PULMONARY EMBOLISM Flashcards

1
Q

How many people have a DVT in UK every year?

A

1 in 1’000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

If untreated how many of those with a DVT will develop a PE?

A

1 in 10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How many PE’s happen as a hospital inpatient? How many deaths?

A

1/2

25’000 deaths every year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the usual cause?

A

A DVT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Explain how a DVT causes a PE?

A

In almost all cases, the cause is a blood clot (thrombus) that has originally formed in a deep vein (known as a DVT). This clot travels through the circulation and eventually gets stuck in one of the blood vessels in the lung. The thrombus that has broken away is now called an embolus (and can therefore cause an embolism). Most DVTs come from veins in the legs or pelvis. Occasionally, a PE may come from a blood clot in an arm vein, or from a blood clot formed in the heart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What other causes, other than blood clots can it be?

A

• Fatty material from the marrow of a broken bone (if a large, long bone is broken - such as the thigh bone (femur).
• Foreign material from an impure injection - for example, with drug misuse.
• Amniotic fluid from a pregnancy or childbirth (rare).
• A large air bubble in a vein (rare).
• A small piece of cancerous material (tumour) that has broken off from a larger tumour in the body.
Rare causes: RV thrombus – post MI/ Septic emboli – R sided endocarditis/ Fat, air or amniotic fluid embolism/ Neoplastic cells/ Parasites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is Virchow’s triad?

A
  1. Altered blood flow
  2. Altered vessel
  3. Altered blood constituents = hypercoagulability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  1. Blood flow
A

These include turbulence, stasis, mitral stenosis, and varicose veins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  1. Damage to vessel
A

Injuries and/or trauma to endothelium includes damage to the veins arising from shear stress or hypertension.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
  1. Hypercoaguability
A

Hyperviscosity, deficiency of antithrombin III, nephrotic syndrome, changes after severe trauma or burn, disseminated cancer, late pregnancy and delivery, race, age, smoking, and obesity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Problems: what happens?

A
  1. Lung tissue is ventilated but not perfused = increased intrapulmonary dead space and decreased gas exchange. After a few hours, the lung tissue then stops producing surfactant => lung collapse => increased hypoxaemia.
  2. Decreased cross-sectional area of pulmonary arterial bed => increased pulmonary arterial pressure (pulmonary hypertension) and a decreased cardiac output
    Zone of lung no longer perfused => can infarct but often doesn’t because lungs are still supplied with O2 by bronchial circulation and the airways
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the risk factors?

A
•	Immobility: surgery or from illness or injury
o	Surgery: Recent surgery esp abdo/pelvic or hip/knee replacement
o	Leg fracture
o	Prolonged bed rest/reduced mobility
•	Travel
•	Prev. DVT (or PE)
•	Blood clotting disorders (clot more easily) i.e. Thrombophilia
•	Other disorders that make you clot more easily: nephrotic syndrome, antiphopholipid 
•	Contraceptive pill or HRT
•	Cancer or heart failure
•	Older people (over  60yrs)
•	Pregnancy/ post partum
•	Obesity
•	Smoking
•	Male
•	Dehydration
•	Malignancy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the key symptoms?

A

Acute breathlessness - Pleuritic chest pain (worse on inspiration) - Haemoptysis - Dizziness - Syncope (RHF) - Dyspnoea (RHF) - Cough

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the onset?

A

Suddenly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What symptoms will a small PE cause?

A
  • No symptoms at all (common).
  • Breathlessness - this can vary in degree from very mild to obvious shortness of breath
  • Chest pain which is pleuritic, meaning sharp pain felt when breathing in. Often you feel like you can’t breathe deeply, as this causes you to catch your breath. This happens because the blood clot may irritate the lining layer (pleura) around the lung. Shallow breathing is more comfortable.
  • Coughing up blood (haemoptysis).
  • A mildly raised temperature (fever).
  • A fast heart rate (tachycardia).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What symptoms will a large PE cause?

A
  • Severe breathlessness.
  • Chest pain - with a large PE the pain may be felt in the centre of the chest behind the breastbone.
  • Feeling faint, feeling unwell, or a collapse. This is because a large blood clot interferes with the heart and blood circulation, causing the blood pressure to drop dramatically.
  • Rarely, in extreme cases, a massive PE can cause cardiac arrest, where the heart stops pumping due to the clot. This can result in death, even if resuscitation is attempted.
17
Q

There may also be symptoms of DVT. What are these symptoms?

A

There may be symptoms of a DVT, such as pain at the back of the calf in the leg, tenderness of the calf muscles or swelling of a leg or foot. The calf may also be warm and red.

18
Q

What do we mean when we say massive PE?

A

A massive PE is so called not due to the actual size of the blood clot (embolus) but due to the size of its effect. A PE is high-risk if it causes serious problems such as a collapse or low blood pressure. Massive PEs are, by definition, high-risk.

19
Q

What signs do you get?

A
  • Hypotension
  • Pyrexia
  • Cyanosis
  • Tachyponea
  • Tachycardia
  • Gallop rhythm
  • Loud P2
  • R ventricular heave
  • AF
  • Raised JVP
  • Pleural rub
  • Pleural effusion
  • DVT – swollen leg
20
Q

What investigations?

A
Doppler, USS
Bloods: D-dimer
Echocardiogram
Isotope scan/ CTPA
ECG
CXR
21
Q

What is 1st line investigation?

A

D-dimer

22
Q

What bloods would you request?

A

o D-dimer (-ve D dimer excludes PE in those with low clinical probability so don’t do if suspect PE; +ve doesn’t prove diagnosis)
o FBC
o U&E’s
o Baseline clotting
o Blood tests: for signs of heart attack, infection or inflammation, ABG’s
• ABG: decr PaO2 and PaCO2

23
Q

What are you looking for in CTPA?

A

Sensitive and specific to see if emboli in PA. If unavailable, V/Q scan (ventilation-perfusion) can aid diagnosis

24
Q

What are you looking for an ECG?

A

tachycardia, RBBB, R ventricular strain (inverted T wave in V1 – V4) may be seen

25
Q

What are you looking for on CXR?

A

may be normal or show oligaemia of affected segment, dilated pul A, linear atelectasis, small pleural effusion, wedge shaped opacities or cavitation

26
Q

What scoring system do we use?

A

WELLS score

27
Q

What do you get points for with WELLS score?

A
Active cancer (treatment within last 6 months or palliative): +1 point
Calf swelling ≥ 3 cm compared to asymptomatic calf (measured 10 cm below tibial tuberosity): +1 point
Swollen unilateral superficial veins (non-varicose, in symptomatic leg): +1 point
Unilateral pitting edema (in symptomatic leg): +1 point
Previous documented DVT: +1 point
Swelling of entire leg: +1 point
Localized tenderness along the deep venous system: +1 point
Paralysis, paresis, or recent cast immobilization of lower extremities: +1 point
Recently bedridden ≥ 3 days, or major surgery requiring regional or general anesthetic in the past 12 weeks: +1 point
Alternative diagnosis at least as likely: −2 points[4]
28
Q

What do WELLS scores mean?

A

2 = likely DVT
4 = likely PE
If you have score of 2 then Doppler to confirm. If you have less 2 but clinical suspicion then do D-Dimer test. Very sensitive so can be used to rule out but not rule in. If you have +ve D-dimmer but negative scan then the scan is repeated 1 week later and can be ruled out with two negative scans.

29
Q

What are the two main things to consider?

A

Anticoagulant treatment

Oxygen

30
Q

What preventative measures?

A
  • TED stockings
  • LMWH prophylactic eg dalteparin 2500U/24hr SC
  • Stop HRT and OCP
  • If past or FH - test for thrombophilia
  • Recurrent PEs prevented by anticoagulation. Vena Cava filters may also be used but not so good.
31
Q

What do you do in large PE?

A
  • Oxygen – 100%
  • Morphine 10mg IV with antiemetic
  • If critically ill, consider immediate thrombolysis (a 50mg bolus of altepase) or surgery
  • IV access and start heparin either LMWH eg tinzaparin SC or unfractionated heparin IV
  • If BP <90mmHg – start rapid colloid infusion and if no improvement consider noradrenaline
  • If BP >90mmHg – start warfarin 10mg/24hr PO
  • Try to prevent thrombosis with compression stockings
  • Heparin concurrently with warfarin for >5d then stop heparin once INR >2
  • If obvious remedial cause, 6 weeks warfarin should be enough; if not cont 3-6 months
  • Look for underlying cause – eg thrombophilic tendency, malignancy, SLE
32
Q

What are the differentials?

A
  • Acute coronary syndrome
  • Aortic dissection
  • Cardiac tamponade
  • Pneumonia
  • Pneumothorax
  • Sepsis
33
Q

What is the prognosis?

A

About 1 in 7 people with a massive PE will die as a result.

Poor if not treated

34
Q

What are the complications?

A

Chronic thromboembolic pulmonary hypertension