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8. Viral diseases
– A p ositive d iagn osis is m ad e w hen at least 2 d ifferen t tests (2 d ifferen t bran d s) are
both clearly p ositive.
– A first n egative test sh ould be rep eated 3 m on th s later to exclud e serocon version
(w in d ow p eriod ).
CD4 lymphocyte counts
– C D 4 cell d ep letion is a m ark er of th e p rogression of im m un e d ep ression . I t is a
p red ictor of the d evelop m en t of op p ortun istic in fection s or n eop lasm s an d can be
used to orien t their d iagn osis (e.g. cerebral toxop lasm osis or cryp tococcal m en in gitis
ap p ear w hen the C D 4 coun t is below 1 0 0 ce3lls/ m m . If clin ical sign s in d icatin g thes
in fection s are p resen t, but the C D 4 coun t is greater than or eq ual to 2 0 0 c3ells/ m m , i
is un lik ely that these in fection s are p resen t).
– T he C D 4 cell coun t is also used as an in d icator for p rim ary p rop hylaxis (see primary
prophylaxis, p age 2 1 1 ) an d in itiation of A R V treatm en t.
Treatment of HIV infection
Antiretroviral treatment (ARV)
A m ulti-d rug (at least 3 ) an tiretroviral regim en (A R T ) is the referen ce treatm en t. It d oes
n ot erad icate th e virus, but slow s th e p rogression of th e d isease an d im p roves th e
p atien t‟s clin ical state by red ucin g viral rep lication an d con seq uen tly in creasin g the
C D 4 cell coun t to levels beyon d the threshold of op p ortun istic in fection s.
Therapeutic classes
T hree m ajor classes of A R V exist:
– N R T I ( n ucleosid e/ n ucleotid e reverse tran scrip tase in h ibitors): z id ovud in e ( A ZT ) ,
lam ivud in e ( 3 T C ) , d id an osin e ( d d I ) , stavud in e ( d 4 T ) , abacavir ( A B C ) ,
ten ofovir
(T D F ), em tricitabin e (F T C ). 8
– N N R T I (n on -n ucleosid e reverse tran scrip tase in hibitors): efaviren z (E F V ),
n evirap in e
(N V P ). H IV -2 is n aturally resistan t to N N R T I.
– P I (p rotease in hibitors): in d in avir (I D V ), lop in avir (L P V ), riton avir (R T V ),
saq uin avir
(S Q V ).
Principles of ARV treatment
– D aily trip le th erap y m ust be tak en for life to p reven t th e rap id d evelop m en t of
resistan ce. I t is im p ortan t that the p atien t un d erstan d s th is an d th at ad heren ce to
treatm en t is op tim al.
– T he m ost w id ely-used an d easiest regim en s to ad m in ister are 2 N R T I + 1
N N R T I : e.g.
d 4 T + 3 T C associated w ith N V P or E F V ( E F V is con tra- in d icated in
p regn an t
w om en ).
– In the even t of treatm en t failure, use as a secon d -lin e: 2 other N R T I + 1 P I .
Other p ossible com bin ation s exist w hich are less com m on ly used or m ore d ifficult to
m an age.
cCoruitenritabfeolroAwR2V0tr0eactmelelsn/t m m ).
A s th ere are large n um bers of p atien ts w h o w ould ben efit from treatm en t, it seem s
legitim ate to p rioritise the treatm en t of p atien ts alread y in clin ical stage 3 an d 4 an d
p atien ts m ost at risk of d evelop in g severe op p ortun istic in fection s (p atien ts w ith a C D 4
3
– A p ositive d iagn osis is m ad e w hen at least 2 d ifferen t tests (2 d ifferen t bran d s) are
both clearly p ositive.
– A first n egative test sh ould be rep eated 3 m on th s later to exclud e serocon version
(w in d ow p eriod ).
CD4 lymphocyte counts
– C D 4 cell d ep letion is a m ark er of th e p rogression of im m un e d ep ression . I t is a
p red ictor of the d evelop m en t of op p ortun istic in fection s or n eop lasm s an d can be
used to orien t their d iagn osis (e.g. cerebral toxop lasm osis or cryp tococcal m en in gitis
ap p ear w hen the C D 4 coun t is below 1 0 0 ce3lls/ m m . If clin ical sign s in d icatin g thes
in fection s are p resen t, but the C D 4 coun t is greater than or eq ual to 2 0 0 c3ells/ m m , i
is un lik ely that these in fection s are p resen t).
– T he C D 4 cell coun t is also used as an in d icator for p rim ary p rop hylaxis (see primary
prophylaxis, p age 2 1 1 ) an d in itiation of A R V treatm en t.
Treatment of HIV infection
Antiretroviral treatment (ARV)
A m ulti-d rug (at least 3 ) an tiretroviral regim en (A R T ) is the referen ce treatm en t. It d oes
n ot erad icate th e virus, but slow s th e p rogression of th e d isease an d im p roves th e
p atien t‟s clin ical state by red ucin g viral rep lication an d con seq uen tly in creasin g the
C D 4 cell coun t to levels beyon d the threshold of op p ortun istic in fection s.
Therapeutic classes
T hree m ajor classes of A R V exist:
– N R T I ( n ucleosid e/ n ucleotid e reverse tran scrip tase in h ibitors): z id ovud in e ( A ZT ) ,
lam ivud in e ( 3 T C ) , d id an osin e ( d d I ) , stavud in e ( d 4 T ) , abacavir ( A B C ) ,
ten ofovir
(T D F ), em tricitabin e (F T C ). 8
– N N R T I (n on -n ucleosid e reverse tran scrip tase in hibitors): efaviren z (E F V ),
n evirap in e
(N V P ). H IV -2 is n aturally resistan t to N N R T I.
– P I (p rotease in hibitors): in d in avir (I D V ), lop in avir (L P V ), riton avir (R T V ),
saq uin avir
(S Q V ).
Principles of ARV treatment
– D aily trip le th erap y m ust be tak en for life to p reven t th e rap id d evelop m en t of
resistan ce. I t is im p ortan t that the p atien t un d erstan d s th is an d th at ad heren ce to
treatm en t is op tim al.
– T he m ost w id ely-used an d easiest regim en s to ad m in ister are 2 N R T I + 1
N N R T I : e.g.
d 4 T + 3 T C associated w ith N V P or E F V ( E F V is con tra- in d icated in
p regn an t
w om en ).
– In the even t of treatm en t failure, use as a secon d -lin e: 2 other N R T I + 1 P I .
Other p ossible com bin ation s exist w hich are less com m on ly used or m ore d ifficult to
m an age.
cCoruitenritabfeolroAwR2V0tr0eactmelelsn/t m m ).
A s th ere are large n um bers of p atien ts w h o w ould ben efit from treatm en t, it seem s
legitim ate to p rioritise the treatm en t of p atien ts alread y in clin ical stage 3 an d 4 an d
p atien ts m ost at risk of d evelop in g severe op p ortun istic in fection s (p atien ts w ith a C D 4
3
