Venous Thromboemboli ; DVT + PE Flashcards
What is a DVT?
Thrombus (blood clot) in deep leg vein
Where are the 2 places a DVT can be?
How dangerous are they?
Which veins are they found in?
Below calf = less concerning (MC) + minor veins (ant + post tibial)
Above calf = life threading (LC) +fewer major veins (eg. Superficial femoral); occlusion here may impede distal flow
What is a PE?
DVT embolises and lodges in pulmonary artery circulation
Risk factors of DVT
Virchows triad
Endothelial damage - trauma, surgery, MI, Smoking
Hyper coagulability - sepsis, pregnancy, obesity, contraceptives
Venous stasis - AF, Immobility
Recent surgery, long haul travel, pregnancy, malignancy, polycythemia(raised RBC count), hormone therapy with oestrogen, thrombophilia (prone to blood clots - antiphospholipid syndrome), systemic lupus erythematosis
Why can trauma cause endothelial damage?
Normally secretes anti coagulant chemicals, damaged endo can’t
Why can venous stasis cause a DVT?
Typically spread out clotting factors (laminar flow)
Stasis = aggregation of clotting factors
What is every patient admitted to hospital assessed for?
Risk of DVT
What happens if you are deemed high risk for DVT?
Receive prophylaxis :
Low molecular weight heparin (enoxaparin)
Anti emboli compression stockings
(CI = peripheral arterial disease)
What does PE cause?
How?
Cor pulmonale
Increased PVR = Increased RV strain to overcome this = increased RVH = RV fails 2^ to pulmonary artery pressure
What is cor pulmonale?
Abnormal enlargement of RHS of heart due to disease of lungs or pulmonary BV
Symptoms of a DVT
Unilateral swollen calf, dilated superficial veins, typically warm & oedematous
Complete occlusion of large vein =phlegmasia ceruleo dolens (severe ischemia, leg turns blue)
What test is done to assess DVT and PE?
What does it check?
Wells score
Predicts risk of patient with symptoms having DVT/PE
Includes RF - recent surgery, clinics, findings (unilateral calf swelling >3cm)
Use online calculator
What’s the wells score for DVT?
> 1 = likely DVT
Eg. Calf swelling 3+cm than other leg =1pt
Pitting oedema =1pt
Symptoms of PE
Pleuritic chest pain (sharp pain when breathing deeply)
Dyspnoea (+/- haemoptysis) - cough up blood - streaks of blood mixed with normal sputum
With evidence of DVT eg. Swollen calf & immobilization history
-tachy, hypo, increased JVP, ankle oedema
Wells score for PE?
> 4 = likely PE
Eg. Evidence of DVT = 3pt, tachy = 1.5pt
Diagnosis of DVT
D dimer & duplex ultrasound (GS)
<1 = D dimer = not raised = not PE
>1 = (raised D dimer) = duplex US = DIAGNOSTIC
What’s a D dimer test ?
How sensitive /specific is it?
Blood test - small protein released into blood when blood clot fibrinolysed
Sensitive -95% of patients with a DVT have increased D dimer
Not specific - many patients with increased d dimer will not have DVT
Good to exclude DVT
Other conditions causing increased d dimer?
Pneumonia, malignancy, heart failure, surgery, pregnancy
Which other diseases present with which symptom same as PE?
PE, pneumothorax, pneumonia all present with pleuritic chest pain
Diagnosis of PE
Key - D dimer, CT pulmonary angiogram CTPA (GS)
ECG - sinus tachycardia - S1Q3T3 (pathognamonic) - major sign of cor pulmonale
-T wave inversion of anterior & inferior leads - most specific finding
- new RBBB
Chest x ray = normal
Wells:
<4 = D dimer = not raised = notPE
4+ = (raised D dimer) = CTPA = diagnostic
How can you differentiate between PE and pneumonia + thorax?
Chest x ray
PE = normal
Others = diagnostic
Treatment for DVT and non massive PE?
Anti coagulation (DOAC)
-Apixaban/ rivaroxaban
(Start immediately where suspected/delay in scan)
LMWH if above CI (renal impairment)
+ mobalisation + compression stockings
Treatment for massive PE?
(Hypo<90)
Thrombolytics (alteplase - clot buster)
Differential diagnosis for DVT
Difference in symptoms & test results?
Cellulitis = skin infection, typically staph aureus & strep pyogenes
Tender, inflamed, swollen calf with pronounced demarcation
Will show leukocytosis (indicative of infection) on blood test FBC , while DVT levels normal
D dimer and duplex us can confirm DVT
