Deep vein trombosis

Question 1

What is the definition of Deep Vein Thrombosis (DVT)?

Answer 1

Formation of a blood clot in one of the deep veins of the body, typically in the leg, arm, or pelvis.

Question 2

Which veins are considered ‘deep veins’ in the context of DVT?

Answer 2

Deep veins are located in the:

• Legs
• Arms
• Pelvis

Question 3

What are the two main types of DVT in the lower limb?

Answer 3

• Distal/Calf: Affects veins below the knee.
• Proximal: Affects popliteal, femoral, or iliac veins.

Question 4

What are the common symptoms of DVT?

Answer 4

• Swelling
• Pain
• Tenderness

Question 5

What are the clinical signs of DVT?

Answer 5

• Calf tenderness
• Pitting edema
• Increased limb circumference
• Elevated temperature
• Superficial venous dilatation
• Homan’s sign (pain on dorsiflexion of the foot)
• Pratt’s sign (pain along the course of a vein)

Question 6

What is Phlegmasia Alba Dolens, and when is it most commonly seen?

Answer 6

• Also known as ‘white leg.’
• Characterized by a pale, cold limb with decreased arterial pulse due to sudden occlusion of iliac and femoral veins.
• Most often seen in the third trimester of pregnancy (due to compression of the left common iliac vein) or related to underlying malignancy.

Question 7

What is Phlegmasia Cerulea Dolens, and what are its key features?

Answer 7

• Painful blue edema caused by extensive thrombotic occlusion.

Features:
- Severe leg pain
- Swelling
- Cyanosis
- Edema
- Venous gangrene
- Compartment syndrome
- High risk of pulmonary embolism (PE).
- 50% of cases related to underlying malignancy.

Question 8

What conditions can mimic DVT symptoms?

Answer 8

• Muscle strain or tear
• Leg swelling in a paralyzed limb
• Lymphangitis
• Venous insufficiency
• Baker’s cyst (popliteal)
• Cellulitis
• Knee abnormality

Question 9

What diagnostic tests are used in the workup of DVT?

Answer 9

• Complete blood count (CBC)
• Prothrombin time (PT), Partial thromboplastin time (PTT), International Normalized Ratio (INR)
• D-dimer
• Duplex ultrasound
• Computed tomography (CT)
• Magnetic resonance imaging (MRI)
• Venography (gold standard)

Question 10

What is the role of D-dimer in DVT diagnosis?

Answer 10

• A degradation product of cross-linked fibrin.
• Sensitivity: 97% (highly sensitive, good for ruling out DVT).
• Specificity: 35% (low specificity, many false positives).
• Persists in blood for 7 days in DVT.

Question 11

What conditions can cause a false positive D-dimer result?

Answer 11

• Recent surgery
• Recent myocardial infarction (MI)
• Acute infection
• Disseminated intravascular coagulation (DIC)
• Pregnancy
• Metastatic cancer

Question 12

What findings on Duplex Ultrasound suggest DVT?

Answer 12

• Decreased compressibility of the vein
• Visualized thrombus
• Change in venous phase blood flow sound

Question 13

What is the gold standard for DVT diagnosis, and what are its side effects?

Answer 13

• Gold Standard: Venography

Side Effects:
- Phlebitis
- Anaphylaxis

Question 14

Which veins are commonly involved in DVT, as mentioned in the document?

Answer 14

• External iliac vein
• Common femoral vein
• Femoral vein (deep vein)

Question 15

What is a clinical example of DVT provided in the document?

Answer 15

An 18-year-old patient with left leg swelling and confirmed left DVT.

Question 16

What are the main anticoagulant treatments for DVT?

Answer 16

• Unfractionated Heparin (UFH)
• Low Molecular Weight Heparin (LMWH, e.g., Enoxaparin)
• Vitamin K antagonist (e.g., Warfarin)
• Factor Xa inhibitors (e.g., Rivaroxaban)
• Direct thrombin inhibitors (e.g., Dabigatran)

Question 17

What is the dosing regimen for Unfractionated Heparin (UFH) in DVT treatment?

Answer 17

• Subsequent dose: 18 units/kg/hour
• Adjusted every 6 hours based on activated partial thromboplastin time (aPTT).

Question 18

What is the dosing for Low Molecular Weight Heparin (LMWH), specifically Enoxaparin, in DVT?

Answer 18

• Prophylactic: 0.8 mg/kg every 24 hours
• Therapeutic: 1 mg/kg every 12 hours

Question 19

How is Warfarin (Vitamin K antagonist) managed in DVT treatment?

Answer 19

• Initial dose: 5 mg/day orally
• Adjustment: Target INR of 2–3
• Interacts with many medications
• Avoid foods rich in vitamin K

Question 20

What is the dosing for Rivaroxaban (Factor Xa inhibitor) in DVT treatment?

Answer 20

• Initial dose: 15 mg every 12 hours for 21 days
• Subsequent dose: 20 mg/day

Question 21

What is the dosing for Dabigatran (Direct Thrombin Inhibitor) in DVT treatment?

Answer 21

Initial dose: 220 mg/day

If transitioning from Warfarin, discontinue Warfarin when INR < 2.0

Question 22

What dietary restrictions apply for patients on Warfarin?

Answer 22

Avoid foods rich in vitamin K. Examples include:

• Leafy greens (e.g., spinach, kale)
• Broccoli
• Brussels sprouts

Question 23

What are the absolute contraindications for anticoagulant therapy in DVT?

Answer 23

Active bleeding
Severe bleeding
Major trauma
Heparin-induced thrombocytopenia (HIT)

Question 24

What are the relative contraindications for anticoagulant therapy in DVT?

Answer 24

Recurrent gastrointestinal (GI) bleeding
Intracranial or spinal tumor
Abdominal aortic aneurysm
Stable aortic dissection

Question 25

What is the purpose of an Inferior Vena Cava (IVC) filter in DVT management?

Answer 25

Decreases the rate of pulmonary embolism (PE). ## Footnote Used when there is an increased risk of PE despite anticoagulant therapy.

Question 26

What is a key feature of the IVC filter mentioned in the document?

Answer 26

The IVC filter has a hook on top for retrieval.

Question 27

What are the key risk factors for DVT mentioned in the document?

Answer 27

Common risk factors include: - Immobility (e.g., prolonged bed rest, long travel) - Surgery or trauma - Pregnancy (especially third trimester) - Malignancy (noted in Phlegmasia conditions) - Oral contraceptives or hormone therapy - Inherited thrombophilias (e.g., Factor V Leiden)

Question 28

What information is provided about the ultrasound equipment used in the DVT document?

Answer 28

Equipment: Toshiba Date: January 7, 2014 Settings: - PVI LEA, REJ T1 - Precision A Pure* - Frame rate: 12 fps - CF 5.3, CG 34 - Additional parameters: DR 80, CR 80, F 3

Question 29

What details are provided about the medical center in the DVT document?

Answer 29

Location: OYPMC PIMPR, Pune Date: March 16, 2013 Time: 10:09

Question 30

What is the Wells Score for DVT, and how is it used?

Answer 30

A clinical prediction tool to assess the probability of DVT. Criteria (1 point each unless specified): - Active cancer (+1) - Paralysis, paresis, or recent immobilization (+1) - Bedridden >3 days or major surgery within 12 weeks (+1) - Localized tenderness along deep veins (+1) - Entire leg swollen (+1) - Calf swelling >3 cm compared to asymptomatic leg (+1) - Pitting edema in symptomatic leg (+1) - Collateral superficial veins (+1) - Previous DVT (+1) - Alternative diagnosis as likely or more likely (-2) Scoring: - Low risk: ≤0 - Moderate risk: 1–2 - High risk: ≥3 ## Footnote Guides diagnostic testing (e.g., D-dimer, ultrasound).

Question 31

What is the most serious complication of DVT, and how does it present?

Answer 31

Complication: Pulmonary Embolism (PE) Presentation: - Sudden dyspnea - Chest pain (pleuritic) - Tachycardia - Hypoxemia - Hemoptysis (rare)

Question 32

What is the duration of anticoagulant therapy for DVT?

Answer 32

Provoked DVT (e.g., surgery, trauma): 3 months Unprovoked DVT: 3–6 months or longer, depending on recurrence risk DVT with cancer: Indefinite or until cancer is resolved

Question 33

What are the components of Virchow’s Triad for DVT risk?

Answer 33

Stasis: Immobility, prolonged bed rest, long flights Endothelial injury: Trauma, surgery, catheters Hypercoagulability: Cancer, pregnancy, oral contraceptives, inherited thrombophilias (e.g., Factor V Leiden)

Question 34

What is the role of compression stockings in DVT management?

Answer 34

Used to reduce swelling and prevent post-thrombotic syndrome. Typically 30–40 mmHg pressure, worn for 1–2 years post-DVT.

Question 35

What is the significance of Homan’s sign in DVT diagnosis?

Answer 35

Pain in the calf on dorsiflexion of the foot. ## Footnote Low sensitivity and specificity; not reliable alone for diagnosis.

Question 36

What is post-thrombotic syndrome (PTS), and how does it present?

Answer 36

A chronic complication of DVT due to venous hypertension. Symptoms: Chronic leg pain Swelling Skin discoloration Ulcers (severe cases) Occurs in 20–50% of DVT patients within 2 years.

Question 37

What is the diagnostic algorithm for suspected DVT?

Answer 37

Assess clinical probability using Wells Score: Low risk: D-dimer test; if negative, DVT unlikely. Moderate/High risk: Proceed to imaging. Imaging: First-line: Duplex ultrasound (non-invasive, high sensitivity for proximal DVT). If ultrasound inconclusive: CT/MRI venography or contrast venography (gold standard).

Question 38

What are the indications for thrombolytic therapy in DVT?

Answer 38

Reserved for severe cases, such as: Phlegmasia cerulea dolens with limb-threatening ischemia Extensive proximal DVT with high risk of complications Agents: Tissue plasminogen activator (tPA) Higher bleeding risk than anticoagulants.

Question 39

What is the role of genetic thrombophilias in DVT?

Answer 39

Inherited conditions increasing DVT risk, including: Factor V Leiden mutation (most common) Prothrombin gene mutation Protein C or S deficiency Antithrombin deficiency Often tested in young patients (<50 years) with unprovoked DVT or family history.

Question 40

What is the significance of the 25-minute duration mentioned in the document?

Answer 40

The document notes '25 min' on page 28, likely referring to the duration of a procedure or observation related to DVT management (e.g., IVC filter placement or ultrasound). Specific context is unclear.