Deep Vein Thrombosis
Scope of the guidance
This item covers the diagnosis and management of patients
suspected of having a deep vein thrombosis (DVT), and the
prevention of subsequent venous thromboembolism (VTE) and
post-thrombotic syndrome. It is derived from summaries of
evidence.(Clinical
Knowledge Summary; June 2007 and Clinical Evidence). It
does not cover the management of DVT and VTE in hospital
(this is
covered by NICE 2007 – see Further Reading), or the
prevention of DVT this NICE guideline is in preparation – see
http://www.nice.org.uk/Guidance/CG/Wave14/26 )
Source
Clinical Knowledge Summaries. Deep Vein Thrombosis.
Newcastle upon Tyne: Clinical Knowledge Summaries, 2007.
Key points
1. Background:
- DVT is difficult to diagnose clinically.
Taken alone, individual symptoms and signs are not helpful when
predicting the presence or absence of a DVT. You need a high
index of suspicion, especially if the patient has risk factors, or
features of pulmonary embolism (PE).
- Complications of DVT are pulmonary embolism
and post-thrombotic syndrome.
- DVT or PE may occur in around two in 1000
people in the UK each year, with around a quarter having a
recurrence. (See Clinical Evidence in Further
Reading)
- Consider DVT as a diagnosis in injecting drug
users with painful swollen leg/s
2. Symptoms:
- Symptoms may be absent. Typical
symptoms are pain and swelling in one leg. Usually onset is
acute
3. Signs:
- Swelling of entire leg, or calf (compare the circumferences
measured from a fixed bony landmark e.g. 10 cm below the
tibial tuberosity)
- Pitting oedema in the affected leg only
- Increased skin temperature in the affected leg
- Tenderness along the course of the deep venous system
- Collateral superficial veins
- Change of colour in affected leg to red or purple colour
4. Major risk factors:
If more than one
risk factor is present, the combined effect tends to be
multiple.
5. Other risk factors
include:
6. Assessment:
- Determine the clinical likelihood of DVT.
Refer for definitive tests; local guidelines will vary as to the
location - usually to secondary care or a specialist centre or
clinic in primary care.
-
Local guidelines and availability will dictate
the type of ultrasound scan and use of the d-dimer blood test. The
d-dimer blood test is used to identify people at low risk of DVT
who may not need an ultrasound scan, and is not a diagnostic test
(see Wells, 1997 in Further Reading for a commonly used risk
scoring system).
7. Treatment:
- Anticoagulation
- Usually consists of heparin combined with warfarin
- Heparin is continued for a minimum of five days until the
warfarin has brought the international normalised ratio (INR)
into the therapeutic range (target INR is 2.5, range 2.0-3.0)
for two successive days.
- Whilst patient on heparin check full blood count every five
days to rule out heparin-related thrombocytopaenia.
- Use warfarin for long-term therapy with the same target INR
(2.5, range 2.0-3.0) and adjust the dose as appropriate.
- Continue warfarin for at least three months - but may be
longer, depending on the risk of recurrence.
- Getting Going
- Encourage patients to get up and about as soon as possible
after starting anticoagulation therapy.
- Elevating the affected leg when sitting will help with any
swelling.
- Graduated elastic compression stockings
- Use once swelling has begun to
reduce.
- Below-knee compression stockings (grade 2)
should be worn on the affected leg for at least two years
following an above-knee DVT, to reduce the risk of post-thrombotic
syndrome.
8. Follow-up:
- Review treatment over time and
progress
- Check for features of post-thrombotic
syndrome – swelling, ulceration
- Assess risk of
recurrent VTE.
- If you suspect
thrombophilia refer for specialist haematology
advice
- If there was no obvious risk factors for DVT, consider if cancer is
possible/likely.
-
EGP 1. May 2008