Zusammenfassung der Ressource
Hypothyroidism
- Congenital hypothyroidism
- detection is important
- CH relatively common
- incidence- 1 in 4000 births
- a preventable cause of
severe learning difficulties
- Causes
- maldescent of thyroid & athyrosis
- commonest cause of
sporadic congenital
hypothyroidsim
- thyroid migrates from sublingual position to normal
site below larynx in early fetal life
- partial or complete failure of thyroid
to develop may occur
- maldescent- thyroid remains as
lingual mass or unilobular small
gland
- reason for
failure of
formation or
migration not
understood
- dyshormonogenesis
- inborn error of
thyroid
hormone
synthesis
- commoner in some ethnic groups w/ consanguineous marriage
- about 5-10% of
congenital hypo
cases
- iodine def
- commonest cause of congenital hypothyroidism worldwide
- but rare in UK
- preventable
- by iodination of salt in diet
- hypothyroidism due to TSH def
- isolated TSH def is rare
- about 1% of cases
- usually assoc w/ panhypopituitarism
- which manifests as
- growth hormone def, gonadotrophin def & ACTH def
- this -> hypoglycaemia & micropenis & undescended testes in affected boys
- the above appear before hypothyroidism becomes evident
- clinical features
- hard to differentiate
from normal in 1st
month of life
- but become more
prominent w/ age
- usually asymptomatic &
picked up on Guthrie
test (neonatal
biochemical screening)
- otherwise
- failure to thrive
- feeding probs
- prolonged jaundice
- constipation
- pale, cold, mottled skin
- coarse facies
- large tongue
- hoarse cry
- goitre (sometimes)
- umbilical hernia
- delayed development
- slight excess
of other
congenital
abnormalities
- esp heart defects
- Ix
- Guthrie test
- raised TSH in blood
- NB: thyroid dysfun secondary
to pituitary abnormalities won't
be detected on Guthrie as they'll
have low TSH
- T4
- in some countries
- Rx
- thyroxine
- start at 2-3 weeks old
- early Rx to
prevent learning
difficulties
- intelligence will be in normal range
- life-long oral replacement
- titrate to maintain normal growth,
TSH & T4 levels
- Juvenile hypothyroidism
- usually caused by autoimmune thyroiditis
- increased risk in children w/ Down or Turner syndrome
- increased risk of developing other autoimmune disease
- vitiligo
- rheumatoid arthritis
- diabetes mellitus
- Addison's
disease in
some families
- Rx
- thyroxine
- clinical features
- goitre
- goitre can also be
physiological in pubertal
girls
- short stature/growth failure
- females> males
- cold
intolerance
- cold peripheries
- bradycardia
- thin, dry hair
- pale, puffy eyes, w/ loss of
eyebrows
- slow-relaxing reflexes
- constipation
- delayed puberty
- obesity
- slipped upper femoral epiphysis
- deterioration
in school
work
- learning difficulties