Tutorial #24: Pulmonary Embolism Flashcards
What three major risk factors for thrombosis? (Virchows Triad)
- Disruption in blood flow (stasis)
- Hypercoagulability
- Endothelial cell damage
What is the most common symptom of a pulmonary embolism?
Dyspnea (breathlessness)
For a patient with a low clinical likelihood of DVT and PE (through Wells and YEARS respectively), what test should be ordered?
D-dimer
For a patient with a high clinical likelihood of DVT and PE (through Wells and YEARS respectively), what test should be ordered?
imaging test (ex. CT chest angiogram)
What is the most common symptom of DVT?
Swelling (present 97% of the time) and pain (present 86% of the time).
Is the d-dimer test for PE a rule-in, or rule-out test, and why?
Rule out test.
This is because the d-dimer lacks specificity. A positive d-dimer can be due to a variety of reasons (MI, pneumonia, sepsis, malignancy, etc) (remember SpIn - SPECIFICITY for RULE IN), and has a high chance of false positive. It’s sensitivity (SnOUT - SENsitivity for RULE OUT) is 90% regardless of risk, but its sensitvity drops significantly the higher risk the patient. Remember, we use d-dimer in patients that have low pre-test probability of having PE.
What is the most common abnormalities found on EKG for a pt. with a Pulmonary Embolism?
sinus tachycardia + T wave inversion in leads V1-V4
Note: The clasically taught “S1Q3T3 sign” is neither sensitive nor specific.
What is Wells Criteria for Pulmonary Embolism? (x7 criteria)
- Clinical signs and symptoms of DVT = 3
- PE is #1 diagnosis OR equally likely = 3
- Heart rate > 100 = 1.5
- Immobilization at least 3 days OR surgery in the previous 4 weeks = 1.5
- Previous, objectivey diagnosied PE or DVT = 1.5
- Hemoptysis = 1
- Malignancy w/ treatment within 6 months or palliative = 1
Pt. has a WELLs score of ≤ 4 , in the two tier model of Wells what is the best investigation at this point in time?
consider D-dimer. If negative, stop work-up for PE, if positive -> CTA
PE unlikely (0-4 points). Remember we use the d-dimer only in patients where the pre-test probability is low.
Pt. has a WELLs score of > 4 , in the two tier model of Wellswhat is the best investigation at this point in time?
Consider CT angiogram
Pt. has a high pre-test probabilty of PE, so d-dimer is not useful at this time.
What is the PERC rule for Pulmonary embolism (definition not criteria)
It is a clinical decision tool that is used to rule out PE.
PE is ruled out if NO criteria are present, and the pre-test probabilily is < 15%
What are the criteria for the PERC rule for PE?
- Age > 50 = 1
- HR > 100 = 1
- SaO2 on room air < 95% = 1
- Unilateral leg swelling = 1
- Hemoptysis = 1
- Recent surgery or trauma = 1
- Prior PE or DVT = 1
- Hormone use = 1
If any of these features are present, you cannot rule out PE.
What are the limitations to clinical decision tools such as Wells, and PERC? (x4)
- Validity (does it actually measure what it says it does)
- Reliability (i.e does it produce consistent results)
- Practicality (it is easy to use)
- Applicability/generalizability (can it be used on your patient population)
What are the top 4 most common symptoms of PE?
- Dyspnea
- Chest pain (pleuritic)
- Calf or thigh pain and/or swelling
- Tachypnea
Tip from A and C - we’ve had a lot of questions where hemoptysis was also a presenting complaint, and although low prevalence in the list above, think about PE if it comes up in a question!
What are the positive predictors of Cardiac chest pain/ACS? (x3)
- Exertional chest pain
- Pain improved with resting
- Pain that radiates to arms or neck.
What are the two MOST IMPORTANT test you would order when suspecting ACS? (x2)
EKG
Troponin
What are positive predictors of Pericarditis on history?
Pleuritic chest pain, that improves with leaning forward, worse when laying flat.
What is a positive predictor for pericarditis on physical exam?
Pericardial friction rub during chest auscultation.
What are the typical findings of pericarditis on ECG?
Diffuse ST elevation and PR depression.
Pericarditis is classically associated with ECG changes that evolve through four stages.
Stage 1 – widespread STE and PR depression with reciprocal changes in aVR (occurs during the first two weeks)
Stage 2 – normalisation of ST changes; generalised T wave flattening (1 to 3 weeks)
Stage 3 – flattened T waves become inverted (3 to several weeks)
Stage 4 – ECG returns to normal (several weeks onwards)
What are the positive predictors of a Spontaneous Pneumothorax? (x4)
- Sudden onset dyspnea
- Pleuritic chest pain on the side of collapse
- Hyper-resonance on percussion on side of collapse
- decreased breath sounds.
What test would you organize when suspecting pneumothorax on a stable patient?
Chest x-ray as initial test - it has reasonable sensitivity and give you measurements for “small vs large”.
Ultra-sound is even more sensitive, but it does not reliably tell you size.
What are the positive predictors of Pneumonia?
- Pleuritic chest pain
- Fever
- productive cough
What are the positive predictors of CHF/pulmonary edema? (x3)
- SOB, orthopnea, PND
- Peripheral edema and elevated JVP (may be present)
- usually not painful.
What are the positive predictors of COPD exacerbation (x3)
- Positive COPD history
- Wheezing and dyspnea (either development of or worsening)
- change in sputum volume or color
What would spirometry or PFT show in a COPD exacerbation?
PFT showing an obstructive pattern, that has lack of response to bronchodilators.
What are the positive predictors of Asthma? (x3)
- Has other atopy (allergies, chronic rhinitis)
- Response to irritants (smoking, smoke, exercise)
- Wheezing on auscultation
What would you see on PFT for a patient that has Asthma?
PFT showing obstructive pattern that is responsive to brhonchodilators.
