Core conditions Flashcards
DVT
A thrombus within the deep venous system, normally in the legs. Can become dislodged becoming an embolus and causing a PE in the lungs. PE and DVT’s are both types of venous thromboembolism (VTE).
Risk factors for DVT
Virchows triad: hypercoagulability, endothelial injury and stasis
- Inherited thrombophilia (factor V leiden)
- Pregnancy and oestrogen
- Malignancy, infection and inflammation
- Dehydration
- Immobility
- Varicose veins
- Obesity
- Physical trauma (including surgery)
- Foreign devices i.e. stents
- Hypertension
Clinical features of a DVT
- Oedema
- Pain (often cramping, may progress over several days)
- Erythema and warmth
- Peripheral venous distention
- Often unilateral unless DVT is on both sides
Red flags for PE
- Sudden onset shortness of breath
- Tachycardia
- Haemoptysis
- Chest pain (usually pleuritic)
Questions asked in the Wells score
- Active cancer (currently receiving treatment or treatment within 6 months or palliative)
- Paralysis, paresis or recent plaster immobilisation
- Recently bedridden (3 days or more), or major surgery within the last 3 months
- Localised tenderness along the distribution of the deep venous system
- Entire leg swollen
- Calf swelling at least 3cm larger than the asymptomatic side
- Pitting oedema in the symptomatic leg
- Collateral superficial veins (non-varicose)
- Previously documented DVT
- An alternative diagnosis is at least as likely as DVT
Interpretation of the Wells score
- DVT likely: ≥2 points
- DVT unlikely: <2 points
DVT likely (>2 points)
- If a DVT is likely, a proximal leg vein doppler ultrasound should be requested with the results available within four hours:
- If the ultrasound is positive: treat the DVT with an anticoagulant.
- If the ultrasound can’t be done within 4 hours: D-dimer and offer an interim anticoagulant until results are available.
- If the ultrasound is negative: check the D-dimer. If it is positive, repeat the scan in 6-8 days (stop interim coagulation if started). If it is negative, another diagnosis should be considered and no anticoagulation given.
DVT unlikely (<2 points)
- If DVT is unlikely, offer a D-dimer test with the results available within four hours:
- If the D-dimer is positive: offer a proximal leg vein doppler ultrasound or provide interim coagulation if ultrasound results cannot be obtained within four hours. If the ultrasound is positive treat the DVT with an anticoagulant.
- If the D-dimer results can’t be obtained within four hours: offer interim anticoagulation until results are available.
- If the D-Dimer is negative: another diagnosis should be considered and no anticoagulation given.
VTE prophylaxis
- If at increased risk of VTE, a low molecular weight heparin such as enoxaparin.
- Contraindicated in active bleeding or existing anticoagulation with warfarin or a DOAC.
- Anti-embolic compression such can be used, contraindicated in peripheral arterial disease.
Diagnosis of VTE
- D dimer
- Doppler ultrasound, repeat negative ultrasound after 6-8 days if positive D-dimer and the wells score suggests DVT is likely
- PE can be diagnosed with CT pulmonary angiogram (CTPA) and ventilation-perfusion (VQ) sscan
Management of VTE
- Immediately start apixaban or rivaroxaban even if there is a delay in getting the scan (direct oral anticoagulant)
- Catheter directed thrombolysis in patients with symptomatic iliofemoral DVT and symptoms last less than 14 days
- Long term anticoagulation is DOAC, warfarin or LMWR
VTE- long term anticoagulation
- DOAC’s: apixaban, rivaroxaban, edoxaban and dabigatran. Suitable for all patients
- Warfarin: vitamin K antagonist, target INR is between 2 and 3. First line treatment for patients with antiphospholipid syndrome
- Low molecular weight heparin is first line in pregnancy
VTE- continue anticoagulation for
- 3 months if there is a reversible cause (then review)
- Beyond 3 months if the cause is unclear, there is recurrent VTE, or there is an irreversible underlying cause such as thrombophilia (often 6 months in practice)
- 3-6 months in active cancer (then review)
Inferior vena cava filter
Inserted into the inferior vena, designed to filter the blood and capture any blood clots going towards the heart and lungs. They are used in patients with recurrent PE’s or those that are unsuitable for anticoagulation
Investigating unprovoked VTE: test for
- Antiphospholipid syndrome: check antiphospholipid antibodies
- Hereditary thrombophilia’s: only if they have a first degree relative also affected by DVT or PE
Types of bleeding
- Primary bleeding: during the surgical procedure
- Reactive bleeding: within 24 hours of the operation, during surgery patients become relatively hypotensive and vasoconstricted. Post-op as blood pressure rises and vasodilation occurs a damaged blood vessel may begin to bleed
- Secondary bleeding: 7-10 days after the operation, often associated with wound infection
Signs of post op bleeding
- Tachycardia
- Hypotension (typically develops late, only after a significant volume of blood has been lost)
- Tachypnoea
- Cool peripheries
- Pre-syncope/syncope
- Confusion/agitation
- Swelling and/or bruising at the wound site (secondary to haematoma formation)
- Bleeding from the wound site
- Increasing tenderness at the wound site
class 1 of blood loss
Blood loss: <750ml, 15%
Heart rate: <100
Blood pressure: normal
Respiratory rate: 14-20
Urine output: >30ml/hr
Class II of blood loss
Blood loss: 750-1500ml, 15-30%
Heart rate: 100-120
Blood pressure: normal
Respiratory rate: 20-30
Urine output: 20-30ml/hr
Class III of blood loss
Blood loss: 1500-2000ml, 30-40%
Heart rate: 120-140
Blood pressure: decreased
Respiratory rate: 30-40
Urine output: 5-20ml/hr
Class IV blood loss
Blood loss:>2000ml, >40%
Heart rate: >140
Blood pressure: Decreased
Respiratory rate: >40
Urine output: <5ml/hr
