View source for WBR1024

{{WBRQuestion
|QuestionAuthor={{AO}}
|ExamType=USMLE Step 2 CK
|MainCategory=Internal medicine
|SubCategory=Cardiovascular
|MainCategory=Internal medicine
|SubCategory=Cardiovascular
|MainCategory=Internal medicine
|SubCategory=Cardiovascular
|MainCategory=Internal medicine
|MainCategory=Internal medicine
|SubCategory=Cardiovascular
|MainCategory=Internal medicine
|SubCategory=Cardiovascular
|MainCategory=Internal medicine
|SubCategory=Cardiovascular
|MainCategory=Internal medicine
|SubCategory=Cardiovascular
|MainCategory=Internal medicine
|MainCategory=Internal medicine
|SubCategory=Cardiovascular
|Prompt=A 70-year-old Caucasian male with a past medical history of hypertension and coronary artery disease was brought to the emergency department (ED) a few hours after he developed sudden, severely worsening epigastric pain and shortness of breath.  The pain was stabbing, radiating to the back and was associated with nausea and profuse sweating.   He confessed he has not been compliant on his anti-hypertensive medication for the past two months.  There is no history of trauma.  At presentation his vitals are: temperature is 39.2°C, pulse 110 beats per minute, respiratory rate 32/min, and blood pressure 90/70 mm Hg.  On examination his neck veins are distended.  Lungs are clear bilaterally.  Cardiovascular examination reveals muffled heart sounds.  Abdomen is tender to palpation, especially in the epigastrium with associated guarding, and the extremities are cold to touch. 
Laboratory results reveal normal parameters.  Electrocardiogram showed sinus tachycardia but no acute ischemic changes.  Chest x-ray and trans-esophageal echocardiogram reveal enlarged cardiac silhouette and right atrial and ventricular collapse, respectively.

Which of the following is likely to be expected in this patient?






|Explanation=This is a case of [[aortic dissection]] complicated by [[cardiac tamponade]].  The triad of hypotension, tachycardia and muffled (distant) heart sound, referred to as Beck’s triad, makes cardiac tamponade a high differential.  In most cases of cardiac tamponade, there is a reduction in systolic blood pressure by ≥ 10 mmHg during inspiration, known as pulsus paradoxus.  This may also be present in acute pulmonary embolus, pericarditis, in patients with chronic lung disease, hypovolemic shock, and pregnancy.

Educational Objective – Always suspect cardiac tamponade when you observe a triad of hypotension, tachycardia and muffled (distant) heart sound, referred to as Beck’s triad.  Pulsus paradoxus should always be measured whenever you suspect cardiac tamponade.  A pulsus paradoxus greater than 10 mm Hg among patients with a pericardial effusion helps in the making a diagnosis of cardiac tamponade.

Reference: http://www.wikidoc.org/index.php/Cardiac_tamponade_resident_survival_guide


|AnswerA=Alternating strong and weak pulses with an equal interval between each pulse
|AnswerAExp=This refers to pulsus alternans, seen in aortic regurgitation, left ventricular heart failure and systemic hypertension
|AnswerB=Alternating strong and weak pulses, but the weak pulse comes in early after the strong pulse
|AnswerBExp=This refers to pulsus bigeminus, seen in premature atrial and ventricular complexes
|AnswerC=A reduced intensity of pulse during inspiration versus expiration
|AnswerCExp=This refers to pulsus paradoxus
|AnswerD=Water-hammer or Corrigan’s Pulse
|AnswerDExp=This is a medical sign which describes a pulse that is bounding and forceful, as if it were the hitting of a water hammer that was causing the pulse. This is often seen in conditions like aortic regurgitation.
|AnswerE=Bounding Pulse
|AnswerEExp=This is generally seen in hyper-dynamic or high-output states such as anemia, hyperthyroidism, exercise, anxiety.  Also seen in aortic regurgitation.
|RightAnswer=C
|WBRKeyword=Cardiac tamponade, Pulsus paradoxus
|Approved=No
}}