow tract gradient. (Choice D) Patients with a ventricular septal defect (VSD) typically have a harsh holosystolic murmur with maximal intensity over the left 3rd and 4th intercostal spaces, often accompanied by a palpable thrill. The presence of a large VSD with significant left-to-right shunt causes right ventricle dilation, along with enlargement of the left ventricle, left atrium, and pulmonary arteries due to volume overload in pulmonary circulation. (Choice E) Patent ductus arteriosus (PDA) causes a characteristic continuous murmur that is heard best in the left infraclavicular area. Moderate to large PDAs with left-to-right shunting cause volume overload of the left atrium and ventricle, resulting in left atrial/ventricle dilation and LV dysfunction. Educational objective: Patients with unexplained right atrial or ventricular dilation should be evaluated for possible atrial septal defect (ASD). Cardiac auscultation in patients with ASD (with large left-to-right shunt and normal pulmonary artery pressure) typically reveals a characteristic wide and fixed splitting of the second heart sound. References: ESC guidelines for the management of grown-up congenital heart disease. (http://www.ncbi.nlm.nih.gov/pubmed/20801927) ACC/AHA 2008 guidelines for the management of adults with congenital heart disease. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. (http://www.ncbi.nlm.nih.gov/pubmed/18997169)

Question 6

A 61-year-old woman comes to the physician due to mild exertional dyspnea.  She has difficulty going up the stairs and feels very tired by the end of the day.  She has no chest pain, orthopnea, lower extremity swelling, or syncope.  The patient is being treated for locally advanced HER2-positive breast cancer.  She underwent left-sided mastectomy and received adjuvant chemotherapy with docetaxel and carboplatin in addition to trastuzumab 6 months ago.  Preoperative evaluation showed normal cardiac function.  Currently, the patient receives periodic trastuzumab infusions.  Echocardiogram shows a left ventricular ejection fraction of 30%.  The patient wonders if her symptoms are related to cancer therapy and wants to know her long-term prognosis.  What is the best response to this patient's concerns?
A)Accelerated atherosclerosis typically underlies these symptoms
B)Damage to the heart is strongly related to cumulative trastuzumab dosage
C)Most patients completely recover heart function after discontinuing trastuzumab
D)There is no need to suspend trastuzumab therapy
E)Traditional therapies for heart failure are commonly ineffective

Accepted Answer

Explanation: This patient has developed trastuzumab-associated cardiotoxicity. Trastuzumab is a monoclonal antibody that targets human epidermal growth factor receptor 2 (HER2). It is used in addition to adjuvant chemotherapy for the treatment of patients with HER2-positive tumors. Trastuzumab may cause a decline in left ventricular ejection fraction (LVEF), which is usually asymptomatic but may occasionally lead to overt clinical heart failure. The incidence of cardiotoxicity is approximately 5% with trastuzumab monotherapy, but it is 25% with trastuzumab combined with anthracycline (eg, doxorubicin) and cyclophosphamide. In most patients, trastuzumab-associated cardiotoxicity is reversible; there is complete recovery of cardiac function after treatment discontinuation. In contrast, chronic anthracycline-associated cardiotoxicity may not be reversible after treatment discontinuation due to myocyte necrosis, destruction, and replacement by fibrous tissue. (Choice A) Trastuzumab-related cardiotoxicity is due to loss of myocardial contractility (myocardial hibernation) leading to a decrease in LVEF. It is not associated with accelerated atherosclerosis. (Choice B) Cardiotoxicity with anthracyclines is strongly related to cumulative doses but trastuzumab-associated cardiotoxicity is not dose-related. (Choice D) Trastuzumab should be withheld for 4 weeks if LVEF decreases by >16% from baseline, or by 10%-15% from baseline to below the lower limits of normal. It should be completely discontinued if patients develop symptomatic heart failure. (Choice E) Trastuzumab-related cardiotoxicity responds well to standard therapy for heart failure, including beta-blockers and angiotensin converting enzyme (ACE) inhibitors. Educational objective: Trastuzumab-related cardiotoxicity usually presents with an asymptomatic decline in left ventricular ejection fraction, but may occasionally lead to overt heart failure. It is unrelated to cumulative dosage and is often reversible in most patients after discontinuation of trastuzumab therapy. References: Trastuzumab-associated cardiotoxicity (http://www.ncbi.nlm.nih.gov/pubmed/12237930) Cardiotoxicity associated with trastuzumab treatment of HER2+ breast cancer (http://www.ncbi.nlm.nih.gov/pubmed/19669637)

Question 7

A 24-year-old Caucasian male was involved in a major motor vehicle accident.  The ambulance service that arrived several minutes after the accident found him dead.  He was found in the driver's seat, and the steering wheel in front of him was broken.  Which of the following is the most likely cause of his death?
A)Cardiac contusion
B)Tension pneumothorax
C)Aortic rupture
D)Stomach rupture
E)Cervical spine injury

Accepted Answer

Explanation: Aortic injury is the most common cause of sudden death due to steering wheel injuries. Patients typically die at the scene before an ambulance service arrives. Rapid deceleration produces a shearing force along the aortic arch where the aorta is firmly attached. It is usually observed in the area of the ligamentum arteriosum, the aortic root, and the diaphragmatic hiatus. The remaining choices on the list are either less common causes of sudden death after a motor vehicle accident, or conditions that do not produce sudden death. (Choice B) Tension pneumothorax is a life-threatening condition that may result in cardiovascular collapse; however, the resulting death is not usually instantaneous. (Choice D) Abdominal injury may result in profound shock if rapid internal bleeding occurs. (Choice A) Cardiac contusion produces sudden death when the injury involves the cardiac chambers or vessels. (Choice E)Cervical spine injury leads to quadriparesis and sometimes respiratory paralysis. Educational Objective: The most common cause of sudden death after a steering wheel injury from motor vehicle accident is aortic injury.

Question 8

A 62-year-old man with a history of hypertension comes to establish care.  He recently moved to the area and states that his prior physician was treating him for high blood pressure.  The patient has no current symptoms and feels healthy.  He describes his lifestyle as mostly sedentary but reports no limitations with walking at a fast pace.  The patient takes chlorthalidone and losartan for hypertension.  Five years ago, he was diagnosed with hyperlipidemia and was offered medication but refused.  The patient has never smoked and does not drink alcohol.  His father had open-heart surgery at age 70, but the patient cannot provide further details.  He has 2 siblings, both of whom are healthy.  Blood pressure is 162/80 mm Hg and heart rate is 72/min.  An ejection-type systolic murmur is heard at the right upper-sternal border.  Which of the following findings is most consistent with severe aortic stenosis in this patient?
A)Early peaking of the murmur
B)High intensity of the second heart sound
C)Presence of a third heart sound
D)Single second heart sound during inspiration
E)Wide pulse pressure

Accepted Answer

Explanation: A detailed physical examination can provide clues to the presence and severity of valvular aortic stenosis (AS). The following examination findings are consistent with severe AS: A soft, single second heart sound (S2) A delayed and diminished carotid pulse ("parvus et tardus") Loud and late-peaking systolic murmur In normal physiology, inspiration pulls blood into the right side of the heart and results in delayed closure of the pulmonic valve and earlier closure of the aortic valve; a noticeable split of the aortic (A2) and pulmonic (P2) components of S2 can be appreciated. However, in severe AS, closure of the aortic valve is delayed, which results in nearly simultaneous closure of the aortic and pulmonic valves during inspiration, and is appreciated on examination as a single S2. The splitting can sometimes be paradoxical, where delayed closure of the aortic valve causes A2 to occur noticeably after P2. (Choice A) Early peaking of an AS murmur is suggestive of mild to moderate AS because relatively low left ventricular pressure (attained early in ventricular systole) is needed to overcome the valvular stenosis. (Choice B) A severely stenotic aortic valve creates a low-intensity sound during closure. High intensity of S2 is more consistent with mild to moderate AS. (Choice C) A third heart sound is typically caused by blood filling a dilated ventricular cavity in a patient with heart failure. Severe AS can lead to heart failure, but this patient's absence of signs of heart failure (eg, dyspnea, peripheral edema) makes the presence of a third heart sound unlikely. In a patient with severe AS and no evidence of heart failure, the presence of a fourth heart sound (due to concentric left ventricular hypertrophy and decreased wall compliance) is more likely. (Choice E) Because pulse pressure (the difference between systolic and diastolic pressure) is directly related to stroke volume, patients with severe AS are unable to create wide pulse pressures. Wide pulse pressures are often seen in patients with aortic regurgitation. Educational objective: The presence of a low-intensity, single second heart sound during inspiration is consistent with severe aortic stenosis. Other findings suggestive of severe AS include delayed and diminished carotid pulse and loud and late-peaking systolic murmur. References: Does this patient have an abnormal systolic murmur? (http://www.ncbi.nlm.nih.gov/pubmed/9032164) Physical examination in valvular aortic stenosis: correlation with stenosis severity and prediction of clinical outcome. (http://www.ncbi.nlm.nih.gov/pubmed/9924164)

Question 9

A 20-year-old man develops substernal chest pain and palpitations, followed by brief syncope while playing soccer.  The patient is rushed to the emergency department where he reports feeling fine.  He describes previous episodes of "chest pressure" while overexerting himself, after which he needs to stop and rest.  He has had no previous episodes of syncope.  Medical history is unremarkable.  The patient does not use tobacco, alcohol, or illicit drugs.  There is no family history of coronary heart disease or sudden death.  Blood pressure is 122/78 mm Hg and pulse is 78/min.  Cardiac examination reveals no murmurs in both the supine and standing positions.  ECG shows normal sinus rhythm with a rate of 72/min.  No ST-segment or T-wave abnormalities are present.  The QTc interval is 410 msec.  The patient is recommended to avoid exercise until he can undergo further workup, but 2 days later he collapses and dies while jogging.  Which of the following is the most likely diagnosis?
A)Anomalous coronary artery
B)Brugada syndrome
C)Congenital long QT syndrome
D)Hypertrophic cardiomyopathy
E)Wolff-Parkinson-White syndrome

Accepted Answer

Explanation: 11ec2b69_c111_758a_8f63_d3f6591fbd7b_MD0005_00 This patient experienced sudden cardiac death (SCD) most likely due to anomalous aortic origin of a coronary artery (AAOCA). In younger patients (age <35), SCD is usually due to underlying structural heart disease, with ventricular tachyarrhythmia as the most common terminal event. The high-risk types of AAOCA are among the most common causes of SCD in young athletes; in one study, autopsies on military recruits with SCD revealed AAOCA to be the cause in about one-third of cases. Two types of AAOCA commonly associated with SCD are the left main coronary artery originating from the right aortic sinus and the right coronary artery originating from the left aortic sinus. These defects create sharp curvature of the anomalous artery, making it less amenable to high-volume flow. In addition, the anomalous artery passes between the aorta and the pulmonary artery, making it susceptible to external compression during exercise. Patients with AAOCA may experience exertional angina, lightheadedness, or syncope; however, some patients experience SCD without any premonitory symptoms. Resting ECG is typically unremarkable. Transthoracic echocardiography can sometimes make the diagnosis, but it can also miss or inaccurately characterize AAOCA. CT coronary angiography or coronary magnetic resonance angiography provide the best visualization of coronary anatomy, and are the diagnostic tests of choice in patients with suspected AAOCA. (Choices B and C) Brugada syndrome and long QT syndrome are associated with an increased risk of SCD; however, the lack of characteristic ECG findings for Brugada syndrome (right bundle branch block and ST-segment elevation in leads V1-V3) or long QT syndrome (QTc >450 msec in men or >470 msec in women) makes these diagnoses less likely. (Choice D) Hypertrophic cardiomyopathy is the most common cause of SCD in young athletes in the United States; however, it is unlikely in the absence of a systolic murmur that increases in intensity with standing. increases in intensity (Choice E) Wolff-Parkinson-White syndrome is an uncommon cause of SCD. Resting ECG typically shows a short PR interval with slurred upstroke and widening of the QRS complex. Educational objective: Anomalous aortic origin of a coronary artery is a common cause of sudden cardiac death in young athletes. Patients may have premonitory symptoms of exertional angina, lightheadedness, or syncope. ECG is typically unremarkable and transthoracic echocardiography or coronary angiographic imaging is required for diagnosis. References: Sudden cardiac death in athletes. (http://www.ncbi.nlm.nih.gov/pubmed/24350833) Sudden death in young adults: a 25-year review of autopsies in military recruits. (http://www.ncbi.nlm.nih.gov/pubmed/15583223)

Question 10

A newborn boy is delivered by cesarean delivery at 39 weeks gestation to a 26-year-old woman, gravida 1 para 1, with gestational diabetes mellitus.  First-trimester laboratory testing was normal, and second-trimester ultrasound showed no anomalies.  At 28 weeks gestation, oral glucose tolerance testing indicated hyperglycemia, for which the patient initiated dietary modification and exercise.  At 34 weeks gestation, maternal fasting blood sugars were consistently >100 mg/dL.  She was started on subcutaneous insulin therapy but was frequently hyperglycemic.  Other than prenatal vitamins, the patient's mother did not take any medications and did not use tobacco, alcohol, or illicit drugs.  The infant's birthweight is 3.99 kg (8.8 lb).  Temperature is 36.8 C (98.2 F), blood pressure is 70/40 mm Hg, pulse is 150/min, and respirations are 62/min.  Pulse oximetry on room air is 92% in the right upper extremity and 93% in the left lower extremity.  Examination shows a nondysmorphic infant with mild tachypnea, nasal flaring, and retractions.  Auscultation reveals a heart murmur, but breath sounds are clear.  Chest radiograph reveals mild pulmonary congestion. An echocardiogram confirms the suspected cardiac abnormality.  After the physician explains the condition, the parents express concerns about the prognosis.  Which of the following is the most appropriate response to the parents?
A)Immediate surgery is recommended to repair the defect.
B)Infants have a good prognosis with daily insulin therapy.
C)Most children recover without surgery, even if they have symptoms.
D)Pacemaker placement will reduce the risk of life-threatening arrhythmias.
E)Symptoms improve immediately after administration of prostaglandins.

Accepted Answer

Explanation: This infant of a mother with gestational diabetes mellitus has transient hypertrophic cardiomyopathy as a result of poor maternal glycemic control during pregnancy. If asymptomatic, no treatment is required. If heart failure symptoms develop, propranolol and appropriate fluid management are indicated. Spontaneous resolution is expected within a few weeks after birth; echocardiogram findings normalize within a year. After birth, the infant is no longer exposed to maternal hyperglycemia, allowing plasma insulin levels to normalize. Excess glycogen within the myocardium is then depleted by normal metabolic processes during periods of fasting. (Choice A) Immediate corrective surgery is required for cyanotic congenital heart abnormalities (eg, tetralogy of Fallot, transposition of the great arteries). Hypertrophic obstructive cardiomyopathy, typically caused by genetically abnormal myocytes rather than by transient hyperinsulinemia, may require a septal myectomy if unresponsive to medical therapy. (Choice B) Insulin is a treatment option for hyperglycemia due to diabetes mellitus; however, infants of mothers with diabetes typically experience hypoglycemia. This occurs because maternal hyperglycemia in utero triggers fetal beta-cell hyperplasia and subsequent hyperinsulinemia. (Choice D) Pacemaker placement is the treatment for arrhythmias (eg, congenital long QT syndrome) and conditions causing heart block (eg, neonatal lupus). Arrhythmias are rare in patients with interventricular septal thickening, and pacemaker placement is not indicated. (Choice E) Prostaglandins maintain the patency of the ductus arteriosus to allow blood flow to the systemic circulation. Prostaglandins are indicated for patients with ductal-dependent lesions (eg, hypoplastic left heart, transposition of the great arteries) and provide immediate symptomatic improvement while awaiting surgery. Educational objective: Hypertrophic cardiomyopathy, with interventricular thickening causing left ventricular outflow tract obstruction, may occur in an infant born to a mother with poorly controlled diabetes. Spontaneous resolution is expected within a few weeks after birth as insulin levels normalize. References: Elevated neonatal insulin-like growth factor I is associated with fetal hypertrophic cardiomyopathy in diabetic women. (http://www.ncbi.nlm.nih.gov/pubmed/24813596)

Question 11

A 32-year-old man is evaluated for a murmur, which was found during a preventive examination.  He has no symptoms, and his past medical history is insignificant.  The patient smokes a pack of cigarettes per day.  He has no family history of cardiovascular disease or sudden death.  Blood pressure is 132/80 mm Hg and heart rate is 68/min.  The patient's height is 178 cm.  Body mass index is 31 kg/m2.  A 2/6 ejection-type murmur is heard at the right upper sternal border.  His physical examination is otherwise unremarkable.  Transthoracic echocardiogram shows normal left atrial and left ventricular size, left ventricular ejection fraction of 60%, bicuspid aortic valve, and trivial aortic regurgitation.  There is no evidence of aortic stenosis on Doppler echocardiography.  For which of the following conditions should this patient be evaluated specifically?
A)Fibrillin gene mutation
B)Myosin gene mutation
C)Nonsustained ventricular tachycardia
D)Renal artery stenosis
E)Thoracic aortic aneurysm

Accepted Answer

Explanation: 11ec2b69_c110_3d09_8f63_1386ebba7b8f_MD0005_00 Bicuspid aortic valve (BAV) is the most common congenital heart disease in adults, affecting about 1% of the general population. It can occur as an isolated lesion or in association with other congenital cardiovascular abnormalities, including coarctation of the aorta, sub- or supravalvular aortic stenosis, ventricular septal defect, and sinus of Valsalva aneurysm. BAV is also a risk factor for aortic dilation, with a reported prevalence of 20%-80%. Progressive aortic dilation can occur in the aortic sinuses, aortic root, or ascending aorta, leading to aortic aneurysm formation and risk for aortic dissection. Patients with BAV should have a thorough evaluation with echocardiogram, CT, or MRI imaging to assess the aortic root and ascending aorta for dilation. Bicuspid aortic valve (BAV) (Choice A) Mutations involving the fibrillin gene are seen in patients with Marfan syndrome. These patients are also at increased risk for dilation of the ascending aorta and aortic dissection. (Choice B) Myosin gene mutation is one of several gene mutations seen in patients with hypertrophic cardiomyopathy. (Choice C) This patient is asymptomatic and has normal left ventricular function. There is no indication for evaluation of this patient for nonsustained ventricular tachycardia. (Choice D) Renal artery stenosis is not found in association with BAV. Educational objective: Patients with bicuspid aortic valve are at risk for developing aortic dilation, aortic aneurysm, and aortic dissection, and should be screened with imaging of the aortic root and proximal aorta. References: The bicuspid aortic valve. (http://www.ncbi.nlm.nih.gov/pubmed/16129122)

Question 12

A 65-year-old man with persistent atrial fibrillation comes to the emergency department with a cold right foot.  He has not been compliant with anticoagulation therapy.  His other medical problems include type 2 diabetes mellitus, hypertension, and chronic nephropathy with low-grade proteinuria.  The patient's blood pressure is 122/70 mm Hg and pulse is 112/min and irregular.  Physical examination shows a cold right leg with absent dorsalis pedis and posterior tibial pulses.  An emergency arteriogram reveals right popliteal artery occlusion, which is treated with thrombus aspiration with good angiographic results.  Two hours later, the patient has intense pain in the right leg, accompanied by an "ant crawling" and burning sensation.  Which of the following is the most likely diagnosis?
A)Compartment syndrome
B)Deep-tissue infection
C)Diabetic neuropathy
D)Ischemic stroke
E)Phantom pain

Accepted Answer

Explanation: 11ec2b69_c113_4a4e_8f63_4763b8c26b14_MD0005_00 This patient, with severe pain following a lower-extremity thrombectomy, has features suspicious for postischemic compartment syndrome (CS). CS is typically associated with traumatic injuries of the extremities, especially long-bone fractures, but may occur in any condition that causes increased pressure in a confined tissue space and compromises blood flow. Postischemic CS is due to interstitial edema and possibly intracellular swelling following tissue ischemia and subsequent reperfusion. Nerve and muscle injury in CS can result in permanent loss of function. Measurement of tissue pressures is diagnostic: Compartment pressure >30 mm Hg or delta pressure (diastolic blood pressure - compartment pressure) <20-30 mm Hg indicates significant CS. If compartment pressures are improving, patients may be observed closely. However, patients with elevated compartment pressures that do not improve rapidly require fasciotomy to avoid long-term complications. (Choice B) Deep-tissue infection, such as necrotizing fasciitis, is also characterized by severe pain out of proportion to obvious clinical signs. Commonly implicated organisms include group A streptococci and mixed anaerobic infections. Symptoms evolve generally over several hours to days and are usually associated with signs of significant systemic toxicity. (Choice C) Diabetic neuropathy may cause chronic lower-extremity pain and paresthesias; acute episodes are not characteristic. (Choice D) Thromboembolic stroke is a common complication of inadequately anticoagulated atrial fibrillation. Characteristic features include acute neurological deficits such as hemiparesis or aphasia, but pain is not typical. (Choice E) Phantom pain refers to perceived pain in an extremity following amputation. It is caused by afferent pain fibers that previously served the affected limb. Educational objective: Compartment syndrome is caused by increased tissue pressures in a confined space leading to impaired perfusion. It is common following traumatic injuries, but can also occur in nontraumatic settings such as arterial occlusion and reperfusion. References: Reperfusion and compartment syndromes: strategies for prevention and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/11400086)

Question 13

A 55-year-old man is brought to the emergency department due to shortness of breath and weakness.  The symptoms have been present for approximately 3 weeks but have rapidly progressed over the last 2 days.  He felt too weak to get up to use the bathroom today.  The patient was diagnosed with non-small cell lung cancer 2 years ago.  At that time, he underwent surgical resection, followed by cisplatin-based combination chemotherapy.  Since then, he has had follow-up CT scans every 6 months without evidence of recurrence.  His last scan was 5 months ago.  Other medical history includes mitral valve prolapse, for which he has been followed with echocardiography every 3 years.  The patient used to take antibiotics prior to dental procedures but stopped a few years ago when his cardiologist advised him that it was no longer necessary.  He currently takes no medications.  His mother died of congestive heart failure at age 80 and his father has emphysema.  The patient does not use tobacco, alcohol, or illicit drugs.  He formerly worked as a diesel mechanic but retired at the time of his cancer diagnosis.  Temperature is 37.8 C (100 F), blood pressure is 85/60 mm Hg, and pulse is 110/min and regular.  Cardiac auscultation reveals distant heart sounds.  The lungs are clear to auscultation.  He has 1+ pitting lower extremity edema bilaterally.  Bedside echocardiography shows moderate pericardial effusion.  Which of the following best confirms the need for immediate invasive management in this patient?
A)Early diastolic right ventricular collapse on echocardiography
B)Increase in height of jugular venous pulsation on expiration
C)Inspiratory fall of 8 mm Hg in the systolic blood pressure
D)Large v wave in the jugular venous pulsation
E)Low-voltage QRS complexes on ECG

Accepted Answer

Explanation: 11ec2b69_c112_11cb_8f63_a32ed0d38c60_MD0005_00 IVC = inferior vena cava; JVD= jugular venous distension; LV = left ventricular; SBP = systolic blood pressure. Cardiac tamponade results from increased hydrostatic pressure in the pericardial space, leading to impaired diastolic filling of the right side of the heart. This patient's moderate pericardial effusion, which raises concern for recurrent lung malignancy, has led to subacute cardiac tamponade. With subacute presentation, patients typically have progressive dyspnea, fatigue, elevated jugular venous pressure (JVP), and lower extremity edema. As the size of the pericardial effusion increases, hypotension and distant heart sounds can eventually develop. Echocardiography visualizes pericardial effusion and can be diagnostic of cardiac tamponade; the most specific findings of tamponade physiology are early diastolic collapse of the right ventricle and right atrium. Other consistent findings include exaggerated respiratory variation of cardiac and venous flow and plethora of the inferior vena cava with lack of inspiratory collapse. Treatment requires rapid removal of pericardial fluid, which can be performed with catheter pericardiocentesis or surgical pericardial window. (Choice B) JVP increase during expiration is normal, as is JVP decrease during inspiration (due to increased compliance of the right ventricle). By contrast, Kussmaul sign refers to an abnormal increase (or a lack of decrease) in JVP during inspiration. It is typically seen in patients with constrictive pericarditis or restrictive cardiomyopathy; however, in patients with cardiac tamponade, although JVP is often elevated, Kussmaul sign rarely occurs. (Choice C) Systemic blood pressure normally decreases slightly during inspiration. Pulsus paradoxus is an exaggerated drop in systolic blood pressure (>10 mm Hg) due to bowing of the right ventricle into the left ventricle during inspiration. It is an important finding in cardiac tamponade. However, the finding is nonspecific as it can also occur in patients with severe asthma or chronic obstructive pulmonary disease, constrictive pericarditis, and marked obesity. (Choice D) A large v wave in jugular venous pulsation is seen in patients with severe tricuspid regurgitation. Patients with cardiac tamponade have an elevated JVP with an absent or a blunted y descent. jugular venous pulsation (Choice E) Low-voltage QRS complexes are seen on ECG in patients with moderate or large pericardial effusion. However, this finding is nonspecific as it can also be seen with conditions such as obesity, severe chronic obstructive pulmonary disease, and amyloidosis. When electrical alternans is present on ECG, it is relatively specific for tamponade. Educational objective: Subacute cardiac tamponade is characterized by progressive dyspnea, fatigue, jugular venous distension, and lower extremity edema. Echocardiography showing early diastolic collapse of the right ventricle and right atrium is the most specific diagnostic finding for tamponade physiology. References: Echocardiographic evaluation of pericardial effusion and cardiac tamponade. (http://www.ncbi.nlm.nih.gov/pubmed/28484689)

Question 14

An 82-year-old man comes to the office for an annual follow-up visit. The patient says, "Over the last 2 months I have had several episodes of shortness of breath and dizziness while walking up the stairs. I also don't have energy like I did before and feel fatigued even after a short stroll around the house." The symptoms improve spontaneously after several minutes of rest, and he has had no chest pain, cough, or palpitations. The patient has no leg swelling or difficulty sleeping at night. Medical history is significant for hypertension, hyperlipidemia, osteoarthritis, depression, and diet-controlled type 2 diabetes mellitus. He lives with his daughter and is independent in his activities of daily living. The patient is a former smoker, with a 15-pack-year history, and quit over 20 years ago. Temperature is 37 C (98.6 F), blood pressure is 146/84 mm Hg, pulse is 78/min, and respirations are 14/min. BMI is 27.6 kg/m². The patient's pulse oximetry shows 98% while resting and breathing ambient air. He is comfortable and engaging and exhibits a full range of affect. Mucous membranes are pink and moist. There is no jugular venous distension or lymphadenopathy. The thyroid is normal to palpation. Bilateral breath sounds are normal with no wheezing or crackles. Cardiac examination reveals that the point of maximal impulse is slightly displaced to the left and that there is an S4 gallop with no murmurs. The abdomen is nondistended, soft, and nontender with normoactive bowel sounds. There is no hepatosplenomegaly. The patient has mild crepitus of the knee joints with no effusion or tenderness. There is no lower extremity edema. Blood cell counts and serum chemistry studies are within normal limits. ECG shows sinus rhythm, evidence of left ventricular hypertrophy, and nonspecific ST-segment and T-wave changes. Which of the following is likely to be most helpful in determining the cause of this patient's symptoms? A)High-resolution CT scan of the chest B)Pharmacologic stress testing C)Pulmonary function testing D)Transthoracic echocardiography E)Ventilation/perfusion scan

Accepted Answer

Explanation: 11ec2b69_c116_0973_8f63_0b92cb0a9945_MD0005_00 This patient has multiple risk factors for cardiovascular disease (eg, advanced age, hypertension, diabetes mellitus), and his symptoms raise suspicion for stable coronary artery disease (CAD). Elderly patients (eg, age >80) are more likely to experience anginal symptoms other than chest pain (eg, shortness of breath, lightheadedness, fatigue). Such patients with suspected stable CAD are best evaluated initially with noninvasive stress testing. Exercise ECG stress testing is preferred for patients able to achieve adequate exertion levels on a treadmill (eg, >85% of maximum heart rate). However, for those with limited exertional walking capacity (eg, due to osteoarthritis), pharmacologic stress testing (eg, adenosine myocardial perfusion imaging, dobutamine echocardiography) is most appropriate. (Choice A) High-resolution CT scan of the chest is useful in diagnosing interstitial lung disease. Although the typical presentation is with progressive shortness of breath, this patient's lack of cough and absence of fine crackles on pulmonary examination make this diagnosis less likely. (Choice C) Pulmonary function testing is appropriate in patients with shortness of breath and fatigue that may be due to chronic obstructive pulmonary disease (COPD). This patient's history of smoking increases his risk of developing COPD; however, the lack of cough and absence of wheezing on physical examination make this diagnosis less likely. (Choice D) Transthoracic echocardiography allows evaluation for ventricular systolic or diastolic dysfunction and for valvular abnormalities (eg, aortic stenosis) that may cause dyspnea and fatigue. This patient's ECG findings and S4 gallop are consistent with left ventricular hypertrophy, which can cause diastolic heart failure. However, the normal jugular venous pressure and absence of lower extremity edema and pulmonary crackles make heart failure an unlikely cause of this patient's symptoms. In addition, the absence of a murmur makes significant valvular abnormality unlikely. Stress testing is most likely to confirm CAD as the cause of this patient's symptoms. (Choice E) Ventilation/perfusion scan is appropriate for evaluating for acute pulmonary embolism in patients who cannot undergo CT pulmonary angiography (eg, those with renal insufficiency). However, the gradual onset of symptoms and absence of pleuritic chest pain and hypoxemia in this patient make acute pulmonary embolism unlikely. Educational objective: Elderly patients (eg, age >80) are more likely to experience anginal symptoms other than chest pain (eg, shortness of breath, lightheadedness, fatigue). Patients with suspected stable coronary artery disease should undergo initial evaluation with noninvasive stress testing. References: 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease: executive summary: a report of the American College of Cardiology Foundation/American Heart Association task force on practice guidelines, and the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. (http://www.ncbi.nlm.nih.gov/pubmed/23166210)

Question 15

A 24-year-old woman is admitted to the hospital after a motor vehicle accident resulted in a right humerus fracture, multiple rib fractures, and a contusion over her right leg.  The patient receives multiple packed red blood cell transfusions.  Chest and abdominal evaluation show a right-sided hemothorax.  A chest tube is inserted.  Pain is controlled with intravenous morphine.  The next morning, she has a crawling and burning sensation and worsening pain in her right leg despite repeated doses of morphine.  Temperature is 37.2 C (99 F), blood pressure is 140/82 mm Hg, heart rate is 96/min, and respirations are 18/min.  The right leg is swollen and tense.  Pulses are palpable in both lower extremities. Laboratory results this morning are as follows:
 Which of the following is the best next step in management of this patient?
A)Blood cultures
B)Creatine kinase level
C)Lower-extremity tissue pressures
D)Packed red blood cell transfusion
E)Therapeutic dose anticoagulation

Accepted Answer

Explanation: Rapidly worsening limb pain and swelling with paresthesias in a crush injury (evidenced by leg hematoma) is highly concerning for acute compartment syndrome (CS). Measurement of tissue pressures is diagnostic: Pressure >30 mm Hg or delta pressure (diastolic blood pressure − compartment pressure) <20-30 mm Hg indicates significant CS. Serial measurements should be performed even if initial pressures are within normal limits. If compartment pressures are improving, patients may be observed closely. Patients with elevated compartment pressures not improving rapidly require fasciotomy to avoid permanent loss of function from nerve and muscle injury. (Choice A) Blood cultures would be indicated in complicated lower-extremity cellulitis that may also present with pain and swelling. However, unlike CS, the leg is usually warm and erythematous and neurologic symptoms are absent. (Choice B) Creatine kinase (CK) levels may be elevated in patients with crush injury with or without CS and may be helpful for predicting possible renal injury. However, waiting for CK level results may unnecessarily delay the more important diagnosis of CS. (Choice D) Red blood cell transfusion would be indicated when hemoglobin (Hgb) is <7 g/dL. When Hgb is 8-10 g/dL, transfusion may be indicated in symptomatic patients or due to ongoing bleeding. This patient has stable hemodynamics and is unlikely to have ongoing bleeding. Red blood cell transfusion (Choice E) Deep venous thrombosis (DVT) may also present with increasing pain and swelling, but symptoms are more insidious in onset and less severe. The presence of neurologic symptoms makes CS more likely due to nerve ischemia. Full therapeutic dose anticoagulation would be indicated if Doppler ultrasonography reveals venous thrombosis; otherwise, a DVT prophylaxis dose would be sufficient. Educational objective: Direct measurement of compartment or tissue pressure is the diagnostic procedure of choice in patients with suspected acute compartment syndrome. Serial measurements should be performed even if initial pressure is within normal limits. References: The estimated sensitivity and specificity of compartment pressure monitoring for acute compartment syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/23595064)

Question 16

A 38-year-old African American man comes to the emergency department after experiencing severe back pain for the past 2 days.  He has a history of hypertension for the last 5 years.  His current medications include hydrochlorothiazide, amlodipine, and valsartan.  The patient has a 15-pack-year history and drinks 4-5 bottles of beer daily.  His temperature is 36.7 C (98 F), blood pressure is 230/112 mm Hg, and pulse is 84/min.  Funduscopic examination shows arteriolar wall thickening and occasional cotton-wool spots.  The rest of the examination is within normal limits.  Initial laboratory studies show serum blood urea nitrogen of 28 mg/dL, potassium of 5.1 mEq/L, and serum creatinine of 2.3 mg/dL.  Transesophageal echocardiogram is consistent with dissection in the descending aorta.  The patient is admitted to the coronary care unit and started on intravenous labetalol and nitroprusside infusion.  The next morning, the nurse finds him confused and agitated.  He then has a generalized tonic-clonic seizure.  His temperature is 36.7 C (98 F), blood pressure is 176/99 mm Hg, and pulse is 102/min.  Physical examination remains otherwise unchanged. Which of the following is the most likely diagnosis?
A)Cyanide toxicity
B)Excessive hypotensive response
C)Extension of the dissection to the aortic arch
D)Hypertensive encephalopathy
E)Intracranial hemorrhage

Accepted Answer

Explanation: 11ec2b69_c116_f3d4_8f63_b37be2940852_MD0005_00 This patient's symptoms suggest acute cyanide toxicity in the setting of renal failure and nitroprusside use. Nitroprusside is a potent vasodilator that works on both arterial and venous circulation and is used for hypertensive emergency management. It has rapid onset and offset of action. The most important side effect is cyanide accumulation and toxicity. Patients with chronic renal failure or those receiving a high-dose or prolonged infusion of sodium nitroprusside are at increased risk for cyanide toxicity. As a result, low infusion rates (<2 µg/kg/min), short-term usage, and close monitoring are recommended. Treatment involves cessation of nitroprusside and administration of sodium thiosulfate. (Choice B) The initial goal in hypertensive emergencies is to rapidly lower diastolic pressure to 100-105 mm Hg over 2-6 hours, with the total drop in blood pressure being no more than 25% of the initial value. Excessive hypotensive therapy with sudden drop in blood pressure can lead to ischemic events (eg, cerebral ischemia, myocardial infarction), altered mental status, or generalized seizures. However, this patient's blood pressure drop is not excessive enough to cause cerebral ischemia. (Choice C) Extension of dissection to the aortic arch and/or carotid arteries can cause symptoms and signs suggestive of a stroke (aphasia with associated motor or sensory abnormalities). It would not be expected to cause altered mental status or seizures. (Choice D) Rapid and severe rise in blood pressure causes increased cerebral perfusion pressure, which results in cerebral edema and hypertensive encephalopathy. Patients typically complain of insidious onset of headaches, nausea, and vomiting; this can progress to restlessness, confusion, agitation, seizures, and coma. This patient's blood pressure has actually improved with treatment, which is not suggestive of hypertensive encephalopathy. (Choice E) Patients with intracerebral hemorrhage typically develop headache and/or vomiting. Seizures may occur and are more common in lobar hemorrhages than other types of intracerebral hemorrhage. Patients typically have focal neurologic deficits such as hemiplegia or paresis and hemianopsia. Educational objective: Nitroprusside is frequently used in the management of acute hypertensive emergency. It is metabolized to cyanide, which may accumulate and can be toxic in patients with chronic renal failure or those receiving a high-dose or prolonged infusion. Toxicity should be suspected in all patients on nitroprusside infusion who have unexplained metabolic acidosis and altered mental status.

Question 17

A 74-year-old man is brought to the emergency department after being involved in a major motor vehicle collision.  According to the report from paramedics, he was a restrained passenger.  The patient has superficial injuries to the lower extremities and blunt chest trauma.  He has pain "all over" but is answering all questions appropriately.  Initial blood pressure is 98/65 mm Hg, pulse is 105/min, and respirations are 18/min.  Oxygen saturation is 100% on 40% oxygen via face mask.  Examination shows some bruises over the anterior chest, clear lungs, and no murmurs or abnormal heart sounds.  The abdomen is soft and nontender.  Which of the following is the most appropriate next step in evaluation of this patient?
A)Bedside ultrasound examination
B)Cardiac biomarkers
C)CT scan of the chest with intravenous contrast
D)Noncontrast CT scan of the head
E)Posteroanterior and lateral chest x-rays

Accepted Answer

Explanation: Motor vehicle collisions are the most common cause of blunt thoracic trauma leading to cardiac and pulmonary injury. Blunt cardiac injury can manifest as cardiac contusion leading to depressed cardiac contractility and acute heart failure; cardiac arrhythmias; or myocardial rupture leading to pericardial effusion, tamponade, and cardiogenic shock. Less commonly, valve injury or coronary artery dissection can occur, resulting in heart failure or myocardial infarction, respectively. The diagnostic priority in patients with blunt thoracic trauma and early signs of shock (eg, hypotension, tachycardia) is identification of injuries that can be rapidly fatal (eg, pneumothorax, aortic dissection, hemoperitoneum, pericardial effusion leading to tamponade), which is best accomplished with bedside ultrasound or focused assessment with sonography in trauma (FAST). Detection of abnormalities should prompt further directed evaluation (eg, CT scan, echocardiography) or specific therapy (eg, laparotomy, pericardiocentesis). (Choice B) Cardiac biomarkers (eg, troponin I) are often elevated in patients with blunt thoracic trauma. However, the elevated levels are nonspecific, and routine measurement is not recommended unless there is high suspicion for myocardial infarction. (Choices C and E) Chest x-rays are always indicated, and CT scan of the chest is often indicated, in patients with blunt thoracic trauma. However, bedside (ie, anteroposterior) chest x-rays are typically performed as obtaining posteroanterior and lateral chest x-rays requires patients to stand; in addition, these tests are typically preceded by FAST to quickly assess for rapidly fatal injuries. (Choice D) A noncontrast CT scan of the head should be obtained in patients with head trauma or abnormal neurologic findings suspicious for stroke. It is not indicated in this patient with injuries confined to the thorax and the lower extremities. Educational objective: Patients with blunt thoracic trauma should have an initial screening with bedside ultrasound or focused assessment with sonography in trauma to assess for injuries that can be rapidly fatal (eg, pneumothorax, aortic dissection, hemoperitoneum, pericardial effusion leading to tamponade). References: AIUM practice guideline for the performance of the focused assessment with sonography for trauma (FAST) examination. (http://www.ncbi.nlm.nih.gov/pubmed/25336497)

Question 18

A 25-year-old man comes to the emergency department due to a sudden onset of left foot pain.  The pain started suddenly an hour ago, when he was sitting at his desk, and has progressed gradually.  He has no history of similar episodes or recent trauma to his left leg.  On review of systems, the patient admits to tiredness and some weight loss over the last 2 months, which he attributes to stress.  He has no significant medical history.  He is a college student.  The patient does not use tobacco, alcohol, or illicit drugs.  His mother was diagnosed with "a blood clot" after elective knee-replacement surgery.  Temperature is 37.2 C (99 F), blood pressure is 122/81 mm Hg, pulse is 86/min, and respirations are 14/min.  Examination shows clear lung fields and a regular rhythm, with a low-pitched diastolic murmur over the cardiac apex.  The abdomen is soft and nontender, with no palpable masses.  Examination of the extremities reveals adequate bilateral femoral pulses.  The left popliteal and dorsalis pedis pulses are absent.  The left foot appears pale and is cooler than the right.  Sensations on the left foot are intact, and the patient is able to voluntarily move the limb.  There is no tenderness on palpation of the lower left leg or foot.  Neurologic examination is within normal limits.  Which of the following is the most likely cause of this patient's condition?
A)Abdominal aortic aneurysm
B)Bicuspid aortic valve
C)Factor V Leiden heterozygosity
D)Hypertrophic cardiomyopathy
E)Left atrial myxoma

Accepted Answer

Explanation: This patient has acute-onset pain, diminished pulses, and paleness and coolness of the left foot, which are consistent with acute arterial occlusion. Acute arterial occlusion can occur due to an embolus from a proximal source, acute thrombosis of an atherosclerotic plaque, or direct trauma to the involved artery. The sudden onset of symptoms in this young, previously asymptomatic patient is most consistent with an embolus. Most emboli originate from a cardiac source, and may occur due to atrial fibrillation, severe ventricular dysfunction, endocarditis, valvular disease, atrial myxoma, or a prosthetic valve. This patient has a regular heart rhythm with an apical diastolic murmur, making left atrial myxoma the most likely cause of the embolus. Atrial myxomas are the most common primary cardiac tumors, with the majority occurring in the left atrium. The tumors are typically pedunculated with a stalk coming from the atrial septum, and can be extremely friable, sometimes leading to the release of tumor emboli into the systemic circulation. Some large tumors can present with signs and symptoms of mitral valve obstruction (causing a diastolic murmur and "tumor plop"), rapidly worsening heart failure, and new-onset atrial fibrillation. The diagnosis is confirmed by echocardiography (transesophageal preferred over transthoracic), and prompt surgical excision is typically indicated. (Choice A) An abdominal aortic aneurysm can thrombose and lead to systemic embolization. However, because an abdominal aortic aneurysm typically results from atherosclerosis, it is unlikely to be present in this young patient. (Choice B) A bicuspid aortic valve can undergo accelerated calcification leading to aortic stenosis, typically in patients age >40. Small pieces of calcification may embolize but would be very unlikely to cause total limb arterial occlusion. (Choice C) Factor V Leiden heterozygosity is associated with increased risk for venous thrombosis (eg, deep, cerebral, or mesenteric venous thrombosis). However, it rarely leads to arterial thrombosis or emboli as seen in this patient. (Choice D) Hypertrophic cardiomyopathy causes left ventricular outflow obstruction, leading to a systolic (rather than a diastolic) murmur on physical examination, and is not associated with embolic events. Educational objective: Left atrial myxomas are the most common cardiac tumors and can present with signs and symptoms of mitral valve obstruction (eg, diastolic murmur and "tumor plop"), rapidly worsening heart failure, and new-onset atrial fibrillation. Myxomas frequently embolize systemically, leading to acute arterial occlusion in otherwise healthy patients. References: Clinical presentation of left atrial cardiac myxoma. A series of 112 consecutive cases. (http://www.ncbi.nlm.nih.gov/pubmed/11388092)

Question 19

A 63-year-old man comes to the emergency department due to chest pain that occurred 2 hours ago when he was shopping for groceries.  The patient experienced left-sided chest discomfort that was dull in nature and lasted 15 minutes.  He had no shortness of breath, diaphoresis, palpitations, or lightheadedness.  He has had no previous chest pain other than a similar episode 2 days ago when he was at home washing dishes.  The pain at that time lasted 10 minutes and resolved spontaneously.  The patient has hypertension and takes valsartan and amlodipine.  Medical history also includes gout, peptic ulcer disease, kidney stones, and severe osteoarthritis of the right knee.  He was offered knee replacement 2 years ago but refused.  The patient walks with a cane.  He has no known drug allergies.  He is a lifetime nonsmoker.  His father had a myocardial infarction at age 53 and his younger brother is healthy.  The patient appears comfortable and has no complaints.  Blood pressure is 147/90 mm Hg, and pulse is 82/min and regular.  He has no heart murmurs or additional sounds.  There are no carotid bruits.  The lungs are clear on auscultation.  There is no peripheral edema.  ECG shows normal sinus rhythm without repolarization changes.  Complete blood count and basic metabolic panel are unremarkable.  Chest x-ray is normal.  Two sets of cardiac troponin I drawn 4 hours apart are undetectable.  Which of the following is the best next step in management of this patient?
A)Adenosine myocardial perfusion imaging
B)Coronary angiography
C)Discharge with 24-hour Holter monitoring
D)Discharge with pantoprazole prescription
E)Exercise ECG

Accepted Answer

Explanation: 11ec2b69_c115_6d32_8f63_4b8a145726a3_MD0005_00 When a patient has acute chest pain that may be due to myocardial ischemia, the first priority is to rule out acute coronary syndrome (ACS). In this patient: A normal ECG rules out ST-elevation myocardial infarction (STEMI). Negative serial troponin levels rule out non-STEMI. The absence of a history of exertional chest pain that gradually worsens over a period of several months (crescendo angina), associated symptoms (eg, dyspnea, diaphoresis), and ECG abnormalities suggestive of ischemia (eg, T-wave inversions) make unstable angina unlikely. Once ACS has been sufficiently ruled out, the diagnostic goal shifts to differentiating cardiac chest pain (stable angina) from noncardiac chest pain. This patient's chest pain is mostly nonanginal in nature (not substernal pressure and not reliably reproduced with exertion or relieved by rest); however, his age, male sex, family history of coronary artery disease (CAD), and personal history of hypertension raise reasonable suspicion for stable angina. In such patients with suspected clinically significant CAD, stress testing is the best initial diagnostic intervention. Exercise ECG is preferred when possible (Choice E); however, patients with conditions that prevent adequate walking exertion (eg, severe osteoarthritis) require pharmacologic stress testing (eg, adenosine myocardial perfusion imaging, dobutamine echocardiography). chest pain (Choice B) Coronary angiography is rarely performed as the initial diagnostic evaluation for stable CAD. If stress testing is positive with evidence of high risk features (eg, severe ischemia), subsequent coronary angiography is indicated to assess for amenability to revascularization. (Choice C) Ambulatory 24-hour Holter monitoring is often helpful in the diagnosis of suspected paroxysmal cardiac arrhythmia, but it has minimal diagnostic use for CAD. (Choice D) Discharge with a prescription for pantoprazole is appropriate for a patient with a low suspicion of CAD and chest pain accompanied by other symptoms suggestive of gastroesophageal reflux disease (eg, reflux, cough). However, it is not appropriate in this patient with reasonable suspicion of clinically significant CAD. Educational objective: Stress testing is the most appropriate initial diagnostic test in patients with reasonable suspicion of clinically significant, stable coronary artery disease. Exercise ECG is preferred when possible, but patients who are unable to perform exertional walking are best evaluated with pharmacologic stress testing. References: 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS Guideline for the diagnosis and management of patients with stable ischemic heart disease. (http://www.ncbi.nlm.nih.gov/pubmed/23182125) Testing of low-risk patients presenting to the emergency department with chest pain: a scientific statement from the American Heart Association. (http://www.ncbi.nlm.nih.gov/pubmed/20660809)

Question 20

A 67-year-old man comes to the physician for fatigue and lower-extremity edema. Seven months ago, he underwent coronary artery bypass graft surgery and mitral valve repair. His postoperative course has been complicated by paroxysmal atrial fibrillation that is treated with amiodarone and anticoagulation. He also has diet-controlled type 2 diabetes mellitus. The patient is a former smoker with a 35-pack-year history. His blood pressure is 132/77 mm Hg and pulse is 102/min. Jugular venous pressure is estimated at 16 cm H₂O. Cardiac auscultation shows a mid-diastolic murmur. Lungs are clear to auscultation. There is significant ascites and bilateral lower-extremity edema. Electrocardiogram shows sinus tachycardia. Echocardiogram shows enlarged atria, normal left ventricular wall thickness and right ventricular size, and left ventricular ejection fraction of 65%. There is mild mitral regurgitation. Chest x-ray shows normal heart size, clear lung fields, and spotty calcifications along the left heart border. Which of the following is the most likely cause of this patient's symptoms? A)Amiodarone toxicity B)Cardiac amyloidosis C)Constrictive pericarditis D)Graft closure E)Superior vena cava syndrome

Accepted Answer

Explanation: 11ec2b69_c114_d0f1_8f63_0543639d9fc3_MD0005_00 This patient's presentation - peripheral edema and elevated jugular venous pressure (JVP) with clear lung fields - is suggestive of right heart failure, most likely due to constrictive pericarditis (CP). Pericarditis is a common complication of coronary artery bypass graft surgery, and some degree of postoperative pericardial effusion develops in almost 85% of patients. Most patients are asymptomatic from small effusions. However, continued pericardial inflammation occurring over months may lead to development of a thickened, fibrous pericardium and constrictive pericarditis. Constrictive pericarditis is an important cause of right heart failure. Patients typically have peripheral edema, ascites, and hepatic congestion with hepatomegaly, which can progress to cirrhosis (cardiac cirrhosis). Other findings may include elevated JVP with prominent "y" descent and hepatojugular reflux, Kussmaul's sign (increase, or lack of decrease, in JVP on inspiration) and pericardial knock (mid-diastolic sound). The electrocardiogram (ECG) in CP may be nonspecific (eg, tachycardia) or can show low-voltage QRS complexes. Chest radiograph often reveals calcified cardiac borders. Echocardiogram may show increased pericardial thickening or calcification, atrial enlargement, and abnormal septal motion; however, these findings are neither sensitive nor specific for the diagnosis. Treatment involves supportive care (eg, anti-inflammatory agents) or pericardiectomy for refractory cases. (Choice A) Long-term amiodarone use is associated with thyroid dysfunction, hepatotoxicity, cardiac bradyarrhythmias, chronic interstitial pneumonitis, neurologic symptoms (eg, ataxia, peripheral neuropathy), blue-gray skin discoloration, and visual disturbances. This patient's right heart failure is not consistent with amiodarone toxicity. (Choice B) Cardiac amyloidosis should be suspected in patients with unexplained congestive heart failure (predominantly diastolic dysfunction), low voltage on ECG, and echocardiogram showing increased ventricular wall thickness with normal left ventricular cavity dimensions (especially in patients without hypertension). (Choice D) Graft closure typically presents with symptoms of angina. ECG may show new ST- or T-wave changes, Q waves, bundle branch block, or arrhythmias suggestive of myocardial ischemia. (Choice E) Superior vena cava syndrome is caused by obstruction of blood flow (typically due to external compression from a tumor). This leads to elevated upper-body venous pressure, with facial swelling and distended neck or chest wall veins. Ascites and lower-extremity edema are usually not present. Educational objective: Constrictive pericarditis is an important cause of right heart failure. It may occur following viral pericarditis or cardiac surgery. Characteristic features include peripheral edema, ascites, elevated jugular venous pressure, hepatojugular reflux, Kussmaul's sign, pericardial knock, and pericardial calcifications on chest radiograph. References: Constrictive pericarditis after cardiac surgery. (http://www.ncbi.nlm.nih.gov/pubmed/23266135)

Exam 2: Foundations of Independent Practice