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Deep vein thrombosis (DVT) (Risk factors (Drugs (COCP, HRT), Trauma,…
Deep vein thrombosis (DVT)
Definition
Thrombus developing in a
deep vein of the leg
Epidemiology
Very common in
surgical patients
Risk factors
Drugs (COCP, HRT)
Trauma
Immobility
Surgery
Pregnancy
Obesity
Age
Clotting disorder
(thrombophilia etc.)
Malignancy
Prevoius VTE
Pathophysiology
Emboli can break off and become stuck
in the pulmonary circulation, causing PE
Thrombus develops in deep vein of the leg,
which is rarely fatal alone
D-dimer is a fibrin degredation product, so high
level indicates thrombosis (but also high in other
inflammatory states); normal level excludes DVT/PE
Lower leg e.g. calf DVTs rarely cause problems
Virchow's triad: stasis, hypercoagulability, endothelial injury
Diagnosis
Examination
Venous exam
Local erythema, swelling, warmth, tenderness (esp on calf palpation), pitting, distended leg veins, Homans sign
(discomfort behind knee on foot dorsiflexion)
Investigations
Bedside
Obs - mild fever
ECG - any signs of PE e.g. tachycardia
Bloods
FBC, CRP, U+E, LFTs,
bone profile (malignancy)
D-dimer (if +ve, do USS)
Thrombophilia testing
Imaging
USS leg (see DVT)
CXR (malignancy)
CT abdo/pelvis (malignancy)
ECHO (exclude CCF)
Urine
MCS (exclude nephrotic syndrome)
History
PC/HPC
Pain, erythema, swelling, tenderness,
any SOB, chest pain, haemoptysis
PMH
Prev VTE, malignancy, clotting disorder,
recent surgery
DH
Meds e.g. OCP/HRT, allergies
FH
DVT/PE/clotting disorder
SH
Living arrangements, occupation,
smoking, mobility, diet, exercise
Clinical probability
scoring (Wells)
Features
Active cancer <6m Paralysis/immobile Bedridden >3d
Major surgery <12w Local tenderness Entire leg swollen Calf swelling >3cm
Pitting oedema
Collat superf veins
Previous DVT
Alt diagnosis as/more likely (-2)
Interpretation
Score 0/1
DVT unlikely
Do D-dimer
If D-D +ve, do USS
If D-D -ve, not DVT
Score 2+
DVT likely, do USS
If USS +ve, start DVT tx
If USS -ve, do D-dimer
If D-D +ve, rpt USS 1wk
If D-D -ve, not DVT
Clinical
presentation
Mild fever
Unilateral pain,
swelling, redness
Management
Definitive
Medical
Graduated compression stockings
Indication: pain, swelling, skin changes post-tx
CI: ischemia e.g. PVD
Anticoagulation
Indication: 1L confirmed DVT
E.g. LMWH (enoxaparin), FXa inhibitor (fondaparinux)
MOA: stop when INR normal, continue 3m if post-op, 6m if cancer, lifelong if non-modifiable cause e.g. thrombophilia
Surgical
SVC filters
Indication: recurrent DVTs
Thrombolytic therapy
Indication: reduce damage to valves
Conservative
Information, advice, support
Identify and manage risk factors
Monitoring, if USS -ve, repeat 1 week
Initial ABCDE
Prevention
Stop OTC/HRT 4wk pre-op
Mobilise early post-op
DVT prophylaxis
(stockings, pneumatic compression devices, LMWH)