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| ==Overview== | | ==Overview== |
| Deep vein thrombosis (DVT) is the formation of a blood clot ("thrombus") in a deep vein. | | Deep vein thrombosis (DVT) is the formation of a blood clot ("thrombus") in a deep vein. |
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| ===Pretest Probability of DVT===
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| Wells scoring system is used for predicting probability of DVT:
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| It is calculated based on following scoring criteria: <br>
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| ❑ Paralysis, paresis or recent orthopedic casting of lower extremity (1 point) <br>
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| ❑ Recently bedridden (more than 3 days) or major surgery within past 4 weeks (1 point) <br>
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| ❑ Localized tenderness in deep vein system (1 point) <br>
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| ❑ Swelling of entire leg (1 point) <br>
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| ❑ Calf swelling 3 cm greater than other leg (measured 10 cm below the tibial tuberosity) (1 point) <br>
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| ❑ Pitting edema greater in the symptomatic leg (1 point) <br>
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| ❑ Collateral non varicose superficial veins (1 point) <br>
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| ❑ Active cancer or cancer treated within 6 months (1 point) <br>
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| ❑ 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)
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| The results are interpreted as follows:
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| <table class="wikitable">
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| <tr class="v-firstrow"><th>Points</th><th>Probability</th></tr>
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| <tr><td>3-8 Points</td><td> High probability of DVT</td></tr>
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| <tr><td>1-2 Points</td><td> Moderate probability</td></tr>
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| <tr><td>-2-0 Points </td><td>Low Probability</td></tr>
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| </table>
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| ==Causes== | | ==Causes== |
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| ===Life Threatening Causes=== | | ===Life Threatening Causes=== |
| Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. Although, deep vein thrombosis is by itself not life threatening, if not treated it may progress to a condition called as pulmonary embolism. Pulmonary embolism is severely life threatening and often a fatal condition.
| | [[Pulmonary embolism]] is a life-threatening condition and must be treated as such irrespective of the underlying cause. |
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| ===Common Causes=== | | ===Common Causes=== |
| Congenital:
| | * [[Blood clot]] |
| * Enzyme deficiency (protein S deficiency, protein C deficiency, antithrombin deficiency) | | * [[Air embolism|Air bubble]] |
| * Mutations (factor V leiden, prothrombin gene) | | * Fragment of a [[tumor]] |
| * Anatomic (May-Thurner syndrome, Cockett syndrome) | | * Fragment of [[fat]] (secondary to [[bone fracture]]) |
| | * Talc in [[IV drug abusers]] |
| | * [[Amniotic fluid]] |
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| Acquired:
| | ==FIRE: Focused Initial Rapid Evaluation== |
| * Medications (oral contraceptives, hormone replacement therapy, tamoxifen)
| | A Focused Initial Rapid Evaluation (FIRE) should be performed to identify patients in need of immediate intervention. |
| * Illness (cancer, acute myocardial infarction, congestive heart failure, sepsis, burns)
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| * Prolonged immobilization (transcontinental flights, operation under general anesthesia, pelvic/hip surgery, stroke/paraplegia)
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| ==Diagnostic approach== | | ==Diagnosis== |
| {{familytree/start}}
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| {{familytree | | | | | | | | | | | | A01 | | | | | | | | | | | | | | | | | | |A01=Pre test probability of DVT }}
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| {{familytree | | | | | | |,|-|-|-|-|-|^|-|-|-|-|-|.| | | | | | | | | | | | | | }}
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| {{familytree | | | | | | B01 | | | | | | | | | | B02 | | | | | | | | | | | | |B01=Low |B02=Moderate }}
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| {{familytree | | | |,|-|-|^|-|-|.| | | | | |,|-|-|^|-|-|.| | | | | | | | | | | }}
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| {{familytree | | | C01 | | | | |!| | | | | C02 | | | | |!| | | | | | | | | | | | | | |C01= Moderate or high sensitivity D Dimer |C02= High sensitivity D Dimer }}
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| {{familytree | |,|-|^|-|.| | | |!| | | |,|-|^|-|.| | | |!| | | | | | | | | | | }}
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| {{familytree | D01 | | D02 |-| D03 | | D04 | | D05 |-|-|(| | | | | | | | | | | | | | |D01=Negative <br> No further testing |D02=Positive|D03=Proximal vein compression ultrasonography |D04=Negative <br> No further testing |D05=Positive }}
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| {{familytree | | | | | | | |,|-|^|-|.| | | | | | |,|-|-|^|-|-|.| | | | | | | | }}
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| {{familytree | | | | | | | E01 | | E02 | |,|-|-| E03 | | | | E04 |-|-|.| | | | | |E01=Negative <br> No further testing |E02=Positive <br> Treat |E03=Proximal vein compression ultrasonography |E04= Whole leg ultrasonography}}
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| {{familytree | | | | | | | | | | | | | | |!| | | |!| | | | | |!| | | |!| | | | | }}
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| {{familytree | | | | | | | | | | | | | | F01 | | F02 | | | | F04 | | F03 | | | | |F01= Negative |F02=Positive <br> Treat |F03=Negative <br> No further testing |F04= Postive <br> Serial ultrasounds over next 2 weeks }}
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| {{familytree | | | | | | | | | | | | | | |!| | | | | | | | |!| |}}
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| {{familytree | | | | | | | | | | | | | | G01 | | | | | | | G02 | |G01= Repeat Compression ultrasonography after 1 week |G02=Treat if thrombus extends proximally }}
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| {{familytree | | | | | | | | | | | |,|-|-|^|-|-|.| | }}
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| {{familytree | | | | | | | | | | | H01 | | | | H02 | |H01=Negative <br> No further testing |H02=Positive <br> Treat}}
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| {{familytree/end}}
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| <br>
| | ==Long Term Treatment== |
| {{familytree/start}}
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| {{familytree | | | | | | | | A01 | | | | | | | | | |A01=Pre test probability of DVT }}
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| {{familytree | | | | | | | | |!| | | | | | | | | | | }}
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| {{familytree | | | | | | | | B01 | | | | | | | | | |B01=High/Unknown }}
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| {{familytree | | | |,|-|-|-|-|^|-|-|-|-|.| | | | | | }}
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| {{familytree | | | C02 | | | | | | | | C01 | | | | |C01=Proximal compression ultrasonography |C02=Whole leg ultrasound }}
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| {{familytree | |,|-|^|-|.| | | | | |,|-|^|-|.| | | | }}
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| {{familytree | D01 | | D02 | | | | D03 | | D04 | | | |D01=Negative <br> No further testing |D02=Positive <br> Treat |D03=Positive <br> Treat |D04=Negative }}
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| {{familytree | | | | | | | | | | | |,|-|-|-|^|-|-|.| }}
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| {{familytree | | | | | | | | | | | E01 | | | | | |!|E01=D Dimer }}
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| {{familytree | | | | | | | | |,|-|-|^|-|-|.| | | |!| }}
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| {{familytree | | | | | | | | F01 | | | | F02 |-| F03 | |F01= Negative <br> No further testing|F02=Positive |F03=Repeat proximal compression ultrasonography in 1 week }}
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| {{familytree | | | | | | | | | | | | | | | |,|-|-|^|-|-|.| | |}}
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| {{familytree | | | | | | | | | | | | | | | G01 | | | | G02 | |G01=Negative <br> No further testing |G02= Positive <br> Treat }}
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| {{familytree/end}}
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| ==Management==
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| {{familytree/start}}
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| {{familytree | | | | | | | | | A01 | | | | | | | | | |A01= Suspected DVT }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | | | | | B01 | | | | | | | | | |B01= Pretest probability }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | C01 | | | | | | C02 | | | | |C01= High/Moderate |C02=Low }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | D01 | | | | | | D02 | | | | |D01= Start anticoagulation unless contraindicated, while awaiting results |D02= Wait to start anticoagulation, if results will be available within 24 hours }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | | | | | E01 | | | | | | | | | |E01= DVT confirmed }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | F01 | | | | | | F02 | | | | |F01=Anticoagulants contraindicated |F02= Anticoagulants not contraindicated }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | G01 | | | | | | | | | | G03 | | | ||G01= Treat with inferior vena cava (IVC) filter |G03= Stable DVT }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | | | | | H02 | | | | | | H03 | | |H02=Acute DVT |H03= Initiate treatment with warfarin 10 mg, first 2 days or other VKA's <br> Adjust dose based on INR }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | | | | | I02 | | | | | | | | | |I02= Home conditions stable? <br> Good living conditions <br> Strong support from friends/family <br> Access to hospital, in case clinical condition deteriorates
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| ----
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| Hemodynamic status stable?}}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | J01 | | | | | | J02 | | | | | |J01=Treat at home |J02=Hospitalize and treat }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | | | | | K01 | | | | | | | | | |K01= Choose one of the following parenteral anticoagulants: <br> LMWH > Fondaparinaux > IV UFH > SC UFH <br> LMWH: <br> Enoxaparin 1 mg/kg every 12 hours <br> Tinzaparin 175 IU/kg four times a day <br> Dalteparin 100 IU/kg every 12 hours <br> Fondaparinaux: 7.5 mg once daily <br> IV UFH: Recommended doses <br> Bolus 80 U/kg followed by 18 U/kg/hour or <br> Bolus 5000 U followed by 1000 U/hour <br> SC UFH: 333 U/kg
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| ----
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| Initate VKA, continue parenteral therapy till INR > 2.0 over 24 hours
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| ----
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| Total duration of therapy: <br> First time DVT: Treat for 3 months <br> Recurrent DVT: Treat for 6 months <br> Recurrent DVT with high/moderate risk of bleeding: Treat for 3 months }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree | | | | | | | | | | | | | | | | | | | | | }}
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| {{familytree/end}}
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| ==Do's == | | ==Do's == |
| *For moderate to high probability suspicion start initial therapy while waiting for diagnostic test results. When there is a low probability, the decision of treatment will depend on the diagnostic test results.
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| *Start vitamin K antagonist(Warfarin) no more than 1 or days after start UFH or LMWH.The initial dose for the first 2 days should be 10 mg daily then in accordance to the required INR measurements.
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| *INR therapeutic ranges are 2.0-3.0 and Target INR is 2.5 and that is applied for patients with hypercoagulable state (antiphospholipid syndrome).
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| *For IV UFH administration use weight adjusted dose for the initial bolus(80 unit/kg) and the following continuous infusion(18 unit/kg/hr), and for subcutaneous UFH (first dose 333 units/kg, then 250 units/kg).
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| *For patients with CKD/ESRD reduce LMWH than standered dose.
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| *Fondaparinux administered subcutaneously in fixed doses 7.5 mg and if the patient weight>100 kg the dose will be 10 mg.<ref name="pmid22315259">{{cite journal| author=Holbrook A, Schulman S, Witt DM, Vandvik PO, Fish J, Kovacs MJ et al.| title=Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. | journal=Chest | year= 2012 | volume= 141 | issue= 2 Suppl | pages= e152S-84S | pmid=22315259 |doi=10.1378/chest.11-2295 | pmc=PMC3278055 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22315259 }} </ref>
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| ==Don'ts== | | ==Don'ts== |
| Avoid with VKA therapy all of the following:
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| *NSAIDs including cox-2 inhibitors.
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| *Antiplatelet unless benefit outweighs harm (ACS, mechanical valves, coronary stents or bypass surgery).
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| *Vitamin K supplement(not recommended).
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| ==References== | | ==References== |