Page 477 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

CHAPTER 23 ■ Myeloproliferative Neoplasms 461

IL-3 h s been note . T is y be jor ctor in the p tho-

genesis o incre se erythropoiesis without incre se eryth- BOX 23-2

ropoietin concentr tions.

In ition, the ng nese n zinc contents o the phys-

iologic lly ctive erythrocytic icroele ents e onstr te Diagnostic Criteria for Polycythemia Vera

isturb nces in erythrocytes o the peripher l venous bloo MAJOR CRITERIA

in p tients with PRV. T ese ch nges in ic te the neopl stic 1. He oglobin gre ter th n 18.5 g/ L in les, 16.5 g/ L

ch r cter o proli er tion o bone rrow cells in PRV. in e les, or other evi ence o incre se re cell

volu e
Karyotype 2. Presence o JAK2V617F or other unction lly si il r

Chro oso l isor ers re oun in only pproxi tely ut tions, or ex ple, JAK2 exon 12 ut tion

15% o p tients, but there is no co on chro oso l MINOR CRITERIA
bnor lity s is oun in CML. A newly escribe gene, 1. Hypercellul r bone rrow with pro inent gr nulo-

PV-1 gene, h s been escribe in neutrophils o p tients cytic, erythrocytic, n eg k ryocytic proli er tion
with PRV, but the signif c nce o this gene is s yet uncert in. 2. Decre ses seru erythropoietin levels

During the f rst 10 ye rs o ise se, pproxi tely one 3. En ogenous erythroi colony or tion in vitro
ourth o p tients e onstr te n bnor l clone; er ore

th n 10 ye rs, gre ter th n three ourths o p tients exhibit
n bnor l clone. P tients with chro oso lly bnor l

clone t the ti e o i gnosis h ve poorer ch nce o sur- Laboratory Data
viv l th n those exhibiting nor l k ryotype in et ph se An incre se erythrocyte cell count, p cke cell volu e, n

cells. Cytogenetic results o not pre ict evolution o the is- he oglobin with nor l erythrocytic in ices re ch r c-
e se but o provi e clues to the he tologic l phenotype, teristic o PRV. Re cell proli er tion is thought to be in e-

ur tion o the ise se, n consequences o yelosuppres- pen ent o en ogenous erythropoietin, n hence, seru
sive ther py.
levels o erythropoietin re usu lly ecre se . A genetic

Clinical Signs and Symptoms lter tion o the erythropoietin receptor is thought to cre te
loss o regul tory unction n bnor l erythroi pro-

Plethor is the h ll rk o PRV. Spleno eg ly is co - li er tion. Pl s levels o thro bopoietin (the growth c-

only oun sign o ise se; it occurs in ore th n three tor or eg k ryocyte pro uction o pl telets) re elev te

ourths o p tients. Reversible, o er te hypertension re- or nor l, i plying loss o the nor l neg tive ee b ck

quently occurs s the result o the exp n e bloo volu e. ech nis .

An incre se tot l bloo volu e (hypervole i ) occurs in Pe k polycythe ic v lues re he oglobin o pproxi-

PRV n in isor ers such s congestive he rt ilure, pri- tely 20.6 g/ L, icrohe tocrit o pproxi tely 80%,

ry l osteronis , n Cushing syn ro e n s result tot l leukocyte (white bloo cell [WBC]) count o 28,000 ×

o overtr ns usion o onor bloo . 10 /L, n pl telet count o 1,400 × 10 /L.
9
9
Neurologic l sy pto s re reporte by 50% to 80% o In p tients with PRV, s in those with the other ise ses,

p tients. Sy pto s such s he ches, izziness, p resthe- the re bloo cell istribution wi th (RDW) ten s to be

si s, n sight lter tions re requently rel te to hypervis- higher th n nor l. T e RDW tr nsiently incre ses ollow-

cosity n respon i e i tely to re uction o cell counts, ing inistr tion o yelosuppressive gent, correspon -

except in ictus p tients. Other neurologic l sy pto s see ing to the tr nsition perio ro icrocytes to nor l bloo

to result ro n ssoci te co gulop thy. cells. T e RDW is even higher uring polycythe ic perio s

T e ost serious co plic tions re rteri l n venous th n uring the yelof brotic perio . T is y be ssoci te

co plic tions (v scul r cci ents) n the tr nsition to with he topoietic bnor lity c use by extramedullary

cute leuke i . PRV, sickle cell ne i , sickle cell–he o- hematopoiesis. RDW see s to re ect ccur tely the p tho-

globin C ise se, n essenti l thro bocythe i re the logic l st tus o PRV.

jor isor ers o or e bloo ele ents c using stroke. Not ll p tients with n elev te re cell count h ve PRV.

He orrh gic pheno en re requent ong p tients with V rious tu ors re known to result in n elev te re cell

igestive ni est tions, inclu ing g strointestin l he or- ss. Ren l cell c rcino s n hep to s re the tu ors

rh ge, b o in l p in, or port l vein thro bosis, or thro - ost note or cre ting erythrocytosis. So e pro uce exog-

bosis o the supr hep tic vein. In ition, thro bophlebitis enous erythropoietin. T e ost co on secon ry c use o

with pul on ry e bolis is co on co plic tion o erythrocytosis is cig rette s oking. S okers h ve elev te

PRV n o en is unrecognize . pl s levels o c rbon onoxi e. C rbon onoxi e is-

Severe psychotic epression is r re in p tients with PRV. pl ces oxygen ro re cell he oglobin, resulting in tis-

In venogr phy- ocu ente Bu -Chi ri syn ro e, the sue hypoxi n n elev te rive to re cell pro uction.

un erlying ise ses inclu e PRV. T e criteri or the i gno- S okers’ erythrocytosis is ost co only istinguishe

sis o PRV re presente in Box 23.2. ro true PRV by the observ tion th t p tients usu lly h ve