Congenital abnormalities.txt

  1. what are the 5 types of congenital abnormalities?
    • 1. structural defect: diaphragmatic hernia
    • 2. chromasomal abnormalities: trisomy 21 Downs
    • 3. inherited abnormalities: cystic fibrosis
    • 4. intrauterine infection: rubella
    • 5. drug exposure: AEDs
  2. what is the aim of a screening test?
    to identify subjects at INCREASED RISK for a given condition
  3. what is sensitivity?
    % of people with the condition that are detected by the test
  4. what is specificity?
    the % of people that DO NOT have the condition and test negative
  5. what is PPV?
    % of people who test positive and have the disease
  6. what is NPV?
    % of people who test negative and don't have the disease
  7. what level in the blood is raised in neural tube defects that can be detected on maternal blood testing?
    AFP - product of fettle liver
  8. how are NTD confirmed and at what age?
    16 weeks ultrasound
  9. give 3 differential for raised AFP in pregnancy
    • 1. NTD
    • 2. gastroschisis: free loops of bowel in amniotic cavity
    • 3. high risk of third trimester complications
  10. when is amniocentesis safest performed?
    16 weeks
  11. which diseases can be diagnosed on amnio? think of 3 categories
    • 1. chromosomal abnormalities
    • 2. infections: toxoplasmosis and CMV
    • 3. inherited disorders: sickle cell, thalassaemia, cystic fibrosis
  12. what % of women miscarry after amniocentesis?
  13. when can CVS be done?
    11 weeks+
  14. what is CVS?
    biopsy of trophoblast
  15. what are the advantages of CVS over amnio?
    • 1. get result quicker
    • 2. as test is done earlier in gestation, it allows abnormal fetes to be identified at a time when abortion can be done under GA if wanted
  16. what is the miscarriage rate of CVS compared to amnio and why?
    • CVS higher than amnio
    • because it is performed earlier when spont misc is more common
    • and because more difficult procedure
  17. what is PGD and in which setting can it be used?
    • pre-implantation genetic diagnosis
    • IVF: cells from an embryo removed for genetic analysis before embryo is transferred to uterus to allow selection and only implant those that not affected by disorder which is tested
  18. how many live births are affected by chromosomal abnormalities?
  19. what is the most common chromosomal abnormality among live births?
    trisomy 21
  20. what is Downs usually the result of?
    • random
    • non-dysjunction (failure of chromosome pairs to separate properly during cell division)
    • at meiosis
  21. what can Downs sometimes be caused by?
    balanced chromosomal translocation in the parents
  22. what are the features of Down's syndrome?
    • flat occiput
    • single palmar crease
    • high arch palate
    • heart: AVSD
    • learning difficulties
  23. what are the soft markers of Downs on USS?
    • echogenic bowel,
    • echogenic intracardiac focus, and
    • dilitation of the kidneys
    • smaller nose
    • cant see stomach - tracheoesophageal fistula
  24. what % of downs have cardiac problems?
  25. what is the risk of recurrence of having another child with downs? and what does it depend on?
    • recurrence risk is low
    • determined largely by maternal age
    • unless there is a balanced translocation
  26. name 4 ultrasound features with give high risk for downs
    • 1. nuchal translucency
    • 2. structural abnormalities
    • 3. tricuspid regurgitation
    • 4. absent or short nasal bone
  27. what are the 2 different types of tests you can have in the 1st trimester as screening for downs?
    • 1. nuchal translucency alone
    • 2. combined test
  28. what is the combined test for down's syndrome? and when can they be done?
    • nuchal translucency
    • serum beta HCG
    • serum PAPPA
    • between 11-14 weeks
  29. what are the 3 different types of tests you can have in the 2nd trimester as screening for downs?
    • double test: measure uE3 and beta HCG
    • triple test: uE3, beta HCG, AFP
    • quadruple test: eE3, beta HCG, AFP and inhibinA
  30. what does uE3 stand for and what is it made by? and what are the levels in Downs?
    • unconjugated estriol
    • made by placenta and fettle adrenals
    • levels REDUCED in downs
  31. what is PAPPA made by and what happens to levels in downs?
    • pregnancy associated plasma protein A
    • made by placental syncytiotrophoblasts
    • levels REDUCED in downs
  32. what is beta HCG made by and what happens to levels in downs?
    • placenta
    • INCREASED in downs
  33. what makes AFP and what happens to levels in downs
    • fettle yolk sac and liver makes it
    • REDUCED level in downs
  34. what makes inhibin-A and what happens to levels in downs?
    • placenta
    • INCREASED levels in downs
  35. what are the 2 different types of tests you can have in the 1st trimester as screening for downs?
  36. what is the quadruple
  37. what is klinefelter's syndrome?
    47 XXY
  38. name 3 symptoms of klinefelters
    • normal intellect
    • small testes
    • infertile
Card Set
Congenital abnormalities.txt
cong abn