Screening Flashcards
What is screening?
Process of identifying apparently healthy people who may have an increased chance of disease or condition
Screening provider then offers further information, further tests, and treatment to reduce associated problems or complications
What are the criteria for a screening programme?
The condition should be an important health problem judged by severity and/or frequency which is well understood
The test should be simple, safe, precise and validated screening test which is acceptable to the target population and an agreed policy on further diagnostic investigation for positive results
The intervention should be effective with evidence of better outcomes for the individual compared to usual care with wider benefits relating to family members
The screening programme should have evidence from RCT’s that programme is effective in reducing morbidity and mortality, is clinically, socially and ethically acceptable and benefits outweigh harm
Implementation criteria including quality standards, adequate trained staff and facilities, evidence based patient information
What can antenatal and newborn screening programmes screen for?
Sickle cell and thalassaemia Infectious diseases screening Down's, Edwards' and Patau's syndrome Foetal anomaly scan Diabetic eye screening NIPE Newborn hearing screen Newborn blood spot
What is the professionals role in screening?
Help women make an informed choice by giving timely unbiased verbal and written information using the PHE booklet - screening tests for you and your baby - as a guide for discussion in a format/language that they can understand
Provide appropriate interpretation services where appropriate
Information should include an explanation of the conditions, purpose of the screening, the test, limitations, results pathways, treatment options
Record the decision to accept or decline screening
Perform the test in accordance with national and local guidelines
Record all results to close the pathway
Revisit any decision to decline at a later date to ensure the information has been understood
Work with PHE national standards for each programme
What is the pathway for screening?
Identify the eligible population
Provide information
Explain the conditions, purpose of screening, the test, limitations, results pathways, treatment options
Document the decision to accept/decline
Perform the test
Communicate the results and document in notes/maternity system
Ensure timely transition into appropriate follow-up and treatment for those that screen positive
Optimise health outcomes
What is sickle cell disease?
Autosomal recessive inheritance
Affects haemoglobin - sickle cell anaemia most serious type
What are the main symptoms of SCD?
Anaemia, episodes of severe pain (sickle cell crisis)
Pain occurs when cells change shape when O2 released causing blockages in capillaries - treated with strong pain killers/hydroyurea to reduce frequency
At risk of stroke/acute chest syndrome/blindness/bone damage/priapism/chronic organ damage
How can people die of SCD?
Complications
What is beta thalassaemia?
Found in people originating from Mediterranean, Middle East, Africa, or Asia
- Group of hereditary disorders that result in reduced/absent synthesis of beta globin chains
- Major - require lifelong transfusion therapy and chelation therapy to treat complications of resulting iron overload
What is alpha thalassaemia?
Alpha 0 - most commonly found in those of Southeast Asian, East Mediterranean origin and in low frequencies in some Middle Eastern countries
Major - fatal without treatment resulting in hydrops fetalis due to severe foetal anaemia
What is the mother at risk of with a child with thalassaemia?
Obstetric complications such as pre-eclampsia particularly in third trimester
What is the sickle cell thalassaemia pathway?
Offered to all pregnant women ideally between 8-10 weeks, biological father of baby if mother if genetic carrier, un-booked women in labour
Family origin questionnaire accompanies blood sample and assists labs to interpret results and request appropriate testing
Newborn screening - parents can wait as all babies tested on blood spot screening
What do you need to do with egg donor pregnancy?
Test biological father
When are infectious disease screened for?
Screening for HIV, hep B, and syphilis offered and recommended to all women in early pregnancy and unbooked women in labour
Re-offered by 20 weeks by screening team to any women who initially declines
Positive/known positive women contacted and informed by screening team within 10 days of result
What happens with babies born to mother with infectious disease?
All babies born to mothers with an infectious disease should have an MDT plan of care and/or neonatal alert process in place for babies requiring assessment and treatment at birth in line with clinical guidance
What happens with babies born to mother with Hep B?
Babies born to mothers with hep B should be vaccinated within 24 hours of birth and at 4, 8, 12, and 16 weeks then at 12 months
When can syphilis be transmitted and what can it cause?
Can be transmitted transplacentally at any stage in pregnancy, may result in miscarriage, pre-term labour, stillbirth, and congenital syphilis
When can HIV be transmitted?
Present in all body fluids, passed on through sexual intercourse, direct contact with blood of infected person, sharing needles, mother to child in pregnancy
What can happen with hep B vertical transmission?
Risk of vertical transmission depend on phase of maternal infection and level of infectivity
- Higher infectivity 70-90% vertical transmission risk without intervention
- Lower infectivity 10% vertical transmission risk without intervention
Baby have acute/chronic HBV infection
Higher change of failing to clear virus and having chronic infection
What is screened in the foetal anomaly screen and when is it?
Down’s (T21), Edwards (T28), Patau (T13) screening
Combined test recommended 11+2 - 14+1 weeks
Quadruple testing for Down’s offered 14+2 - 20+0 if NT not possible after 2 attempts or too late
Screening strategy for T18/13 after quadruple testing is 18+0 - 20+6 scan
What is Down’s syndrome?
Trisomy 21
How common is Down’s syndrome?
1 in every 1000 births - incidence increases with maternal age
What are the symptoms, risks and outcomes of Down’s syndrome?
Distinctive facial features
Learning disability
Attend mainstream primary
Increased incidence of childhood leukaemia, epilepsy, thyroid disorders, heart conditions, and problems with hearing and vision
Have good QoL and with support can get jobs, have relationships and live semi-independently
For babies with serious health problems, survival similar to that of other children and most people with Down’s will live to 60s or longer
What is Edward’s syndrome?
Trisomy 18
How common is Edward’s syndrome?
3 of every 10,000 births
Incidence increases with maternal age
Survival rates low and those babies born alive only around 10% live past first birthday
What are the symptoms of Edward’s syndrome?
Severe learning disability and wide range of extremely serious physical problems
Heart defects, problems with resp system, kidneys, and digestive system
What is Patau’s syndrome?
Trisomy 13
How common is Patau’s syndrome?
Incidence increases with maternal age
2 of every 10,000 births
What are the symptoms of Patau’s syndrome?
Most will die shortly after birth/stillborn Associated with multiple severe foetal abnormalities - 80% have congenital heart defects - Holoprosencephaly - Midline facial defects - Abdominal wall defects - Urogenital malformations - Abnormalities of hands and feet
What is the combined anomaly screen?
Uses combination of maternal age, USS measurement of crown rump length and nuchal translucency, two biochemical markers to calculate change of affected pregnancy
Blood sample same day/later - can be taken 10+0 to 14+1
Serum levels PAPP-A and free beta HCG
How accurate is the combined anomaly screen?
Detection rate 85%, screen positive rate < 3%
What is the quadruple testing?
Uses serum markers only - alpha feto protein, total beta HCG, oestriol, inhibin A
Offered when head circumference 101-172mm or gestational age 14+2 to 20+0
How accurate is the quadruple test?
> 80% detection rate and screen positive of < 3.5%
How is the result calculated with the combined and quadruple tests?
Scan measurements of CRL to calculate gestational age and NT measurement
Mother’s DOB including age of donor if donor egg
Serum markers - reported as multiples of the median
Levels of serum markers affected by number of foetuses, gestation, maternal weight, ethnicity, IVF pregnancy, smoking, diabetes, previously affected pregnancy - these are taken into account
How are the results calculated for dichorionic twins?
Individual change estimates for each baby on combined test
Pregnancy change on quadruple test - detection rate 40-50%
How are results calculated for monochorionic twins?
Change same for each baby on combined test
Pregnancy chance on quadruple - detection rate 80%
What further options are available if the chances of one of the syndromes is high?
No further testing - await anomaly scan (not diagnostic)
Non-invasive prenatal testing in private sector
Invasive diagnostic test - CVD/amniocentesis (carries 0.5-1% risk of miscarriage)
How many ultrasounds do you get during pregnancy?
At least 2
Timing allows further diagnostic tests and ensures women have time to consider continuing pregnancy
What is the point of the early pregnancy scan?
Confirm viability
Ascertain if singleton/multiple pregnancy
Estimate gestational age
Detect major structural anomalies that may be identified in early pregnancy eg anencephaly
If woman accepts screening for T21 and/or T18/T13 syndromes scan one component of screening test - CRL and NT
Ultrasound scanning performed transabdominally
What is the point of the mid pregnancy/anomaly scan?
Identify major abnormalities which indicate baby may die shortly after birth
Identify conditions that may benefit from treatment before birth
Plan delivery in appropriate hospital/centre
Optimise treatment after baby born
Provide choices for women and family about continuance or termination of pregnancy
What anomalies can be detected in the anomaly scan?
Anencephaly Open spina bifida Cleft lip Diaphragmatic hernia Gastroschisis Exomphalos Serious cardiac abnormalities Lethal skeletal dysplasia T13 and T18
When should the anomaly scan be offered?
Offered at 18+0 to 20+6 weeks
Who is diabetic eye screening offered to?
Proportion of pregnant women with diabetes seen < 6 weeks of notification of their pregnancy to the screening provider
Offered to existing diabetics who become pregnant
How many times are diabetics eyes screened during pregnancy?
Twice
When is the NIPE examination carried out?
First within 72 hours of birth and then at 6-8 weeks
How common are eye problems in neonates?
Including congenital cataracts 2-3 babies per 100,000
How common are congenital heart defects in neonates?
1 in 200 babies require treatment
How common is DDH in neonates?
1 to 2 per 1000 babies
How common are undescended testes in neonates?
1 in 100 baby boys
What is the referral pathway for eye problems from the NIPE?
Seen by ophthalmologist within 2 weeks
What is the referral pathway for heart problems from the NIPE?
Any suspected cardiac abnormality to be seen as soon as possible by neonatologist/paediatrician
What is the referral pathway for testes problems from the NIPE?
Bilateral undescended to be seen within 24 hours by consultant neonatologist
Unilateral by GP at 6 weeks
What is the referral pathway for hips problems from the NIPE?
Referred for scan at 2 weeks if DDH suspected r by 6 weeks for risk factors
What is the aim of the newborn hearing screen?
Aim of programme to identify permanent moderate, severe, and profound deafness and hearing impairment in newborns
How common are newborn hearing problems?
27 babies identified in England each week with permanent childhood hearing impairment
Why is it important to catch hearing problems in newborns early?
Early identification important for development of speech, language, and social development
Average age for fitting of hearing aids reduced from 300 to 80 days since programme began
When are babies screened for hearing problems?
All babies screened within 4 weeks of birth (up to 3 months)
Babies referred from programme should have audiological assessment within 4 weeks
What happens in the newborn hearing screen?
Automated otoacoustic emission test
AOAE - small soft-tipped earpiece in ear and gentle clicking sounds played, ear response picked up by screening equipment
What happens if babies need second test after AOAE in newborn hearing screen?
AABR 3 small sensors on babies forehead, nape of neck and shoulder, soft headphones placed over babies ears and clicking sounds played, takes 5-15 mins
Automated auditory brainstem response test
