Monday, June 6, 2011

Intern Report Case Discussion 4.0


Case Presentation by Dr. Stephanie Wise



Case Presentation

Answers


1) A. The most common inherited hypercoagulable state is Factor V Leiden. This is characterized by the production of a “rogue clotter” protein, which is also resistant to proteolysis by protein C. It is inherited in an autosomal recessive fashion, and is most common in people of northern European descent.  Von Willebrand disease is the most common genetic cause of excessive bleeding. The other options are other inherited hypercoagulable disorders.

2) B. Of the options provided, the correct statement is that T wave inversions are the most specific finding (81%) in the presence of pulmonary embolism. This has been the most common finding in some studies (68%).

S1Q3T3 is an indicator of cor pulmonale, which makes it less specific of a finding, and it is also not considered sensitive as it is only present in approximately 50% of cases.

Typically an ECG of a PE patient is abnormal; the difficulty is that the abnormalities are non-specific. The value of the ECG is more in ruling out other causes of the patient’s symptoms, especially myocardial infarction.

Sinus tachycardia is a common finding, but again, very non-specific.

3) C. Pulmonary angiography is the gold standard for diagnosis of pulmonary embolism. Doppler imaging can indicate a source of PE, but up to 60% of ambulatory patients (the people we’ll be seeing in the ED) do not have DVT.

In the presence of pulmonary embolism, the chest x-ray typically has some abnormality, but the abnormalities are usually both non-sensitive and non-specific. The findings more specific to PE (Hampton’s hump, Westermark sign and Fleischner’s lines) are rare. If you see them, however, you should be able to recognize them. Also, if you suspect PE, you should at least be aware of these findings so that you can identify them when present.

The value of D-dimer in diagnosis of PE is to rule it out. If clinical suspicion is low and the D-dimer is normal, PE is rare (2% or less). Thus, the value is in its negative predictive value.

4) C. Half of patients who present to the ED with a pulmonary embolism will have no identifiable clinical risk factors. Work-up will ultimately try to identify previously unidentied risk factors, but for the ED physician, a high index of suspicion needs to be present even if there is not a “convenient” history like what our patient in this case provided. Otherwise cases will be missed, which could be detrimental to our patients.

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