Pediatrics · Year 3 · from Pediatrics
Case 1: Down Syndrome
Patient Demographics
- Age: Newborn (1 day old)
- Sex: Female
Chief Complaint
"The baby looks different and I'm worried something is wrong."
History of Present Illness
A 1-day-old female infant is in the newborn nursery after an uncomplicated vaginal delivery at 39 weeks gestation. The mother is 38 years old (G2P2) and had prenatal care starting at 12 weeks. First-trimester combined screening showed increased risk for Down syndrome (1:150), but the mother declined further genetic testing. The infant was noted to have dysmorphic features at birth. She is having difficulty latching for breastfeeding and seems "floppy" according to the nursing staff.
Physical Examination
- Vital Signs: Weight 3.0 kg (25th percentile), Length 48 cm (25th percentile), HC 34 cm (50th percentile), HR 145 bpm, RR 45/min, SpO2 98% on room air
- General: Alert infant with distinctive facial features
- HEENT:
- Flat facial profile
- Upslanting palpebral fissures
- Epicanthal folds
- Small ears with overfolded helices
- Flat nasal bridge
- Small mouth with protruding tongue
- Flat occiput (brachycephaly)
- Neck: Redundant nuchal skin
- Cardiovascular: Regular rate, 3/6 holosystolic murmur at left lower sternal border
- Abdomen: Soft, no hepatosplenomegaly
- Extremities:
- Single transverse palmar crease (simian crease) bilaterally
- Wide space between first and second toes (sandal gap)
- Fifth finger clinodactyly (curved fifth fingers)
- Neurologic: Marked hypotonia, decreased Moro reflex, poor suck
Laboratory and Imaging Findings
- Chromosome analysis (karyotype): 47,XX,+21 (Trisomy 21)
- Echocardiogram: Complete atrioventricular canal defect (AVCD)
- TSH: 8.5 mIU/L (mildly elevated; will repeat at 2 weeks)
- Hearing screen: Refer bilaterally (needs formal audiology)
Diagnosis
Down syndrome (Trisomy 21) with complete atrioventricular canal defect
Clinical Reasoning
This infant has classic features of Down syndrome including: hypotonia (nearly universal), characteristic facial features (upslanting palpebral fissures, epicanthal folds, flat nasal bridge, small ears), single palmar crease, sandal gap deformity, and brachycephaly. The karyotype confirms trisomy 21. The cardiac murmur prompted echocardiography, revealing an atrioventricular canal defect, the most common congenital heart defect in Down syndrome. Approximately 40-50% of children with Down syndrome have congenital heart disease. Early identification allows appropriate health supervision and cardiac surgical planning.
Management
- Genetics consultation: Confirm diagnosis, provide counseling, discuss recurrence risk (approximately 1% for non-disjunction)
- Cardiology consultation: Plan for surgical repair of AV canal defect (typically around 4-6 months of age)
- Health supervision per AAP guidelines:
- Thyroid: TSH at birth, 6 months, 12 months, then annually (high risk for hypothyroidism)
- Hearing: Formal audiology by 3 months; ongoing monitoring (high risk for hearing loss)
- Vision: Ophthalmology exam by 6 months (risk of cataracts, strabismus)
- Atlantoaxial instability: Screening radiographs before sports participation or procedures
- Hematology: Monitor for leukemia (10-20x increased risk)
- Early intervention referral: Physical therapy, occupational therapy, speech therapy
- Family support: Connect with Down syndrome support organizations
- Feeding support: Lactation consultation; may need specialized nipples or feeding therapy
- Growth monitoring: Use Down syndrome-specific growth charts
Clinical Image
Image Description: Newborn with Down syndrome demonstrating characteristic facial features including upslanting palpebral fissures, epicanthal folds, and flat nasal bridge.
Source: Wikimedia Commons URL: https://commons.wikimedia.org/wiki/File:Down_Syndrome.jpg License: CC BY-SA 4.0