Hemodynamics

Question 1

1. While camping, a 15-year-old boy is bitten by
   a mosquito. At the site of the mosquito bite, his skin
   turns red and a small but noticeable bump forms.
   Which of the following terms best describes the
   color change in the skin?
   A. Lividity
   B. Ecchymosis
   C. Contusion
   D. Congestion
   E. Hyperemia

Answer 1

1. Correct: Hyperemia (E).
   The red discoloration of the skin is a sign of acute
   inflammation due to the mosquito bite and occurs
   due to dilation of blood vessels, an active process.
   The correct term in this situation is hyperemia (E).
   Congestion is a passive process, which results from
   impaired venous return (D). Lividity is the postmortem
   pooling of blood in the skin due to gravity (A). A contusion (i.e., bruise) is due to extravasation of
   red blood cells into the tissue as a result of trauma
   (C), and an ecchymosis is also due to extravasation of
   red blood cells (B), as opposed to hyperemia, where
   red blood cells should be essentially confined to the
   blood vessels.

Question 2

2. A 66-year-old male has a long-standing history
   of congestive heart failure due to uncontrolled
   hypertension and has had multiple admissions to the
   hospital for treatment of pulmonary edema. During
   his most recent admission, he sustains a fatal cardiac
   dysrhythmia. Which of the following is likely to be
   observed in this patient’s lungs at autopsy?
   A. Dilated alveolar septal capillaries filled with red
   blood cells
   B. Fibrotic and thickened alveolar septal capillaries
   C. Loss of alveolar septa, resulting in large airspaces
   D. Congestion of centrilobular sinusoids
   E. Diffuse macrovesicular steatosis of the liver

Answer 2

2. Correct: Fibrotic and thickened alveolar septal
   capillaries (B)
   With congestive heart failure, a chronic process, causing
   multiple episodes of pulmonary edema, chronic pulmonary congestion, characterized by fibrotic and thick alveolar septa and macrophages with hemosiderin
   would be most characteristic of the clinical scenario
   (B). For the most recent episode, dilated alveolar septal
   capillaries filled with red blood cells would be appropriate;
   however, it would not best describe the overall clinical scenario. For (C–E), see previous information.

Question 3

3. A 71-year-old male with a history of poorly controlled
   hypertension due to noncompliance with medications
   is brought to the emergency room by his family
   because of increasing shortness of breath. An X-ray of the chest reveals bilateral pleural effusions and enlargement
   of the heart. Given these features, of the following,
   which is the most likely causative mechanism for the
   condition producing his shortness of breath?
   A. Increased hydrostatic pressure
   B. Increased vascular permeability
   C. Decreased colloid osmotic pressure
   D. Lymphatic obstruction
   E. Sodium retention

Answer 3

3. Correct: Increased hydrostatic pressure (A)
   The fluid in the pleural cavities represents pulmonary
   edema due to heart failure from the uncontrolled
   hypertension. Although the other mechanisms listed
   can lead to pulmonary edema, the most likely cause,
   given the scenario, would be congestive heart failure.
   Congestive heart failure will increase hydrostatic
   pressure in the pulmonary vasculature, causing fluid
   to leak into the surrounding space (A). For (B–E), see
   previous information.

Question 4

4. A 68-year-old male with poorly controlled
   hypertension presents to the emergency room with
   shortness of breath. A chest X-ray reveals bilateral
   pleural effusions. An S3 gallop is heard and crackles
   (rales) are present in both lung fields. Which of the
   following pigments is most likely to be found within
   macrophages in his lungs?
   A. Bilirubin
   B. Hemosiderin
   C. Melanin
   D. Lipofuscin
   E. Calcium

Answer 4

4. Correct: Hemosiderin (B).
   This individual has a clinical scenario consistent with
   congestive heart failure. In congestive heart failure,
   a common histologic finding is heart-failure cells,
   which are macrophages filled with hemosiderin that
   are found in the alveolar airspaces (B). For (A, C–E),
   see previous information.

Question 5

5. A 56-year-old male presents to his physician
   because of swelling in the right lower extremity distal
   to the knee. He has a history of mild hypertension,
   which is well controlled with medication. He also
   reports no trauma to the extremity, and no skin infections
   or other known sites of infection. On examination
   edema is noted, with the circumference of the right calf
   measuring 3 cm larger than the circumference of the
   left calf. There is a palpable cord present. Of the following,
   which aspect of the history, physical, or laboratory
   testing would be most likely to indicate the cause?
   A. AST/ALT levels
   B. CK-MB levels
   C. BUN/creatinine levels
   D. Family history of colon cancer
   E. History of recent surgery

Answer 5

5. Correct: History of recent surgery (E)
   This patient has sustained a deep venous thrombosis.
   Given the unilateral nature, edema due to liver failure, renal failure, or heart failure is less likely (A–C). Unilateral edema of a lower extremity could be due to venous or lymphatic obstruction. A neoplasm would be a rare cause for unilateral swelling of a lower extremity (D). Of the choices, only the history of recent surgery would be expected to reveal a potential cause for this deep venous thrombosis (E).

Question 6

6. A 40-year-old male is brought to the emergency
   department by his wife because of his shortness
   of breath. He reports the onset of a cough two days
   prior with increasing shortness of breath. On arrival
   his temperature is 100.5°F (38.0°C), his heart rate is
   135/min, and blood pressure is 88/55 mm Hg. Physical
   examination is unremarkable except for tachycardia.
   The patient is alert and oriented. His leukocyte
   count is 18,000/μL, his pCO2 on arterial blood gas is
   30 mm Hg, and serum lactic acid is slightly elevated
   at 4 mmol/L. A plain chest radiograph shows a right
   lower lobe infiltrate. What is the most likely diagnosis?
   A. Acute pulmonary embolism
   B. Septic shock
   C. Cardiogenic shock
   D. Anaphylactic shock
   E. Acute myocardial infarction

Answer 6

6. Correct: Septic shock (B)
   The patient has multiple diagnostic criteria for sepsis,
   including fever, a leukocyte count > 12,000/μL, heart
   rate > 90/min, and CO2 < 32 mm Hg (B). All of these findings can also be seen in acute pulmonary embolism;
   however, the finding of an infiltrate on the chest radiograph is consistent with pneumonia and would not be expected in acute pulmonary embolism (A). There is no
   additional information to suggest cardiogenic shock,
   anaphylaxis, or acute myocardial infarction (C–E).

Question 7

7. A 76-year-old man is evaluated in the emergency
   department for hypotension and dyspnea. His temperature
   is 97.8°F (36.5°C), pulse 125/min, and blood pressure
   88/58 mm Hg. Bilateral crackles are present in the
   lung fields. Pedal edema is noted bilaterally. His extremities
   are cool, and his urine output is minimal. A plain
   chest radiograph reveals cardiomegaly and pulmonary
   edema. What is the pathophysiology of his shock?
   A. Septic shock
   B. Anaphylactic shock
   C. Cardiogenic shock
   D. Hypovolemic shock
   E. Distributive shock

Answer 7

7. Correct: Cardiogenic shock (C)
   The patient has all the signs and symptoms of cardiogenic
   shock (C). The presence of signs and symptoms of volume overload such as pedal and pulmonary edema would not be expected in the other types of shock (A–B, D–E).

Question 8

8. In the previous clinical scenario, of the following,
   which is most likely the underlying cause of this
   man’s shock?
   A. Acute pulmonary embolism
   B. Acute right ventricular myocardial infarction
   C. Pulmonary hypertension
   D. Aortic stenosis
   E. Pericardial tamponade

Answer 8

8. Correct: Aortic stenosis (D)
   Aortic stenosis can produce cardiogenic shock and
   left ventricular failure resulting in pulmonary edema
   (D). The other causes listed are associated with right
   ventricular failure and would not be expected to
   cause pulmonary edema (A–C, E).

Question 9

9. A 67-year-old man is brought to the emergency
   department with hypotension and tachycardia.
   He has had no urine output. Which of the following
   additional findings would suggest hypovolemia
   rather than sepsis as the underlying cause of this
   man’s low urine output?
   A. Low leukocyte count
   B. Elevated leukocyte count
   C. Hypernatremia
   D. Hyperglycemia
   E. Elevated serum lactic acid

Answer 9

9. Correct: Hypernatremia (C)
   Leukocyte count is frequently low in sepsis, due to
   bone marrow suppression (A). A high leukocyte count
   may be seen either in sepsis, due to the response to
   an infection, or in hypovolemia and dehydration
   because of the hemoconcentration that occurs (B).
   Hyperglycemia could be seen in either septic shock
   or hypovolemic shock, due to cortisol release in the
   stress response (D). Elevated serum lactic acid levels
   are a common finding in all forms of shock (E).
   Hypernatremia occurs when there is severe loss of
   free water (dehydration), a situation that would be
   consistent with hypovolemic shock but not septic
   shock (C).

Question 10

10. A 76-year-old man is found dead at home.
    Microscopic examination of samples of the liver and
    lung reveals centrilobular hemorrhagic necrosis of
    the liver and hemosiderin-laden macrophages in the
    lungs. Of the following, what additional finding at
    autopsy would be most likely?
    A. Pleural effusion
    B. Aortic dissection
    C. Deep venous thrombosis
    D. Disseminated intravascular coagulation
    E. Pericardial tamponade

Answer 10

10. Corect: Pleural effusion (A)
    Centrilobular hemorrhagic necrosis of the liver (“nutmeg
    liver”) and hemosiderin-laden macrophages in the lungs are manifestations of chronic passive congestion, which is seen in chronic heart failure. Of the choices, pleural effusions are most characteristic of congestive heart failure (A). The other options (B–E) would not be expected as routine autopsy findings in congestive heart failure.

Question 11

11. A 60-year-old female status post right radical
    mastectomy and right axillary lymph node dissection
    develops chronic edema of the right arm. Which
    of the following is the cause of her edema?
    A. Increased plasma oncotic pressure
    B. Renal sodium retention
    C. Increased interstitial protein
    D. Increased vascular permeability
    E. Decreased plasma albumin

Answer 11

11. Correct: Increased interstitial protein (C)
    The lymphatic system returns proteins back to the
    intravascular space that have been forced out of the
    arterial capillary system and into interstitial space by
    hydrostatic pressure. Up to 50% of serum proteins are
    transported via the lymphatic route each day (C). For
    (A–B, D–E), see previous information.

Question 12

12. A 79-year-old male nursing home resident with
    dementia is admitted to the hospital for failure to
    thrive. According to his primary caregiver he has taken
    very little fluids or food over the preceding three weeks.
    On admission his serum sodium is 165 mmol/L, and he
    subsequently receives a large amount of free water in
    the form of intravenous D5W over a two-hour period.
    Shortly after finishing the fluids he becomes unresponsive.
    He dies after a brief attempt at resuscitation. Blood
    for a chemistry panel is drawn during resuscitation,
    with laboratory testing revealing the serum sodium to
    be 124 mmol/L. Examination of the brain at autopsy is
    most likely to reveal which of the following findings?
    A. Liquefactive necrosis
    B. Acute thrombosis of the middle cerebral artery
    C. Narrowed sulci and distended gyri
    D. Passive venous congestion
    E. Diffuse axonal injury

Answer 12

12. Correct: Narrowed sulci and distended gyri (C)
    This patient sustained cerebral edema due to
    overcorrection of hypernatremia. The finding of
    narrowed sulci and distended gyri is the classic
    description of the edematous brain (C). Liquefactive
    necrosis would be seen in acute infarction, as
    would middle coronary artery thrombosis; however,
    the clinical scenario gives no indication of stroke (A,
    B). Passive venous congestion would be expected in
    strangulation or in central venous thrombosis (D).
    Diffuse axonal injury is seen in trauma (E).

Question 13

13. A 58-year-old man with a history of deep
    venous thrombosis following right total knee replacement
    is recovering from multiple injuries sustained
    in a motor vehicle collision. His injuries include
    fractures to both tibial plateaus. He is on subcutaneous
    unfractionated heparin for prevention of deep
    venous thrombosis. On his 6th hospital day his platelet
    count dropped from 250,000/μL to 110,000/μL. He
    is otherwise recovering well with no complications,
    and a lower extremity Doppler is performed, which
    is negative for deep venous thrombosis. Which of the
    following additional tests would be most helpful in
    determining the cause of his thrombocytopenia?
    A. PT and PTT
    B. Anti-platelet factor 4 antibody
    C. Protein C activity
    D. Protein S activity
    E. Factor Xa level

Answer 13

13. Correct: Anti-platelet factor 4 antibody (B)
    The > 50% drop in the platelet count is suggestive of
    heparin-induced thrombocytopenia, and his prior
    treatment for deep venous thrombosis would likely
    have meant prior exposure to heparin. Heparin induced
    thrombocytopenia is caused by antibodies to heparin-platelet factor-4 complexes (B). Coagulation studies (PT, PTT, Factor Xa level) are unlikely to be helpful as these tests mainly assess coagulation rather than platelet function (A, E). Protein C and S levels would be indicated in the workup for recurrent deep venous thrombosis, or for unprovoked deep venous thrombosis in patients under age 50 (C, D).

Question 14

14. A 37-year-old female with a history of deep
    venous thrombosis during her first pregnancy and
    two spontaneous abortions is evaluated in the emergency
    department. Forty minutes prior to arrival she
    experienced the sudden onset of weakness of the
    right face, right arm, and right leg. Neurologic examination
    reveals flaccid paralysis of the right side of the
    body with expressive aphasia without visual field
    defect. Magnetic resonance imaging (MRI) of the
    brain and basic lab work including complete blood
    count, prothrombin time (PT), and activated thromboplastin
    time (aPTT) are ordered in the emergency
    department. The treating physician administers
    tissue plasminogen activator (t-PA) to the patient
    according to hospital protocol in the treatment of
    acute stroke. Which of the following is true regarding
    the mechanism of t-PA?
    A. t-PA prevents platelet activation by inhibiting
    GpIIb-IIIa complex.
    B. t-PA prevents platelet activation by inhibiting
    GpIb receptors.
    C. t-PA increases the degradation of fibrin.
    D. t-PA binds anti-thrombin III, leading to thrombin
    inactivation.
    E. t-PA binds and inactivates clotting factors.

Answer 14

14. Correct: t-PA increases the degradation of
    fibrin. (C)
    t-PA converts plasminogen to plasmin, which in turn
    cleaves fibrin, releasing fibrin degradation products
    (C). By this mechanism, t-PA prevents further deposition
    of thrombin and thus clot propagation. GpIb and GpIIb-IIIa are platelet membrane glycoproteins present on the platelet surface that promote platelet aggregation (A, B). Inhibition of GpIIb-IIIa is the mechanism of action of eptifibatide (Intergrilin) (A). There is no drug currently available that inhibits GpIa. Heparin, not t-PA, activates anti-thrombin III (D). (E) is incorrect because t-PA acts by promoting fibrinolysis, not by inactivating clotting factors.

Question 15

15. Ristocetin is an antibiotic, which is no longer
    in use, that causes platelet agglutination by facilitating
    binding of von Willebrand’s factor (vWF)
    to GpIb. Two tests used in the workup of von Willebrand’s
    disease are the ristocetin cofactor assay and
    the ristocetin-induced platelet aggregation (RIPA).
    The ristocetin cofactor assay measures the ability of
    formalin-fixed (i.e., dead) control platelets to agglutinate
    in the patient’s plasma. The ristocetin-induced
    platelet aggregation test involves adding ristocetin
    to a sample of the patient’s platelet-rich plasma.
    Which results on the ristocetin cofactor assay and
    the RIPA would be consistent with Bernard-Soulier’s
    syndrome?
    A. Normal agglutination on ristocetin cofactor assay
    and normal agglutination on RIPA
    B. Normal agglutination on ristocetin cofactor assay
    and hypoactive agglutination on RIPA
    C. Hypoactive agglutination on ristocetin cofactor
    assay and normal agglutination on RIPA
    D. Hypoactive agglutination on ristocetin cofactor
    assay and hypoactive agglutination on RIPA
    E. Hyperactive agglutination on ristocetin cofactor
    assay and normal agglutination on RIPA

Answer 15

15. Correct: Normal agglutination on ristocetin
    cofactor assay and hypoactive agglutination on
    RIPA (B)
    Ristocetin induces platelet aggregation in a von Willebrand factor (vWF) dependent mechanism by promoting
    the binding of vWF to GpIb. The ristocetin cofactor assay is an indirect measurement of von Willebrand’s factor, which uses control platelets and measures the amount of ristocetin induced platelet agglutination. In von Willebrand’s disease, caused by a deficiency of the vWF, platelet agglutination would be hypoactive on both the ristocetin cofactor assay and the RIPA (D). Bernard-Soulier’s disease is caused by a genetic deficiency of glycoprotein Ib (GpIb) on platelets. In Bernard-Soulier’s disease ristocetininduced platelet agglutination would be normal on the ristocetin cofactor assay (which uses control
    platelets) and hypoactive on the RIPA (which uses the patient’s own, in this case defective, platelets) (B). For (A, C, E), see previous information.

Question 16

16. A 17-year-old male sustains a mid-shaft
    femur fracture after a fall from a horse. The fracture
    is repaired operatively and the patient is discharged.
    On the second postoperative day he becomes acutely
    dyspneic. In the emergency department he is
    hypoxic and tachypneic, appears confused, and has a
    petechial rash on his neck and anterior thorax. What
    is the most likely diagnosis?
    A. Aortic dissection
    B. Fat embolism
    C. Venous thromboembolism
    D. Acute myocardial infarction
    E. Disseminated intravascular coagulation

Answer 16

16. Correct: Fat embolism (B)
    The rapid onset of respiratory failure associated with
    petechiae and neurologic dysfunction 1 to 3 days
    after a long bone fracture is classic for fat embolism
    syndrome (B). The presence of confusion and petechiae
    make venous thromboembolism less likely (C). There is no history to suggest aortic dissection, acute myocardial infarction, or disseminated intravascular coagulation (A, D, E).

Question 17

17. A 23-year-old man is flying home from a
    10-day scuba diving vacation. One hour into the
    flight he develops some mild to moderate pain in his
    shoulders and knees. Shortly thereafter he reports a
    substernal burning sensation with inspiration that
    is associated with low back pain. By the time the
    flight lands, which is four hours after takeoff, he is
    unable to move his legs. He is immediately taken to
    the nearest hospital, but dies of respiratory failure en
    route. Which of the following would have reduced
    his risk of developing this illness?
    A. Delaying his flight home for 48 hours
    B. Wearing insect repellent during his trip
    C. Taking a dose of aspirin for a week before and
    during his trip
    D. Walking frequently during his airplane flight
    E. Avoiding dental work a month prior to his trip

Answer 17

17. Correct: Delaying his flight home for 48
    hours (A)
    This man’s symptoms are characteristic of severe
    decompression sickness (DCS). Mild cases of DCS usually
    present with mild joint pains, a mottled appearance
    of the skin, and pruritis. In severe cases, gas
    embolism causes damage to the spinal cord resulting
    in paralysis. Air travel immediately after scuba diving
    increases the risk of decompression sickness because
    of the low atmospheric pressure at altitude (A). There
    is no evidence that aspirin can reduce the risk of DCS
    (C). For (B, D–E), see previous information.

Question 18

18. A 76-year-old woman is found down at home
    by a relative and is unresponsive on arrival to the
    emergency department. A CT scan of the head preformed
    shortly after arrival shows multiple infarcts
    of the right and left cerebral hemispheres and an
    infarct of the cerebellum, which were confirmed
    with magnetic resonance imaging (MRI) of the brain.
    Which of the following tests is most likely to reveal
    the cause of her strokes?
    A. A complete blood count
    B. Bilateral lower extremity venous Doppler
    C. Bilateral lower extremity arterial Doppler
    D. Cerebral angiogram
    E. Transesophageal echocardiogram

Answer 18

18. Correct: Transesophageal echocardiogram (E)
    The presence of multiple cerebral infarcts suggests
    embolic stroke. Emboli from thrombi of the left heart
    or the thoracic aorta would be most likely; thus, a
    transesophageal echocardiogram is the most appropriate
    diagnostic test (E). A complete blood count is
    unlikely to be helpful unless the cause is bacterial
    endocarditis, which would be much less common in
    this patient population than cardiac thrombus (A).
    Deep venous thrombosis would not cause arterial
    emboli in the absence of a right to left cardiac shunt,
    making lower extremity venous Doppler unhelpful
    (B). Arterial Doppler of the lower extremities, being
    distal, again would not be helpful (C). Finally since
    in-situ thrombosis is unlikely to happen in multiple
    vascular territories simultaneously, a cerebral angiogram
    would not add any additional information (D).

Question 19

19. A 72-year-old man with morbid obesity,
    hypertension, and diabetes mellitus is evaluated by
    his primary care physician for progressively worsening
    edema of the lower extremities over the preceding
    years. He reports pain in both legs with standing
    and walking but improvement in the pain and edema
    with elevation of the legs. His body mass index is
    39.5 kg/m2. His vital signs are normal. Auscultation
    of the heart and lungs is normal. He has 3+ pitting
    edema of the bilateral lower extremities with normal
    warmth, mild tenderness and numerous varicose
    veins. Inspection of the skin reveals a reddish-brown
    hyperpigmented and indurated dermatitis involving
    the anterior lower legs bilaterally. What is the most
    likely underlying cause of the patient’s symptoms?
    A. Damage to valves in the deep venous system of
    the legs
    B. Acute thrombosis of the deep venous system of
    the legs
    C. Atherosclerotic disease of the bilateral iliac
    arteries
    D. Impaired lymphatic drainage of the legs
    E. Bacterial soft tissue infection of the legs

Answer 19

19. Correct: Damage to valves in the deep venous
    system of the legs (A)
    This patient has the classic signs and symptoms of
    chronic venous insufficiency, including lipodermatosclerosis, varicose veins, and edema. The underlying mechanism is damage to the valves of the deep and perforating system, resulting in venous reflux
    and venous hypertension (A). A history of prior deep
    venous thrombosis is common (post-phlebitic syndrome);
    however, given the bilateral symptoms and gradual onset, an acute DVT in this patient is unlikely (B). Atherosclerotic disease with arterial insufficiency would not cause edema (C), and the presence of characteristic skin changes (lipodermatosclerosis) and varicosities helps distinguish venous insufficiency from lymphedema (D). Mistaking lipodermatosclerosis for cellulitis is a common diagnostic error in the evaluation of chronic venous insufficiency (E).

Question 20

20. A 78-year-old man with chronic atrial fibrillation
    presents with abdominal pain. The patient
    reports the pain started 3 hours ago, is very severe,
    and is periumbilical. His temperature is 99.0°F
    (37.0°C), pulse 110/min, and blood pressure 98/58
    mm Hg. The patient appears to be in severe pain.
    Physical examination is remarkable for an irregularly
    irregular heart rhythm and mild abdominal
    distension. The abdomen is mildly tender. His leukocyte
    count is 19.3 × 103/μL, hemoglobin is 19.0 g/
    dL, and serum bicarbonate is 18 mmol/L. Five hours
    after arrival his condition deteriorates, his abdomen
    becomes grossly distended, his bowel sounds
    become inaudible, and he dies. Which of the following
    is the most likely diagnosis?
    A. Mesenteric embolic infarction
    B. Ruptured abdominal aortic aneurysm
    C. Acute appendicitis
    D. Acute diverticulitis
    E. Small bowel obstruction

Answer 20

20. Correct: Mesenteric embolic infarction (A)
    This patient presents with abdominal pain out of
    proportion to physical examination findings and has
    atrial fibrillation, a risk factor for systemic embolism.
    This is a classic presentation of mesenteric infarction
    (A). For (B–E), see previous information.

Question 21

21. A 55-year-old male with well-controlled type
    2 diabetes mellitus, hypertension, and paroxysmal
    atrial fibrillation presents with acute onset of right
    flank pain with hematuria. His temperature is 98.8°F
    (37°C), pulse is 90/min, blood pressure is 155/92 mm
    Hg, respirations are 18/min, and O2 saturation is 98% on
    room air. On examination he appears to be in moderate
    pain, his lungs are clear, he has an irregularly irregular
    rhythm, and his right flank is tender to palpation. His
    leukocyte count is 12 × 103/μL, creatinine is 1.8 mg/dL
    (from a value of 1.1 mg/dL six months previously), and
    his aminotransferases are normal. Urinalysis shows
    numerous red cells with no white cells and no casts.
    Noncontrast helical CT scan of the kidneys and collection
    system is unremarkable. Of the following, what is
    the most likely diagnosis?
    A. Acute pyelonephritis
    B. Ureterolithiasis
    C. Acute appendicitis
    D. Glomerulonephritis
    E. Renal infarction

Answer 21

21. Correct: Renal infarction (E)
    This patient has embolic renal infarction from atrial
    fibrillation (E). In the absence of urine leukocytes,
    white cell casts, or fever, pyelonephritis is unlikely
    (A). The absence of a stone on helical CT of the kidneys
    makes a kidney stone unlikely (B). Appendicitis should be considered; however, appendicitis usually presents with right lower quadrant rather than right flank pain and would not cause hematuria (C). Glomerulonephritis would not cause flank pain (D).

Question 22

22. A 32-year-old woman has routine lab work
    done as part of her annual physical examination.
    She returns to the clinic 3 days after her blood draw
    complaining of pain in the left antecubital fossa. On
    examination there is mild erythema without induration,
    no palpable fluctuence, and the basilic vein is
    tender and palpated as a nodular “cord.” What is the
    appropriate management?
    A. Anticoagulation with Coumadin
    B. Oral antibiotics
    C. Warm compresses
    D. Topical corticosteroids
    E. Incision and drainage

Answer 22

22. Correct: Warm compresses (C)
    The management of uncomplicated superficial
    venous thrombophlebitis is symptomatic. Warm
    compresses and nonsteroidal anti-inflammatory
    medication are usually effective (C). In the absence of
    significant erythema and induration or fever, antibiotics
    are unnecessary (B). Topical steroids would be indicated for atopic dermatitis but would not help in this case (D). There is no evidence of abscess or septic thrombophlebitis; thus, no indication for incision
    and drainage (E). Anticoagulation is unnecessary (A).

Question 23

23. A pathologist is examining tissue removed
    from a 57-year-old deceased male. The tissue has
    preservation of normal architecture; however, there
    is loss of nuclear and cytoplasmic basophilia. Associated
    with these changes are abundant extravasated
    red blood cells in the tissue. The man had no resuscitation
    performed. Of the following, where did this
    tissue most likely originate?
    A. The heart
    B. A kidney
    C. The spleen
    D. The brain
    E. A lung

Answer 23

23. Correct: A lung (E)
    The tissue description is that of coagulative necrosis,
    with preservation of architecture but loss of basophilia.
    The abundant extravasated red blood cells indicate
    a red infarct, which most commonly occur in the
    liver and lungs, organs with dual blood supplies (E).
    Organs with single blood supplies, such as the heart,
    kidney, and spleen, have white infarcts unless there
    has been reperfusion (A–C). The brain can have red
    infarcts with venous lesions; however, liquefactive
    and not coagulative necrosis is most common (D).

Question 24

24. A 22-year-old female in active labor suddenly
    develops hypotension and dyspnea. She becomes
    hypoxic and is intubated for acute respiratory failure.
    Chest radiograph shows acute pulmonary edema.
    She dies prior to delivery. Which of the following is
    most likely to be found at autopsy?
    A. Left ventricular hypertrophy
    B. Femoral vein deep venous thrombosis
    C. Plaque rupture in the left anterior descending
    coronary artery
    D. Disseminated intravascular coagulation
    E. Thrombus in the right main pulmonary artery

Answer 24

24. Correct: Disseminated intravascular
    coagulation (D)
    The patient in this scenario dies of an acute catastrophic
    cardiovascular/pulmonary event (amniotic fluid embolism). Left ventricular hypertrophy is an adaptation to chronic stress (A). (B, E) would be expected if the patient had died of pulmonary embolism; however, pulmonary edema is rare in pulmonary embolism and common in amniotic fluid embolism. Acute myocardial infarction from a ruptured atherosclerotic plaque (C) would be extremely rare in a 22-year-old female. Common pathologic findings in amniotic fluid embolism include fetal squamous cells and hair in the arterioles, disseminated intravascular coagulation, pulmonary edema, and diffuse alveolar damage (D).

Question 25

25. A 67-year-old woman has a central venous
    catheter placed during hospitalization for dehydration.
    The catheter is placed using guidewire technique
    and ultrasound guidance, and the tip of the
    catheter is demonstrated to be in good position in
    the superior vena cava. On the third hospital day
    the nurse finds the patient sitting up in bed with
    the venous catheter partially dislodged. The nurse
    removes the catheter and holds pressure; however,
    the patient rapidly becomes tachycardic and
    hypoxic. Electrocardiogram shows sinus tachycardia
    and a new right axis deviation. What is the most
    likely diagnosis?
    A. Pulmonary embolism
    B. Air embolism
    C. Acute myocardial infarction
    D. Aortic dissection
    E. Sepsis

Answer 25

25. Correct: Air embolism (B)
    The history of sudden onset of respiratory failure
    with central venous catheter placement or removal
    in the upright position is highly suggestive of an air
    embolism (B). The EKG findings of tachycardia and
    right axis deviation are indicative of right ventricular
    overload. Pulmonary embolism could present in a
    similar fashion; however, again, the history of puncture
    of a large central vein makes air embolism more
    likely (A). For (C–E), see previous information.

Question 26

26. A 63-year-old male undergoes left heart catheterization
    in preparation for possible aortic valve
    replacement to treat severe aortic regurgitation. The
    procedure revealed extensive calcification in the
    thoracic aorta and moderate nonobstructive coronary
    artery disease. A week after the procedure he
    presents to his primary care physician complaining
    that his left big toe has turned blue. In addition to
    a patchy cyanosis of several toes on both feet, he is
    noted to have livedo reticularis of the lower extremities
    and elevation of the serum creatinine. Pulses are
    brisk in both lower extremities. What is the most
    likely diagnosis?
    A. Granulation tissue in the dermis
    B. Excessive collagen deposition in the dermis
    C. Foreign body granulomas in the dermis
    D. Fibrin thrombi in the arterioles of the dermis
    E. Cholesterol deposition in arterioles of the dermis

Answer 26

26. Correct: Cholesterol deposition in arterioles
    of the dermis (E)
    The history of recent angiography in the setting of
    atherosclerotic disease in the setting of acute kidney
    injury and livedo reticularis is highly suggestive of
    cholesterol embolization (E). “Blue toe syndrome”
    is a less common, but classic finding in cholesterol
    embolization. (A, B) describe findings associated
    with wound healing and scar tissue formation,
    respectively. Foreign body granulomas are uncommon
    and inconsistent with the clinical presentation;
    however, occasionally macrophage granulomas
    can be seen in cholesterol embolism but would be
    expected in the arteriole, not the dermis (C). (D)
    describes characteristic findings in disseminated
    intravascular coagulation.

Question 27

27. A 57-year-old man is evaluated in the emergency
    room for sudden onset of left hemiparesis,
    which began 45 minutes prior to his arrival. A CT
    scan of the head in the emergency department is
    unremarkable. t-PA is not administered because of
    his uncontrolled hypertension. He is admitted to
    a neurologic ICU, and a 2D echocardiogram is performed,
    which shows a mobile mural thrombus of
    the left ventricle. Which of the following additional
    findings are likely to be found on echocardiogram?
    A. Atrial fibrillation
    B. A large area of poorly contracting left ventricular
    muscle
    C. Hypokinetic right ventricle and dilated
    pulmonary artery
    D. Aortic valve calcification and stenosis
    E. Mitral valve vegetation

Answer 27

27. Correct: A large area of poorly contracting
    left ventricular muscle (B)
    This patient has developed a ventricular mural
    thrombus, which most commonly develops after a
    myocardial infarction. The damaged ventricular wall
    is highly thrombogenic, and poor contractility of the
    damaged myocardium creates turbulence that predisposes
    to thrombus formation. If the infarct results
    in ventricular wall aneurysm, the risk of thrombus
    formation is increased further. The infarct should
    be visible on echocardiogram as an akinetic portion
    of the ventricular wall (B). Thrombi that form as a
    result of atrial fibrillation are usually visualized in
    the atria or atrial appendage (A). (C) describes findings
    typical of pulmonary embolism. Neither (D) nor
    (E) are associated with left ventricular thrombus in
    the absence of other pathology.

Question 28

28. A 27-year-old male presents with his second
    unprovoked deep venous thrombosis. He is started
    on Coumadin and returns in 5 days to check his INR
    (International Normalized Ratio). Which of the following
    tests would be least useful to order at his
    follow-up visit?
    A. Homocysteine level
    B. Prothrombin Gene Mutation (G20210A)
    C. Factor V Leiden
    D. Proteins C and S activity
    E. Antiphospholipid antibody

Answer 28

28. Correct: Proteins C and S activity (D)
    Proteins C and S are potent inhibitors of several clotting
    factors. Inherited deficiency of either will lead
    to a hypercoagulable state. However, Proteins C and
    S and antithrombin III levels are often low in the setting
    of acute VTE (venous thromboembolism) due to
    consumption by the clotting process. Furthermore,
    both proteins C and S are vitamin K dependent and
    will be low in the setting of Coumadin therapy (D).
    The remainder of the laboratory studies (A–C, E)
    are all appropriate in the initial workup for possible
    thrombophilia.

Question 29

29. A 30-year-old man involved in a motor vehicle
    collision is brought in by EMS for severe bleeding
    from a laceration of the femoral artery. Shortly after
    arrival to the emergency department, his systolic
    pressure has dropped to 65 mm Hg, and his heart
    rate is 140. He is noted to be confused, and his urine
    output is low. He is receiving a blood transfusion
    and is started on Vasopressin. Which of the following
    physiologic effects would not be expected from
    Vasopressin?
    A. Increase in systolic blood pressure
    B. Platelet activation
    C. Vasoconstriction
    D. Hyponatremia
    E. Increased renal tubular sodium absorption

Answer 29

29. Correct: Increased renal tubular sodium
    absorption (E)
    The increase in renal tubular sodium reabsorption
    (E) seen in hypovolemia is due to activation of the
    renin-angiotensin-aldosterone system, not vasopressin
    secretion. Vasopressin (antidiuretic hormone)
    plays a role both in vascular tone and blood pressure
    control and in water homeostasis. Vasopressin, as its
    name implies, has vasoconstrictive effects (C), which
    raises blood pressure (A) and promotes hemostasis.
    It also increases water absorption on the distal nephron
    and thus will cause hyponatremia if its secretion
    is uncoupled from regulation by plasma osmolality,
    as is the case in severe hypovolemia (D). It also activates
    platelets (B).

Question 30

30. A 37-year-old female with a history of deep
    venous thrombosis during her first pregnancy and
    two spontaneous abortions is being evaluated in
    the emergency department. Forty minutes prior to
    arrival she experienced the sudden onset of weakness
    of the right face, right arm, and right leg. Neurologic
    examination reveals flaccid paralysis of the
    right side of the body with expressive aphasia without
    visual field defect. Magnetic resonance imaging
    (MRI) of the brain and basic lab work including
    complete blood count, prothrombin time (PT), and
    activated thromboplastin time (aPTT) are ordered in
    the emergency department. Which of the following
    is most likely to be found on the brain MRI?
    A. Acute stroke of the right anterior cerebral artery
    B. Acute stroke of the left anterior cerebral artery
    C. Acute stroke of the right middle cerebral artery
    D. Acute stroke of the left middle cerebral artery
    E. Acute stroke of the right posterior cerebral artery
    F. Acute stroke of the left posterior cerebral artery

Answer 30

30. Correct: Acute stroke of the left middle
    cerebral artery (D)
    A middle cerebral artery (MCA) stroke would be
    expected to cause neurologic deficits of the contralateral
    arm, leg, and face (D). The presence of aphasia in this case indicates damage of the left posterior inferior frontal gyrus (Broca’s area). Anterior cerebral artery (ACA) strokes are less common and would produce contralateral hemiparesis but would not produce hemifacial weakness (A, B). The classic finding in posterior cerebral artery (PCA) stroke is homonymous hemianopsia, with larger PCA strokes producing contralateral hemiparesis and hemisensory loss (E, F).

Question 31

31. In the previous scenario, which of the following
    clinical or laboratory findings would suggest a
    diagnosis other than antiphospholipid antibody syndrome
    (APS)?
    A. Prolonged activated partial thromboplastin time
    (aPTT)
    B. Positive VDRL test
    C. Low platelet count
    D. Positive antinuclear antibody (ANA)
    E. Elevated homocysteine levels

Answer 31

31. Correct: Elevated homocysteine levels (E)
    Elevated homocysteine levels suggest a diagnosis of
    hyperhomocysteinemia (E). Inherited deficiency of
    cystathione β-synthetase or methylene-tetrahydrofolate
    reductase can cause a familial hypercoagulable
    state characterized by venous and arterial thrombosis
    and elevated serum homocysteine levels. Prolongation
    of aPTT can be seen in antiphospholipid antibody syndromes (APS) with Lupus Anticoagulant (A). Thrombocytopenia is a common manifestation of APS (C). Despite low platelet counts, these patients are prone to thrombosis rather than bleeding. A positive antinuclear antibody is suggestive of systemic
    lupus, a common cause of secondary APS (D). VDRL
    (Venereal Disease Research Laboratory) antigen consists
    of cardiolipin-cholesterol-lecithin mixtures that
    may produce a false positive syphilis test in patients
    with APS who have anticardiolipin antibodies (B).