DVT Flashcards
Deep Vein Thrombosis (DVT) is a common disease although often asymptomatic. True or false?
The deep veins of the lower limbs are affected most commonly, but thrombosis may affect other sites, including the upper limbs, intracranial and splanchnic veins.
True— Deep Vein Thrombosis (DVT) is a common disease although often asymptomatic.
True— The deep veins of the lower limbs are affected most commonly, but thrombosis may affect other sites, including the
— upper limbs,
— intracranial and
— splanchnic veins.
Definition
DVT is the formation of blood clot in a deep vein, usually in the legs.
This condition is serious because blood clots can loosen and lodge in the lungs.
Complications of DVT
Complications include
pulmonary thromboembolism, which can be life-threatening.
The 2 main complications of deep vein thrombosis (DVT) are
— pulmonary embolism and
— post-thrombotic syndrome.
Risk Factors of DVT
It is therefore essential to have a reliable method for establishing the DVT risk of patients and to take active steps to provide prophylactic treatment as necessary.
Common risk factors for DVT include
— obesity,
— smoking,
— prolonged immobility (e.g. bed rest, long haul flights),
— major surgery e.g. orthopaedic,
abdominal and pelvic surgery,
— pregnancy and the puerperium,
— after caesarean section,
— malignancies,
— inherited blood disorders,
— oestrogen therapy and
— medical conditions, e.g. congestive cardiac failure,
— myocardial infarction,
— nephrotic syndrome,
— stroke,
— systemic lupus erythematosus.
Note
In cases of confirmed DVT, treatment with anticoagulants must not be delayed unnecessarily unless there are significant contraindications to their use such as
— recent intracerebral bleed,
— severe liver disease,
— active peptic ulcer,
— bleeding disorders, and
— severe hypertension.
Causes of DVT
Causes
y Stagnation of blood in the vein
y Increased viscosity of blood
y Inflammation of the blood vessel causing damage
Signs and symptoms
Symptoms
y Swelling or firmness of affected limb (usually unilateral)
y Pain in the affected limb
y Mild fever
Signs
y Swelling of affected limb 🦵
y Differential warmth
y Tenderness
y Redness
y Pitting oedema
y Prominent superficial veins
Well’s Scoring for DVT probability
STG page 124
Well’s Scoring for DVT probability
The Well’s scoring system for DVT probability objectifies clinical suspicion of DVT risk and provides criteria for initiating treatment.
The presence or absence of the clinical features below are computed to give a pretesting probability score for that particular patient which is used to prioritise investigation and treatment.
y Paralysis, paresis or recent orthopedic casting of lower extremity (1 point)
y Recently bedridden (more than 3 days) or major surgery within past 4
weeks (1 point)
y Localized tenderness in deep vein system (1 point)
y Swelling of entire leg (1 point)
y Calf swelling 3 cm greater than other leg (measured 10 cm below the tibial
tuberosity) (1 point)
y Pitting oedema greater in the symptomatic leg (1 point)
y Collateral non varicose superficial veins (1 point)
y Active cancer or cancer treated within 6 months (1 point)
y Alternative diagnosis more likely than DVT (Baker’s cyst, cellulitis, muscle damage, superficial venous thrombosis, post phlebitic syndrome, inguinal lymphadenopathy, external venous compression) (-2 points)
Well’s Score Interpretation for DVT
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:
— D-Dimer test with additional Doppler/compression ultra sound scan is recommended.
Investigations
Investigations
y D-Dimer test
y Doppler ultrasound
y Thrombophiliascreen e.g. proteinC, protein S levels (inpatients with
recurrent DVT)
y FBC
Treatment
View STG page 125
Treatment
Treatment objectives
y To prevent clot propagation and pulmonary embolism y To prevent recurrence
Non-pharmacological treatment
y Avoidance of prolonged recumbency and dehydration
y Avoidance of excess amounts of coffee, tea and alcohol, especially
on long journeys
y Increase water intake during long journeys or periods of immobility y Regularexerciseduringlongjourneyse.g.stoppingonroadjourneys
to take a walk or moving about on a plane during long flights and leg
flexing exercises while seated
y Avoid crossing legs for long periods on long journeys y Use of elastic compression stockings
Pharmacological treatment
A. DVT Prophylaxis
1st Line treatment
Evidence Rating: [A]
y Heparin, SC, Adults
5,000 units 8-12 hourly
Children
1 month-18 years; 250 units/kg 12 hourly
2nd Line Treatment
Evidence Rating: [A]
y Enoxaparin, SC, Adults
40 mg daily Children
2 months-18 years; 1-2 months;
500 microgram /kg 12 hourly (max 40 mg) 750 microgram /kg 12 hourly
B� DVT Treatment
1st Line Treatment
Evidence Rating: [A]
y Heparin, SC, Children
1 month-18 years; 250 units /kg 12 hourly
Or
y Heparin, IV, Adults
Or
250 units/kg, SC, continue with 250 units /kg 12 hourly
Children
1-18 years; 75 units/kg stat. continue with 20 units/kg/hour
1 month-1 year; 75 units/kg stat. continue with 25 units/kg/ hour Neonates (term baby); 75 units/kg stat. continue with 25 units/kg/ hour
Neonates (< 35 weeks); 50 Units /kg stat. continue with 25 units/ kg/hour
2nd Line Treatment
Evidence Rating: [A]
y Enoxaparin, SC, Adults
1.5 mg/kg (150 units/kg) daily
Children
2 months-18 years; 1-2 months; Neonates;
Or
1 mg/kg 12 hourly
1.5 mg/kg 12 hourly 1.5-2 mg/kg 12 hourly
y Dalteparin, SC, Adults
200 mg/kg (max. of 18,000 units) daily
Children
12-18 years; daily)
1 month-12 years; Neonates;
y Warfarin, oral, Adults
200 units/kg once daily (max 18,000 units
100 units/kg 12 hourly 100 units/kg 12 hourly
And
Loading Dose
DAY— DOSE— INR
1— 10 mg— -
2 — 10 mg — -
3 — 5 mg— Check INR
Note
Note 7-4
Wafarin is not to be given in pregnancy.
Continue 5 mg daily INR until a target INR of 2 to 3 is achieved. After this the low molecular weight heparin is stopped and a maintenance warfarin dose of 2.5 mg to 5 mg (some patients may require 7.5 mg) is continued guided at all times by a target INR of 2 to 3.
Long-term treatment requires continuation of warfarin for three to six months if the risk factor is temporary or unknown. Recurrent DVT and permanent risk factors such as thrombophilia may require long-term anticoagulation.
Referral Criteria
Referral Criteria
Refer to physician specialist for management and monitoring.
