Case Report ~ Discussion

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Case Report Discussion

• Antiphospholipid syndrome ? pulmonary embolism
• diagnosis and approach

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Antiphospholipid Syndrome (APS)

• APS is characterized by
• Recurrent venous or arterial thrombosis
• Recurrent fetal loss
• Thrombocytopenia
• Presence of antibodies to phospholipid such as
  anticardiolipin antibody (aCL) and lupus
  anticoagulant (LA)

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APS - Epidemiology

• Prevalence of antiphospholipid antibodies in
  healthy population is 2 5
• For all the patient with APS
• female male 2 1
• Mean and median ages of patients in most reports
  is 35 to 45 years old

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APS - Pathophysiology

• Alteration of endothelial cell function
• Alteration of the coagulation regulatory system,
  erythrocyte and platelet
• A cofactor, beta2 glycoprotein-I ,is required and
  enhances the binding of aCL to cardiolipid

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APS Diagnosis 1
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APS Diagnosis 2
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APS Clinical Manisfestation
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APS Thromboembolic Disease

• Noninflammatory thromboembolic disease
• All venous and arterial systems have been
  cited,including large,median and small vessels
• Most common site and presentation
• v. lower extremity in the femoral and
• popliteal system
• a. embolic cerebrovascular accident
• and transient ischemic attack
• The recurrent rate is high

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APS pulmonary complication

• Pulmonary embolism and infarction
• Pulmonary hypertension
• Major pulmonary arterial thrombosis
• Pulmonary microthrombosis
• Adult respiretory distress syndrome
• Intraalveolar pulmonary hemorrhage
• Post partum syndrome

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APS pulmonary complication Pulmonary
embolism and infarction

• Recurrent deep venous thromboses are the most
  common vascular occlusive events encountered in
  patient with antiphosphlipid antibody and these
  are accompanied by pulmonary embolism and
  infarction in 1/3 of cases

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Pulmonary Embolism (PE)

• the third most common cardiovascular emergency
  after myocardial infarction
• Mortality rate
• untreated 30
• anticoagulant treatment 10
• Nonspecific signs and symptoms cannot be
  accurately diagnosed on clinical grounds

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PE Clinical Presentation and Differential
Diagnosis

• Clinical triad dyspnea , pleuritic chest pain,
  and hemoptysis
• Most common symptom dyspnea
• Uncommon manifestation include unexplained fever,
  arterial tachyarhythmias, wheezing

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Diagnosis of PE - Assessment 1

• Chest radiography
• Many patients with PE have a normal chest
  radiography
• radiologic abnormalities nonspecific, cannot
  distinguished from other pulmonary disorder
• Electrocardiogram
• Frequently normal or nonspecific
• Useful in differentiating between PE and
  myocardial infarction

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Diagnosis of PE Assessment 2

• Blood Gas Estimation
• A normal arterial PaO2 does not exclude PE (PE
  patients 1015)
• A low arterial PaO2 is nonspecific and cannot be
  used to rule-in PE
• Danger of hemorrhage following arterial puncture
  if the patient is treated with heparin or
  thrombolytic therapy
• Of limited value in the diagnosis of PE

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Diagnosis of PE Pulmonary angiography 1

• The standard for diagnosing pulmonary embolism
  (diagnostic accuracy 80 95)
• Relative contraindication
• (1)significant bleeding risk -
• platelet gt 75000
• (2)allergy to the contrast medium
• (3)renal insufficiency ? adequent
• hydration after angiography

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Diagnosis of PE Pulmonary angiography 2

• Side effect
• Flushing
• Transient hypotension
• Catheter induced ectopic beats

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Diagnosis of PE Pulmonary angiography 3

• Increased risk of complication
• (1)acute or severe chronic pulmonary
• hypertension
• (2)right heart failure
• (3)resperatory failure
• Reduced risk of complication selective arterial
  injection and limiting amount of contrast medium
  (low osmolality)

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Diagnosis of PE Pulmonary angiography 4

• Mortality rate 0.5
• Mordality required intubation 0.4
• required dialysis
  0.3
• Limitation expensive, invasive, has small but
  significant risks and requires experienced
  physicians and supporting staff
• Most commonly ued when ventilation-perfusion
  scanning is nondiagnostic but clinical suspicion
  remains high

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Diagnosis of PE Ventilation perfusion
scintigraphy 1

• Most commonly used non-invasive technique with
  clinical suspicion
• Perfusion lung scan not specific enough for
  diagnosis of PE
• Ventilation imaging differentiate vascular
  occlusion from disorder of ventilation

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Diagnosis of PE Ventilation perfusion
scintigraphy 2

• Segmental defect
• Occlusion of a branch of a branch of the
  pulmonary artery
• Wedge shape and pleural based
• Conforms to segmental anatomy of the lung
• Large (gt75), moderate(2575), small(lt25)
• Nonsegmental defect

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Diagnosis of PE Ventilation perfusion
scintigraphy 3

• V / Q match
• Both scintigrams are abnormal in the same area,
  defects of equal size
• V / Q mismatch
• Abnormal perfusion in the area of normal
  ventilation or much larger perfusion abnormality
  than ventilation defect

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Diagnosis of PE Ventilation perfusion
scintigraphy 4

• High probability
• Segmental or lobar perfusion defect with normal
  ventilation
• Low probability of PE
• Perfusion defect with matched ventilation
  abnormality

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Diagnosis of PE Ventilation perfusion
scintigraphy 5

• Modified PIOPED Criteria
• High probability (gt80)
• 2? large mismatched segmental defects without
  radiographic abnormality
• Any combination of mismatched defects equivalent
  to the above
• (2 moderate 1 large)
• Intermediate probability (2080)

• Low probability (lt20)
• Nonsegmental perfusion defect
• Any perfusion defect with a substantially larger
  radiographic abnormality
• Matched ventilation and perfusion defects with
  normal chest radiograph
• Small subsegmental perfusion defects
• Normal
• ( No perfusion defect )

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Diagnosis of PE Ventilation perfusion
scintigraphy 6

• Condition associated with V/Q mismatch
• Acute or chronic PE
• Other cause of embolism drug abuse, iatrogenic
• Bronchogenic carcinoma
• Hypoplasia or aplasia of pulmonary artery
• Vasculitis
• Post radiation therapy
• Mediastinal or hilar adenopathy with obstruction
  of pulmonary artery or veins
• Swyer James syndrme

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Diagnosis of PE Ventilation perfusion
scintigraphy 7

• Determinining Clinical Likelihood of PE
• Assessment of risk factor for venous
  thromboembolism (leg paralysis, bed rest,
  malignancy, CHF, presence of central venous
  catheter )
• Evaluation of symptoms and signs
• Interpretation of preliminary investigation (eg.
  chest radiograph and electrocardiogram)

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Diagnosis of PE Ventilation perfusion
scintigraphy 8
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Diagnosis of PE Ventilation perfusion
scintigraphy 9

• In PIOPED, ventilation-perfusion scans
• 34 were read as low probability
• 39 were read as intermediate probability
• ?additional diagnostic studies must be
  pursued
• After pulmonary angiography, PE ()
• patients with low-probability 16
• patients with intermediate-probability
  33
• the interobserver disagreement for intermediate-
  and low-probability ventilation-perfusion scans
  was 25 and 30, respectively

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Diagnosis of PE Spiral tomographic scan 1

• capable of imaging nearly the entire thorax
  during a single breath-hold ?intravenous contrast
  can be timed to arrive pulmonary vasculature
• Sensitivity 64 93
• Specificity 89100
• Especially when PE is involved the main,
  lobar, or segmental pulmonary arteries

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Diagnosis of PE Spiral tomographic scan 2

• Advantage
• High sensitivity and specificity
• Visualize the clot
• Indentify other disease states that can mimic PE
  (lung tumor, pleyral disease, pericardial
  disease) ? provide alternative diagnosis
• Cost 1/6 1/8 angiography

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Diagnosis of PE Spiral tomographic scan 3

• Limitation
• Inability of spiral scanning to detect PE in
  subsegmental pulmonary arteries (sensitivity
  29)

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Diagnosis of PE Spiral tomographic scan 4

• Clinical guidelines
• It should be used as a rule-in modality, rather
  than a rule-out procedure
• if an alternative diagnosis is being considered
  in addition to pulmonary embolism, spiral CT
  scanning can provide new information that a
  ventilation-perfusion scan cannot.

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Diagnosis of PE D-dimer assay 1

• Rapid, noninvasive and inexpensive
• Commonly found in the circulation when venous
  thromboembolism is present
• Also found in other disease state (cancer, CHF,
  inflammatory condition)

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Diagnosis of PE D-dimer assay 2

• Two general methods of measuring D-dimers ELISA
  method, latex agglutination
• Elevated D-dimer fragments are too nonspecific
  for diagnosis of venous thromboembolism by
  themselves. With negative predictive values close
  to 100, certain D-dimer assays have the
  potential to be the only screening test necessary
  to rule out venous thromboembolism.

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Diagnosis of PE D-dimer assay 3

• To be used in a diagnostic strategy, the details
  of the assay should be known type (latex or
  ELISA), operating characteristics (sensitivity
  and negative predictive value), and outcomes of
  clinical studies supporting the particular assay.
• Testing for D-dimers should be restricted to
  patients in whom clinical suspicion of venous
  thromboembolism is low or moderate.

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Diagnosis of PE MRI 1

• Helpful for the diagnosis of pelvic and thigh
  deep venous thrombosis
• Acute, symptomatic, proximal deep vein thromboses
  sensitivity approaching 100
• Less sensitive for detecting calf deep venous
  thrombosis
• PE can demonstrate an embolus directly as an
  intrvascular filling defect
• (sensitivity lt pulmonary angiography)

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Diagnosis of PE MRI 2

• Advantage and Limitation

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PE Diagnostic Approach 1
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PE Diagnostic Approach 2
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References 1

• Antiphospholipid-Thrombosis Syndromes /
  Haemostasis 1999 29100-110
• Antiphospholipid Syndrome / The journal of Family
  Practice, Vol.38, No.6(Jun), 1994
• Review Antiphospholipid Antibodies and the Lung
  / The journal of Rheumatology 1995 2262-6

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Reference 2

• The Diagnosis of Pulmonary Embolism / Haemostasis
  1995 2572-87
• Non-invasive diagnosis of pulmonary aembolism /
  International Jounal of Cardiology
  65(Suppl.1)1998 s83-s86
• Improving Detection of venous thromboembolism /
  Postgraduate Medicine vol.108, No.4, September15,
  2000

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