Infectious diseases - Vaccination, influenza, TB, Zica and COVID Flashcards
What are the 4 main types of vaccine?
Killed organisms
Live-attanuated - replicate of host
Sub-unit vaccines - use antigen subunit
Toxoid - bacterial exotoxin
Which vaccines are live attenuated
Bacterial
- BCG, tuberculous
Viral
- MMR
- Polio
- Varicella zoster
- Adenovirus
- Yellow fever
What 2 vaccines are offered in pregnancy?
Whooping cough, offered between 16-32 weeks.
Most deaths occur in children before they can be vaccinated, vaccinating the mother protects the baby
Influenza
- Risk higher in pregnancy, also risk to baby, offered Sep-Feb
Rubella offered pre-pregnancy if not already vaccinated.
What antivirals can be give in the treatment of influenza? When should they be commenced?
Oseltamivir (tamiflu) 75mg OD- 48hrs
Zanamivir (relenza) 10mg inhaled OD - 36hr
Can still be given with 7 days
Which antiviral for influenza is preferred in pregnancy +/- breastfeeding.
Pregnancy - Zanamivir, oseltamivir if severe/zanamivir not available
Oseltamivir if breastfeeding
If pregnant women are in close contacting with H1N1 influenza, what should occur?
1) Zanamivir (10 mg inhaled daily) or oseltamivir (75 mg daily by mouth) for 10 days after exposure
When are people infectious with influenza?
1 day before symptoms up tp 5-7 days after becoming sick.
Children and people with weakened immune system may be unwell for longer than 7 days.
How long is protection conferred after influenza vaccine?
2 weeks
Note H1N1 vaccine is different - Pandemrix
What type of pathogen is malaria
Protozoa called plasmodium. There are 4 types that effect humans - P. falciparum, viva, oval and malariae
Primary host - female anopheles mosquito
Which parasite causes the most severe infection?
P falciparum (cerebral complications)
What % of malaria infection in UK are due to P.falciparum?
80%
Which trimester is highest risk of severe infection with malaria?
2nd
What are the maternal complications of malaria in pregnancy?
Anaemia
Severe cerebral malaria
Acute pulmonary oedema / ARDS
Hypoglycaemia – commoner in pregnancy and may be worsened by treatment with iv quinine
Renal failure with haemoglobinuria
DIC
Maternal mortality
What are the fetal complications of malaria in pregnancy?
Miscarriage
Pre-term delivery
Stillbirth
Low birth weight
Fetal anaemia
Neonatal death
Neonatal anaemia
Congenital malaria - evidence of placental infection at delivery in up to 25% of cases. P falciparum infection in pregnancy is typically has parasites sequestered in the placenta
Increased susceptibility to other infections
Failure to thrive
Prevention of malaria using ABCD Mnemonic?
Awareness - avoid endemic area, avoidance strategies, can sitill present within 1 year of visit
Bite prevention - Dusk til dawn, 50% DEET, bed nets, clothing
Chemoprophyalxsis - Take until 7 days after leaving area, should not become pregnancy during this time and need to await the clearance time of those drugs.
Diagnose & treat
Drug excretion time of
- Mefloquine
3 months
Drug excretion time of
- Atovaquone and proguanil (Malarone®)
2 weeks
Drug excretion time of
- Doxycycline and proguanil
1 week
Which is the prophylaxis of choice if 2nd/3rd trimester or breastfeeding?
When is it contraindicated?
Mefloquine
CI Hx depression, Neuro-psychiatric disorder, epilepsy, hypersentivity to mefloquine/quinine
What investigation should be performed to Ix malaria.
Thick and thin blood films - need 3 negative films 12-24hrs apart to exclude malaria.
FBC, glucose, ABD, U+E, LFT, CRP, urine, CXR, stool culture, blood culture. Consider LP
Obs USS
Where should pregnancy women with malaria be treated?
Uncomplicated - admit to hospital
Complicated - ITU
What is the treatment of choice for severe falciparum malaria?
IV artesunate
or
IV quinine + clindamycin
What is the treatment of choice for uncomplicated falciparum malaria?
Qunine and clindamycin
What is the treatment of choice for P. vivax, P. ovale or P. malariae.
Chloroquine
What signs are of severe falciparum infection?
- Impaired GCS
- Hypoglyceamia
- Pulmonary oedema or ARDS
- Hyperparasitaemia >2% parasite RBC
- Severe anaemia <80
- Abnormal bleeding/DIC
- Haemglobinuira
- Renal impairment/electrolyte, acidosis <7.3
Hyperlactaemia
Shick
Placental parasitaemia is asssocaitewd with congenital malaria and increased mortality.
how should this be tested for?
Cord blood film + weekly blood films from neonate for 28 days
Send placenta to histology
Incidence of TB in pregnancy women?
4.2/100 000
Risk factors of TB
Close contact with infectious cases
Travel to or receiving visitors from places where TB is endemic
Living in ethnic minority communities originating from places where TB is endemic
Immune compromise – HIV positive, the very young / elderly
Chronic poor health and mal-nutrition, drug abuse or alcoholism
Living in over-crowded housing conditions
How to IX TB
Microbiology of sputum, CSF - acid-fast bacilli
Mantous test - not effect by pregnancy, but +ve if previous BCG
Bloods/CXR +/- MRI
Treatment of TB
Isoniazid, rifampicin and ethambutol for 6 months.
What is a common side effect of isoniazid? How is it prevented?
Isoniazide-induced neuropathy - pyridoxine 10mg OD
Monthly LFT
Side effect of ethambutol?
Retrobulbar neuritis - blurred vision and mental scotomata
Can you breastfeed with TB?
Anti-TB drugs cross into breastmilk but not contraindicated
What contact tracing should occur with TB
All close contacts based on history, examination, tuberculin testing and chest X-ray.
TB is a notifiable disease
Can the BCG vaccine be given in pregnancy?
No, live vaccine so contraindicated
Should be offered to neonates & infants in areas where annual TB incidence > 40 per 100,000/ Fax TB in last 5 years, parent/grandparternt from country with high incidence
Do not give to babies who mothers are HIV +ve until shown to be HIV -ve
How is Zica virus transmitted?
Infected Aedes species of mosquito (same as dengue, yellow fever)
Can maternal - fetal transmission of zica occur?
Yes via placental barrier
Not though breastmilk
When to screen for Zica infection in pregnancy
At booking ask re travel history
- If area with active zica, present with zica symptoms or symptoms within 2 weeks of travel should be tested
If woman test +ve for Zica virus infection, What should be done?
Redere to FMU for 4 weekly USS and consider MRI
If +ve travel Hx offer baseline fetal USS
If travelled to Zica area but does not have symptoms of the infections
Offer baseline USS then 4 weekly USS
How long should conception be avoided if travelled to Zica country?
3 months if both travelled or male partner travelled
2 month if female travelled
From date left area or sexual contact with a potential infectious partner
If women develops symptoms compatible with Zica should avoid pregnancy for 2 month
At what gestation can a Dx of microcephalic be given?
Until 28 weeks but not possible to given definitive Dx at all.
Consider amniocentesis for zica virus if microcephaly
If person has zica virus, when can they try to concieve/donate gametes/fertility treatment?
6 months
When can a sperm donor donate sperm after visiting a zica country?
Asymptomatic sperm donors should be deferred for six months after return unless the semen tests negative for Zika virus by NAT
Which covid variant is associated with the most severe disease?
Delta varient
Effects of COVID 19 on foetus?
Double risk of stillbirth
?Increased SGA
- no congenital abnormality, vertical transmission is rare
Can breastfeeding or pregnant women receive the covid 19 vaccine?
Yes both can, do not need to stop breast-feeding.
If a patient has COVID 19 and is on aspirin?
Should be discontinued, duration of infection as may increase risk of thrombocytopenia and bleeding
What treatments can be given for COVID 19 following MDT discussion?
Steroids - PO preg 40mg PD or IV hydrocortisone 80mg BD for 10 days or until discharge
Tocilizumab if evidence of systemic infection CRP >75
According to UKOSS, what % of hospitalised women required ITU care?
5%
Maternal mortality of hospitalised pregnancy women 2.4/100 000
