Pulmonary Embolism Flashcards
What are the symptoms of PE?
pleuritic chest pain
haemoptysis
dyspnoea
tachycardia >100bpm
tachypnoea >20/min
classically patients present with a clear chest but in real life you may have what on respiratory examination?
crackles
PERC criteria?
criteria for excluding PE in low-risk patients
How do you get a negative PERC result?
all criteria absent
a negative PERC reduces the probability of PE to < 2%
criteria of PERC
age >50
HR >/100
previous DVT or PE
oestrogen use
oxygen saturations 94%
recent surgery / trauma (4 weeks)
haemoptysis
unilateral leg swelling
What is defined as low-probability of having a PE?
< 15%
If a PE is suspected what score should be performed?
Wells Score
Which components of the wells score are worth 3 points?
Clinical signs and symptoms of DVT (minimum of leg swelling and pain with palpation of the deep veins)
An alternative diagnosis is less likely than PE
Which components of the wells score are worth 1.5 points?
Heart rate > 100 beats per minute
Immobilisation for more than 3 days or surgery in the previous 4 weeks
Previous DVT/PE
Which components of the wells score are worth 1 point?
Haemoptysis
Malignancy (on treatment, treated in the last 6 months, or palliative)
Describe wells scoring
Clinical signs and symptoms of DVT (minimum of leg swelling and pain with palpation of the deep veins) 3
An alternative diagnosis is less likely than PE 3
Heart rate > 100 beats per minute 1.5
Immobilisation for more than 3 days or surgery in the previous 4 weeks 1.5
Previous DVT/PE 1.5
Haemoptysis 1
Malignancy (on treatment, treated in the last 6 months, or palliative) 1
Describe the clinical probability of a PE according to Well’s score
PE likely - more than 4 points
PE unlikely - 4 points or less
What should you do if PE is likely according to Well’s score?
arrange an immediate computed tomography pulmonary angiogram (CTPA)
If there is a delay in getting the CTPA then interim therapeutic anticoagulation should be given until the scan is performed.
What does interim therapeutic anticoagulation refer to?
Giving a direct oral anticoagulant (DOAC)
I.e. apixaban or rivaroxaban
What would you consider if CTPA is negative for PE?
consider a proximal leg vein ultrasound scan if DVT is suspected
What would you do if a PE is ‘unlikely’ according to Well’s Score?
arrange a D-dimer test (within 4 hours)
IF D DIMER POSITIVE:
Follow up with CTPA
If there is a delay in getting the CTPA then give interim therapeutic anticoagulation until the scan is performed
IF D DIMER NEGATIVE
if negative then PE is unlikely - stop anticoagulation and consider an alternative diagnosis
D dimers should be performed within what time frame?
4 hours
If can’t get results within 4 hours give interim therapeutic anticoagulation
What are the advantages of CTPA over V/Q scans?
speed, easier to perform out-of-hours
a reduced need for further imaging and the possibility of providing an alternative diagnosis if PE is excluded
What is the investigation of choice if there is renal impairment?
V/Q scanning
doesn’t require the use of contrast unlike CTPA
What is the sensitivity and specificty of D Dimers?
sensitivity = 95-98%, but poor specificity
When should age adjusted d-dimers levels be considered?
> 50 years
What are the classic ECG changes in PE?
‘S1Q3T3’
large S wave in lead I
large Q wave in lead III
an inverted T wave in lead III
However, this change is seen in no more than 20% of patients
Which bundle branch block is associated with PE?
right bundle branch block
Which axis deviation is associated with PE?
right axis deviation
Why is CXR reccomended in all suspect PE patients? What would you find?
to exclude other pathology
typically normal in PE
possible findings include a wedge-shaped opacification
What is the sensitivity & specifity of V/Q?
What else can cause a V/Q mismatch?
sensitivity of around 75% and specificity of 97%
other causes of mismatch in V/Q include old pulmonary embolisms, AV malformations, vasculitis, previous radiotherapy
What is a shortcoming of CTPA?
peripheral emboli affecting subsegmental arteries may be missed
In recent years, more and more ‘low risk’ patients are treated as outpatients. Key requirements to being low risk include what?
haemodynamic stability, lack of comorbidities and support at home
What is the cornerstone of VTE management?
anticoagulant therapy