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BNH THY U

ThS BS Bi Phan Qunh Phng

Mc tiu hc tp:

1. Bit c tc nhn gy bnh thy u.

2. M t c nhng c im dch t ca bnh thy u, xc nh c cc

thi k ly nhim.

3. M t c im lm sng, tnh cht mn nc in hnh ca bnh thy u

4. K cc bin chng thng gp ca bnh thy u.

5. Nu c k hach d phng v iu tr bnh thy u.

I. I CNG

Bnh thy u l bnh truyn nhim rt hay ly, do siu vi Varicella-zoster

(VZV) gy ra, bnh c kh nng gy thnh i dch. Bnh c c im lm

sng l pht ban dng mn nc rt nga da v nim mc; bnh thng lnh

tnh tr em hn ngi ln, tuy nhin c mt s trng hp c th t vong do

bin chng.

II. TC NHN GY BNH

Varicella-zoster thuc gia nh Herpesviridae, y l loi DNA virus c ng

knh khong 200nm, c v bc cha lipid vi hng ro l glycoprotein. Virus

d nui cy mi trng canh cy t bo.

VZV c th gy 2 bnh cnh khc nhau: thy u v Zona.

- Thy u xut hin ngi cha c min dch vi VZV.

- Zona l do tnh trng ti hot ng ca nhim VZV tim tng, ch xut

hin nhng ngi c min dch mt phn vi VZV, him gp tr em,

hay gp c a thun li nh: ngi gi, c thai, chn thng, suy gim

min dch....

Nu ngi c min dch ton phn vi VZV sau khi b thy u cng c th

chng li bnh Zona v ngc li. Virus ny d b c ch bi Acyclovir v cc

thuc virus c lin quan.

Hnh 1. Varicella zoster virus

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III. DCH T HC

1. Ngun bnh

Ngi l ngun bnh duy nht ca bnh thy u, thi gian ly bnh t 2 ngy

trc khi pht ban n khi ton b sang thng trc my.

2. ng ly

Ch yu l ng h hp, qua nhng git nc bt c cha virus bn ra t

ngi bnh, mt s t ly t sang thng da v nim mc. Trong nhng v

dch, c th ly qua khng kh.

3. C th cm th

Bnh xy ra khp ni trn th gii, c bit l nhng ni dn c ng c nh

nh tr, mu gio, k tc x, tri lnh

Bnh gp mi tui, k c s sinh, 90% tr di 10 tui, nam v n c kh

nng mc bnh nh nhau.

C a nguy c: Suy gim min dch, lymphoma

Bnh thng xy ra vo cui ma ng n u xun (thng 1-5).

4. Min dch:

Thy u gy min dch vnh vin sau khi nhim ln u, nhng cng c th b

bnh ln hai, thng nh. Bnh ln hai c th gp ngi c tn thng h

thng min dch hay c chch nga thy u, a s ngi ln bnh ln 2 di

dng Zona. Mt s trng hp c th gp thy u v Zona xy ra cng lc

trn mt bnh nhn.

IV. SINH BNH HC

Sau khi xm nhp vo c th qua ng h hp, virus sinh sn v pht trin ti

t bo thng b ng h hp ri vo mu (nhim virus nguyn pht). T ,

virus tng sinh v gy nhim virus huyt th pht, lan rng trc khi to thnh

sang thng da. Khi virus sinh sn, t bo biu m thoi ho v phnh ra km

theo s xut hin nhiu t bo khng l nhiu nhn v t bo a nhn i toan

hnh thnh mn nc trong. Sau , mn nc s ho c vi s hin din ca

nhng bch cu a nhn, cc t bo thoi ho v fibrin, cha rt nhiu virus.

Him khi c hoi t v xut huyt ti nhng mn nc. Mn nc c th v ra

v tit dch nhim trng hay ti hp thu dn dn.

V. LM SNG

1. Th in hnh

1.1. Thi k bnh: 10-20 ngy (trung bnh 14 ngy), khng c triu chng

lm sng.Thi k ny c th ngn hn mt s ngi suy gim min dch.

1.2. Thi k khi pht: 1-2 ngy, vi cc triu chng khng in hnh nh

St nh khong 38oC, mt mi, chn n, vi hng ban vi mm ri rc trn da,

y l tin thn ca mn nc, c th km theo nga.

1.3. Thi k ton pht: (thi k u mc) 3-4 ngy

Khi u l nhng sn hng ban nh , sau xut hin nhng mn nc

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trong hnh trn hay bu dc, ng knh 3-10mm trn nn hng ban. Sau 24

gi, mn nc ho c, d v, ng my. Sang thng rt nga. Lc u sang

thng tp trung nhiu u, mt, ngc; v sau c th gp bt k vng no

trn c th, k c nim mc ming, kt mc, m o Trn cng mt vng da,

sang thng hin din cc thi k tin trin khc nhau.

ngi ln, sang thng cng nhiu cng nng.

St va hay khng st, c khi st cao nhng tnh trng nhim c nng hay

gp trn c a suy gim min dch.

1.4. Thi k hi phc

T khi sau 7-10 ngy, hu ht cc mn nc ng my v khng li so.

Nhng trng hp bi nhim c th li so nh.

Nhng ngi c tin s bnh v da, bnh s hi phc chm hn.

2. Th ngi suy gim min dch

Hay gp ngi bnh ung th mu, suy ty, ung th cc c quan, iu tr c

ch min dch ko di, AIDS Tnh trng nhim trng nng hn, nt u

thng km theo hoi t v xut huyt, bnh din tin ko di hn.

Tn thng nhiu tng ng thi bao gm phi, gan, thn kinh v ng mu

ni mch ri rc. T l t vong cao nu khng iu tr tch cc (15%).

3. Thy u v thai k

Ph n mang thai b thy u c nguy c cao b vim phi thy u v nhim

trng bo thai, c th gy thy u bm sinh.

Nu m mang thai b thy u trong ba thng u thai k, tr s b d tt bm

sinh nh gim sn mt hoc nhiu chi, vim hc vng mc, c thy tinh th,

v cc sang thng da li so.

Nu m b thy u trong vng 5 ngy trc khi sinh, th tr s c nguy c

nhim trng ton thn.

Nu m b thy u 2 ngy sau sinh c th ly cho con qua ng h hp.

VI. BIN CHNG

1. Bi nhim sang thng da:

y l bin chng thng gp nht ca bnh thy u. Cc vi trng thng

Hnh 2. Sang thng da ca bnh thy u Hnh 3. Zona

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hin din l t cu (Staphylococcus aureus), lin cu (Streptococcus pyognes).

Ngoi ra cn c bin chng nhim trng khc nh vim m t bo, vim hch,

p xe di da, hoi th, vim phi, vim khp, ct ty vim.

2. Vim phi

Him gp tr em, thng gp thiu nin v ngi ln, ph n mang thai, tr

s sinh con ca b m bnh thy u v tr suy gim min dch. Thng cc

triu chng h hp ch thong qua, khi hon ton trong vng 24-72 gi, tuy

nhin cng c mt vi trng hp suy h hp dn n t vong.

Cc triu chng h hp thng gp bao gm ho, kh th, tm ti, au ngc v

khc ra mu bt u trong vng 1-6 ngy sau khi pht ban. X-quang phi c

biu hin tn thng dng nt hay vim phi m k.

iu tr sm bng Acyclovir v th oxygen s ci thin nhanh tnh trng kh

th

3. Bin chng thn kinh:

Thng gp tr 20 tui.

Gm cc bnh vim no, vim tu ct ngang, vim mng no v trng, vim

thn kinh ngoi bin

Vim no l bin chng thn kinh thng gp nht, c th gy t vong. Biu

hin lm sng l st, ri lon tri gic, tht iu, co git, hn m. Dch no ty

cho thy bch cu lympho chim u th v m tng, c th chn on xc

nh da vo k thut PCR-DNA pht hin VZV trong dch no ty

4. Hi chng Reye:

Lin quan n vic iu tr Aspirin cho tr di 15 tui trong thi gian u

mc.

Trong giai on hi phc s xut hin cc tiu chng: i, bt rt, kh chu, ph

no, bnh l no do tng NH3, xut huyt, tng ng huyt, tng men gan.

5. Bin chng khc:

Gim tiu cu.

Vim thn, hi chng thn h, hi chng tn huyt do tng ur mu

Vim khp

Vim c tim

Vim mng ngoi tim

Vim gan

Vim ty cp, vim tinh hon...

VII. CHN ON:

1. Chn on xc nh

Thng khng kh, ch yu da vo yu t dch t, cc triu chng lm sng, t

khi cn n cc xt nghim cn lm sng:

+ Yu t dch t:

Tip xc vi bnh nhn thy u

Gio trnh Bnh nhim

377

Tin s cha mc bnh ln no.

+ Lm sng: Pht ban mn nc c trng, ban nhiu thi k khc nhau trn

cng mt vng da

+ Cn lm sng:

- Phn lp siu vi: VZV c th c phn lp t mu trong giai on sm ca

bnh, hay c th t mn nc, dch no ty; tuy nhin thi gian ko di t 7-10

ngy.

- Pht hin t bo a nhn khng l trn da: pht Tzank trn sang thng mn

nc, nhy 60%

- Huyt thanh chn on: Test ELISA (enzyme-linked Immunoabsorbent

assay) da vo s hin din ca khng th IgM antivaricelle-zona.

2. Chn on phn bit

- Nhim Herpes simplex: Thng trn c a tn thng da sn c, hay ti pht

cng mt v tr, c chu k, sang thng l nhng mn nc nh, i khi au

rt, chn on da vo phn lp virus.

- Bnh tay chn ming: Hay gp tr em, bnh nhim trng ton thn, do

Enterovirus, sang thng l nhng mn nc nh vi mm, thng tp trung

lng bn tay, bn chn; hng c th c mn nc lm tr au, kh nut.

- Cc pht ban mn nc do nguyn nhn khc nh Staphylococcus aureus,

vim da do tip xc, cn trng t, chc u, zona

VIII. IU TR

1. iu tr triu chng:

Chng nga ti ch hay ton thn bng khng Histamin, trnh gi lm mn

nc b v, c th iu tr an thn.

Gim au, h st bng Acetaminophen (khng dung Aspirin trnh hi

chng Reye).

2. Phng nga v iu tr bi nhim

V sinh c nhn, ct mng tay, mc qun o thong mt, sch

Lm sch da, tm ra hng ngy bng dung dch st trng v thay qun o hng

ngy.

Khi c du hiu bi nhim th s dng khng sinh

3. iu tr bin chng (nu c).

4.Thuc chng virus: Acyclovir.

Bnh thy u thng din tin lnh tnh, thng t khi; tuy nhin c th s

dng thuc chng virus rt ngn thi gian bnh hay trong nhng trng hp

nguy c cao. Thuc hiu qua nht khi s dng sm trong vng 24-48 gi khi

bnh.

Ch nh: Thy u xy ra trong khi mang thai, trn bnh nhn bnh c tnh,

ghp ty xng v c quan, ang iu tr corticoide liu cao, suy gim min

dch, tr s sinh, c bin chng vim phi v vim no.

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378

Liu dng: Tr di 1 tui: 10mg/kg/ ln/ mi 8 gi.

Tr trn 1 tui: 20mg/kg/ln 4 ln/ngy, khng qu 800mg/ ln

Ngi ln: 800mg/ ln 5 ln/ ngy

Thi gian iu tr l 5-7 ngy hay cho n khi khng cn sang thng mi mc

trong vng 48 gi.

Nhng trng hp nng c th dng Acyclovir tnh mch, liu 500mg/m2/ liu/

mi 8 gi .

Ngoi ra cn c mt s thuc chng virus khc nh: Valacyclovir,

Famciclovir,Vidarabine, Foscarnet

IX. PHNG NGA

1. Phng nga chung

- Cch ly bnh nhn nhm hn ch ly lan, c bit l trong thi k pht ban.

Thi gian cch ly thng cho n khi nt u ng my.

2. Chng nga:

2.1. To min dch ch ng:

Thuc chng nga lm bng virus sng gim c lc, c ch nh trong cc

trng hp:

i tng khe mnh: gy min dch ch ng chng VZV (t 12 thng

tui).

Bnh nhn c nguy c cao v tip xc gn

Hin nay trn th trng dng thuc c tn Varilrix, tim di da, liu dng:

T 12 thng tr ln n 12 tui: 1 liu (0,5mL/liu)

T 13 tui tr ln: 2 liu vi khong cch gia 2 liu t 6-10 tun.

2.2. To min dch th ng:

Dng Varicella-zoster immune globuline (VZIG) d phng cho ngi tip

xc vi ngi bnh. Liu dng l 1 l cho mi 10kg cn nng, tim bp cng

sm cng tt trong vng 96 gi sau khi tip xc vi bnh nhn thu u, tuy

nhin cng cn theo di st iu tr Acyclovir khi cn thit.

TI LIU THAM KHO

1. Cao Ngc Nga, Bnh thy u, Bnh truyn nhim, Nh xut bn Y hc,

TPHCM, 1997, 337-347.

2. Richard J. Whiley, Herpes Zoster virus, Principles and Practice of

Infectious diseases, 6th edition, 2005, 1780-1786.

3. Richard J. Whiley, Herpes Zoster, Harrisons Principles of Internal

Medicine- 13th 1994:825-827.

4. Maladies es Infectieuses et Tropicals- E.PIlly 2004- 19 dition- pages

443-444.

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379

CU HI T LNG GI

1. Virus gy bnh thy u

A. L Varicella- zoster.

B. H Flavivirus.

C. Khng c thuc no c ch c

D. Khc vi virus gy bnh Zona

E. Khng ly lan ng k

2. Thi gian ly nhiu nht

A. Lc ban ng my

B. Lc bnh nhn bt u st

C. Lc xut hin sang thng mn nc c

D. Ngn trong vi gi.

E. Khng cu no ng

3. K tn cc thi k tin trin ca nt u

A. Sn / mn nc trong/mn nc c/my vng

B. Sn /mn nc c/mn nc trong/my vng.

C. Sn / my vng/mn nc trong/mn nc c

D. Mn nc trong/my vng/mn nc c/sn .

E. Khng theo th t ny.

4. Bnh thy u khng xy ra ngi ln v tr s sinh

A. ng

B. Sai

5. Thuc chng virus Acyclovir:

A. Hiu qu cao khi dng cng sm trong vng 24 gi u.

B. Cc trng hp nng c th dng ng tnh mch

C. C ch nh trong trng hp bin chng vim phi v vim no

D. Tt c sai

E. Tt c ng