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WILLIAM'S HEMATOLOGY > 132 The Antiphospholipid Syndrome > Flashcards

132 The Antiphospholipid Syndrome Flashcards

1
Q

A disorder in which vascular thrombosis and/or pregnancy complications attributable to placental insufficiency occur in patients with laboratory evidence for antibodies directed against proteins that bind to phospholipids

A

Antiphospholipid (aPL) antibody syndrome (APS)

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2
Q

Percentage with venous thrombosis

A

10%

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3
Q

Percentage with three unexplained fetal losses before 12 weeks of gestation or at least one intrauterine fetal death after 12 weeks of gestation

A

20%

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4
Q

Infection with propensity to develop aPL antibodies

A

Syphilis

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5
Q

aPL antibodies may also be detected through coagulation tests, collectively termed

A

Lupus anticoagulant (LA) tests

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6
Q

Medications that may also develop clinically inconsequential antibodies against phospholipids

A

Chlorpromazine or procainamide

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7
Q

Sydney Investigational Criteria for Diagnosis of APS

Clinical Criteria

“Definite APS” is considered to be present if at least one of the
clinical criteria and one of the laboratory criteria are met.

A
  • Vascular thrombosis (one or more episodes of arterial, venous, or small-vessel thrombosis). For histopathologic diagnosis, there should not be evidence of inflammation in the vessel wall.
  • Pregnancy morbidities attributable to placental insufficiency, including three or more otherwise unexplained recurrent spontaneous miscarriages, before 10 weeks of gestation.
    Also, one or more fetal losses after the 10th week of gestation, stillbirth, episode of preeclampsia, preterm labor, placental abruption, intrauterine growth restriction, or oligohydramnios that are otherwise unexplained.
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8
Q

Sydney Investigational Criteria for Diagnosis of APS

Laboratory Criteria

“Definite APS” is considered to be present if at least one of the
clinical criteria and one of the laboratory criteria are met.

A
  • aCL or anti–β2-glycoprotein I (anti-β2GPI) immunoglobulin (Ig) G and/or IgM antibody present in medium or high titer on two or more occasions, at least 12 weeks apart, measured by standard ELISAs
  • LA in plasma, on two or more occasions, at least 12 weeks apart detected according to the guidelines of the International Society on Thrombosis and Haemostasis Scientific Standardisation Committee on Lupus Anticoagulants and Phospholipid- Dependent Antibodies
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9
Q

Intriguing evidence points to the possibility that _____ mechanisms may play a significant role in triggering the formation of aPL autoantibodies in susceptible individuals.

A

Molecular mimicry

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10
Q

It has been established that human leukocyte antigen (HLA) ___ and ____ are associated with predisposition to developing APS and with positive tests for LA and aCLs.

A

HLA DR4 and DRw53

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11
Q

aPL autoantibodies recognize phospholipid-binding proteins, primarily

A

β2GPI (also named apolipoprotein H)

IgG antibodies against an epitope comprising Gly40-Arg43 in the domain I of β2GPI have been reported to have a stronger correlation with thrombosis than antibodies against other epitopes.

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12
Q

Proposed Pathogenic Mechanisms for
Antiphospholipid Syndrome

A
  • I. Formation of APS macroimmmune complexes
  • II. Disruption of endothelial surface and annexin A5 anticoagulant shield
  • III. Enhanced cell signaling
  • IV. Complement-mediated injury
  • V. Impeding of fibrinolysis and endogenous anticoagulation
  • IV. Complement-mediated injury
  • V. Impeding of fibrinolysis and endogenous anticoagulation
  • VI Others
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13
Q

Forms 2- dimensional crystals over the phospholipid bilayers that shield them from binding coagulation factors

A

Annexin A5

Annexin A5 is a potent anticoagulant protein with high affinity for phospholipid membranes that contain anionic phospholipids, specifically phosphatidylserine.

May play a thrombomodulatory role on the surfaces of cells lining the placental and systemic vasculatures

aPL antibody–antigen complexes disrupt the crystallization of annexin A5 and displace the protein from phospholipid membrane surfaces.

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14
Q

The Ig____ subtype of aPL most closely correlates with thrombosis.

A

IgG2

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15
Q

CRITERIA CLINICAL MANIFESTATIONS

A
  • Venous thromboembolism
  • Arterial thromboembolism
  • Small-vessel thrombosis or thrombotic microangiopathy
  • Pregnancy complications attributable to placental insufficiency, including:
  • Three or more unexplained spontaneous pregnancy losses at ess than 10 weeks’ gestation
  • One or more fetal losses after 10 weeks’ gestation
  • Stillbirth
  • Intrauterine growth restriction
  • Preeclampsia
  • Preterm labor
  • Placental abruption
  • Oligohydramnios
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16
Q

NONCRITERIA CLINICAL MANIFESTATIONS

A
  • Thrombocytopenia
  • Bleeding caused by hypoprothrombinemia, acquired platelet function abnormality, acquired inhibitor to specific coagulation factor (eg, factor VIII), acquired von Willebrand syndrome
  • Livedo reticularis, necrotizing skin vasculitis
  • Coronary artery disease
  • Valvular heart disease
  • Kidney disease
  • Pulmonary hypertension
  • Acute respiratory distress syndrome
  • Atherosclerosis and peripheral artery disease
  • Nonthrombotic retinal disease
  • Adrenal failure, hemorrhagic adrenal infarction
  • Esophageal necrosis, gallbladder necrosis, gastric and colonic ulceration
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17
Q

Most common clinical thrombotic manifestation

A
  • Deep venous thrombosis (DVT) of the lower extremity (48%)
  • Pulmonary embolism (38%)
  • Stroke or transient ischemic attacks (TIAs) (35%)
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18
Q

Percentage of Systemic Vascular Thrombosis
Venous:
Arterial:
Both:

A

Venous: 60%
Arterial: 30%
Both: 10%

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19
Q

The usual age at presentation with thrombosis is approximately

A

35–45 years

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20
Q

TRUE OR FALSE

Like for patients with SLE,women are more susceptible to thrombotic manifestations than men.

A

FALSE

Except for patients with SLE, men and women are equally susceptible to thrombotic manifestations.

No differences have been observed between the arterial and venous distributions of thromboses of primary and patients with secondary APS.

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21
Q

TRUE OR FALSE

APS should be suspected in young patients with TIAs or stroke, particularly when the more typical risk factors for cerebrovascular disease are absent.

A

TRUE

APS should be suspected in young patients with TIAs or stroke, particularly when the more typical risk factors for cerebrovascular disease are absent.

Cerebral venous thrombosis in APS presents at a younger age and is more extensive than in non-APS patients with the disorder.

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22
Q

About ___% of patients with APS have concurrent genetic thrombophilic conditions such as the factor V Leiden variant and prothrombin gene mutation.

A

16%

Both the factor V Leiden variant and prothrombin gene mutation have not be shown to increase the thrombotic risk in patients with APS.

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23
Q

In approximately half of patients, the pregnancy losses occur in the ____ trimester

A

First trimester

Pregnant patients with APS are also more prone to develop DVT during pregnancy or the puerperium.

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24
Q

TRUE OR FALSE

Histologic abnormalities were found in many, but not all, placentas of patients with aPL.

A

TRUE

Histologic abnormalities were found in many, but not all, placentas of patients with aPL.

Most common findings were placental infarction, impaired spiral artery remodeling, decidual inflammation, increased syncytial knots, decreased vasculosyncytial membranes, and the deposition of complement split product C4d

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25
Q

TRUE OR FALSE

Early reproductive failure (ie, infertility) is associated with APS.

A

FALSE

Early reproductive failure (ie, infertility) is not associated with APS.

The current consensus is that aPL antibodies are not a cause of infertility.
There is no evidence to screen patients with infertility for aPL antibodies.

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26
Q

Defined as the presence of valve morphologic lesions, including leaflet thickening, irregular nodules or nonbacterial vegetations (ie, Libman-Sacks endocarditis), or severe valve dysfunction (regurgitation, stenosis) in the absence of a history of rheumatic fever and infective endocarditis

A

APS with valvular heart disease

Approximately 65% of patients with APS have cardiac valvular abnormalities detected by echocardiography.

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27
Q

Approximately 40% to 60% of patients with _____ are positive for at least one aPL antibody positivity.

A

Multiple sclerosis

The presence of aPL antibodies in patients with multiple sclerosis may represent disease progression or a disease flare.

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28
Q

Cutaneous Manifestations: the most frequent histopathologic feature

A

Noninflammatory vascular thrombosis

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29
Q

The most frequently affected abdominal organ in patients with APS

A

Liver

With occlusion of hepatic vessels, including those supplying the biliary tree

30
Q

TRUE OR FALSE

Patients with ITP who are triple positive for aPL antibodies have also been shown to have lower platelet counts and are at risk for thrombosis with concurrent steroid therapies.

A

TRUE

Patients with ITP who are triple positive for aPL antibodies have also been shown to have lower platelet counts and are at risk for thrombosis with concurrent steroid therapies.

The decrease in platelet count is generally mild or moderate and is rarely significant enough to cause bleeding complications or affect anticoagulant therapy.

The majority of patients with APS and thrombocytopenia have antibodies directed against glycoproteins on the wall of platelets (GPIIb/IIIa, GPIb/IX, GPIa/IIa, and GPIV).

31
Q

Most Likely Causes of Bleeding in Patients with Antiphospholipid Syndrome

A
  • Hypoprothrombinemia
  • Thrombocytopenia
  • Acquired platelet function abnormality
  • Acquired inhibitor to specific coagulation factor (eg, factor VIII)
  • Acquired von Willebrand syndrome
32
Q

TRUE OR FALSE

An ophthalmologic assessment is recommended for all patients with APS.

A

TRUE

An ophthalmologic assessment is recommended for all patients with APS.

As many as 80% of patients with APS have ocular involvement.

In the absence of known risk factors, APS should be suspected in patients with recurrent ocular thrombosis and in younger patients with central retinal artery or vein occlusion.

33
Q

Has been reported as the most common endocrine manifestation of APS

A

Adrenal insufficiency

34
Q

A relatively infrequent but devastating presentation of APS and is characterized by severe widespread vascular occlusions and a high mortality rate

A

Catastrophic Antiphospholipid Syndrome

The majority of patients with CAPS are female (69%) and in their late 30s (mean age, 38.5 years), but the condition can present at any age (range, 0–85 years).

In half of CAPS cases, the patients’ catastrophic event was their first APS manifestation.

35
Q

Diagnostic criteria for CAPS

A
  • Evidence of involvement of at least three organs, systems, or tissues
  • Development of manifestations simultaneously or in less than 1 week
  • Histopathologic confirmation of small-vessel occlusion
  • Laboratory confirmation of the presence of aPL antibodies.
36
Q

Precipitating factors of CAPS

A

Infections, drugs (sulfur-containing diuretics, captopril, and oral contraceptives), surgical procedures, and cessation of prior anticoagulant therapy

37
Q

The most frequently affected organ in CAPS

A
  • Kidney (73%)
  • Lungs (58.9%)
  • Brain (55.9%)
  • Heart (49.7%)
  • Skin (45.4%)
38
Q

Features of Antiphospholipid Syndrome in Children

A
  • Children with primary APS were younger and had a higher frequency of arterial thrombotic events, the children with secondary APS had a higher frequency of venous thrombotic events associated with hematologic and skin manifestations.
  • Pediatric primary APS were more likely to develop other autoimmune diseases, present with cerebrovascular thrombotic events (ie, sinus venous thrombosis and ischemic stroke), and develop more noncriteria manifestations.
  • Rate of recurrent thrombosis is higher in pediatric APS.
39
Q

Criteria laboratory assays used to diagnose definite APS

A

aCL, anti-β2GPI (IgG and IgM), and LA

Positivity for all three criteria assays (“triple positivity”) has been correlated with an increased risk for a future thrombotic event, and these patients may require additional attention.

40
Q

Non criteria laboratory assays

A
  • Anticardiolipin and Anti–β2-Glycoprotein I IgA Assays
  • Antiphosphatidylserine and Prothrombin Assays
  • Annexin A5 Resistance Assay
  • Other Antiphospholipid Immunoassays
  • Anti-Domain I of β2GPI Immunoassay
  • Antivimentin–Anticardiolipin Complex Immunoassay
  • Other Methods for Detecting Lupus Anticoagulant
  • Complement Testing
  • Genomic and Biomarker Testing in Antiphospholipid Syndrome
41
Q

Criteria assays: two coagulation assays recommended to be performed if lupus anticoagulant or antiphospholipid syndrome (APS) is suspected

A
  • dRVVT with mixing incubations and neutralization with excess phospholipid
  • aPTT with mixing incubation and neutralization with excess phospholipids
42
Q

Positive results using the criteria assays have to be obtained on

A

Two or more occasions at least 12 weeks apart

43
Q

TRUE OR FALSE

aCL antibody testing has high sensitivity but poor specificity, especially in asymptomatic patients.

A

TRUE

aCL antibody testing has high sensitivity but poor specificity, especially in asymptomatic patients.

The presence of elevated titers of aCL antibodies 6 months after an episode of VTE is a predictor for increased risk of recurrence and of death.

Women with an aCL IgG titer greater than 20 binding units or a positive LA result were more likely to develop complications.

44
Q

Believed to be the major protein cofactor for aPL antibodies

A

β2GPI

Usually present in conjunction with abnormal aCL and antiphosphatidylserine (aPS) antibodies, patients with APS can present with only antibodies to β2GPI.

Anti-β2GPI antibodies were more often associated with venous than arterial thrombosis.

45
Q

Considered to be more specific but less sensitive to APS

A

Anti–β2-Glycoprotein I IgG and IgM Antibody Assays

46
Q

TRUE OR FALSE

Even though a large variety of assays are used, there is no consensus on a “gold standard” for the detection of aCL and anti-β2GPI antibodies.

A

TRUE

Even though a large variety of assays are used, there is no consensus on a “gold standard” for the detection of aCL and anti-β2GPI antibodies.

The study recommends using the same testing system for patient diagnosis and follow-up.

47
Q
A
48
Q

TRUE OR FALSE

Anticoagulant therapy may cause false-positive LA test results.

A

TRUE

Anticoagulant therapy may cause false-positive LA test results.

Importantly, direct-acting oral anticoagulants (DOAC) can mimic the effects of LAs including the confirmatory assays.

49
Q

Considered the second major cofactor for aPL antibodies

A

Prothrombin

50
Q

Antibodies to the phospholipid ______________ are reported to correlate more specifically with APS than aCL antibodies, particularly in arterial thrombosis.

A

Phosphatidylserine

The presence of aPS–PT antibodies strongly correlated with the presence of LA, had a higher sensitivity and specificity than aPT antibodies alone for the diagnosis of APS, and had comparable sensitivity and specificity to aCL for the diagnosis of APS.

51
Q

Antibodies against this zwitterionic phospholipid have been associated with thrombosis and with APC resistance.

A

Phosphatidylethanolamine

52
Q

Numerous aPL antibodies (aPT, anti–annexin V, antiphosphatidylinositol, phosphatidylethanolamine, and antiphosphatidylglycerol) did not show any significant thrombotic risk except for

A

Antiphosphatidylserine and antiphosphatidic acid Ig

53
Q

Because of the prevalence of aPL antibodies in normal and reactive conditions, clinicians should determine the appropriateness of testing in their patients to avoid misdiagnosis.

High appropriateness group:
Moderate appropriateness group:
Low appropriateness group:

A

High appropriateness group: unprovoked and unexplained VTE, arterial thrombosis in young patients (younger than 50 years of age), thrombosis at unusual sites, late pregnancy loss, and any thrombosis or pregnancy morbidity in patients with autoimmune diseases (SLE, rheumatoid arthritis, autoimmune thrombocytopenia, autoimmune hemolytic anemia)

Moderate appropriateness group: asymptomatic patients who are incidentally found prolonged aPTT (often during routine testing) and young patients with recurrent spontaneous early pregnancy loss and provoked VTE

Low appropriateness group: older adult patients with venous or arterial thromboembolism.

In addition, it may not be appropriate to test patients who are on long-term anticoagulation because this may cause false-positive LA results, leading to misdiagnosis.

54
Q

TRUE OR FALSE

aPL screening of otherwise asymptomatic obstetric patients with no history of prior complications is not warranted because of the high frequency of false-positive test results.

A

TRUE

aPL screening of otherwise asymptomatic obstetric patients with no history of prior complications is not warranted because of the high frequency of false-positive test results

55
Q

MULTIPOSITIVITY FOR ANTIPHOSPHOLIPID SYNDROME CRITERIA ASSAYS

Considered high risk for future manifestations of APS

A

Both symptomatic and asymptomatic patients with triple-positive laboratory results (LA positive, aCL [IgG or IgM >40 GPL]) and anti-β2GPI (IgG or IgM >99th percentile)

Single positivity for aCL (IgG or IgM >40 GPL) or anti-β2GPI (IgG or IgM >99th percentile should be considered low risk for APS, but treatment may be warranted in the presence of thrombosis or pregnancy complications or other high-risk factors

56
Q

A clinical scoring system combining points for the presence of six features—arterial hypertension, hyperlipidemia, LA, aCL antibodies, anti-β2GPI antibodies, and aPS/ PT antibodies.

A

Global APS Score (GAPSS)

Higher GAPSS values were associated with recurrence of thrombotic events was observed

57
Q

Treatment for women with a history of three or more spontaneous pregnancy losses and evidence of aPL antibodies

A

Combination of low-dose aspirin (75–81 mg/ day orally) and prophylactic doses of UFH (ie, 5000 U every 12 hours subcutaneously)

The presence of positive aPL laboratory assays alone is not an indication for treatment in pregnant women without a history of spontaneous pregnancy losses, other attributable pregnancy complications, thrombosis, or SLE.

Therefore, the inclusion of aPL tests in routine prenatal testing panels should be discouraged.

57
Q

Many physicians recommend continuing prophylactic therapy for ___ weeks after delivery even if the patient has not experienced thrombosis

A

6 weeks

For patients who experienced thromboembolism, prophylaxis by heparin or oral anticoagulant therapy is warranted for at least 6 weeks after delivery.

58
Q

Should be considered only for patients who are refractory to anticoagulant therapy, who have a severe immune thrombocytopenia, or who have a significant contraindication to heparin therapy

A

Glucocorticoids or IVIG

59
Q

Acute management of patients with thrombotic APS

A

UFH or LMWH should be initially given followed 4–5 days later with a vitamin K antagonist (ie, warfarin)

Warfarin for the long term and maintained at a therapeutic international normalized ratio (INR) of 2.0–3.0.

60
Q

Duration of anticoagulation in thrombotic APS

A

Indefinitely

61
Q

TRUE OR FALSE

In patients with APS with stroke, high-intensity warfarin (INR >3) or concomitant use of low-dose aspirin or antiplatelet therapy has shown benefit over current standard therapy with warfarin.

A

FALSE

In patients with APS with stroke, high-intensity warfarin (INR >3) or concomitant use of low-dose aspirin or antiplatelet therapy has not been shown to benefit over current standard therapy with warfarin.

62
Q

The current recommendation to treating patients with obstetric APS

A

Daily low-dose aspirin (75–81 mg/day orally) and either UFH or LMWH

63
Q

Anticoagulation is resumed ___ weeks postpartum because of the increased risk of VTE in this time period.

A

6 weeks postpartum

63
Q

In patients with obstetric APS who are planning to become pregnant, low-dose aspirin should be preferably started ____________, and heparin (LMWH or UFH) should be added ______________

A

Before conception

As soon as pregnancy is confirmed

64
Q

Treatment for CAPS

A

Anticoagulation, glucocorticoids, and either IVIG or plasma exchange

In addition, concurrent treatment of precipitating factors is also recommended (eg, infections, gangrene, or malignancy).

65
Q

Treatment considered for patients with refractory CAPS

A

Rituximab (B-cell depletion) or Eculizumab (complement inhibition)

66
Q

Treatment for asymptomatic patient with a high-risk antibody profile

A

Low-dose aspirin

67
Q

High-risk antibody profile

A
  • Presence (in two or more occasions at least 12 weeks apart) of LA
  • Double (any combination of LA, aCL antibodies or anti–β2GPI antibodies)
  • Triple (all three subtypes) aPL positivity
  • Presence of persistently high aPL antibody titers.
68
Q

Antimalarial drug that has been shown to directly disrupt aPL IgG–β2GPI complexes and reverse the aPL antibody-mediated disruption of annexin A5 binding on phospholipid bilayers and on human placental syncytiotrophoblasts.

A

Hydroxychloroquine

69
Q

Clinical trial on role of HCQ in APS

A

HIBISCUS: Hydroxychloroquine for the secondary prevention of thrombotic and obstetrical events in primary antiphospholipid syndrom

European League Against Rheumatism guidelines state that HCQ could be used in women with refractory obstetric APS not responding to standard therapy.

70
Q

Anti-CD20 agent shown to be effective in treating noncriteria manifestations refractory to conventional therapy

A

Rituximab

WILLIAM'S HEMATOLOGY (89 decks)

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