Page 530 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

514 PART 7 ■ Principles and Disorders of Hemostasis and Thrombosis

aintain the nor a quantity o circu ating ate ets. Disor ers sur ace o b oo ce s to the actin cytoske eton, the network o

that ay ro uce s eno ega y with resu tant s enic oo ing bers that ake u a ce u ar structura ra ework. Actin is

or e aye intras enic transit inc u e a coho ic or osthe atic an u trastructura co onent o the ce u ar architecture that

cirrhosis with orta hy ertension, y ho as an euke ias, is invo ve in intrace u ar an ce substrate interactions an

an i i isor ers such as Gaucher’s isease. signa ing via its ro e in ce or ho ogy an ove ent. T e

actin cytoske eton is res onsib e or ce u ar unctions such as
Posttransfusion Throm bocytopenia growth, en ocytosis, exocytosis, an cytokinesis.

Massive b oo trans usion is co ete re ace ent o A ack o unctiona WAS in ate ets i airs their eve -

atient’s b oo vo u e with 24 hours. When units o acke o ent, ea ing to re uce size, icrothro bocyto enia,

RBCs an as a ex an ers trans use , there is a re uc- an ys unctiona ate ets with an intrinsic e ect.

tion in the ate et count, i utiona thro bocyto enia.

Signi cant changes to a ate et count o 50.0 to 100 × 10 /L Signs and Sym ptom s
9
are not a arent unti ore than 15 units o acke RBCs an Microthro bocyto enia (Fig. 26.8) is ty ica y resent ro

as a ex an ers are trans use . Severe thro bocyto enia birth an can ea to easy bruising or e iso es o ro onge

(a ate et count o ess than 50.0 × 10 /L) is co on when b ee ing o owing inor trau a. A ecte boys rare y sur-
9
ore than 20 units o acke RBCS an as a ex an ers vive beyon 10 years o age. Patients usua y ie ro se sis,

are trans use . See associate coagu o athy in Cha ter 28. he orrhage, or a ignancy.

Wiskott-A rich syn ro e is characterize by the tria o :
Hereditary Defects of Platelet Function w ith

Throm bocytopenia 1. T ro bocyto enic ur ura

2. Increase susce tibi ity to bacteria , vira , an unga
Here itary thro bocyto enias inc u e Fanconi’s syn- in ections

ro e, constitutiona a astic ane ia an its variants (see 3. Ecze a o the skin, ato ic er atitis

Cha ter 13), a eiosis thro bocyto enia ( AR syn ro e),

X- inke a egakaryocytic thro bocyto enia, WAS, May- C inica rob e s cause by autoi unity are co -

Hegg in ano a y, an here itary acrothro bocyto enia on in WAS an a ect a ost ha o a atients. A ong

(e.g., A ort syn ro e). the ost co on autoi une ani estations is he o ytic

When exa ining a eri hera b oo s ear, ate et or- ane ia or i io athic thro bocyto enic ur ura cause

ho ogy shou be observe . Abnor a variations in size by se -reactive antibo ies generate ina ro riate y by the

shou be note . Disor ers o ate et size inc u e the o owing: atient’s i une syste .

Another co on autoi une isor er in WAS is vascu-
1. Wiskott-A rich syn ro e, which e onstrates the itis that ty ica y causes ever an skin rash on the extre i-
s a est ate ets seen.

2. May-Hegg in ano a y, which is characterize by the res- ties. Occasiona y, vascu itis ay a ect the usc es, heart,
brain, or other interna organs with a range o sy to s.
ence o arge ate ets an the resence o Döh e- ike bo - Patients with WAS have an increase risk o a ignan-

ies in the granu ocytic eukocytes.
3. A ort syn ro e, a isor er that exhibits giant ate ets cies co are to nor a in ivi ua s. It is esti ate that 15%
to 20% o WAS atients eventua y eve o a ignancies.
an thro bocyto enia.
4. Bernar -Sou ier syn ro e (BSS), which e onstrates the

argest ate ets seen an is a so re erre to as giant ate et
syn ro e.

Wiskott-Aldrich Syndrome (WAS)

Wiskott-A rich syn ro e (WAS) is a artia co bine

e ciency isor er that is unique a ong ri ary i u-

no e ciency iseases. In a ition to being susce tib e to

in ections, atients have rob e s with abnor a b ee ing.

In WAS, there is a re uce abi ity to or b oo c ots as the

resu t o unusua y s a , ys unctiona ate ets.

Etiology

In 1994, the X- inke gene that is e ective in atients with WAS

was iscovere . T e gene is ocate on the short ar o the X

chro oso e, so the isease is inherite in an X- inke recessive.

Te ri ary e ect in this unco on X- inke recessive

e iatric isease is cause by a utations in the WAS gene. FIGURE 26.8 iny ate ets ( icrothro bocytes) in a thro bo-

Te utate gene is ex resse unique y in he ato oietic ce s. cyto enic atient with Wiskott-A rich syn ro e. (Fro Pereira

WAS gene rovi es instructions or aking a rotein ca e I, George I, Arber DA. Atlas o Peripheral Blood, Phi a e hia, PA:

WAS . T is rotein is invo ve in re aying signa s ro the Li incott Wi ia s & Wi kins, 2011.)