GTG (+ other sources): Viruses in pregnancy Flashcards
(119 cards)
1
Q
What are the names of the virus responsible for chickenpox?
A
Varicella Zoster Virus/Human Herpes Virus 3
2
Q
What type of virus is VZV?
A
DNA virus
3
Q
What is the incubation period for VZV, Rubella, Parvovirus and Measles?
A
Parvovirus: 4-21 days
VZV: 7-21 days
Measles: 7-21 days
Rubella: 14-21 days
4
Q
When is the infectivity period for VZV, Rubella, Parvovirus and Measles?
A
Parvovirus: 10 days before to day of rash
Measles: 4 days before to 4 days after
Rubella: 7 days before to 10 days after
VZV: 2 days before until vesicles crusted
5
Q
What percentage of the population is seropositive for VZV, Rubella, Parvovirus, Measles?
A
Parvovirus: 50-60%
Measles: >95%
Rubella: 93%
Chickenpox: >90%
6
Q
How frequently does primary infection with VZV occur in pregnancy?
A
3 in 1000 pregnancies
7
Q
What type of vaccine VZV?
A
Live attenuated vaccine
8
Q
How long does the immunity persist post VZV vaccination?
A
20 years
9
Q
How many doses of VZV vaccine and when?
A
2 doses 4-8 weeks apart
10
Q
Effect of VZV vaccination
A
Reduces primary infection 80%
Reduces mortality 2/3
11
Q
How long after vaccination should pregnancy be avoided for?
A
4 weeks
12
Q
Risks of varicella in pregnancy
A
Maternal risks:
- Pneumonia
- Hepatitis
- Encephalitis
- Death
Fetal varicella syndrome
Neonatal varicella infection
13
Q
What percentage of mothers with VZV with contract pneumonia?
A
5%
14
Q
Mortality rate associated with VZV in pregnancy
A
0-14%
15
Q
When does fetal varicella syndrome occur?
A
Patients who contracted varicella in first 28 weeks. Virus subsequently reactivates in utero.
16
Q
How often does fetal varicella syndrome occur?
A
1%
17
Q
Features of fetal varicella syndrome
A
Dermatomal skin scarring
Eye defects (microphthalmia, chorioretinitis, cataracts)
Limb hypoplasia
Neurological abnormalities (microcephalic, Corsica atrophy, mental retardation, sphincter dysfunction)
18
Q
Risk of miscarriage with VZV
A
No increase in risk of first trimester miscarriage
19
Q
When does neonatal varicella infection occur?
A
When maternal infection occurs 1-4 weeks before delivery or immediately postpartum.
20
Q
How is neonatal varicella infection contracted?
A
Transplacental, ascending vaginal or direct contact with lesions.
21
Q
What proportion of babies whose mothers develop VZV in the 4 weeks prior or immediate postpartum period will become infected?
A
50% infected.
23% clinical varicella.
22
Q
Management of babies born within 7 days of mothers rash or where rash occurs within 7 days of birth.
A
Babies should have VZIG +/- aciclovir.
23
Q
What constitutes a significant contact?
A
Same room for 15 minutes or more
Face-to-face contact
Contact in setting of large open ward
24
Q
Management of a pregnant woman who has a VZV contact?
A
If history of chickenpox - no further action required.
If uncertain history (or woman from tropical/subtropical country) - check booking sample for VZV IgG. If present - no further action.
If not immune then give VZIG if less than 10 days since contact (or for continuous exposure less than 10 days since appearance of rash in index case). Advise potentially infectious from 8-28 days after contact. Discuss postpartum varicella immunisation.
25
Management of pregnant woman with chickenpox
If <24 hours since appearance of rash and >20+0 weeks pregnant, aciclovir 800mg 5 x per day for 7 days. Consider if <20 weeks. Avoid delivery of baby until at least 7 days after rash.
If <28 weeks then refer to FMU at 16-20 weeks or 5 weeks after the infection and consider amniocentesis to detect varicella DNA.
26
Which pregnant women with chickenpox should be inpatients?
Severe disease - respiratory, neurological, haemorrhagic rash, bleeding.
IV Aciclovir.
27
RIsk of anaphylaxis with VZIG
<0.1%
28
Benefits of VZIG on fatal varicella syndrome
2.8% FVS if no VZIG, 0% if VZIG.
29
When can you give a second dose of VZIG?
Further exposure reported and 3 weeks elapsed since last dose.
30
What is the positive predictive value for the presence of VZV antibodies in a patient with a history of chickenpox?
99%
31
What type of virus is CMV?
DNA virus (herpes virus)
32
What percentage of pregnant population are seropositive for CMV?
Around 50%.
| Within Asian population - 90%, White 45%.
33
What percentage of pregnant women seroconvert for CMV in pregnancy?
1-7%
34
What percentage of live births are affected by CMV?
0.2-2.2%
35
What are the consequences of congenital CMV?
12% sensorineural hearing loss
| 8% of cerebral palsy
36
Most common viral cause of congenital infection
CMV
37
Most common non-genetic cause of sensorineural hearing loss
CMV
38
What is the risk of congenital infection if mother has primary infection in pregnancy?
T1: 30%
T3: 47%
(But cases more severe and more likely to be detected antenatally in T1)
39
What is the risk of congenital infection if mother has secondary infection (reactivation) in pregnancy?
1-2%
40
What percentage of infected infants with CMV will be symptomatic at birth?
13%
41
What is the mortality rate associated with symptomatic congenital CMV?
30%
42
What proportion of infants who are asymptomatic at birth will go on to develop symptoms with CMV?
6-23%
43
What percentage of women will be asymptomatic with a primary infection with CMV?
90%
44
Who to suspect CMV seroconversion in?
- Anyone with flu-like illness
- Anyone with glandular fever and negative EBV serology
- Anyone with hepatitis and negative hepatitis serology
- Anyone with ultrasound features suggestive of CMV (only present in 25%)
45
How to test for maternal CMV?
- Presence of IgG in previously seronegative individual
OR
- Presence of IgG and IgM of LOW avidity (<30%) suggests infection within last 3 months (>60% High avidity suggestive of infection more than 3 months ago or secondary infection)
46
How to confirm fetal infection with CMV?
Amniocentesis for CMV DNA - must be after 20 weeks and 6-7 weeks since infection.
47
Incubation period of CMV
3-12 WEEKS
48
What proportion of infants with congenital CMV are born to women with pre-existing immunity?
2/3
49
Clinical features of congenital CMV at birth
```
Jaundice
Petechial rash
Hepatosplenomegaly
Microcephalic
SGA
```
50
Treatment for maternal CMV
Nothing. Supportive.
51
Treatment for congenital neonatal CMV
Vanganciclovir or ganciclovir within first 4 weeks of life.
52
Management of neonate with suspected congenital CMV
Confirm diagnosis with urine or mouth swab for PCR within first 3 weeks of life
53
Management of fetus with known CMV infection
- Serial growth scans to include imaging of brain every 2-3 weeks
- Fetal brain MRI 3-32 weeks
- Consider fetal blood sample for platelet level
If severely symptomatic (USS brain abnormalities and low platelets) then prognosis poor)
54
What type of virus is HSV?
DsDNA herpes virus
55
What are the types of HSV?
Type 1 - usually oral herpes (responsible for 30% of genital infections)
Type 2 - usually genital herpes
56
Prevalence of symptomatic HSV
37 per 100,000
57
Incidence of neonatal herpes
1 in 60,000 births
58
How to make diagnosis of primary HSV infection?
Swab lesion for viral PCR and compare type to maternal serology.
59
Types of neonatal infection (HSV)
- Localised (skin, eyes, mouth) - 30% of cases
| - CNS or disseminated - 70% of cases
60
Risks of localised infection (HSV)
Good prognosis
| <2% risk of neurological/ocular morbidity
61
Risks of CNS/dissemination infection (HSV)
CNS infection:
- Mortality rate 6%
- Neurological morbidity rate 70%
Disseminated infection:
- Mortality rate 30%
- Neurological morbidity rate 17%
62
Effect of first trimester primary herpes
Nil fetal risks
| Maternal risk of disseminated infection
63
Management of primary HSV
Before 28 weeks - treat aciclovir and offer prophylaxis from 36 weeks (32 weeks if HIV positive)
After 28 weeks - treat Aciclovir and continue treatment until delivery.
Deliver via CS if within last 6 weeks of pregnancy.. If vaginal delivery then for neonatal aciclovir (20mg/kg TDS 10 days whilst awaiting result of lumbar puncture).
64
Management of recurrent HSV
Acyclovir for any flare ups and then prophylactic from 36 weeks.
65
Risk of neonatal herpes with recurrent HSV at time of delivery
1%
66
Risk of neonatal herpes with primary HSV within 6 weeks prior to delivery
41%
67
Recurrence rate of HSV infections
4 per year for HSV2
1 per year for HSV1
Recurrence rate reduces over time.
68
Type of virus Zika virus
Flavivirus
| SsRNA
69
Vector for Zika virus transmission
Aedes Egypti mosquito
70
Incubation period Zika virus
3-12 days
71
Transmission methods of Zika virus
```
Primarily bite from aedes mosquito
Trans placental
Sexually transmitted
Blood transfusion
(Present in breast milk but no transmission confirmed via this route)
```
72
How long is Zika virus detected in sperm for?
188 days but infectious only 69 days
73
When is Zika virus mosquito Most active?
During daylight
74
Prevention of Zika virus
Clothing
DEET
Mosquito nets
75
Symptoms of Zika virus
Majority minimal symptoms. 2-7d short illness with rash, itching, fever, headache, arthralgia, myalgia, conjunctivitis, retro-orbital pain.
Can trigger Guillan Barre
76
How long to avoid pregnancy for after travel to Zika virus country?
2 months if female partner.
| 3 months if male partner.
77
What percentage does congenital Zia syndrome occur?
10%
78
Features of congenital Zika syndrome?
FGR
Oligohydramnios
Talipes
Microcephalic, microopthalmia, cerebral calcification, ventriculomegaly, periventricular cysts, cerebellar atrophy, cysts,
79
Investigation of a pregnant woman who has been to a Zika virus country
If she is symptomatic (or has been symptomatic within 2 weeks of return) then test serum for viral PCR and do baseline ultrasound. If infection confirmed or USS abnormalities then refer to FMU. If negative and confirmed on second sample then routine pregnancy care.
If she is asymptomatic then store serum and offer baseline USS and repeat at 18-20 weeks and consider at 30-32 weeks if normal. If USS abnormal then refer to FMU.
80
Type of virus parvovirus
ssDNA
81
What cells does parvovirus target?
Erythroid progenitor cells
82
What does parvovirus cause?
Slapped cheek syndrome (erythema infectiosum or fifth disease)
83
Percentage of adults with parvovirus infection who are asymptomatic
25-50%
84
What age range is parvovirus most common in?
6-10 year olds
85
What percentage of pregnancies are affected by parvovirus?
1 in 500
86
What is the infectivity rate of parvovirus?
50%
87
What is the risk of intrauterine infection with parvovirus at different gestations?
<4 weeks: 0%
4-16 weeks: 15%
>16 weeks: 25-70%
88
What percentage of pregnancies exposed to parvovirus will develop non-immune hydrops?
3% of pregnancies exposed at < 20 weeks
89
What is the mortality rate associated with parvovirus associated hydrops?
50%
90
What is the average length of time between maternal infection and fetal symptoms in parvovirus?
6 weeks
91
What is the fetal death rate associated with parvovirus?
9% if <20 weeks, <1% if >20 weeks
92
What is mirror syndrome?
Rare condition which presents in late pregnancy with maternal oedema, hypertension, proteinuria and anaemia during conservative management of hydrops.
93
How to make diagnosis of parvovirus in pregnancy?
Test IgM - if not detected, it excludes infection in the four weeks prior.
If present then confirm diagnosis by testing for viral DNA titre and looking at IgG on booking sample.
94
What to do in someone exposed to parvovirus in pregnancy?
Test IgG and IgM.
If IgG positive and IgM negative - immune.
If both negative - susceptible.
If IgM positive - suspect infection.
95
Management if parvovirus infection confirmed in pregnancy
Refer to FMU (to be seen within 4 weeks)
- Serial USS 4 weeks from symptoms/seroconversion
If suspected hydrops:
- Amnio
- Fetal blood sample and intrauterine RBC transfusion
96
What benefit is seen from RBC transfusion in parvovirus infection?
Improves resolution from 5% to 55%
97
At what gestation can a woman be reassured if no hydrops present when parvovirus contracted <20 weeks?
30 weeks
98
Type of virus rubella
ssRNA
| Togaviridae
99
Infectivity risk with rubella
90%
100
Percentage of people with rubella infection asymptomatic
50%
101
Risk of intrauterine infection at different gestations with rubella infection
<11 weeks: 90%
11-16 weeks: 55%
>16 weeks: 45%
102
Risk of adverse fetal outcome after rubella infection at different gestations
<11 weeks: 90%
11-16 weeks: 20 weeks
16-20 weeks: Mild deafness
>20 weeks: No risk
103
Features of congenital rubella syndrome
Eye defects (cataracts)
Hearing impairment
Cardiac abnormalities (PDA and pulmonary artery stenosis)
CNS defects (microcephaly, mental and psychomotor retardation and progressive pancephalitis)
IUGR
Autism
Endocrine abnormalities (DM, thyroid)
104
Risk of miscarriage after first trimester rubella infection
20%
105
What to do if you suspect rubella in pregnancy?
Notifiable condition - contact health protection team who tell you how to test!
If positive - refer to FMU if <20 weeks and reassure if >20 weeks.
106
What to do if contact with suspected rubella?
Contact local health protection team.
Conditions for immunity:
- 2 x documented vaccine doses
OR - 1 x antibody test
If not met immunity - test antibodies
107
What to do if antibody tests show susceptible to rubella and has had contact?
Repeat 4 weeks
108
For how long can infants with Congenital Rubella Syndrome transmit the virus?
Up to 1 year
109
Mosquito responsible for malaria
Anopheles
110
What is the most common type of malaria?
P. falciparum (80%, biggest burden in UK travellers, mostly West Africa)
111
Risk of contracting malaria during 1 month stay without chemoprophylaxis in various continents:
```
Oceania: 1 in 20
Africa: 1 in 50
Asia/India: 1 in 500
South America: 1 in 2500
Central America/Caribbean: 1 in 10000
```
112
Chemoprophylaxis in pregnancy for malaria
Mefloquine in 2nd/3rd trimesters (not if epileptic/neuropsychiatric disorders)
Chloroquine safe but may not be effective.
Malarone if chloroquine resistant and mefloquine CI.
113
Definition of severe/complicated malaria
Parasitaemia >2% or severe clinical features
114
What is Algid malaria?
Gram negative septicaemia secondary to malaria
115
Mortality rate for uncomplicated and severe malaria
Uncomplicated 0.1%
| Severe 15-20% non-pregnant, pregnant 50%
116
Diagnosis of malaria
Blood film microscopy
117
When can malaria be excluded in a febrile patient?
Three negative malaria smears 12-24h apart
118
Treatment for malaria in pregnancy
Uncomplicated: Admit to hospital
Severe: Admit to ICU
Uncomplicated:
- Falciparum: Quinine and clindamycin
- Other: Chloroquine
Complicated:
- IV Artesunate
- IV Quinine
119
Most common and important adverse effect of quinine
Hypoglycemia
