Immunology Flashcards
(40 cards)
Which microorganisms are splenectomy patients particularly at risk from?
- Strep pneumoinae
- Haemophilus influenzae type B
- Nisseria meningitidis
Which vaccines should be offered to splenectomy patients?
- HiB
- Men WACY
- Men B
- Pneumococcal
- Influenza
Where possible vaccines should be administered 2 weeks prior to elective splenectomy, though if not vaccinated surgery should not be delayed
In emergency splenectomy, vaccinations should be administered after 2 weeks, unless risk of failure to vaccinate, in that case can be given earlier
Which prophylactic Abx should be given to splenectomy patients? - for how long?
- Phenoxymethylpenicillin 250mg BD
– Or Amoxicillin 250gm OD - Erythromycin 500mg BD if Pen allergic
Should be given for at least the first 2 years, then continued lifelong if at continued high risk of pneumococcal infection (strep pneumoniae)
Which are the live vaccines?
MMR BOYZZ
- MMR
- BCG
- Oral polio
- Yellow fever
- vZv (chickenpox / shingles)
- influenZa (live attenuated intranasal vaccine)
What are the risks for pregnant women who are exposed to VZV (chickenpox or shingles)?
Women who are seropositive to VZV IgG are not at risk
The risk to seronegative women is:
- Fetal varicella syndrome before 28 weeks
- Neonatal infection if delivered within 4 weeks of infection
How should a pregnant woman who has had contact with chickenpox be assessed?
(exposed, not developed rash)
- Determine significance of the exposure
- Women with absent or uncertain history of VZV immunity (previous chicken pox / shingles / vaccine) should have bloods checked for VZV IgG
- If not immune, and had significant exposure, should be offered IVIG as soon as possible- it is effective if given within 10 days of exposure
what is the treatment for pregnant women who develop VZV in pregnancy?
(have a rash)
- If they present within 24 hours of rash onset and at 20+ gestation (consider use before 20 weeks also), then give Oral Aciclovir (800mg 5 times daily for 7 days)
- Avoid contact with susceptible individuals (pregnant women, neoneates…) until all lesions crusted over (around 5 days after onset of rash)
- Referral to fetal medicine to be arranged at 16-20 weeks, or 5 weeks after infection
What are the complications of Fetal Varicella Syndrome?
- Skin scarring in dermatomal distribution
- Eye defects (microphthalmia, chorioretinitis, cataracts)
- Hypoplasia of the limbs
- Neurological abnormalities (microcephaly, cortical atrophy, mental retardation, bowel and bladder sphincter dysfunction)
What are the possible complications of Rubella in pregnancy?
- Can result in fetal loss
-
CRS congenital rubella syndrome:
- Cateracts
- Deafness
- CArdiac abnormalities
- Microcephaly
- IUGR
CRS most likely to cause damage when infected in first 8 weeks gestation
After 20 weeks gestation, only deafness reported
When is antibody testing necessary to guide rubella vaccination?
Healthcare workers need to be immune to measles and rubella
Satisfactory evidence includes:
- evidence of having received 2 doses of MMR, or
- positive antibody test for measles and rubella
Interpretation of Hep B serology; what is the relevance of HBsAg?
(Hepatitis B surface antigen)
Interpretation of Hep B serology; what is the relevance of anti-HBs?
(Hepatitis B surface antibody)
Interpretation of Hep B serology; what is the relevance of Total antibody to Hepatitis B core antigen?
- note, positive Total anti-HBc with other serology negative can mean:
- Transfer of maternal antibodies to an infant
- Resolved infection where anti-HBs levels have weaned
- A false positive
- A mutant HBsAg strain that is not detectable by lab assay
Interpretation of Hep B serology; what is the relevance of IgM antibody to Hepatitis B core antigen?
Which patients are most at risk of developing chronic Hep B infection?
- Infants- 9 in 10 infected infants will go on to develop chronic infection
- Before age six 1 in 3 infected children will develop chronic infection
- At age 6 and above almost all infected individuals recover completely and do not develop chronic infection
Who should be screened for Hep B infection?
- All adults above the age of 18 should be screened at least once during their lifetime
- All infants born to mothers who are HBsAg positive at 9-12 months, or 1-2 months after a course of vaccination
- Pregnant women should all be screened in the first trimester regardless of testing / vaccination status
Who should be periodically screened for Hep B?
- Anybody who requests it- regardless of disclosure of risk, as they may be reluctant to disclose stigmatising risks
What factors put people at increased risk of Hep B?
- Infants born to HBsAg-positive mothers
- People born in regions of the worls with infection prevalence >2%
- Injection drug use
- Prison / detention setting
- HIV infection
- Hep C infection
- MSM
- STIs or multiple sexual partners
- Household contacts of people with known HepB infection
- Needle sharing / sexual contact with known HBV carriers
- Maintenance dialysis
- Elevated AST / ALT of unknown origin
Who should receive post-vaccination Hep B testing?
- Healthcare workers / public safety workers at risk of continued exposure to blood or body fluids
- Infants born to people who test positive for HBsAg
- Patients on haemodialysis / HIV / immunocompromised
- Sexual partners of people with chronic HBV infection
How is HBV infection managed?
Mostly supportive, occasionally require antivirals
Interpretation of Hep C serology- what is tested for?
HCV antibody will be checked first, if positive should be re-checked along with HCV RNA
If the person is immunocompromised, both HCV antibody and RNA will be checked
HCV antibody positive =
Past infection, or
Current infection, or
False positive…
HCV RNA detected =
Current infection
What are the complications of HCV?
- Acute infection
- This rarely progresses to fulminant infection (<1%)
- Chronic infection can lead to:
- Liver cirrhosis (10-30% after 20 years infection)
- HCC (1-3% cirrhosis progresses to HCC annually)
- Liver failure
Which are the 4 most common comorbidities seen in people with HCV infection?
- Depression
- Diabetes mellitus
- Sjorgen syndrome
- CKD
How should suspected Hep C infection be managed in primary care?
- If acute HCV suspected (positive antibody with clinical features or recent source of transmission), arrange same-day assessment or immediate clinical advice
- If chronic HCV suspected (antibody and RNA positive with no clinical features), arrange urgent referral
- Notify local health protection team
- Consider screening for other STIs if thought to be sexually acquired
