Downs syndrome Flashcards
(21 cards)
What is Down’s syndrome?
Also called Trisomy 21. It’s caused by 3 copies of chromosome 21 and gives characteristic dysmorphic features.
What dysmorphic features are seen in Down’s syndrome?
Hypotonia, brachycephaly (small head with flat back), short neck, short stature, flattened face and nose, prominent epicanthic folds, upward sloping palpebral fissures, single palmar crease.
What are epicanthic folds?
Folds of skin covering the medial portion of the eye and eyelid.
What are palpebral fissures?
Gaps between the lower and upper eyelid.
What are some complications of Down’s syndrome?
Learning disability, recurrent otitis media, deafness + eustachian tube abnormalities, visual problems such as myopia, strabismus and cataracts, hypothyroidism, cardiac defects (ASD, VSD, PDA, AVSD, TOF), atlantoaxial instability, leukaemia, and dementia.
Is antenatal screening for Down’s syndrome available?
All women are offered screening for Down’s to determine which women should receive more invasive tests for a definitive diagnosis.
What screening tests are available for Down’s syndrome?
Combined test, triple test, quadruple test.
What is the combined test?
First line and most accurate test performed between 11 and 14 weeks gestation. It combines results from USS and maternal blood tests.
What does the USS measure and what do the blood tests look at in the combined test?
USS measures nuchal translucency (thickness of the back of the neck of the fetus; Down’s can cause nuchal thickness over 6mm). Blood tests include beta-HCG (higher result indicates greater risk) and PAPPA (lower result indicates greater risk).
When is the triple test performed?
Between 14 and 20 weeks gestation.
What does the triple test involve?
Beta-HCG (higher result indicates greater risk), alpha-fetoprotein (lower result indicates greater risk), and serum oestriol (lower result indicates greater risk).
What is the quadruple test and when is it performed?
Performed between 14 and 20 weeks gestation. Identical to the triple test but also includes inhibin A (higher inhibin A indicates greater risk).
What do antenatal screening tests provide?
A risk score for the fetus having Down’s syndrome.
At what risk is a woman offered further testing and what are these tests?
When the risk of Down’s is greater than 1 in 150, the woman is offered amniocentesis and chorionic villus sampling.
What do amniocentesis and chorionic villus sampling involve?
Taking a sample of fetal cells for karyotyping to determine if the fetus is affected by Down’s. Chorionic villus sampling involves an USS guided biopsy of the placental tissue (used earlier in pregnancy). Amniocentesis involves USS guided aspiration of amniotic fluid (done later in pregnancy).
What is non-invasive prenatal testing (NIPT)?
A test for detecting abnormalities in the fetus during pregnancy, involving a simple blood test from the mother that contains fragments of fetal DNA.
Is NIPT definitive?
No, but it gives a good indication of whether the fetus is affected. It’s gradually being used in the NHS as an alternative to invasive testing for women with a higher than 1 in 150 risk of Down’s.
Who is involved in the management of Down’s syndrome patients?
Occupational therapy, SALT, physiotherapy, dietician, paediatrician, GP, health visitors, cardiologist, ENT specialist, audiologist, optician, social services, and charities.
What are some routine follow-up investigations for children with Down’s syndrome?
Regular thyroid checks (2 yearly), echocardiogram to diagnose cardiac defects, regular audiometry for hearing impairment, and regular eye checks.
