Down Syndrome
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Introduction
Down syndrome is the most common autosomal chromosome abnormality.
Incidence of 1:600-1:800.
Mental retardation accompanies Down syndrome, with IQ between 20-80.
Children frequently have a
- small head
- characteristic face: upslanting palpebral fissures, epicahtal folds, midface hypoplasia, small displastic ears
Between 30-50% of children have congenital heart disease
The Case of...
a simple case introducing clincial presentation and calling for a differential diagnosis. To get students thinking.
Causes and Risk Factors
Risk is ~1/2000 for a 20 year old mother, ~1/100 for a 40 year old mother, and ~1/30 for a 45 year old mother.
Pathophysiology
- trisomy 21
- Robertsonian Translocation
- mosaicism
Signs and Symptoms
no one feature that all children with Down's syndrome have, and no one feature distinguishes Down's children from others
- history
- physical exam
History
- recurrent infections
- 15-20x increase in leukemia
- male infertility
- IQ: 25-50
- dementia in 100% of people over 45
Physical Exam
Microcephaly
Eyes: upslanted epicanthal folds, speckled iris (Brushfield spots), refractive errors, strabismus
Ears: low-set, small, overfolded upper helix
Face: protruding tongue, large cheeks, low, flat nasal bridge
Skin: excess nuchal skin
MSK: short, joint hyperflexibility, atlantoxaial instability
GI: duodenal, esophageal, anal atresia, TE fistula, Hirschprung disease, chronic constipation
CV: 40%, especially AVSD
GU: cryptorchidism, small penis
CNS: hypotonia
hands: palmar (Simian) crease
- short stature, hypothyroidism
- palmar crease
Investigations
- lab investigations
- diagnostic imaging
- screening
Lab Investigations
Diagnostic Imaging
Screening
Thyroid function should be assessed
Eyes in newborn period: strabismus and cataracts
Hearing
Lateral flexion-extension of cervical spine for instability
Heart (50% congenital haert defects)
Celiac
Differential Diagnosis
Treatments
Consequences and Course
life expectancy is ~60 without CHD
increased mortaility due to infections, CHD, malignancy
congenital heart disease is present in 40% of people with Down's Syndrome.
Common problems include:
- endocardial cushion defect
- atrial septal defect
- ventricular septal defect
- patent ductus arteriosus
- common atriventricular canal
Gastrointestinal conditions include esophageal and duondenal atresia, as well as celiac disease.
Infants can have increased length of physiologic jaundice, polycythemia, and a temporary leukocytosis.
Increased
Resources and References
Topic Development
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