Page 586 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

570 PART 7 ■ Principles and Disorders of Hemostasis and Thrombosis

anti hos ho i i antibo ies (aPL) antibo ies or abnor a i- have c inica courses si i ar to he o hi ia A atients with

ties in hos ho i i - e en ent tests o coagu ation. Patients inhibitors. Factor V inhibitors ay cause c inica b ee ing,

with various autoi une or rheu atic iseases have a a though the egree o he orrhage varies consi erab y.

high inci ence o aPL antibo ies. T ese isor ers inc u e Inhibitors o actors XIII, II, VII, IX, an X; brin; or brino-

syste ic u us erythe atosus, Sjögren syn ro e, rheu a- gen can resu t in serious he orrhagic events.

toi arthritis, an autoi une thro bocyto enic ur ura.

So e bacteria an vira in ections are associate with the Laboratory Findings

occurrence o aPL. Fa i ia association exists with re atives Pro onge rothro bin ti e (P ) or activate artia

o atients with known APS are ore ike y to have aPL anti- thro bo astic ti e (AP ) are c assic aboratory n ings.

bo ies. An association has been oun between aCL anti- Incubation o atient’s as a with nor a as a at 37°C

bo y an in ivi ua s who have DRw53 an DR7 HLA genes. ( ixing stu y) an eter ination o AP an P ay

Laboratory n ings in icate ro ongation o c otting etect the resence o an inhibitor. T e ixing stu y wi be

assays, such as activate artia thro bo astin ti e (AP ), ro onge in the resence o an inhibitor. Inhibitors are ore

kao in c otting ti e, an i ute Russe ’s vi er veno ti e ti e an te erature stab e than their s eci c c otting actors.

(DRVV ). T e resence o u us anticoagu ant is con r e o quantitate the eve s o inhibitors, the Bethes a assay

by a ixing stu y. I a c otting actor is e cient, the a ition is ost co on y use in the Unite States. One Bethes a

o nor a as a corrects the ro onge c otting ti e. I the unit is e ne as the a ount o antibo y that wi neutra -

c otting ti e oes not nor a ize uring ixing stu ies, an ize 50% o the inhibitor activity in a ixture o equa arts

inhibitor is resent; the absence o a s eci c c otting actor o nor a as a an antibo y-containing as a that has

inhibitor con r s that a u us anticoagu ant is resent. been incubate or 2 hours at 37°C.

Laboratory tests shou be consi ere in a atient sus- Detection o anti hos ho i i (aPL) antibo y is base on

ecte o having anti hos ho i i syn ro e: ro ongation o hos ho i i - e en ent coagu ation assays.

aPL antibo y is consi ere one o the ost co on causes
■ aCL antibo ies (IgG, IgM) o a ro onge AP . Assays inc u e the Russe ’s vi er

■ Anti–beta-2-g yco rotein 1 antibo ies (IgG, IgM) veno ti e, kao in c otting ti e, ate et neutra ization ro-

■ Activate artia thro bo astin ti e (AP )
ce ure, an tissue thro bo astin inhibition test.

Lu us anticoagu ant assays such as DRVV (a thresho

o a roxi ate y 1.6 or the DRVV ratio) has been rec- Impaired Fibrinolysis

o en e or he ing iscri inate anti hos ho i i syn- I aire brino ysis (Figs. 28.4 an 28.5) has been note

ro e ro non- anti hos ho i i syn ro e.
to be both genetic an acquire in their origin. I air ent

Clinical Presentation o brino ysis ay re is ose an in ivi ua to thro bosis.
Patients with ty e II hy er i o roteine ia cause by a i ia
Lu us anticoagu ant (LA) is the ost co on y acquire hy ercho estero e ia e onstrate i air ent o brino ysis.

an has an interesting resentation. In the absence o other A high inci ence o recurrent thro bosis has been note in

he ostatic abnor a ities, the LA is rare y associate with atients with here itary e ciencies o rotein C or antithro -

b ee ing ten encies, even with surgica roce ures. B ee ing bin. Protein S e ciency a so joins the grou o other as a

e iso es in these atients are usua y the resu t o thro bo- rotein e ciencies associate with inherite thro bo hi ia

cyto enia or another ano a y. Para oxica y, atients with ( ab e 28.12). De ciencies o inhibitors to actors VIII an V

LA are at increase risk or arteria an venous thro botic have a so been corre ate with recurrent thro bosis.

e bo is . Venous thro bosis invo ving the eg veins, with C inica resentations o atients with e ciencies o natu-

associate u onary e bo i, is the ost requent co i- ra y occurring anticoagu ants are si i ar. De ciencies o 50%

cation. S ontaneous abortion an intrauterine eaths are o nor a or rotein C, rotein S, an antithro bin ay

a so increase in atients with LA. ea to serious thro botic events. Frequent resenting con i-

Te resence o a s eci c actor inhibitor can be sus ecte tions inc u e thro bo h ebitis, ee venous thro bosis, an

in atients with no history o b ee ing e iso es who ex eri- u onary e bo i. T e requency o rotein e ciencies cor-

ence he orrhage ro various sites or in he o hi iac atients re ate with recurrent thro boe bo ic isease is as o ows:

not res onsive to their usua osage o b oo ro uct in usion.

B ee ing e iso es in he o hi iac atients with inhibitors o ■ Protein C: 7%

not a ear to be any ore requent or severe than in atients ■ Protein S: 5% to 10%

without inhibitors. When he orrhagic events o occur, treat- ■ Antithro bin 2% to 4%

ent o a atient with inhibitor is i cu t.

Nonhe o hi iac atients with acquire inhibitors o Protein C De ciencies

actor VIII can have ajor b ee ing requiring trans usion. Protein C activity has been e onstrate to be re ate to the

Patients with inhibitors to vWF, actor XI, an actor XII co on y occurring thro botic e iso es in atients with

o not genera y exhibit a he orrhagic ten ency. However, an inherite e ciency o rotein C an rotein S. However,

thera y or these atients can be co icate by the resence the hy ercoagu ab e state in atients with roteinuria is not

o the inhibitor. Patients with acquire actor IX inhibitors cause by ecrease eve s o rotein C. E evate rotein C