Deep Vein Thrombosis (DVT)

CLINICAL DESCRIPTION

DVT in lower limbs are the most common. Other sites include upper limbs, intracranial and splanchnic veins

Risk factors:

Obesity,
Smoking,
Prolonged immobility (long haul flights, long road trip, bed rest due to sickness),
Major surgery (e.g. Orthopaedic,abdominal and pelvic surgery),
Pregnancy and the puerperium, after caesarean section,
Malignancies,
Inherited blood disorders,
Oestrogen therapy (oral contraceptives)
Medical conditions (e.g., HIV infection, congestive cardiac failure, myocardial infarction, nephrotic syndrome, stroke, systemic lupus erythematous, antiphospholipid syndrome)

POSSIBLE COMPLICATION OF DVT

CLINICAL FEATURES

SIGNS AND SYMPTOMS

Well’s score calculation for DVT (provides clinical likelihood of DVT)

Paralysis, paresis or recent orthopedic casting of lower extremity (1 point)
Recently bedridden (more than 3 days) or major surgery within past 4 weeks (1 point)
Localized tenderness in deep vein system (1 point)
Swelling of entire leg (1 point)
Calf swelling 3 cm greater than other leg (measured 10 cm below the tibial tuberosity) (1 point)
Pitting oedema greater in the symptomatic leg (1 point)
Collateral non varicose superficial veins (1 point)
Active cancer or cancer treated within 6 months (1 point)
Alternative diagnosis more likely than DVT (Baker’s cyst, cellulitis, muscle damage, superficial venous thrombosis, post phlebitic syndrome, inguinal lymphadenopathy, xternal venous compression) (-2 points).

Well’s Score Interpretation for DVT

3-8 Points: High probability of DVT
1-2 Points: Moderate probability
2-0 Points: Low Probability Low probability: D-Dimer test is recommended. Low pre-test probability combined with a negative D-Dimer test essentially rules out a DVT.
Moderate or High Probability: Doppler/compression ultra sound scan is recommended (plus D-dimer test if available).

INVESTIGATIONS

FBC
HIV test
In patients with recurrent DVT and tests available: thrombophilia screen e.g. protein C, protein S levels;
SLE/antiphospholipid screen tests

TREATMENT

Treatment objectives of DVT

Initiate treatment (anticoagulation) as soon as possible without delay to prevent further extension of the thrombus and complication of DVT (e.g., pulmonary embolism)
Treat/modify risk factors where possible to prevent recurrence.

NON-PHARMACOLOGICAL

Prevention of DVT/ DVT recurrence:
Regular exercise during long journeys e.g., stopping on road journeys to take a walk or moving about on a plane during long flights and leg flexing exercises while seated.
Avoid crossing legs for long periods on long journeys
Use of elastic compression stockings
Change of oral contraceptives to alternative contraceptive

PHARMACOLOGICAL

Exclude contraindications for anticoagulants: severe liver disease, active bleeding PUD, recent haemorrhagic stroke, severe thrombocytopenia
Anticoagulation:
- Low molecular weight heparin e.g., Enoxaparin 1mg/kg 12 hourly SC or unfractionated Heparin (UFH) 15 000 IU 12 hourly SC Plus
- Adult loading dose Warfarin 10mg daily on Day 1, Day 2 and then 5mg daily on Day 3 and check INR. Aim at achieving INR target 2 -3.
- When INR is therapeutic (2-3) stop Heparin and continue with Warfarin 5mg (adjust dose as per INR) for minimum of 3 months if risk is temporary or unknown.

Note:

Warfarin should ONLY be prescribed if INR can be monitored. Warfarin is contraindicated in pregnancy (teratogenicity risk).
Therefore, heparin is recommended anticoagulant in pregnancy
Monitor platelet level when patient is on Heparin (risk of heparin induced thrombocytopenia)
Some patients may require longer period of anticoagulation (active risk factor: ongoing active cancer, SLE, antiphospholipid syndrome).
Where available can use new oral anticoagulant e.g., Rivaroxaban or Dabigatran

DVT prophylaxis for immobile in-hospital patients

Unfractionated Heparin: adults 5000 Units 8-12 hourly SC Or Enoxaparin 40mg daily SC

Criteria for referral of DVT patient for specialist care