Hematology - Clotting Disorders

Question 1

Discuss virchow’s triad

Answer 1

Stasis
- bed rest
- post-surgery
- long leg cast
- long flights
Hypercoagulable State
- Inherited thrombophilia: Factor V leiden, protein C/S deficiency, anti-phospholipid antibody syndrome
- Active malignancy
- Inflammatory disorder
- Pregnancy, post-partum
- Hormone replacement, OCP
Endothelial injury
- surgery
- Venous catheter

Question 2

Discuss the presentation and management of deep vein thrombosis

Answer 2

Presentation
- Pain and tenderness in thigh or calf
- unilateral swelling of leg with erythema and warmth
- Phlegmasia alba dolens: severe DVT with arterial spasm leading to cold, pale limb with weak pulse
- Phlegmasia cerulea dolens: total DVT causes severe edema, cyanosis, venous gangrene, compartment syndrome
- palpable cord
- pitting edema
- Homan’s sign: calf tenderness with forced dorsiflexion
Investigation
- D-dimer
- Compression ultrasound
Management
- Acute: LMWH Enoxaparin 1mg/kg/dose SC Q12H
- continue until warfarin INR 2-3
- Long term: NOAC or warfarin started on first day
- warfarin start at 2-5mg PO
- 3 months for provoked DVT
- 6 months or lifetime if unprovoked

Question 3

List the wells score for DVT

Answer 3

• <=1 point then unlikely and D-dimer
• > 1 then DVT likely and go to CUS
  - if CUS initially negative but f/u D-dimer positive then require serial CUS
  Wells Score
• Active cancer
• bed rest or major surgery within last 4 weeks
• calf swelling >3cm compared to other leg
• Collateral non varicose superficial veins
• Entire leg swollen
• tenderness along deep vein trajectory
• pitting edema in symptomatic leg
• paralysis, paresis, or recent plaster immobilization
• Past History of DVT
• Alternative diagnose more likely (-2 points)

Question 4

Discuss the presentation and management of pulmonary embolus

Answer 4

Presentation
- Pain on one side of chest that is worse with inspiration
- dyspnea, cough, syncope, hemoptysis and palpitation
- increase JVP, peripheral edema
- DVT signs
Investigations
- Wells criteria
- CXR band atelectasis decrease volume on one side
- ECG: right ventricular strain (inverted T wave and ST depression in V1-V4), RBBB, S1Q3T3
- d-dimer positive
- CT pulmonary angiography
Management
- massive PE resulting in cardiovascular compromise then tPA 100mg IV over 2hrs
- stable then low molecular weight heparin and bridge to warfarin

Question 5

List the PERC Score

Answer 5

• no follow up testing if none of the following are present
• Age >50
• Tachycardia >100
• O2 sat <94%
• Prior DVT or PE
• Recent trauma or surgery
• prior DVT or PE
• Hemoptysis
• Exogenous estrogen use
• symptoms and signs of DVT

Question 6

List the Wells criteria for PE

Answer 6

• Active Cancer
• Hemoptysis
• Recent immobilization or surgery +1.5
• Tachycardia (>100bpm) +1.5
• Past Hx of DVT or PE +1.5
• Signs or symptoms of DVT +3
• No alternative diagnosis more like +3
  >4 then high risk and go right to CTPA
• <4 do D-Dimer first and then if positive move to CTPA

Question 7

Discuss the discharge criteria for PE

Answer 7

PE Severity Index
- age >80
- Hx of Cancer
- Hx of Heart Failure or chronic lung disease
- Tachycardia >100
- Hypotension where SBP <100
- Hypoxia <90%
High risk if >=1