299

A. Medical problems

Newborn • cardiac defects (50% ): AVSD [most common], VSD, ASD, TOF or PDA • gastrointestinal (12%): duodenal atresia [commonest], tracheo-oesophageal fistula, anorectal malformation, pyloric stenosis and Hirshsprung disease. • vision: congenital cataracts (3%), glaucoma. • hypotonia & joint laxity • feeding problems. Usually resolve after a few weeks. • congenital hypothyroidism (1%) • congenital dislocation of the hips

Infancy and Childhood • delayed developmental milestones • mild to moderate intellectual impairment (IQ 25 to 50) • seizure disorder (6%) • recurrent respiratory infections • hearing loss (>60%) due to secretory otitis media, sensorineural deafness, or both • visual Impairment – squint (50%), cataract (3%), nystagmus (35%), glaucoma, refractive errors (70%) • sleep related upper airway obstruction. Often multifactorial. • leukaemia (relative risk:15 to 20 times). Incidence 1% • atlantoaxial instability. Symptoms of spinal cord compression include neck pain, change in gait, unusual posturing of the head and neck (torticollis), loss of up per body strength, abnormal neurological reflexes, and change in bowel/bladder functioning. (see below) • hypothyroidism (10%). Prevalence increases with age • short stature – congenital heart disease, sleep related upper airway obstruction, coeliac disease, nutritional inadequacy due to feeding problems and thyroid hormone deficiency may contribute to this • over/underweight

Adolescence and Adulthood • puberty - in Girls menarche is only slightly delayed. Fertility presumed - in Boys are usually infertile due to low testosterone levels • increased risk of dementia /Alzheimer disease in adult life • shorter life expectancy

Management • communicating the diagnosis is preferably handled in private by a senior medical officer or specialist who is familiar with the natural history, genetic aspect and management of Down syndrome.• careful examination to look for associated complications.• investigations: 1. echocardiogram by 2 weeks (if clinical examination or ECG were abnormal) or 6 weeks. 2. Chromosomal analysis. 3. T4 /TSH at birth or by 1-2 weeks of life.

DOWN SYNDROME

Table 1. Incidence of Down syndrome

Age (years)20 3035 40 41 42 43 44 45

Incidence1 in15001 in 9001 in 3501 in 1001 in 701 in 551 in 401 in 301 in 25

Overall Incidence: 1 in 800-1000 newborns

Maternal Age-Specific Risk for Trisomy 21 at livebirth

Source Hecht and Hook ‘94

META

BOLIC

300

• early intervention programme should begin at diagnosis if health conditions permit• assess strength & needs of family. Contact with local parent support group should be provided (Refer list of websites below)• health surveillance & monitoring: see Table 5

Atlantoaxial instability • seen in X rays in 14% of patients; symptomatic in 1-2%. • small risk for major neurological damage but cervical spine X rays in children have no predictive validity for subsequent acute dislocation/ subluxation at the atlantoaxial joint • children with Down’s syndrome should not be barred from taking part in sporting activities • appropriate care of the neck while under general anaesthesia or after road traffic accident is advisable

Useful websites• The Down Syndrome Medical Interest Group (UK): www.dsmig.org.uk• Down Syndrome: Health Issues: www.ds-health.com• Growth charts for children with Down Syndrome: www.growthcharts.com• Educational issues: www.downsed.org• Kiwanis Down Syndrome Foundation: www.kdsf.netmyne.com• Educational & support centre. http://www.disabilitymalaysia.com/ • Parents support group. http://groups.yahoo.com/group/DownSyndromeMalaysia • Jabatan Pendidikan Khas. http://www.moe.gov.my/jpkhas/.• Jabatan Kebajikan Malaysia. http://www.jkm.gov.my/

Table 2. Karyotyping in Down syndrome

Non-disjunction trisomy 21Robertsonian TranslocationMosaicism

95%3%2%

Recurrence Risk by KaryotypeNondisjunction Trisomy 47(XX or XY) + 21 Translocation both parents normal other carrier father carrier either parent t(21q;21q)Mosaics

1%

low; <1%10%2.5%100%< 1%

MET

ABO

LIC

301

Birt

h - 6

wee

ks

T4 &

TSH

Visu

al b

ehav

iour

.Ch

eck

for

cong

enita

l cat

arac

t

Neo

nata

l scr

eeni

ng,

if lo

cally

ava

ilabl

eEc

hoca

rdio

gram

0-

6 w

eeks

6 - 1

0 m

onth

s

Visu

al b

ehav

iour

.Ch

eck

for

cong

enita

l cat

arac

t

12 m

onth

s

T4 &

TSH

in

cludi

ng a

ntibo

dies

Visu

al b

ehav

iour

.Ch

eck

for

cong

enita

l cat

arac

t

18 m

ths -

2½

yrs

Ort

hopti

c ex

ami-

natio

n, re

frac

tion

and

opht

halm

ic

exam

inati

on³

dent

al a

dvic

e

3 - 3

½ y

ears

T4 &

TSH

in

cludi

ng a

ntibo

dies

Leng

th, w

eigh

t and

hea

d ci

rcum

fere

nce

chec

ked

regu

-la

rly

and

plott

ed o

n D

own’

s sy

ndro

me

grow

th c

hart

s.Le

ngth

and

wei

ght s

houl

d be

che

cked

at l

east

ann

ually

an

d pl

otted

on

Dow

n’s

synd

rom

e gr

owth

cha

rts.

Thyr

oid

bloo

d te

sts¹

Gro

wth

mon

itorin

g ²

Eye

chec

k

Hea

ring

chec

k

Hea

rt c

heck

and

ot

her a

dvic

e

Ful

l aud

iolo

gica

l rev

iew

(hea

ring

, im

peda

nce,

oto

scop

y) b

y 6-

10 m

onth

s an

d th

en a

nnua

lly

Tabl

e 5.

Rec

omm

enda

tions

for M

edic

al S

urve

illan

ce fo

r chi

ldre

n w

ith D

own

Synd

rom

e

foot

note

: 1.

Asy

mpt

omati

c pa

tient

with

mild

ly ra

ised

TSH

(not

gre

ater

than

10

mu/

l) bu

t nor

mal

T4

does

not

usu

ally

war

rant

trea

tmen

t but

sh

ould

be

test

ed m

ore

freq

uent

ly b

ecau

se o

f inc

reas

ed li

kelih

ood

of d

evel

opin

g un

com

pens

ated

hyp

othy

roid

ism

. 2.

Dow

n sy

ndro

me

centi

le c

hart

s av

aila

ble

[ww

w.g

row

thch

arts

.co

m].

Cons

ider

usi

ng w

eigh

t for

leng

th c

hart

of t

ypic

ally

dev

elop

-in

g ch

ildre

n fo

r wei

ght a

sses

smen

t. Th

ose

with

BM

I > 9

8th

centi

le

or u

nder

wei

ght s

houl

d be

refe

rred

for n

utriti

onal

ass

essm

ent &

gu

idan

ce. T

hyro

id fu

nctio

n sh

ould

be

chec

ked

if th

ere’

s ac

cele

r-at

ed w

eigh

t gai

n.3.

Per

form

ed b

y op

tom

etris

t/op

htha

lmol

ogis

t

Age

5 to

19

year

sPa

edia

tric

revi

ew

Hea

ring

Visio

n / O

rtho

ptic

chec

kTh

yroi

d bl

ood

test

s Sc

hool

per

form

ance

Sexu

ality

& e

mpl

oym

ent

Annu

ally

2 ye

arly

aud

iolo

gica

l rev

iew

(as a

bove

)2

year

lyAt

age

5 y

ears

, the

n 2

year

ly

Chec

k pe

rfor

man

ce a

nd p

lace

men

tTo

disc

uss w

hen

appr

opria

te d

urin

g ad

oles

cenc

e

Not

e: T

he a

bove

tabl

e ar

e su

gges

ted

ages

. Che

ck a

t any

oth

er ti

me

if th

ere

are

pare

ntal

or o

ther

conc

erns

. Per

form

dev

elop

men

tal a

sses

smen

t dur

ing

each

visi

t.

4 - 4

½ y

ears

Visu

al a

cuity

, re

frac

tion

and

opht

halm

ic

exam

inati

on³

(ada

pted

from

Dow

n Sy

ndro

me

Med

ical

Inte

rest

Gro

up (D

SMIG

) gui

delin

es)

META

BOLIC