Deep vein thrombosis resident survival guide: Difference between revisions
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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 }} | {{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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Revision as of 19:44, 24 February 2014
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Abdurahman Khalil, M.D. [2]
Definition
Deep vein thrombosis (DVT) is the formation of a blood clot ("thrombus") in a deep vein.
Pretest Probability of DVT
Wells scoring system is used for predicting probability of DVT:
It is calculated based on following scoring criteria:
❑ 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 edema 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, external venous compression) (-2 points)
The results are interpreted as follows:
Points | Probability |
---|---|
3-8 Points | High probability of DVT |
1-2 Points | Moderate probability |
-2-0 Points | Low Probability |
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.
Common Causes
Congenital:
- Enzyme deficiency (protein S deficiency, protein C deficiency, antithrombin deficiency)
- Mutations (factor V leiden, prothrombin gene)
- Anatomic (May-Thurner syndrome, Cockett syndrome)
Acquired:
- Medications (oral contraceptives, hormone replacement therapy, tamoxifen)
- Illness (cancer, acute myocardial infarction, congestive heart failure, sepsis, burns)
- Prolonged immobilization (transcontinental flights, operation under general anesthesia, pelvic/hip surgery, stroke/paraplegia)
Diagnostic approach
Pre test probability of DVT | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Low | Moderate | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Moderate or high sensitivity D Dimer | High sensitivity D Dimer | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Negative No further testing | Positive | Proximal vein compression ultrasonography | Negative No further testing | Positive | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Negative No further testing | Positive Treat | Proximal vein compression ultrasonography | Whole leg ultrasonography | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Negative | Positive Treat | Postive Serial ultrasounds over next 2 weeks | Negative No further testing | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Repeat Compression ultrasonography after 1 week | Treat if thrombus extends proximally | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Negative No further testing | Positive Treat | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Pre test probability of DVT | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
High | Unknown | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Whole leg ultrasound | Proximal compression ultrasonography | Whole leg ultrasound | Proximal compression ultrasonography | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Negative No further testing | Positive Treat | Negative | Negative No further testing | Positive Treat | Negative | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
D Dimer | Whole leg ultrasound | D Dimer | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Negative No further testing | Positive | Repeat proximal compression ultrasonography in 1 week | Positive Treat | Negative No further testing | Repeat Proximal compression ultrasonography in 1 week | Positive | Negative No further testing | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Negative No further testing | Positive Treat | Negative No further testing | Positive Treat | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Management
DVT confirmed | |||||||||||||||||||||||||||||||
Hemodynamically unstable(massive PE) SBP<90 mm Hg or 40 mm Hg drop Syncope Severe hypoxemia or respiratory distress | Hemodynamically stable | Contraindication for Anticoagulation therapy Absolute Active severe hemorrhage Intracranial hemorrhage Relative Recent surgery, trauma, anemia,GI bleeding, PUD | |||||||||||||||||||||||||||||
Thrombolytic therapy | LMWH or UFH(target INR:2.5, monitor Plt count)+ Warfarin or Fondaparinux | IVC filter | |||||||||||||||||||||||||||||
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.
- 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.
- 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).
- 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).
- For patients with CKD/ESRD reduce LMWH than standered dose.
- Fondaparinux administered subcutaneously in fixed doses 7.5 mg and if the patient weight>100 kg the dose will be 10 mg.[1]
Don'ts
Avoid with VKA therapy all of the following:
- NSAIDs including cox-2 inhibitors.
- Antiplatelet unless benefit outweighs harm (ACS, mechanical valves, coronary stents or bypass surgery).
- Vitamin K supplement(not recommended).
References
- ↑ Holbrook A, Schulman S, Witt DM, Vandvik PO, Fish J, Kovacs MJ; et al. (2012). "Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines". Chest. 141 (2 Suppl): e152S–84S. doi:10.1378/chest.11-2295. PMC 3278055. PMID 22315259.