Flashcards in Venous Thrombosis Deck (20):
At which site(s) does DVT most commonly occur?
Pelvis and leg. Can occur in any vein.
How does DVT typically present?
1. Often asymptomatic
5. Superficial venous distension
What are the differentials for a warm and swollen leg with tenderness?
1. Ruptured Baker's cyst
2. Oedema from other causes
How might the clinical probability of a DVT be estimated?
History (+1 for each)
- Lower limb trauma/surgery/immobilisation in plaster cast
- Bedridden for >3 days or surgery within last 4 weeks
- Malignancy (including treatment up to 6 months previously)
Clinical findings (+1 for each)
- Entire limb swollen
- Calf swelling >3 cm compared to asymptomatic side (measured at 10 cm below tibial tuberosity
- Pitting oedema (greater in symptomatic leg)
- Dilated collateral superficial veins (non-varicose)
Possible alternative Dx (-2)
- Musculoskeletal injury
- Chronic oedema
- Cellulitis of leg
- Arthritis of leg
- Baker's cyst
≤0: 3% (low risk)
1-2: 17% (moderate risk)
≥3: 75% (high risk)
What is the main aim of therapy in DVT?
Prevent pulmonary embolism
How is DVT managed?
- Heparin then warfarin (continued for 3 months)
- 4 weeks if significant risk factor, e.g. bed rest
2. Thrombolytic therapy
- If large iliofemoral thrombosis
3. Elastic support stocking
- For post-thrombotic syndrome
What are the main complications of DVT?
2. Post-thrombotic syndrome (from destruction of deep-vein valves)
- Persistant pain
- Venous eczema
3. Recurrence of thrombosis
What is main complication of chronic venous obstruction?
- Persistant pain
- Venous eczema
Name 2 drugs implicated in the prevention and treatment of thromboembolism
2. Warfarin or NOAC
Which drugs might be considered as an alternative to warfarin? Describe the pros and cons
Novel oral anticoagulants (NOACs) - e.g. apixaban, dabigatran, riveroxaban
- Direct thrombin inhibitors
- Used in VTE, AF and MI
- Rapid onset of action
- Administered in fixed dose without need for monitoring
- Fewer drug interactions
- But elimination primarily renal
- Abnormalities of liver function
How many people die from preventable hospital-acquired VTE each year?
Name 3 prophylactic measures against hospital-acquired VTE
1. Early mobilisation
2. Leg elevation
3. Compression stockings
4. Thromboprophylaxis with LMWH
In which patients is thromboprophylaxis with LMWH indicated?
1. Medical inpatients with any risk factor
2. Patients undergoing minor surgery (anaesthetic 60 mins) without risk factors (20 mg)
4. Patients undergoing major surgery (anaesthetic >60 mins) and with risk factors (40 mg)
What should you obtain before starting treatment of an established thromboembolism?
1. Coagulation screen
2. Platelet count
To exclude pre-existing thrombotic tendency.
Obtain objective evidence of thrombosis asap - though heparin is often started on basis of clinical suspicion .
True or false: you must obtain objective evidence of thrombosis before starting anticoagulation
False - heparin is often started on basis of clinical suspicion; obtain evidence asap
True or false: patient requiring LMWH can be safely treated as outpatients
True - where feasible in selected patients
Describe the anticoagulation regime for treating VTE
- Warfarin and heparin started at same time
- Overlap for minimum of 5 days
- Heparin continued until INR is in therapeutic range (INR: 2-3)
- Measure platelet count if receiving heparin >5 days
- Anticoagulation (warfarin) continued for 6 weeks after 1st thrombosis with precipitating cause (provided no risk factors)
- Long-term anticoagulation if repeated episodes or continuing risk factors
What are the major side-effects of heparin therapy?
Measure platelet count in all patients receiving heparin for >5 days.
List the indications for oral anticoagulation and their target INRs (11 in total)
Dose adjusted to maintain INR, usually 2-3 times control value.
2.5: PE, DVT, thrombophilia, AF, cardioversion, mural thrombus, cardiomyopahty
3.5: Reccurrence of VTE while of warfarin therapy, antiphospholipid syndrome, prosthetic heart valve, coronary artery graft thrombosis